Generally, APICv for all vcpus in the VM are enable/disable in the same
manner. So, get_enable_apicv() should represent APICv status of the VM
instead of each VCPU.
Modify kvm_x86_ops.get_enable_apicv() to take struct kvm as parameter
instead of struct kvm_vcpu.
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Handle caching CR3 (from VMX's VMCS) into struct kvm_vcpu via the common
cache_reg() callback and drop the dedicated decache_cr3(). The name
decache_cr3() is somewhat confusing as the caching behavior of CR3
follows that of GPRs, RFLAGS and PDPTRs, (handled via cache_reg()), and
has nothing in common with the caching behavior of CR0/CR4 (whose
decache_cr{0,4}_guest_bits() likely provided the 'decache' verbiage).
This would effectivel adds a BUG() if KVM attempts to cache CR3 on SVM.
Change it to a WARN_ON_ONCE() -- if the cache never requires filling,
the value is already in the right place -- and opportunistically add one
in VMX to provide an equivalent check.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Add helpers to prettify code that tests and/or marks whether or not a
register is available and/or dirty.
Suggested-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Rework vmx_set_rflags() to avoid the extra code need to handle emulation
of real mode and invalid state when unrestricted guest is disabled. The
primary reason for doing so is to avoid the call to vmx_get_rflags(),
which will incur a VMREAD when RFLAGS is not already available. When
running nested VMs, the majority of calls to vmx_set_rflags() will occur
without an associated vmx_get_rflags(), i.e. when stuffing GUEST_RFLAGS
during transitions between vmcs01 and vmcs02.
Note, vmx_get_rflags() guarantees RFLAGS is marked available.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
[Replace "else" with early "return" in the unrestricted guest branch. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Capture struct vcpu_vmx in a local variable to improve the readability
of vmx_{g,s}et_rflags().
No functional change intended.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Skip the VMWRITE to update GUEST_CR3 if CR3 is not available, i.e. has
not been read from the VMCS since the last VM-Enter. If vcpu->arch.cr3
is stale, kvm_read_cr3(vcpu) will refresh vcpu->arch.cr3 from the VMCS,
meaning KVM will do a VMREAD and then VMWRITE the value it just pulled
from the VMCS.
Note, this is a purely theoretical change, no instances of skipping
the VMREAD+VMWRITE have been observed with this change.
Tested-by: Reto Buerki <reet@codelabs.ch>
Tested-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Write the desired L2 CR3 into vmcs02.GUEST_CR3 during nested VM-Enter
instead of deferring the VMWRITE until vmx_set_cr3(). If the VMWRITE
is deferred, then KVM can consume a stale vmcs02.GUEST_CR3 when it
refreshes vmcs12->guest_cr3 during nested_vmx_vmexit() if the emulated
VM-Exit occurs without actually entering L2, e.g. if the nested run
is squashed because nested VM-Enter (from L1) is putting L2 into HLT.
Note, the above scenario can occur regardless of whether L1 is
intercepting HLT, e.g. L1 can intercept HLT and then re-enter L2 with
vmcs.GUEST_ACTIVITY_STATE=HALTED. But practically speaking, a VMM will
likely put a guest into HALTED if and only if it's not intercepting HLT.
In an ideal world where EPT *requires* unrestricted guest (and vice
versa), VMX could handle CR3 similar to how it handles RSP and RIP,
e.g. mark CR3 dirty and conditionally load it at vmx_vcpu_run(). But
the unrestricted guest silliness complicates the dirty tracking logic
to the point that explicitly handling vmcs02.GUEST_CR3 during nested
VM-Enter is a simpler overall implementation.
Cc: stable@vger.kernel.org
Reported-and-tested-by: Reto Buerki <reet@codelabs.ch>
Tested-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Commit bf653b78f9 ("KVM: vmx: Introduce handle_unexpected_vmexit
and handle WAITPKG vmexit") introduced specialized handling of
specific exit-reasons that should not be raised by CPU because
KVM configures VMCS such that they should never be raised.
However, since commit 7396d337cf ("KVM: x86: Return to userspace
with internal error on unexpected exit reason"), VMX & SVM
exit handlers were modified to generically handle all unexpected
exit-reasons by returning to userspace with internal error.
Therefore, there is no need for specialized handling of specific
unexpected exit-reasons (This specialized handling also introduced
inconsistency for these exit-reasons to silently skip guest instruction
instead of return to userspace on internal-error).
Fixes: bf653b78f9 ("KVM: vmx: Introduce handle_unexpected_vmexit and handle WAITPKG vmexit")
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The l1tf_vmx_mitigation is only set to VMENTER_L1D_FLUSH_NOT_REQUIRED
when the ARCH_CAPABILITIES MSR indicates that L1D flush is not required.
However, if the CPU is not affected by L1TF, l1tf_vmx_mitigation will
still be set to VMENTER_L1D_FLUSH_AUTO. This is certainly not the best
option for a !X86_BUG_L1TF CPU.
So force l1tf_vmx_mitigation to VMENTER_L1D_FLUSH_NOT_REQUIRED to make it
more explicit in case users are checking the vmentry_l1d_flush parameter.
Signed-off-by: Waiman Long <longman@redhat.com>
[Patch rewritten accoring to Borislav Petkov's suggestion. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The following was reported on i386:
arch/x86/kvm/vmx/vmx.c: In function 'hv_enable_direct_tlbflush':
arch/x86/kvm/vmx/vmx.c:503:10: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
pr_debugs() in this function are more or less useless, let's just
remove them. evmcs->hv_vm_id can use 'unsigned long' instead of 'u64'.
Also, simplify the code a little bit.
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Now that VMREAD flows require a taken branch, courtesy of commit
3901336ed9 ("x86/kvm: Don't call kvm_spurious_fault() from .fixup")
bite the bullet and add full error handling to VMREAD, i.e. replace the
JMP added by __ex()/____kvm_handle_fault_on_reboot() with a hinted Jcc.
To minimize the code footprint, add a helper function, vmread_error(),
to handle both faults and failures so that the inline flow has a single
CALL.
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Rework the VMX instruction helpers using asm-goto to branch directly
to error/fault "handlers" in lieu of using __ex(), i.e. the generic
____kvm_handle_fault_on_reboot(). Branching directly to fault handling
code during fixup avoids the extra JMP that is inserted after every VMX
instruction when using the generic "fault on reboot" (see commit
3901336ed9, "x86/kvm: Don't call kvm_spurious_fault() from .fixup").
Opportunistically clean up the helpers so that they all have consistent
error handling and messages.
Leave the usage of ____kvm_handle_fault_on_reboot() (via __ex()) in
kvm_cpu_vmxoff() and nested_vmx_check_vmentry_hw() as is. The VMXOFF
case is not a fast path, i.e. the cleanliness of __ex() is worth the
JMP, and the extra JMP in nested_vmx_check_vmentry_hw() is unavoidable.
Note, VMREAD cannot get the asm-goto treatment as output operands aren't
compatible with GCC's asm-goto due to internal compiler restrictions.
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
As the latest Intel 64 and IA-32 Architectures Software Developer's
Manual, UMWAIT and TPAUSE instructions cause a VM exit if the
RDTSC exiting and enable user wait and pause VM-execution
controls are both 1.
Because KVM never enable RDTSC exiting, the vm-exit for UMWAIT and TPAUSE
should never happen. Considering EXIT_REASON_XSAVES and
EXIT_REASON_XRSTORS is also unexpected VM-exit for KVM. Introduce a common
exit helper handle_unexpected_vmexit() to handle these unexpected VM-exit.
Suggested-by: Sean Christopherson <sean.j.christopherson@intel.com>
Co-developed-by: Jingqi Liu <jingqi.liu@intel.com>
Signed-off-by: Jingqi Liu <jingqi.liu@intel.com>
Signed-off-by: Tao Xu <tao3.xu@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
UMWAIT and TPAUSE instructions use 32bit IA32_UMWAIT_CONTROL at MSR index
E1H to determines the maximum time in TSC-quanta that the processor can
reside in either C0.1 or C0.2.
This patch emulates MSR IA32_UMWAIT_CONTROL in guest and differentiate
IA32_UMWAIT_CONTROL between host and guest. The variable
mwait_control_cached in arch/x86/kernel/cpu/umwait.c caches the MSR value,
so this patch uses it to avoid frequently rdmsr of IA32_UMWAIT_CONTROL.
Co-developed-by: Jingqi Liu <jingqi.liu@intel.com>
Signed-off-by: Jingqi Liu <jingqi.liu@intel.com>
Signed-off-by: Tao Xu <tao3.xu@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
UMONITOR, UMWAIT and TPAUSE are a set of user wait instructions.
