Reinitialize IA32_FEAT_CTL on the BSP during wakeup to handle the case
where firmware doesn't initialize or save/restore across S3. This fixes
a bug where IA32_FEAT_CTL is left uninitialized and results in VMXON
taking a #GP due to VMX not being fully enabled, i.e. breaks KVM.
Use init_ia32_feat_ctl() to "restore" IA32_FEAT_CTL as it already deals
with the case where the MSR is locked, and because APs already redo
init_ia32_feat_ctl() during suspend by virtue of the SMP boot flow being
used to reinitialize APs upon wakeup. Do the call in the early wakeup
flow to avoid dependencies in the syscore_ops chain, e.g. simply adding
a resume hook is not guaranteed to work, as KVM does VMXON in its own
resume hook, kvm_resume(), when KVM has active guests.
Fixes: 21bd3467a5 ("KVM: VMX: Drop initialization of IA32_FEAT_CTL MSR")
Reported-by: Brad Campbell <lists2009@fnarfbargle.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Liam Merwick <liam.merwick@oracle.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Tested-by: Brad Campbell <lists2009@fnarfbargle.com>
Cc: stable@vger.kernel.org # v5.6
Link: https://lkml.kernel.org/r/20200608174134.11157-1-sean.j.christopherson@intel.com
Without at least minimal handling for split lock detection induced #AC,
VMX will just run into the same problem as the VMWare hypervisor, which
was reported by Kenneth.
It will inject the #AC blindly into the guest whether the guest is
prepared or not.
Provide a function for guest mode which acts depending on the host
SLD mode. If mode == sld_warn, treat it like user space, i.e. emit a
warning, disable SLD and mark the task accordingly. Otherwise force
SIGBUS.
[ bp: Add a !CPU_SUP_INTEL stub for handle_guest_split_lock(). ]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Link: https://lkml.kernel.org/r/20200410115516.978037132@linutronix.de
Link: https://lkml.kernel.org/r/20200402123258.895628824@linutronix.de
A split-lock occurs when an atomic instruction operates on data that spans
two cache lines. In order to maintain atomicity the core takes a global bus
lock.
This is typically >1000 cycles slower than an atomic operation within a
cache line. It also disrupts performance on other cores (which must wait
for the bus lock to be released before their memory operations can
complete). For real-time systems this may mean missing deadlines. For other
systems it may just be very annoying.
Some CPUs have the capability to raise an #AC trap when a split lock is
attempted.
Provide a command line option to give the user choices on how to handle
this:
split_lock_detect=
off - not enabled (no traps for split locks)
warn - warn once when an application does a
split lock, but allow it to continue
running.
fatal - Send SIGBUS to applications that cause split lock
On systems that support split lock detection the default is "warn". Note
that if the kernel hits a split lock in any mode other than "off" it will
OOPs.
One implementation wrinkle is that the MSR to control the split lock
detection is per-core, not per thread. This might result in some short
lived races on HT systems in "warn" mode if Linux tries to enable on one
thread while disabling on the other. Race analysis by Sean Christopherson:
- Toggling of split-lock is only done in "warn" mode. Worst case
scenario of a race is that a misbehaving task will generate multiple
#AC exceptions on the same instruction. And this race will only occur
if both siblings are running tasks that generate split-lock #ACs, e.g.
a race where sibling threads are writing different values will only
occur if CPUx is disabling split-lock after an #AC and CPUy is
re-enabling split-lock after *its* previous task generated an #AC.
- Transitioning between off/warn/fatal modes at runtime isn't supported
and disabling is tracked per task, so hardware will always reach a steady
state that matches the configured mode. I.e. split-lock is guaranteed to
be enabled in hardware once all _TIF_SLD threads have been scheduled out.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Co-developed-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Co-developed-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20200126200535.GB30377@agluck-desk2.amr.corp.intel.com
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.
By default all files without license information are under the default
license of the kernel, which is GPL version 2.
Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.
This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.
How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,
Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.
The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.
The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.
Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).
All documentation files were explicitly excluded.
The following heuristics were used to determine which SPDX license
identifiers to apply.
- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.
