Pull x86 tlb updates from Ingo Molnar:
"The x86 MM changes in this cycle were:
- Implement concurrent TLB flushes, which overlaps the local TLB
flush with the remote TLB flush.
In testing this improved sysbench performance measurably by a
couple of percentage points, especially if TLB-heavy security
mitigations are active.
- Further micro-optimizations to improve the performance of TLB
flushes"
* tag 'x86-mm-2021-04-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
smp: Micro-optimize smp_call_function_many_cond()
smp: Inline on_each_cpu_cond() and on_each_cpu()
x86/mm/tlb: Remove unnecessary uses of the inline keyword
cpumask: Mark functions as pure
x86/mm/tlb: Do not make is_lazy dirty for no reason
x86/mm/tlb: Privatize cpu_tlbstate
x86/mm/tlb: Flush remote and local TLBs concurrently
x86/mm/tlb: Open-code on_each_cpu_cond_mask() for tlb_is_not_lazy()
x86/mm/tlb: Unify flush_tlb_func_local() and flush_tlb_func_remote()
smp: Run functions concurrently in smp_call_function_many_cond()
There is not a consistent pattern for checking Hyper-V hypercall status.
Existing code uses a number of variants. The variants work, but a consistent
pattern would improve the readability of the code, and be more conformant
to what the Hyper-V TLFS says about hypercall status.
Implemented new helper functions hv_result(), hv_result_success(), and
hv_repcomp(). Changed the places where hv_do_hypercall() and related variants
are used to use the helper functions.
Signed-off-by: Joseph Salisbury <joseph.salisbury@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/1618620183-9967-2-git-send-email-joseph.salisbury@linux.microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
To improve TLB shootdown performance, flush the remote and local TLBs
concurrently. Introduce flush_tlb_multi() that does so. Introduce
paravirtual versions of flush_tlb_multi() for KVM, Xen and hyper-v (Xen
and hyper-v are only compile-tested).
While the updated smp infrastructure is capable of running a function on
a single local core, it is not optimized for this case. The multiple
function calls and the indirect branch introduce some overhead, and
might make local TLB flushes slower than they were before the recent
changes.
Before calling the SMP infrastructure, check if only a local TLB flush
is needed to restore the lost performance in this common case. This
requires to check mm_cpumask() one more time, but unless this mask is
updated very frequently, this should impact performance negatively.
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Michael Kelley <mikelley@microsoft.com> # Hyper-v parts
Reviewed-by: Juergen Gross <jgross@suse.com> # Xen and paravirt parts
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/r/20210220231712.2475218-5-namit@vmware.com
We've observed crashes due to an empty cpu mask in
hyperv_flush_tlb_others. Obviously the cpu mask in question is changed
between the cpumask_empty call at the beginning of the function and when
it is actually used later.
One theory is that an interrupt comes in between and a code path ends up
changing the mask. Move the check after interrupt has been disabled to
see if it fixes the issue.
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Cc: stable@kernel.org
Link: https://lore.kernel.org/r/20210105175043.28325-1-wei.liu@kernel.org
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
When the 'start' parameter is >= 0xFF000000 on 32-bit
systems, or >= 0xFFFFFFFF'FF000000 on 64-bit systems,
fill_gva_list() gets into an infinite loop.
With such inputs, 'cur' overflows after adding HV_TLB_FLUSH_UNIT
and always compares as less than end. Memory is filled with
guest virtual addresses until the system crashes.
Fix this by never incrementing 'cur' to be larger than 'end'.
Reported-by: Jong Hyun Park <park.jonghyun@yonsei.ac.kr>
Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 2ffd9e33ce ("x86/hyper-v: Use hypercall for remote TLB flush")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Commit 1268ed0c47 ("x86/hyper-v: Fix the circular dependency in IPI
enlightenment") pre-filled hv_vp_index with VP_INVAL so it is now
(theoretically) possible to observe hv_cpu_number_to_vp_number()
returning VP_INVAL. We need to check for that in hyperv_flush_tlb_others().
Not checking for VP_INVAL on the first call site where we do
if (hv_cpu_number_to_vp_number(cpumask_last(cpus)) >= 64)
goto do_ex_hypercall;
is OK, in case we're eligible for non-ex hypercall we'll catch the
issue later in for_each_cpu() cycle and in case we'll be doing ex-
hypercall cpumask_to_vpset() will fail.
It would be nice to change hv_cpu_number_to_vp_number() return
value's type to 'u32' but this will likely be a bigger change as
all call sites need to be checked first.
Fixes: 1268ed0c47 ("x86/hyper-v: Fix the circular dependency in IPI enlightenment")
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: "Michael Kelley (EOSG)" <Michael.H.Kelley@microsoft.com>
Cc: devel@linuxdriverproject.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Link: https://lkml.kernel.org/r/20180709174012.17429-3-vkuznets@redhat.com
While working on Hyper-V style PV TLB flush support in KVM I noticed that
real Windows guests use TLB flush hypercall in a somewhat smarter way:
When the flush needs to be performed on a subset of first 64 vCPUs or on
all present vCPUs Windows avoids more expensive hypercalls which support
sparse CPU sets and uses their 'cheap' counterparts.
This means that HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED name is actually a
misnomer: EX hypercalls (which support sparse CPU sets) are "available",
not "recommended". This makes sense as they are actually harder to parse.
Nothing stops us from being equally 'smart' in Linux too. Switch to doing
cheaper hypercalls whenever possible.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: "Michael Kelley (EOSG)" <Michael.H.Kelley@microsoft.com>
Cc: Tianyu Lan <Tianyu.Lan@microsoft.com>
Cc: devel@linuxdriverproject.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Link: https://lkml.kernel.org/r/20180621133238.30757-1-vkuznets@redhat.com
Hyper-V TLB flush hypercalls definitions will be required for KVM so move
them hyperv-tlfs.h. Structures also need to be renamed as '_pcpu' suffix is
irrelevant for a general-purpose definition.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
When hypercall-based TLB flush was enabled for Hyper-V guests PCID feature
was deliberately suppressed as a precaution: back then PCID was never
exposed to Hyper-V guests and it wasn't clear what will happen if some day
it becomes available. The day came and PCID/INVPCID features are already
exposed on certain Hyper-V hosts.
From TLFS (as of 5.0b) it is unclear how TLB flush hypercalls combine with
PCID. In particular the usage of PCID is per-cpu based: the same mm gets
different CR3 values on different CPUs. If the hypercall does exact
matching this will fail. However, this is not the case. David Zhang
explains:
"In practice, the AddressSpace argument is ignored on any VM that supports
PCIDs.
Architecturally, the AddressSpace argument must match the CR3 with PCID
bits stripped out (i.e., the low 12 bits of AddressSpace should be 0 in
long mode). The flush hypercalls flush all PCIDs for the specified
AddressSpace."
With this, PCID can be enabled.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: David Zhang <dazhan@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: "Michael Kelley (EOSG)" <Michael.H.Kelley@microsoft.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: devel@linuxdriverproject.org
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Aditya Bhandari <adityabh@microsoft.com>
Link: https://lkml.kernel.org/r/20180124103629.29980-1-vkuznets@redhat.com