This patch adds support for user wait instructions in KVM. Availability
of the user wait instructions is indicated by the presence of the CPUID
feature flag WAITPKG CPUID.0x07.0x0:ECX[5]. User wait instructions may
be executed at any privilege level, and use 32bit IA32_UMWAIT_CONTROL MSR
to set the maximum time.
The behavior of user wait instructions in VMX non-root operation is
determined first by the setting of the "enable user wait and pause"
secondary processor-based VM-execution control bit 26.
If the VM-execution control is 0, UMONITOR/UMWAIT/TPAUSE cause
an invalid-opcode exception (#UD).
If the VM-execution control is 1, treatment is based on the
setting of the “RDTSC exiting†VM-execution control. Because KVM never
enables RDTSC exiting, if the instruction causes a delay, the amount of
time delayed is called here the physical delay. The physical delay is
first computed by determining the virtual delay. If
IA32_UMWAIT_CONTROL[31:2] is zero, the virtual delay is the value in
EDX:EAX minus the value that RDTSC would return; if
IA32_UMWAIT_CONTROL[31:2] is not zero, the virtual delay is the minimum
of that difference and AND(IA32_UMWAIT_CONTROL,FFFFFFFCH).
Because umwait and tpause can put a (psysical) CPU into a power saving
state, by default we dont't expose it to kvm and enable it only when
guest CPUID has it.
Detailed information about user wait instructions can be found in the
latest Intel 64 and IA-32 Architectures Software Developer's Manual.
Co-developed-by: Jingqi Liu <jingqi.liu@intel.com>
Signed-off-by: Jingqi Liu <jingqi.liu@intel.com>
Signed-off-by: Tao Xu <tao3.xu@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
VMX's EPT misconfig flow to handle fast-MMIO path falls back to decoding
the instruction to determine the instruction length when running as a
guest (Hyper-V doesn't fill VMCS.VM_EXIT_INSTRUCTION_LEN because it's
technically not defined for EPT misconfigs). Rather than implement the
slow skip in VMX's generic skip_emulated_instruction(),
handle_ept_misconfig() directly calls kvm_emulate_instruction() with
EMULTYPE_SKIP, which intentionally doesn't do single-step detection, and
so handle_ept_misconfig() misses a single-step #DB.
Rework the EPT misconfig fallback case to route it through
kvm_skip_emulated_instruction() so that single-step #DBs and interrupt
shadow updates are handled automatically. I.e. make VMX's slow skip
logic match SVM's and have the SVM flow not intentionally avoid the
shadow update.
Alternatively, the handle_ept_misconfig() could manually handle single-
step detection, but that results in EMULTYPE_SKIP having split logic for
the interrupt shadow vs. single-step #DBs, and split emulator logic is
largely what led to this mess in the first place.
Modifying SVM to mirror VMX flow isn't really an option as SVM's case
isn't limited to a specific exit reason, i.e. handling the slow skip in
skip_emulated_instruction() is mandatory for all intents and purposes.
Drop VMX's skip_emulated_instruction() wrapper since it can now fail,
and instead WARN if it fails unexpectedly, e.g. if exit_reason somehow
becomes corrupted.
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Fixes: d391f12070 ("x86/kvm/vmx: do not use vm-exit instruction length for fast MMIO when running nested")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Deferring emulation failure handling (in some cases) to the caller of
x86_emulate_instruction() has proven fragile, e.g. multiple instances of
KVM not setting run->exit_reason on EMULATE_FAIL, largely due to it
being difficult to discern what emulation types can return what result,
and which combination of types and results are handled where.
Now that x86_emulate_instruction() always handles emulation failure,
i.e. EMULATION_FAIL is only referenced in callers, remove the
emulation_result enums entirely. Per KVM's existing exit handling
conventions, return '0' and '1' for "exit to userspace" and "resume
guest" respectively. Doing so cleans up many callers, e.g. they can
return kvm_emulate_instruction() directly instead of having to interpret
its result.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Now that EMULATE_FAIL is completely unused, remove the last remaning
usage where KVM does something functional in response to EMULATE_FAIL.
Leave the check in place as a WARN_ON_ONCE to provide a better paper
trail when EMULATE_{DONE,FAIL,USER_EXIT} are completely removed.
Opportunistically remove the gotos in handle_invalid_guest_state().
With the EMULATE_FAIL handling gone there is no need to have a common
handler for emulation failure and the gotos only complicate things,
e.g. the signal_pending() check always returns '1', but this is far
from obvious when glancing through the code.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Request triple fault in kvm_inject_realmode_interrupt() instead of
returning EMULATE_FAIL and deferring to the caller. All existing
callers request triple fault and it's highly unlikely Real Mode is
going to acquire new features. While this consolidates a small amount
of code, the real goal is to remove the last reference to EMULATE_FAIL.
No functional change intended.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Consolidate the reporting of emulation failure into kvm_task_switch()
so that it can return EMULATE_USER_EXIT. This helps pave the way for
removing EMULATE_FAIL altogether.
This also fixes a theoretical bug where task switch interception could
suppress an EMULATE_USER_EXIT return.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Immediately inject a #GP when VMware emulation fails and return
EMULATE_DONE instead of propagating EMULATE_FAIL up the stack. This
helps pave the way for removing EMULATE_FAIL altogether.
Rename EMULTYPE_VMWARE to EMULTYPE_VMWARE_GP to document that the x86
emulator is called to handle VMware #GP interception, e.g. why a #GP
is injected on emulation failure for EMULTYPE_VMWARE_GP.
Drop EMULTYPE_NO_UD_ON_FAIL as a standalone type. The "no #UD on fail"
is used only in the VMWare case and is obsoleted by having the emulator
itself reinject #GP.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The VMware backdoor hooks #GP faults on IN{S}, OUT{S}, and RDPMC, none
of which generate a non-zero error code for their #GP. Re-injecting #GP
instead of attempting emulation on a non-zero error code will allow a
future patch to move #GP injection (for emulation failure) into
kvm_emulate_instruction() without having to plumb in the error code.
Reviewed-and-tested-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Move the stat.mmio_exits update into x86_emulate_instruction(). This is
both a bug fix, e.g. the current update flows will incorrectly increment
mmio_exits on emulation failure, and a preparatory change to set the
stage for eliminating EMULATE_DONE and company.
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Hyper-V provides direct tlb flush function which helps
L1 Hypervisor to handle Hyper-V tlb flush request from
L2 guest. Add the function support for VMX.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* ARM: ITS translation cache; support for 512 vCPUs, various cleanups
and bugfixes
* PPC: various minor fixes and preparation
* x86: bugfixes all over the place (posted interrupts, SVM, emulation
corner cases, blocked INIT), some IPI optimizations
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.0.22 (GNU/Linux)
iQEcBAABAgAGBQJdf7fdAAoJEL/70l94x66DJzkIAKDcuWXJB4Qtoto6yUvPiHZm
LYkY/Dn1zulb/DhzrBoXFey/jZXwl9kxMYkVTefnrAl0fRwFGX+G1UYnQrtAL6Gr
ifdTYdy3kZhXCnnp99QAantWDswJHo1THwbmHrlmkxS4MdisEaTHwgjaHrDRZ4/d
FAEwW2isSonP3YJfTtsKFFjL9k2D4iMnwZ/R2B7UOaWvgnerZ1GLmOkilvnzGGEV
IQ89IIkWlkKd4SKgq8RkDKlfW5JrLrSdTK2Uf0DvAxV+J0EFkEaR+WlLsqumra0z
Eg3KwNScfQj0DyT0TzurcOxObcQPoMNSFYXLRbUu1+i0CGgm90XpF1IosiuihgU=
=w6I3
-----END PGP SIGNATURE-----
Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Paolo Bonzini:
"s390:
- ioctl hardening
- selftests
ARM:
- ITS translation cache
- support for 512 vCPUs
- various cleanups and bugfixes
PPC:
- various minor fixes and preparation
x86:
- bugfixes all over the place (posted interrupts, SVM, emulation
corner cases, blocked INIT)
- some IPI optimizations"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (75 commits)
KVM: X86: Use IPI shorthands in kvm guest when support
KVM: x86: Fix INIT signal handling in various CPU states
KVM: VMX: Introduce exit reason for receiving INIT signal on guest-mode
KVM: VMX: Stop the preemption timer during vCPU reset
KVM: LAPIC: Micro optimize IPI latency
kvm: Nested KVM MMUs need PAE root too
KVM: x86: set ctxt->have_exception in x86_decode_insn()
KVM: x86: always stop emulation on page fault
KVM: nVMX: trace nested VM-Enter failures detected by H/W
KVM: nVMX: add tracepoint for failed nested VM-Enter
x86: KVM: svm: Fix a check in nested_svm_vmrun()
KVM: x86: Return to userspace with internal error on unexpected exit reason
KVM: x86: Add kvm_emulate_{rd,wr}msr() to consolidate VXM/SVM code
KVM: x86: Refactor up kvm_{g,s}et_msr() to simplify callers
doc: kvm: Fix return description of KVM_SET_MSRS
KVM: X86: Tune PLE Window tracepoint
KVM: VMX: Change ple_window type to unsigned int
KVM: X86: Remove tailing newline for tracepoints
KVM: X86: Trace vcpu_id for vmexit
KVM: x86: Manually calculate reserved bits when loading PDPTRS
...
