Several places in code for Hyper-V reference the
per-CPU variable hyperv_pcpu_input_arg. Older code uses a multi-line
sequence to reference the variable, and usually includes a cast.
Newer code does a much simpler direct assignment. The latter is
preferable as the complexity of the older code is unnecessary.
Update older code to use the simpler direct assignment.
Signed-off-by: Nischala Yelchuri <niyelchu@linux.microsoft.com>
Link: https://lore.kernel.org/r/1687286438-9421-1-git-send-email-niyelchu@linux.microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
In the case where page tables are not freed, native_flush_tlb_multi()
does not do a remote TLB flush on CPUs in lazy TLB mode because the
CPU will flush itself at the next context switch. By comparison, the
Hyper-V enlightened TLB flush does not exclude CPUs in lazy TLB mode
and so performs unnecessary flushes.
If we're not freeing page tables, add logic to test for lazy TLB
mode when adding CPUs to the input argument to the Hyper-V TLB
flush hypercall. Exclude lazy TLB mode CPUs so the behavior
matches native_flush_tlb_multi() and the unnecessary flushes are
avoided. Handle both the <=64 vCPU case and the _ex case for >64
vCPUs.
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/1679922967-26582-3-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
KASAN detected the following issue:
BUG: KASAN: slab-out-of-bounds in hyperv_flush_tlb_multi+0xf88/0x1060
Read of size 4 at addr ffff8880011ccbc0 by task kcompactd0/33
CPU: 1 PID: 33 Comm: kcompactd0 Not tainted 5.14.0-39.el9.x86_64+debug #1
Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine,
BIOS Hyper-V UEFI Release v4.0 12/17/2019
Call Trace:
dump_stack_lvl+0x57/0x7d
print_address_description.constprop.0+0x1f/0x140
? hyperv_flush_tlb_multi+0xf88/0x1060
__kasan_report.cold+0x7f/0x11e
? hyperv_flush_tlb_multi+0xf88/0x1060
kasan_report+0x38/0x50
hyperv_flush_tlb_multi+0xf88/0x1060
flush_tlb_mm_range+0x1b1/0x200
ptep_clear_flush+0x10e/0x150
...
Allocated by task 0:
kasan_save_stack+0x1b/0x40
__kasan_kmalloc+0x7c/0x90
hv_common_init+0xae/0x115
hyperv_init+0x97/0x501
apic_intr_mode_init+0xb3/0x1e0
x86_late_time_init+0x92/0xa2
start_kernel+0x338/0x3eb
secondary_startup_64_no_verify+0xc2/0xcb
The buggy address belongs to the object at ffff8880011cc800
which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 960 bytes inside of
1024-byte region [ffff8880011cc800, ffff8880011ccc00)
'hyperv_flush_tlb_multi+0xf88/0x1060' points to
hv_cpu_number_to_vp_number() and '960 bytes' means we're trying to get
VP_INDEX for CPU#240. 'nr_cpus' here is exactly 240 so we're trying to
access past hv_vp_index's last element. This can (and will) happen
when 'cpus' mask is empty and cpumask_last() will return '>=nr_cpus'.
Commit ad0a6bad44 ("x86/hyperv: check cpu mask after interrupt has
been disabled") tried to deal with empty cpumask situation but
apparently didn't fully fix the issue.
'cpus' cpumask which is passed to hyperv_flush_tlb_multi() is
'mm_cpumask(mm)' (which is '&mm->cpu_bitmap'). This mask changes every
time the particular mm is scheduled/unscheduled on some CPU (see
switch_mm_irqs_off()), disabling IRQs on the CPU which is performing remote
TLB flush has zero influence on whether the particular process can get
scheduled/unscheduled on _other_ CPUs so e.g. in the case where the mm was
scheduled on one other CPU and got unscheduled during
hyperv_flush_tlb_multi()'s execution will lead to cpumask becoming empty.
It doesn't seem that there's a good way to protect 'mm_cpumask(mm)'
from changing during hyperv_flush_tlb_multi()'s execution. It would be
possible to copy it in the very beginning of the function but this is a
waste. It seems we can deal with changing cpumask just fine.
When 'cpus' cpumask changes during hyperv_flush_tlb_multi()'s
execution, there are two possible issues:
- 'Under-flushing': we will not flush TLB on a CPU which got added to
the mask while hyperv_flush_tlb_multi() was already running. This is
not a problem as this is equal to mm getting scheduled on that CPU
right after TLB flush.
- 'Over-flushing': we may flush TLB on a CPU which is already cleared
from the mask. First, extra TLB flush preserves correctness. Second,
Hyper-V's TLB flush hypercall takes 'mm->pgd' argument so Hyper-V may
avoid the flush if CR3 doesn't match.