For non */uapi/* files that summary was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139
and resulted in the first patch in this series.
If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930
and resulted in the second patch in this series.
- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:
SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1
and that resulted in the third patch in this series.
- when the two scanners agreed on the detected license(s), that became
the concluded license(s).
- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.
- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).
- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.
- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.
In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.
Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.
Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.
In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.
Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct
This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.
These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
- ACPI support for guests on ARM platforms.
- Generic steal time support for arm and x86.
- Support cases where kernel cpu is not Xen VCPU number (e.g., if
in-guest kexec is used).
- Use the system workqueue instead of a custom workqueue in various
places.
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Merge tag 'for-linus-4.8-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen updates from David Vrabel:
"Features and fixes for 4.8-rc0:
- ACPI support for guests on ARM platforms.
- Generic steal time support for arm and x86.
- Support cases where kernel cpu is not Xen VCPU number (e.g., if
in-guest kexec is used).
- Use the system workqueue instead of a custom workqueue in various
places"
* tag 'for-linus-4.8-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: (47 commits)
xen: add static initialization of steal_clock op to xen_time_ops
xen/pvhvm: run xen_vcpu_setup() for the boot CPU
xen/evtchn: use xen_vcpu_id mapping
xen/events: fifo: use xen_vcpu_id mapping
xen/events: use xen_vcpu_id mapping in events_base
x86/xen: use xen_vcpu_id mapping when pointing vcpu_info to shared_info
x86/xen: use xen_vcpu_id mapping for HYPERVISOR_vcpu_op
xen: introduce xen_vcpu_id mapping
x86/acpi: store ACPI ids from MADT for future usage
x86/xen: update cpuid.h from Xen-4.7
xen/evtchn: add IOCTL_EVTCHN_RESTRICT
xen-blkback: really don't leak mode property
xen-blkback: constify instance of "struct attribute_group"
xen-blkfront: prefer xenbus_scanf() over xenbus_gather()
xen-blkback: prefer xenbus_scanf() over xenbus_gather()
xen: support runqueue steal time on xen
arm/xen: add support for vm_assist hypercall
xen: update xen headers
xen-pciback: drop superfluous variables
xen-pciback: short-circuit read path used for merging write values
...
Currently we don't save ACPI ids (unlike LAPIC ids which go to
x86_cpu_to_apicid) from MADT and we may need this information later.
Particularly, ACPI ids is the only existent way for a PVHVM Xen guest
to figure out Xen's idea of its vCPUs ids before these CPUs boot and
in some cases these ids diverge from Linux's cpu ids.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
It serves no purpose -- raw_smp_processor_id() works fine. This
change will be needed to move thread_info off the stack.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/a2bf4f07fbc30fb32f9f7f3f8f94ad3580823847.1468527351.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add generic functions which calc family, model and stepping from
the CPUID_1.EAX leaf and stick them into the library we have.
Rename those which do call CPUID with the prefix "x86_cpuid" as
suggested by Paolo Bonzini.
No functionality change.
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1448273546-2567-2-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit removes the open-coded CPU-offline notification with new
common code. Among other things, this change avoids calling scheduler
code using RCU from an offline CPU that RCU is ignoring. It also allows
Xen to notice at online time that the CPU did not go offline correctly.
Note that Xen has the surviving CPU carry out some cleanup operations,
so if the surviving CPU times out, these cleanup operations might have
been carried out while the outgoing CPU was still running. It might
therefore be unwise to bring this CPU back online, and this commit
avoids doing so.
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: <x86@kernel.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: <xen-devel@lists.xenproject.org>
The __cpuinit type of throwaway sections might have made sense
some time ago when RAM was more constrained, but now the savings
do not offset the cost and complications. For example, the fix in
commit 5e427ec2d0 ("x86: Fix bit corruption at CPU resume time")
is a good example of the nasty type of bugs that can be created
with improper use of the various __init prefixes.
After a discussion on LKML[1] it was decided that cpuinit should go
the way of devinit and be phased out. Once all the users are gone,
we can then finally remove the macros themselves from linux/init.h.