Commit cd7764fe9f ("KVM: x86: latch INITs while in system management mode")
changed code to latch INIT while vCPU is in SMM and process latched INIT
when leaving SMM. It left a subtle remark in commit message that similar
treatment should also be done while vCPU is in VMX non-root-mode.
However, INIT signals should actually be latched in various vCPU states:
(*) For both Intel and AMD, INIT signals should be latched while vCPU
is in SMM.
(*) For Intel, INIT should also be latched while vCPU is in VMX
operation and later processed when vCPU leaves VMX operation by
executing VMXOFF.
(*) For AMD, INIT should also be latched while vCPU runs with GIF=0
or in guest-mode with intercept defined on INIT signal.
To fix this:
1) Add kvm_x86_ops->apic_init_signal_blocked() such that each CPU vendor
can define the various CPU states in which INIT signals should be
blocked and modify kvm_apic_accept_events() to use it.
2) Modify vmx_check_nested_events() to check for pending INIT signal
while vCPU in guest-mode. If so, emualte vmexit on
EXIT_REASON_INIT_SIGNAL. Note that nSVM should have similar behaviour
but is currently left as a TODO comment to implement in the future
because nSVM don't yet implement svm_check_nested_events().
Note: Currently KVM nVMX implementation don't support VMX wait-for-SIPI
activity state as specified in MSR_IA32_VMX_MISC bits 6:8 exposed to
guest (See nested_vmx_setup_ctls_msrs()).
If and when support for this activity state will be implemented,
kvm_check_nested_events() would need to avoid emulating vmexit on
INIT signal in case activity-state is wait-for-SIPI. In addition,
kvm_apic_accept_events() would need to be modified to avoid discarding
SIPI in case VMX activity-state is wait-for-SIPI but instead delay
SIPI processing to vmx_check_nested_events() that would clear
pending APIC events and emulate vmexit on SIPI.
Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
Co-developed-by: Nikita Leshenko <nikita.leshchenko@oracle.com>
Signed-off-by: Nikita Leshenko <nikita.leshchenko@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The hrtimer which is used to emulate lapic timer is stopped during
vcpu reset, preemption timer should do the same.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Receiving an unexpected exit reason from hardware should be considered
as a severe bug in KVM. Therefore, instead of just injecting #UD to
guest and ignore it, exit to userspace on internal error so that
it could handle it properly (probably by terminating guest).
In addition, prefer to use vcpu_unimpl() instead of WARN_ONCE()
as handling unexpected exit reason should be a rare unexpected
event (that was expected to never happen) and we prefer to print
a message on it every time it occurs to guest.
Furthermore, dump VMCS/VMCB to dmesg to assist diagnosing such cases.
Reviewed-by: Mihai Carabas <mihai.carabas@oracle.com>
Reviewed-by: Nikita Leshenko <nikita.leshchenko@oracle.com>
Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Move RDMSR and WRMSR emulation into common x86 code to consolidate
nearly identical SVM and VMX code.
Note, consolidating RDMSR introduces an extra indirect call, i.e.
retpoline, due to reaching {svm,vmx}_get_msr() via kvm_x86_ops, but a
guest kernel likely has bigger problems if increasing the latency of
RDMSR VM-Exits by ~70 cycles has a measurable impact on overall VM
performance. E.g. the only recurring RDMSR VM-Exits (after booting) on
my system running Linux 5.2 in the guest are for MSR_IA32_TSC_ADJUST via
arch_cpu_idle_enter().
No functional change intended.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Refactor the top-level MSR accessors to take/return the index and value
directly instead of requiring the caller to dump them into a msr_data
struct.
No functional change intended.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The PLE window tracepoint triggers even if the window is not changed,
and the wording can be a bit confusing too. One example line:
kvm_ple_window: vcpu 0: ple_window 4096 (shrink 4096)
It easily let people think of "the window now is 4096 which is
shrinked", but the truth is the value actually didn't change (4096).
Let's only dump this message if the value really changed, and we make
the message even simpler like:
kvm_ple_window: vcpu 4 old 4096 new 8192 (growed)
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The VMX ple_window is 32 bits wide, so logically it can overflow with
an int. The module parameter is declared as unsigned int which is
good, however the dynamic variable is not. Switching all the
ple_window references to use unsigned int.
The tracepoint changes will also affect SVM, but SVM is using an even
smaller width (16 bits) so it's always fine.
Suggested-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
We can easily route hardware interrupts directly into VM context when
they target the "Fixed" or "LowPriority" delivery modes.
However, on modes such as "SMI" or "Init", we need to go via KVM code
to actually put the vCPU into a different mode of operation, so we can
not post the interrupt
Add code in the VMX and SVM PI logic to explicitly refuse to establish
posted mappings for advanced IRQ deliver modes. This reflects the logic
in __apic_accept_irq() which also only ever passes Fixed and LowPriority
interrupts as posted interrupts into the guest.
This fixes a bug I have with code which configures real hardware to
inject virtual SMIs into my guest.
Signed-off-by: Alexander Graf <graf@amazon.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Wanpeng Li <wanpengli@tencent.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
If kvm_intel is loaded with nested=0 parameter an attempt to perform
KVM_GET_SUPPORTED_HV_CPUID results in OOPS as nested_get_evmcs_version hook
in kvm_x86_ops is NULL (we assign it in nested_vmx_hardware_setup() and
this only happens in case nested is enabled).
Check that kvm_x86_ops->nested_get_evmcs_version is not NULL before
calling it. With this, we can remove the stub from svm as it is no
longer needed.
Cc: <stable@vger.kernel.org>
Fixes: e2e871ab2f ("x86/kvm/hyper-v: Introduce nested_get_evmcs_version() helper")
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
KVM implementations that wrap struct kvm_vcpu with a vendor specific
struct, e.g. struct vcpu_vmx, must place the vcpu member at offset 0,
otherwise the usercopy region intended to encompass struct kvm_vcpu_arch
will instead overlap random chunks of the vendor specific struct.
E.g. padding a large number of bytes before struct kvm_vcpu triggers
a usercopy warn when running with CONFIG_HARDENED_USERCOPY=y.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
When shadow paging is enabled, KVM tracks the allowed access type for
MMIO SPTEs so that it can do a permission check on a MMIO GVA cache hit
without having to walk the guest's page tables. The tracking is done
by retaining the WRITE and USER bits of the access when inserting the
MMIO SPTE (read access is implicitly allowed), which allows the MMIO
page fault handler to retrieve and cache the WRITE/USER bits from the
SPTE.
Unfortunately for EPT, the mask used to retain the WRITE/USER bits is
hardcoded using the x86 paging versions of the bits. This funkiness
happens to work because KVM uses a completely different mask/value for
MMIO SPTEs when EPT is enabled, and the EPT mask/value just happens to
overlap exactly with the x86 WRITE/USER bits[*].
Explicitly define the access mask for MMIO SPTEs to accurately reflect
that EPT does not want to incorporate any access bits into the SPTE, and
so that KVM isn't subtly relying on EPT's WX bits always being set in
MMIO SPTEs, e.g. attempting to use other bits for experimentation breaks
horribly.
Note, vcpu_match_mmio_gva() explicits prevents matching GVA==0, and all
TDP flows explicit set mmio_gva to 0, i.e. zeroing vcpu->arch.access for
EPT has no (known) functional impact.
[*] Using WX to generate EPT misconfigurations (equivalent to reserved
bit page fault) ensures KVM can employ its MMIO page fault tricks
even platforms without reserved address bits.
Fixes: ce88decffd ("KVM: MMU: mmio page fault support")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
On AMD, kvm_x86_ops->skip_emulated_instruction(vcpu) can, in theory,
fail: in !nrips case we call kvm_emulate_instruction(EMULTYPE_SKIP).
Currently, we only do printk(KERN_DEBUG) when this happens and this
is not ideal. Propagate the error up the stack.