Fix the immediate issue with cpumask_last()/hv_cpu_number_to_vp_number()
and remove the pointless cpumask_empty() check from the beginning of the
function as it really doesn't protect anything. Also, avoid the hypercall
altogether when 'flush->processor_mask' ends up being empty.
Fixes: ad0a6bad44 ("x86/hyperv: check cpu mask after interrupt has been disabled")
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20220106094611.1404218-1-vkuznets@redhat.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
- 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.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'x86-mm-2021-04-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
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>
If we don't use paravirt; don't play unnecessary and complicated games
to free page-tables.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Rik van Riel <riel@surriel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.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
Commit 1268ed0c47 ("x86/hyper-v: Fix the circular dependency in IPI
enlightenment") made cpumask_to_vpset() return '-1' when there is a CPU
with unknown VP index in the supplied set. This needs to be checked before
we pass 'nr_bank' to hypercall.
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/20180709174012.17429-2-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
Do not consider the fixed size of hv_vp_set when passing the variable
header size to hv_do_rep_hypercall().
The Hyper-V hypervisor specification states that for a hypercall with a
variable header only the size of the variable portion should be supplied
via the input control.
For HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX/LIST_EX calls that means the
fixed portion of hv_vp_set should not be considered.
That fixes random failures of some applications that are unexpectedly
killed with SIGBUS or SIGSEGV.
Signed-off-by: Marcelo Henrique Cerri <marcelo.cerri@canonical.com>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Jork Loeser <Jork.Loeser@microsoft.com>
Cc: Josh Poulson <jopoulso@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Simon Xiao <sixiao@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: devel@linuxdriverproject.org
Fixes: 628f54cc64 ("x86/hyper-v: Support extended CPU ranges for TLB flush hypercalls")
Link: http://lkml.kernel.org/r/1507210469-29065-1-git-send-email-marcelo.cerri@canonical.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
hv_do_hypercall() does virt_to_phys() translation and with some configs
(CONFIG_SLAB) this doesn't work for percpu areas, we pass wrong memory to
hypervisor and get #GP. We could use working slow_virt_to_phys() instead
but doing so kills the performance.
Move pcpu_flush/pcpu_flush_ex structures out of percpu areas and
allocate memory on first call. The additional level of indirection gives
us a small performance penalty, in future we may consider introducing
hypercall functions which avoid virt_to_phys() conversion and cache
physical addresses of pcpu_flush/pcpu_flush_ex structures somewhere.
Reported-by: Simon Xiao <sixiao@microsoft.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Jork Loeser <Jork.Loeser@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: devel@linuxdriverproject.org
Link: http://lkml.kernel.org/r/20171005113924.28021-1-vkuznets@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
hv_flush_pcpu_ex structures are not cleared between calls for performance
reasons (they're variable size up to PAGE_SIZE each) but we must clear
hv_vp_set.bank_contents part of it to avoid flushing unneeded vCPUs. The
rest of the structure is formed correctly.
To do the clearing in an efficient way stash the maximum possible vCPU
number (this may differ from Linux CPU id).
Reported-by: Jork Loeser <Jork.Loeser@microsoft.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: devel@linuxdriverproject.org
Link: http://lkml.kernel.org/r/20171006154854.18092-1-vkuznets@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add Hyper-V tracing subsystem and trace hyperv_mmu_flush_tlb_others().
Tracing is done the same way we do xen_mmu_flush_tlb_others().
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Stephen Hemminger <sthemmin@microsoft.com>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Jork Loeser <Jork.Loeser@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Simon Xiao <sixiao@microsoft.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: devel@linuxdriverproject.org
Link: http://lkml.kernel.org/r/20170802160921.21791-10-vkuznets@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Hyper-V hosts may support more than 64 vCPUs, we need to use
HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX/LIST_EX hypercalls in this
case.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Jork Loeser <Jork.Loeser@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Simon Xiao <sixiao@microsoft.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: devel@linuxdriverproject.org
Link: http://lkml.kernel.org/r/20170802160921.21791-9-vkuznets@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Hyper-V host can suggest us to use hypercall for doing remote TLB flush,
this is supposed to work faster than IPIs.
Implementation details: to do HvFlushVirtualAddress{Space,List} hypercalls
we need to put the input somewhere in memory and we don't really want to
have memory allocation on each call so we pre-allocate per cpu memory areas
on boot.
pv_ops patching is happening very early so we need to separate
hyperv_setup_mmu_ops() and hyper_alloc_mmu().
It is possible and easy to implement local TLB flushing too and there is
even a hint for that. However, I don't see a room for optimization on the
host side as both hypercall and native tlb flush will result in vmexit. The
hint is also not set on modern Hyper-V versions.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Jork Loeser <Jork.Loeser@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Simon Xiao <sixiao@microsoft.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: devel@linuxdriverproject.org
Link: http://lkml.kernel.org/r/20170802160921.21791-8-vkuznets@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