Note that some harmless section mismatch warnings may result, since
notify_cpu_starting() and cpu_up() are arch independent (kernel/cpu.c)
are flagged as __cpuinit -- so if we remove the __cpuinit from
arch specific callers, we will also get section mismatch warnings.
As an intermediate step, we intend to turn the linux/init.h cpuinit
content into no-ops as early as possible, since that will get rid
of these warnings. In any case, they are temporary and harmless.
This removes all the arch/x86 uses of the __cpuinit macros from
all C files. x86 only had the one __CPUINIT used in assembly files,
and it wasn't paired off with a .previous or a __FINIT, so we can
delete it directly w/o any corresponding additional change there.
[1] https://lkml.org/lkml/2013/5/20/589
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
CONFIG_DEBUG_HOTPLUG_CPU0 is for debugging the CPU0 hotplug feature. The switch
offlines CPU0 as soon as possible and boots userspace up with CPU0 offlined.
User can online CPU0 back after boot time. The default value of the switch is
off.
To debug CPU0 hotplug, you need to enable CPU0 offline/online feature by either
turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during compilation or giving
cpu0_hotplug kernel parameter at boot.
It's safe and early place to take down CPU0 after all hotplug notifiers
are installed and SMP is booted.
Please note that some applications or drivers, e.g. some versions of udevd,
during boot time may put CPU0 online again in this CPU0 hotplug debug mode.
In this debug mode, setup_local_APIC() may report a warning on max_loops<=0
when CPU0 is onlined back after boot time. This is because pending interrupt in
IRR can not move to ISR. The warning is not CPU0 specfic and it can happen on
other CPUs as well. It is harmless except the first CPU0 online takes a bit
longer time. And so this debug mode is useful to expose this issue. I'll send
a seperate patch to fix this generic warning issue.
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Link: http://lkml.kernel.org/r/1352835171-3958-15-git-send-email-fenghua.yu@intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Instead of waiting for STARTUP after INITs, BSP will execute the BIOS boot-strap
code which is not a desired behavior for waking up BSP. To avoid the boot-strap
code, wake up CPU0 by NMI instead.
This works to wake up soft offlined CPU0 only. If CPU0 is hard offlined (i.e.
physically hot removed and then hot added), NMI won't wake it up. We'll change
this code in the future to wake up hard offlined CPU0 if real platform and
request are available.
AP is still waken up as before by INIT, SIPI, SIPI sequence.
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Link: http://lkml.kernel.org/r/1352896613-25957-1-git-send-email-fenghua.yu@intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
We use it in non __cpuinit code now too so drop marker.
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
LKML-Reference: <20110211171754.GA21047@aftab>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
ea53069231 made a CPU use monitor/mwait
when offline. This is not the optimal choice for AMD wrt to powersavings
and we'd prefer our cores to halt (i.e. enter C1) instead. For this, the
same selection whether to use monitor/mwait has to be used as when we
select the idle routine for the machine.
With this patch, offlining cores 1-5 on a X6 machine allows core0 to
boost again.
[ hpa: putting this in urgent since it is a (power) regression fix ]
Reported-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: stable@kernel.org # 37.x
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Venkatesh Pallipadi <venki@google.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.hl>
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
LKML-Reference: <1295534572-10730-1-git-send-email-bp@amd64.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
boot_cpu_id is there for historical reasons and was renamed to
boot_cpu_physical_apicid in patch:
c70dcb7 x86: change boot_cpu_id to boot_cpu_physical_apicid
However, there are some remaining occurrences of boot_cpu_id that are
never touched in the kernel and thus its value is always 0.
This patch removes boot_cpu_id completely.
Signed-off-by: Robert Richter <robert.richter@amd.com>
LKML-Reference: <1279731838-1522-8-git-send-email-robert.richter@amd.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
x86/Voyager can boot on non-zero processors. While that can probably
be fixed by properly remapping the physical CPU IDs, keep boot_cpu_id
for now for easier transition - and expand it to all of x86.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Change header guards named "ASM_X86__*" to "_ASM_X86_*" since:
a. the double underscore is ugly and pointless.
b. no leading underscore violates namespace constraints.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