On VMX, skip_emulated_instruction() doesn't fail, we have two call
sites calling it explicitly: handle_exception_nmi() and
handle_task_switch(), we can just ignore the result.
On SVM, we also have two explicit call sites:
svm_queue_exception() and it seems we don't need to do anything there as
we check if RIP was advanced or not. In task_switch_interception(),
however, we are better off not proceeding to kvm_task_switch() in case
skip_emulated_instruction() failed.
Suggested-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
After commit d73eb57b80 (KVM: Boost vCPUs that are delivering interrupts), a
five years old bug is exposed. Running ebizzy benchmark in three 80 vCPUs VMs
on one 80 pCPUs Skylake server, a lot of rcu_sched stall warning splatting
in the VMs after stress testing:
INFO: rcu_sched detected stalls on CPUs/tasks: { 4 41 57 62 77} (detected by 15, t=60004 jiffies, g=899, c=898, q=15073)
Call Trace:
flush_tlb_mm_range+0x68/0x140
tlb_flush_mmu.part.75+0x37/0xe0
tlb_finish_mmu+0x55/0x60
zap_page_range+0x142/0x190
SyS_madvise+0x3cd/0x9c0
system_call_fastpath+0x1c/0x21
swait_active() sustains to be true before finish_swait() is called in
kvm_vcpu_block(), voluntarily preempted vCPUs are taken into account
by kvm_vcpu_on_spin() loop greatly increases the probability condition
kvm_arch_vcpu_runnable(vcpu) is checked and can be true, when APICv
is enabled the yield-candidate vCPU's VMCS RVI field leaks(by
vmx_sync_pir_to_irr()) into spinning-on-a-taken-lock vCPU's current
VMCS.
This patch fixes it by checking conservatively a subset of events.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Marc Zyngier <Marc.Zyngier@arm.com>
Cc: stable@vger.kernel.org
Fixes: 98f4a1467 (KVM: add kvm_arch_vcpu_runnable() test to kvm_vcpu_on_spin() loop)
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
After reverting commit 240c35a378 (kvm: x86: Use task structs fpu field
for user), struct kvm_vcpu is 19456 bytes on my server, PAGE_ALLOC_COSTLY_ORDER(3)
is the order at which allocations are deemed costly to service. In serveless
scenario, one host can service hundreds/thoudands firecracker/kata-container
instances, howerver, new instance will fail to launch after memory is too
fragmented to allocate kvm_vcpu struct on host, this was observed in some
cloud provider product environments.
This patch dynamically allocates user_fpu, kvm_vcpu is 15168 bytes now on my
Skylake server.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Dedicated instances are currently disturbed by unnecessary jitter due
to the emulated lapic timers firing on the same pCPUs where the
vCPUs reside. There is no hardware virtual timer on Intel for guest
like ARM, so both programming timer in guest and the emulated timer fires
incur vmexits. This patch tries to avoid vmexit when the emulated timer
fires, at least in dedicated instance scenario when nohz_full is enabled.
In that case, the emulated timers can be offload to the nearest busy
housekeeping cpus since APICv has been found for several years in server
processors. The guest timer interrupt can then be injected via posted interrupts,
which are delivered by the housekeeping cpu once the emulated timer fires.
The host should tuned so that vCPUs are placed on isolated physical
processors, and with several pCPUs surplus for busy housekeeping.
If disabled mwait/hlt/pause vmexits keep the vCPUs in non-root mode,
~3% redis performance benefit can be observed on Skylake server, and the
number of external interrupt vmexits drops substantially. Without patch
VM-EXIT Samples Samples% Time% Min Time Max Time Avg time
EXTERNAL_INTERRUPT 42916 49.43% 39.30% 0.47us 106.09us 0.71us ( +- 1.09% )
While with patch:
VM-EXIT Samples Samples% Time% Min Time Max Time Avg time
EXTERNAL_INTERRUPT 6871 9.29% 2.96% 0.44us 57.88us 0.72us ( +- 4.02% )
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This fixes the following coccinelle warning:
WARNING: return of 0/1 in function 'vmx_need_emulation_on_page_fault'
with return type bool
Return false instead of 0.
Signed-off-by: Yi Wang <wang.yi59@zte.com.cn>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
- Add support for chained PMU counters in guests
- Improve SError handling
- Handle Neoverse N1 erratum #1349291
- Allow side-channel mitigation status to be migrated
- Standardise most AArch64 system register accesses to msr_s/mrs_s
- Fix host MPIDR corruption on 32bit
-----BEGIN PGP SIGNATURE-----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=yfCs
-----END PGP SIGNATURE-----
Merge tag 'kvm-arm-for-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD
KVM/arm updates for 5.3
- Add support for chained PMU counters in guests
- Improve SError handling
- Handle Neoverse N1 erratum #1349291
- Allow side-channel mitigation status to be migrated
- Standardise most AArch64 system register accesses to msr_s/mrs_s
- Fix host MPIDR corruption on 32bit
This allows userspace to know which MSRs are supported by the hypervisor.
Unfortunately userspace must resort to tricks for everything except
MSR_IA32_VMX_VMFUNC (which was just added in the previous patch).
One possibility is to use the feature control MSR, which is tied to nested
VMX as well and is present on all KVM versions that support feature MSRs.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Raise #GP when guest read/write IA32_XSS, but the CPUID bits
say that it shouldn't exist.
Fixes: 203000993d (kvm: vmx: add MSR logic for XSAVES)
Reported-by: Xiaoyao Li <xiaoyao.li@linux.intel.com>
Reported-by: Tao Xu <tao3.xu@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Based on 1 normalized pattern(s):
this work is licensed under the terms of the gnu gpl version 2 see
the copying file in the top level directory
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 35 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.797835076@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
VMWRITEs to the major VMCS controls, pin controls included, are
deceptively expensive. CPUs with VMCS caching (Westmere and later) also
optimize away consistency checks on VM-Entry, i.e. skip consistency
checks if the relevant fields have not changed since the last successful
VM-Entry (of the cached VMCS). Because uops are a precious commodity,
uCode's dirty VMCS field tracking isn't as precise as software would
prefer. Notably, writing any of the major VMCS fields effectively marks
the entire VMCS dirty, i.e. causes the next VM-Entry to perform all
consistency checks, which consumes several hundred cycles.
As it pertains to KVM, toggling PIN_BASED_VMX_PREEMPTION_TIMER more than
doubles the latency of the next VM-Entry (and again when/if the flag is
toggled back). In a non-nested scenario, running a "standard" guest
with the preemption timer enabled, toggling the timer flag is uncommon
but not rare, e.g. roughly 1 in 10 entries. Disabling the preemption
timer can change these numbers due to its use for "immediate exits",
even when explicitly disabled by userspace.
Nested virtualization in particular is painful, as the timer flag is set
for the majority of VM-Enters, but prepare_vmcs02() initializes vmcs02's
pin controls to *clear* the flag since its the timer's final state isn't
known until vmx_vcpu_run(). I.e. the majority of nested VM-Enters end
up unnecessarily writing pin controls *twice*.
Rather than toggle the timer flag in pin controls, set the timer value
itself to the largest allowed value to put it into a "soft disabled"
state, and ignore any spurious preemption timer exits.
Sadly, the timer is a 32-bit value and so theoretically it can fire
before the head death of the universe, i.e. spurious exits are possible.
But because KVM does *not* save the timer value on VM-Exit and because
the timer runs at a slower rate than the TSC, the maximuma timer value
is still sufficiently large for KVM's purposes. E.g. on a modern CPU
with a timer that runs at 1/32 the frequency of a 2.4ghz constant-rate
TSC, the timer will fire after ~55 seconds of *uninterrupted* guest
execution. In other words, spurious VM-Exits are effectively only
possible if the host is completely tickless on the logical CPU, the
guest is not using the preemption timer, and the guest is not generating
VM-Exits for any other reason.
To be safe from bad/weird hardware, disable the preemption timer if its
maximum delay is less than ten seconds. Ten seconds is mostly arbitrary
and was selected in no small part because it's a nice round number.
For simplicity and paranoia, fall back to __kvm_request_immediate_exit()
if the preemption timer is disabled by KVM or userspace. Previously
KVM continued to use the preemption timer to force immediate exits even
when the timer was disabled by userspace. Now that KVM leaves the timer
running instead of truly disabling it, allow userspace to kill it
entirely in the unlikely event the timer (or KVM) malfunctions.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
... now that it is fully redundant with the pin controls shadow.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Or: Don't re-initialize vmcs02's controls on every nested VM-Entry.
VMWRITEs to the major VMCS controls are deceptively expensive. Intel
CPUs with VMCS caching (Westmere and later) also optimize away
consistency checks on VM-Entry, i.e. skip consistency checks if the
relevant fields have not changed since the last successful VM-Entry (of
the cached VMCS). Because uops are a precious commodity, uCode's dirty
VMCS field tracking isn't as precise as software would prefer. Notably,
writing any of the major VMCS fields effectively marks the entire VMCS
dirty, i.e. causes the next VM-Entry to perform all consistency checks,
which consumes several hundred cycles.
Zero out the controls' shadow copies during VMCS allocation and use the
optimized setter when "initializing" controls. While this technically
affects both non-nested and nested virtualization, nested virtualization
is the primary beneficiary as avoid VMWRITEs when prepare vmcs02 allows
hardware to optimizie away consistency checks.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Prepare to shadow all major control fields on a per-VMCS basis, which
allows KVM to avoid costly VMWRITEs when switching between vmcs01 and
vmcs02.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Prepare to shadow all major control fields on a per-VMCS basis, which
allows KVM to avoid VMREADs when switching between vmcs01 and vmcs02,
and more importantly can eliminate costly VMWRITEs to controls when
preparing vmcs02.
Shadowing exec controls also saves a VMREAD when opening virtual
INTR/NMI windows, yay...
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Prepare to shadow all major control fields on a per-VMCS basis, which
allows KVM to avoid costly VMWRITEs when switching between vmcs01 and
vmcs02.
Shadowing pin controls also allows a future patch to remove the per-VMCS
'hv_timer_armed' flag, as the shadow copy is a superset of said flag.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
KVM provides a module parameter to allow disabling virtual NMI support
to simplify testing (hardware *without* virtual NMI support is hard to
come by but it does have users). When preparing vmcs02, use the accessor
for pin controls to ensure that the module param is respected for nested
guests.
Opportunistically swap the order of applying L0's and L1's pin controls
to better align with other controls and to prepare for a future patche
that will ignore L1's, but not L0's, preemption timer flag.
Fixes: d02fcf5077 ("kvm: vmx: Allow disabling virtual NMI support")
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Checking for 32-bit PAE is quite common around code that fiddles with
the PDPTRs. Add a function to compress all checks into a single
invocation.
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
KVM unconditionally intercepts WRMSR to MSR_IA32_DEBUGCTLMSR. In the
unlikely event that L1 allows L2 to write L1's MSR_IA32_DEBUGCTLMSR, but
but saves L2's value on VM-Exit, update vmcs12 during L2's WRMSR so as
to eliminate the need to VMREAD the value from vmcs02 on nested VM-Exit.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
For L2, KVM always intercepts WRMSR to SYSENTER MSRs. Update vmcs12 in
the WRMSR handler so that they don't need to be (re)read from vmcs02 on
every nested VM-Exit.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
As alluded to by the TODO comment, KVM unconditionally intercepts writes
to the PAT MSR. In the unlikely event that L1 allows L2 to write L1's
PAT directly but saves L2's PAT on VM-Exit, update vmcs12 when L2 writes
the PAT. This eliminates the need to VMREAD the value from vmcs02 on
VM-Exit as vmcs12 is already up to date in all situations.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
When switching between vmcs01 and vmcs02, there is no need to update
state tracking for values that aren't tied to any particular VMCS as
the per-vCPU values are already up-to-date (vmx_switch_vmcs() can only
be called when the vCPU is loaded).
Avoiding the update eliminates a RDMSR, and potentially a RDPKRU and
posted-interrupt update (cmpxchg64() and more).
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
When switching between vmcs01 and vmcs02, KVM isn't actually switching
between guest and host. If guest state is already loaded (the likely,
if not guaranteed, case), keep the guest state loaded and manually swap
the loaded_cpu_state pointer after propagating saved host state to the
new vmcs0{1,2}.
Avoiding the switch between guest and host reduces the latency of
switching between vmcs01 and vmcs02 by several hundred cycles, and
reduces the roundtrip time of a nested VM by upwards of 1000 cycles.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
vmx->loaded_cpu_state can only be NULL or equal to vmx->loaded_vmcs,
so change it to a bool. Because the direction of the bool is
now the opposite of vmx->guest_msrs_dirty, change the direction of
vmx->guest_msrs_dirty so that they match.
Finally, do not imply that MSRs have to be reloaded when
vmx->guest_state_loaded is false; instead, set vmx->guest_msrs_ready
to false explicitly in vmx_prepare_switch_to_host.
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The behavior of WRMSR is in no way dependent on whether or not KVM
consumes the value.
Fixes: 4566654bb9 ("KVM: vmx: Inject #GP on invalid PAT CR")
Cc: stable@vger.kernel.org
Cc: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Nested virtualization involves copying data between many different types
of VMCSes, e.g. vmcs02, vmcs12, shadow VMCS and eVMCS. Rename a variety
of functions and flags to document both the source and destination of
each sync.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Per commit 1b6269db3f ("KVM: VMX: Handle NMIs before enabling
interrupts and preemption"), NMIs are handled directly in vmx_vcpu_run()
to "make sure we handle NMI on the current cpu, and that we don't
service maskable interrupts before non-maskable ones". The other
exceptions handled by complete_atomic_exit(), e.g. async #PF and #MC,
have similar requirements, and are located there to avoid extra VMREADs
since VMX bins hardware exceptions and NMIs into a single exit reason.
Clean up the code and eliminate the vaguely named complete_atomic_exit()
by moving the interrupts-disabled exception and NMI handling into the
existing handle_external_intrs() callback, and rename the callback to
a more appropriate name. Rename VMexit handlers throughout so that the
atomic and non-atomic counterparts have similar names.
In addition to improving code readability, this also ensures the NMI
handler is run with the host's debug registers loaded in the unlikely
event that the user is debugging NMIs. Accuracy of the last_guest_tsc
field is also improved when handling NMIs (and #MCs) as the handler
will run after updating said field.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
[Naming cleanups. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
VMX can conditionally call kvm_{before,after}_interrupt() since KVM
always uses "ack interrupt on exit" and therefore explicitly handles
interrupts as opposed to blindly enabling irqs.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Although the kernel may use multiple IDTs, KVM should only ever see the
"real" IDT, e.g. the early init IDT is long gone by the time KVM runs
and the debug stack IDT is only used for small windows of time in very
specific flows.
Before commit a547c6db4d ("KVM: VMX: Enable acknowledge interupt on
vmexit"), the kernel's IDT base was consumed by KVM only when setting
constant VMCS state, i.e. to set VMCS.HOST_IDTR_BASE. Because constant
host state is done once per vCPU, there was ostensibly no need to cache
the kernel's IDT base.
When support for "ack interrupt on exit" was introduced, KVM added a
second consumer of the IDT base as handling already-acked interrupts
requires directly calling the interrupt handler, i.e. KVM uses the IDT
base to find the address of the handler. Because interrupts are a fast
path, KVM cached the IDT base to avoid having to VMREAD HOST_IDTR_BASE.
Presumably, the IDT base was cached on a per-vCPU basis simply because
the existing code grabbed the IDT base on a per-vCPU (VMCS) basis.
Note, all post-boot IDTs use the same handlers for external interrupts,
i.e. the "ack interrupt on exit" use of the IDT base would be unaffected
even if the cached IDT somehow did not match the current IDT. And as
for the original use case of setting VMCS.HOST_IDTR_BASE, if any of the
above analysis is wrong then KVM has had a bug since the beginning of
time since KVM has effectively been caching the IDT at vCPU creation
since commit a8b732ca01c ("[PATCH] kvm: userspace interface").
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Generic x86 code invokes the kvm_x86_ops external interrupt handler on
all VM-Exits regardless of the actual exit type. Use the already-cached
EXIT_REASON to determine if the VM-Exit was due to an interrupt, thus
avoiding an extra VMREAD (to query VM_EXIT_INTR_INFO) for all other
types of VM-Exit.
In addition to avoiding the extra VMREAD, checking the EXIT_REASON
instead of VM_EXIT_INTR_INFO makes it more obvious that
vmx_handle_external_intr() is called for all VM-Exits, e.g. someone
unfamiliar with the flow might wonder under what condition(s)
VM_EXIT_INTR_INFO does not contain a valid interrupt, which is
simply not possible since KVM always runs with "ack interrupt on exit".
WARN once if VM_EXIT_INTR_INFO doesn't contain a valid interrupt on
an EXTERNAL_INTERRUPT VM-Exit, as such a condition would indicate a
hardware bug.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The reason for skipping handling of NMI and #MC in handle_exception is
the same, namely they are handled earlier by vmx_complete_atomic_exit.
Calling the machine check handler (which just returns 1) is misleading,
don't do it.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
A previous fix to prevent KVM from consuming stale VMCS state after a
failed VM-Entry inadvertantly blocked KVM's handling of machine checks
that occur during VM-Entry.
Per Intel's SDM, a #MC during VM-Entry is handled in one of three ways,
depending on when the #MC is recognoized. As it pertains to this bug
fix, the third case explicitly states EXIT_REASON_MCE_DURING_VMENTRY
is handled like any other VM-Exit during VM-Entry, i.e. sets bit 31 to
indicate the VM-Entry failed.
If a machine-check event occurs during a VM entry, one of the following occurs:
- The machine-check event is handled as if it occurred before the VM entry:
...
- The machine-check event is handled after VM entry completes:
...
- A VM-entry failure occurs as described in Section 26.7. The basic
exit reason is 41, for "VM-entry failure due to machine-check event".
Explicitly handle EXIT_REASON_MCE_DURING_VMENTRY as a one-off case in
vmx_vcpu_run() instead of binning it into vmx_complete_atomic_exit().
Doing so allows vmx_vcpu_run() to handle VMX_EXIT_REASONS_FAILED_VMENTRY
in a sane fashion and also simplifies vmx_complete_atomic_exit() since
VMCS.VM_EXIT_INTR_INFO is guaranteed to be fresh.
Fixes: b060ca3b2e ("kvm: vmx: Handle VMLAUNCH/VMRESUME failure properly")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Make it available to AMD hosts as well, just in case someone is trying
to use an Intel processor's CPUID setup.
Suggested-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
There is an imperfection in get_vmx_mem_address(): access length is ignored
when checking the limit. To fix this, pass access length as a function argument.
The access length is usually obvious since it is used by callers after
get_vmx_mem_address() call, but for vmread/vmwrite it depends on the
state of 64-bit mode.
Signed-off-by: Eugene Korenevsky <ekorenevsky@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Make all code consistent with kvm_deliver_exception_payload() by using
appropriate symbolic constant instead of hard-coded number.
Reviewed-by: Nikita Leshenko <nikita.leshchenko@oracle.com>
Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Allow guest reads CORE cstate when exposing host CPU power management capabilities
to the guest. PKG cstate is restricted to avoid a guest to get the whole package
information in multi-tenant scenario.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Add a wrapper to invoke kvm_arch_check_processor_compat() so that the
boilerplate ugliness of checking virtualization support on all CPUs is
hidden from the arch specific code. x86's implementation in particular
is quite heinous, as it unnecessarily propagates the out-param pattern
into kvm_x86_ops.
While the x86 specific issue could be resolved solely by changing
kvm_x86_ops, make the change for all architectures as returning a value
directly is prettier and technically more robust, e.g. s390 doesn't set
the out param, which could lead to subtle breakage in the (highly
unlikely) scenario where the out-param was not pre-initialized by the
caller.
Opportunistically annotate svm_check_processor_compat() with __init.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Advance lapic timer tries to hidden the hypervisor overhead between the
host emulated timer fires and the guest awares the timer is fired. However,
it just hidden the time between apic_timer_fn/handle_preemption_timer ->
wait_lapic_expire, instead of the real position of vmentry which is
mentioned in the orignial commit d0659d946b ("KVM: x86: add option to
advance tscdeadline hrtimer expiration"). There is 700+ cpu cycles between
the end of wait_lapic_expire and before world switch on my haswell desktop.
This patch tries to narrow the last gap(wait_lapic_expire -> world switch),
it takes the real overhead time between apic_timer_fn/handle_preemption_timer
and before world switch into consideration when adaptively tuning timer
advancement. The patch can reduce 40% latency (~1600+ cycles to ~1000+ cycles
on a haswell desktop) for kvm-unit-tests/tscdeadline_latency when testing
busy waits.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Liran Alon <liran.alon@oracle.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Userspace can easily set up invalid processor state in such a way that
dmesg will be filled with VMCS or VMCB dumps. Disable this by default
using a module parameter.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* POWER: support for direct access to the POWER9 XIVE interrupt controller,
memory and performance optimizations.
* x86: support for accessing memory not backed by struct page, fixes and refactoring
* Generic: dirty page tracking improvements
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.0.22 (GNU/Linux)
iQEcBAABAgAGBQJc3qV/AAoJEL/70l94x66Dn3QH/jX1Bn0P/RZAIt4w0SySklSg
PqxUKDyBQqB9vN9Qeb9jWXAKPH2CtM3+up/rz7oRnBWp7qA6vXcC/R/QJYAvzdXE
nklsR/oYCsflR1KdlVYuDvvPCPP2fLBU5zfN83OsaBQ8fNRkm3gN+N5XQ2SbXbLy
Mo9tybS4otY201UAC96e8N0ipwwyCRpDneQpLcl+F5nH3RBt63cVbs04O+70MXn7
eT4I+8K3+Go7LATzT8hglD21D/7uvE31qQb6yr5L33IfhU4GB51RZzBXTNaAdY8n
hT1rMrRkAMAFWYZPQDfoMadjWU3i5DIfstKjDxOr9oTfuOEp5Z+GvJwvVnUDg1I=
=D0+p
-----END PGP SIGNATURE-----
Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Paolo Bonzini:
"ARM:
- support for SVE and Pointer Authentication in guests
- PMU improvements
POWER:
- support for direct access to the POWER9 XIVE interrupt controller
- memory and performance optimizations
x86:
- support for accessing memory not backed by struct page
- fixes and refactoring
Generic:
- dirty page tracking improvements"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (155 commits)
kvm: fix compilation on aarch64
Revert "KVM: nVMX: Expose RDPMC-exiting only when guest supports PMU"
kvm: x86: Fix L1TF mitigation for shadow MMU
KVM: nVMX: Disable intercept for FS/GS base MSRs in vmcs02 when possible
KVM: PPC: Book3S: Remove useless checks in 'release' method of KVM device
KVM: PPC: Book3S HV: XIVE: Fix spelling mistake "acessing" -> "accessing"
KVM: PPC: Book3S HV: Make sure to load LPID for radix VCPUs
kvm: nVMX: Set nested_run_pending in vmx_set_nested_state after checks complete
tests: kvm: Add tests for KVM_SET_NESTED_STATE
KVM: nVMX: KVM_SET_NESTED_STATE - Tear down old EVMCS state before setting new state
tests: kvm: Add tests for KVM_CAP_MAX_VCPUS and KVM_CAP_MAX_CPU_ID
tests: kvm: Add tests to .gitignore
KVM: Introduce KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2
KVM: Fix kvm_clear_dirty_log_protect off-by-(minus-)one
KVM: Fix the bitmap range to copy during clear dirty
KVM: arm64: Fix ptrauth ID register masking logic
KVM: x86: use direct accessors for RIP and RSP
KVM: VMX: Use accessors for GPRs outside of dedicated caching logic
KVM: x86: Omit caching logic for always-available GPRs
kvm, x86: Properly check whether a pfn is an MMIO or not
...
The RDPMC-exiting control is dependent on the existence of the RDPMC
instruction itself, i.e. is not tied to the "Architectural Performance
Monitoring" feature. For all intents and purposes, the control exists
on all CPUs with VMX support since RDPMC also exists on all VCPUs with
VMX supported. Per Intel's SDM:
The RDPMC instruction was introduced into the IA-32 Architecture in
the Pentium Pro processor and the Pentium processor with MMX technology.
The earlier Pentium processors have performance-monitoring counters, but
they must be read with the RDMSR instruction.
Because RDPMC-exiting always exists, KVM requires the control and refuses
to load if it's not available. As a result, hiding the PMU from a guest
breaks nested virtualization if the guest attemts to use KVM.
While it's not explicitly stated in the RDPMC pseudocode, the VM-Exit
check for RDPMC-exiting follows standard fault vs. VM-Exit prioritization
for privileged instructions, e.g. occurs after the CPL/CR0.PE/CR4.PCE
checks, but before the counter referenced in ECX is checked for validity.
In other words, the original KVM behavior of injecting a #GP was correct,
and the KVM unit test needs to be adjusted accordingly, e.g. eat the #GP
when the unit test guest (L3 in this case) executes RDPMC without
RDPMC-exiting set in the unit test host (L2).
This reverts commit e51bfdb687.
Fixes: e51bfdb687 ("KVM: nVMX: Expose RDPMC-exiting only when guest supports PMU")
Reported-by: David Hill <hilld@binarystorm.net>
Cc: Saar Amar <saaramar@microsoft.com>
Cc: Mihai Carabas <mihai.carabas@oracle.com>
Cc: Jim Mattson <jmattson@google.com>
Cc: Liran Alon <liran.alon@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Pull x86 MDS mitigations from Thomas Gleixner:
"Microarchitectural Data Sampling (MDS) is a hardware vulnerability
which allows unprivileged speculative access to data which is
available in various CPU internal buffers. This new set of misfeatures
has the following CVEs assigned:
CVE-2018-12126 MSBDS Microarchitectural Store Buffer Data Sampling
CVE-2018-12130 MFBDS Microarchitectural Fill Buffer Data Sampling
CVE-2018-12127 MLPDS Microarchitectural Load Port Data Sampling
CVE-2019-11091 MDSUM Microarchitectural Data Sampling Uncacheable Memory
MDS attacks target microarchitectural buffers which speculatively
forward data under certain conditions. Disclosure gadgets can expose
this data via cache side channels.
Contrary to other speculation based vulnerabilities the MDS
vulnerability does not allow the attacker to control the memory target
address. As a consequence the attacks are purely sampling based, but
as demonstrated with the TLBleed attack samples can be postprocessed
successfully.
The mitigation is to flush the microarchitectural buffers on return to
user space and before entering a VM. It's bolted on the VERW
instruction and requires a microcode update. As some of the attacks
exploit data structures shared between hyperthreads, full protection
requires to disable hyperthreading. The kernel does not do that by
default to avoid breaking unattended updates.
The mitigation set comes with documentation for administrators and a
deeper technical view"
* 'x86-mds-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits)
x86/speculation/mds: Fix documentation typo
Documentation: Correct the possible MDS sysfs values
x86/mds: Add MDSUM variant to the MDS documentation
x86/speculation/mds: Add 'mitigations=' support for MDS
x86/speculation/mds: Print SMT vulnerable on MSBDS with mitigations off
x86/speculation/mds: Fix comment
x86/speculation/mds: Add SMT warning message
x86/speculation: Move arch_smt_update() call to after mitigation decisions
x86/speculation/mds: Add mds=full,nosmt cmdline option
Documentation: Add MDS vulnerability documentation
Documentation: Move L1TF to separate directory
x86/speculation/mds: Add mitigation mode VMWERV
x86/speculation/mds: Add sysfs reporting for MDS
x86/speculation/mds: Add mitigation control for MDS
x86/speculation/mds: Conditionally clear CPU buffers on idle entry
x86/kvm/vmx: Add MDS protection when L1D Flush is not active
x86/speculation/mds: Clear CPU buffers on exit to user
x86/speculation/mds: Add mds_clear_cpu_buffers()
x86/kvm: Expose X86_FEATURE_MD_CLEAR to guests
x86/speculation/mds: Add BUG_MSBDS_ONLY
...
Pull x86 FPU state handling updates from Borislav Petkov:
"This contains work started by Rik van Riel and brought to fruition by
Sebastian Andrzej Siewior with the main goal to optimize when to load
FPU registers: only when returning to userspace and not on every
context switch (while the task remains in the kernel).
In addition, this optimization makes kernel_fpu_begin() cheaper by
requiring registers saving only on the first invocation and skipping
that in following ones.
What is more, this series cleans up and streamlines many aspects of
the already complex FPU code, hopefully making it more palatable for
future improvements and simplifications.
Finally, there's a __user annotations fix from Jann Horn"
* 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (29 commits)
x86/fpu: Fault-in user stack if copy_fpstate_to_sigframe() fails
x86/pkeys: Add PKRU value to init_fpstate
x86/fpu: Restore regs in copy_fpstate_to_sigframe() in order to use the fastpath
x86/fpu: Add a fastpath to copy_fpstate_to_sigframe()
x86/fpu: Add a fastpath to __fpu__restore_sig()
x86/fpu: Defer FPU state load until return to userspace
x86/fpu: Merge the two code paths in __fpu__restore_sig()
x86/fpu: Restore from kernel memory on the 64-bit path too
x86/fpu: Inline copy_user_to_fpregs_zeroing()
x86/fpu: Update xstate's PKRU value on write_pkru()
x86/fpu: Prepare copy_fpstate_to_sigframe() for TIF_NEED_FPU_LOAD
x86/fpu: Always store the registers in copy_fpstate_to_sigframe()
x86/entry: Add TIF_NEED_FPU_LOAD
x86/fpu: Eager switch PKRU state
x86/pkeys: Don't check if PKRU is zero before writing it
x86/fpu: Only write PKRU if it is different from current
x86/pkeys: Provide *pkru() helpers
x86/fpu: Use a feature number instead of mask in two more helpers
x86/fpu: Make __raw_xsave_addr() use a feature number instead of mask
x86/fpu: Add an __fpregs_load_activate() internal helper
...
... now that there is no overhead when using dedicated accessors.
Opportunistically remove a bogus "FIXME" in handle_rdmsr() regarding
the upper 32 bits of RAX and RDX. Zeroing the upper 32 bits is
architecturally correct as 32-bit writes in 64-bit mode unconditionally
clear the upper 32 bits.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Except for RSP and RIP, which are held in VMX's VMCS, GPRs are always
treated "available and dirtly" on both VMX and SVM, i.e. are
unconditionally loaded/saved immediately before/after VM-Enter/VM-Exit.
Eliminating the unnecessary caching code reduces the size of KVM by a
non-trivial amount, much of which comes from the most common code paths.
E.g. on x86_64, kvm_emulate_cpuid() is reduced from 342 to 182 bytes and
kvm_emulate_hypercall() from 1362 to 1143, with the total size of KVM
dropping by ~1000 bytes. With CONFIG_RETPOLINE=y, the numbers are even
more pronounced, e.g.: 353->182, 1418->1172 and well over 2000 bytes.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Use kvm_vcpu_map when mapping the virtual APIC page since using
kvm_vcpu_gpa_to_page() and kmap() will only work for guest memory that has
a "struct page".
One additional semantic change is that the virtual host mapping lifecycle
has changed a bit. It now has the same lifetime of the pinning of the
virtual APIC page on the host side.
Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Update the PML table without mapping and unmapping the page. This also
avoids using kvm_vcpu_gpa_to_page(..) which assumes that there is a "struct
page" for guest memory.
As a side-effect of using kvm_write_guest_page the page is also properly
marked as dirty.
Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Smatch complains about this:
arch/x86/kvm/vmx/vmx.c:5730 dump_vmcs()
warn: KERN_* level not at start of string
The code should be using pr_cont() instead of pr_err().
Fixes: 9d609649bb ("KVM: vmx: print more APICv fields in dump_vmcs")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Ten percent of nothin' is... let me do the math here. Nothin' into
nothin', carry the nothin'...
Cc: Wanpeng Li <wanpengli@tencent.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Refactor kvm_x86_ops->set_hv_timer to use an explicit parameter for
stating that the timer has expired. Overloading the return value is
unnecessarily clever, e.g. can lead to confusion over the proper return
value from start_hv_timer() when r==1.
Cc: Wanpeng Li <wanpengli@tencent.com>
Cc: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Since commits 668fffa3f8 ("kvm: better MWAIT emulation for guestsâ€)
and 4d5422cea3 ("KVM: X86: Provide a capability to disable MWAIT interceptsâ€),
KVM was modified to allow an admin to configure certain guests to execute
MONITOR/MWAIT inside guest without being intercepted by host.
This is useful in case admin wishes to allocate a dedicated logical
processor for each vCPU thread. Thus, making it safe for guest to
completely control the power-state of the logical processor.
The ability to use this new KVM capability was introduced to QEMU by
commits 6f131f13e68d ("kvm: support -overcommit cpu-pm=on|offâ€) and
2266d4431132 ("i386/cpu: make -cpu host support monitor/mwaitâ€).
However, exposing MONITOR/MWAIT to a Linux guest may cause it's intel_idle
kernel module to execute c1e_promotion_disable() which will attempt to
RDMSR/WRMSR from/to MSR_IA32_POWER_CTL to manipulate the "C1E Enable"
bit. This behaviour was introduced by commit
32e9518005 ("intel_idle: export both C1 and C1Eâ€).
Becuase KVM doesn't emulate this MSR, running KVM with ignore_msrs=0
will cause the above guest behaviour to raise a #GP which will cause
guest to kernel panic.
Therefore, add support for nop emulation of MSR_IA32_POWER_CTL to
avoid #GP in guest in this scenario.
Future commits can optimise emulation further by reflecting guest
MSR changes to host MSR to provide guest with the ability to
fine-tune the dedicated logical processor power-state.
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The not-so-recent change to move VMX's VM-Exit handing to a dedicated
"function" unintentionally exposed KVM to a speculative attack from the
guest by executing a RET prior to stuffing the RSB. Make RSB stuffing
happen immediately after VM-Exit, before any unpaired returns.
Alternatively, the VM-Exit path could postpone full RSB stuffing until
its current location by stuffing the RSB only as needed, or by avoiding
returns in the VM-Exit path entirely, but both alternatives are beyond
ugly since vmx_vmexit() has multiple indirect callers (by way of
vmx_vmenter()). And putting the RSB stuffing immediately after VM-Exit
makes it much less likely to be re-broken in the future.
Note, the cost of PUSH/POP could be avoided in the normal flow by
pairing the PUSH RAX with the POP RAX in __vmx_vcpu_run() and adding an
a POP to nested_vmx_check_vmentry_hw(), but such a weird/subtle
dependency is likely to cause problems in the long run, and PUSH/POP
will take all of a few cycles, which is peanuts compared to the number
of cycles required to fill the RSB.
Fixes: 453eafbe65 ("KVM: VMX: Move VM-Enter + VM-Exit handling to non-inline sub-routines")
Reported-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Co-developed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Automatically adjusting the globally-shared timer advancement could
corrupt the timer, e.g. if multiple vCPUs are concurrently adjusting
the advancement value. That could be partially fixed by using a local
variable for the arithmetic, but it would still be susceptible to a
race when setting timer_advance_adjust_done.
And because virtual_tsc_khz and tsc_scaling_ratio are per-vCPU, the
correct calibration for a given vCPU may not apply to all vCPUs.
Furthermore, lapic_timer_advance_ns is marked __read_mostly, which is
effectively violated when finding a stable advancement takes an extended
amount of timer.
Opportunistically change the definition of lapic_timer_advance_ns to
a u32 so that it matches the style of struct kvm_timer. Explicitly
pass the param to kvm_create_lapic() so that it doesn't have to be
exposed to lapic.c, thus reducing the probability of unintentionally
using the global value instead of the per-vCPU value.
Cc: Liran Alon <liran.alon@oracle.com>
Cc: Wanpeng Li <wanpengli@tencent.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Cc: stable@vger.kernel.org
Fixes: 3b8a5df6c4 ("KVM: LAPIC: Tune lapic_timer_advance_ns automatically")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This check will soon be done on every nested vmentry and vmexit,
"parallelize" it using bitwise operations.
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This is not needed, PAT writes always take an MSR vmexit.
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The SVI, RVI, virtual-APIC page address and APIC-access page address fields
were left out of dump_vmcs. Add them.
KERN_CONT technically isn't SMP safe, but it's okay to use it here since
the whole of dump_vmcs() is a single huge multi-line piece of output
that isn't SMP-safe.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
RSM emulation is currently broken on VMX when the interrupted guest has
CR4.VMXE=1. Stop dancing around the issue of HF_SMM_MASK being set when
loading SMSTATE into architectural state, e.g. by toggling it for
problematic flows, and simply clear HF_SMM_MASK prior to loading
architectural state (from SMRAM save state area).
Reported-by: Jon Doron <arilou@gmail.com>
Cc: Jim Mattson <jmattson@google.com>
Cc: Liran Alon <liran.alon@oracle.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Fixes: 5bea5123cb ("KVM: VMX: check nested state and CR4.VMXE against SMM")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Tested-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
RSM emulation is currently broken on VMX when the interrupted guest has
CR4.VMXE=1. Rather than dance around the issue of HF_SMM_MASK being set
when loading SMSTATE into architectural state, ideally RSM emulation
itself would be reworked to clear HF_SMM_MASK prior to loading non-SMM
architectural state.
Ostensibly, the only motivation for having HF_SMM_MASK set throughout
the loading of state from the SMRAM save state area is so that the
memory accesses from GET_SMSTATE() are tagged with role.smm. Load
all of the SMRAM save state area from guest memory at the beginning of
RSM emulation, and load state from the buffer instead of reading guest
memory one-by-one.
This paves the way for clearing HF_SMM_MASK prior to loading state,
and also aligns RSM with the enter_smm() behavior, which fills a
buffer and writes SMRAM save state in a single go.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Issue was discovered when running kvm-unit-tests on KVM running as L1 on
top of Hyper-V.
When vmx_instruction_intercept unit-test attempts to run RDPMC to test
RDPMC-exiting, it is intercepted by L1 KVM which it's EXIT_REASON_RDPMC
handler raise #GP because vCPU exposed by Hyper-V doesn't support PMU.
Instead of unit-test expectation to be reflected with EXIT_REASON_RDPMC.
The reason vmx_instruction_intercept unit-test attempts to run RDPMC
even though Hyper-V doesn't support PMU is because L1 expose to L2
support for RDPMC-exiting. Which is reasonable to assume that is
supported only in case CPU supports PMU to being with.
Above issue can easily be simulated by modifying
vmx_instruction_intercept config in x86/unittests.cfg to run QEMU with
"-cpu host,+vmx,-pmu" and run unit-test.
To handle issue, change KVM to expose RDPMC-exiting only when guest
supports PMU.
Reported-by: Saar Amar <saaramar@microsoft.com>
Reviewed-by: Mihai Carabas <mihai.carabas@oracle.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
guest xcr0 could leak into host when MCE happens in guest mode. Because
do_machine_check() could schedule out at a few places.
For example:
kvm_load_guest_xcr0
...
kvm_x86_ops->run(vcpu) {
vmx_vcpu_run
vmx_complete_atomic_exit
kvm_machine_check
do_machine_check
do_memory_failure
memory_failure
lock_page
In this case, host_xcr0 is 0x2ff, guest vcpu xcr0 is 0xff. After schedule
out, host cpu has guest xcr0 loaded (0xff).
In __switch_to {
switch_fpu_finish
copy_kernel_to_fpregs
XRSTORS
If any bit i in XSTATE_BV[i] == 1 and xcr0[i] == 0, XRSTORS will
generate #GP (In this case, bit 9). Then ex_handler_fprestore kicks in
and tries to reinitialize fpu by restoring init fpu state. Same story as
last #GP, except we get DOUBLE FAULT this time.
Cc: stable@vger.kernel.org
Signed-off-by: WANG Chao <chao.wang@ucloud.cn>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
As mentioned in the comment, there are some special cases where we can simply
clear the TPR shadow bit from the CPU-based execution controls in the vmcs02.
Handle them so that we can remove some XFAILs from vmx.flat.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Dave Hansen asked for __read_pkru() and __write_pkru() to be
symmetrical.
As part of the series __write_pkru() will read back the value and only
write it if it is different.
In order to make both functions symmetrical, move the function
containing only the opcode asm into a function called like the
instruction itself.
__write_pkru() will just invoke wrpkru() but in a follow-up patch will
also read back the value.
[ bp: Convert asm opcode wrapper names to rd/wrpkru(). ]
Suggested-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Juergen Gross <jgross@suse.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: kvm ML <kvm@vger.kernel.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20190403164156.19645-13-bigeasy@linutronix.de
The CPUID flag ARCH_CAPABILITIES is unconditioinally exposed to host
userspace for all x86 hosts, i.e. KVM advertises ARCH_CAPABILITIES
regardless of hardware support under the pretense that KVM fully
emulates MSR_IA32_ARCH_CAPABILITIES. Unfortunately, only VMX hosts
handle accesses to MSR_IA32_ARCH_CAPABILITIES (despite KVM_GET_MSRS
also reporting MSR_IA32_ARCH_CAPABILITIES for all hosts).
Move the MSR_IA32_ARCH_CAPABILITIES handling to common x86 code so
that it's emulated on AMD hosts.
Fixes: 1eaafe91a0 ("kvm: x86: IA32_ARCH_CAPABILITIES is always supported")
Cc: stable@vger.kernel.org
Reported-by: Xiaoyao Li <xiaoyao.li@linux.intel.com>
Cc: Jim Mattson <jmattson@google.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Errata#1096:
On a nested data page fault when CR.SMAP=1 and the guest data read
generates a SMAP violation, GuestInstrBytes field of the VMCB on a
VMEXIT will incorrectly return 0h instead the correct guest
instruction bytes .
Recommend Workaround:
To determine what instruction the guest was executing the hypervisor
will have to decode the instruction at the instruction pointer.
The recommended workaround can not be implemented for the SEV
guest because guest memory is encrypted with the guest specific key,
and instruction decoder will not be able to decode the instruction
bytes. If we hit this errata in the SEV guest then log the message
and request a guest shutdown.
Reported-by: Venkatesh Srinivas <venkateshs@google.com>
Cc: Jim Mattson <jmattson@google.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
