On Wed, May 22, 2019 at 10:51 PM Jonathan Corbet wrote:
>
> Documentation/gpu/i915.rst is not included in the TOC tree, but newer
> versions of sphinx parse it anyway. That leads to this hard build failure:
It is included I think: Documentation/gpu/index.rst -> drivers.rst ->
i915.rst. With that
On 5/29/2019 10:38 AM, Paolo Bonzini wrote:
On 29/05/19 04:05, Tao Xu wrote:
Thank you Paolo, but I have another question. I was wondering if it is
appropriate to enable X86_FEATURE_WAITPKG when QEMU uses "-overcommit
cpu-pm=on"?
"-overcommit" only establishes the behavior of KVM, it doesn'
On 29/05/19 04:25, Tao Xu wrote:
>>
> OK, but should we just drop this patch?
> Or add the VMX_EXIT_REASONS bits of UMWAIT and TPAUSE and handle like
> XSAVES/XRSTORS:
> "kvm_skip_emulated_instruction(vcpu);"
> "WARN(1, "this should never happen\n");"
Yes, this sounds good to me.
Paolo
On 29/05/19 04:05, Tao Xu wrote:
>>
>
> Thank you Paolo, but I have another question. I was wondering if it is
> appropriate to enable X86_FEATURE_WAITPKG when QEMU uses "-overcommit
> cpu-pm=on"?
"-overcommit" only establishes the behavior of KVM, it doesn't change
the cpuid bits. So you'd need
On 29/05/2019 09:28, Paolo Bonzini wrote:
On 24/05/19 09:56, Tao Xu wrote:
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.
This pa
On 29/05/2019 09:24, Paolo Bonzini wrote:
On 24/05/19 09:56, Tao Xu wrote:
+7.19 KVM_CAP_ENABLE_USR_WAIT_PAUSE
+
+Architectures: x86
+Parameters: args[0] whether feature should be enabled or not
+
+With this capability enabled, a VM can use UMONITOR, UMWAIT and TPAUSE
+instructions. If the ins
On 29/05/2019 09:29, Paolo Bonzini wrote:
On 24/05/19 09:56, Tao Xu wrote:
+
+ if (rdmsrl_safe(MSR_IA32_UMWAIT_CONTROL, &host_umwait_control))
+ return;
+
Does the host value ever change? If not, this can perhaps be read once
when kvm_intel is loaded. And if it changes of
On 24/05/19 09:56, Tao Xu wrote:
> +
> + if (rdmsrl_safe(MSR_IA32_UMWAIT_CONTROL, &host_umwait_control))
> + return;
> +
Does the host value ever change? If not, this can perhaps be read once
when kvm_intel is loaded. And if it changes often, it should be
shadowed into a percpu v
On 24/05/19 09:56, Tao Xu wrote:
> 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.
>
> This patch is to handle the vm-exit for
On 28/05/19 09:19, Tao Xu wrote:
>
> Thank you! This information really helped me. After I read the code in
> KVM/QEMU, I was wondering that with qemu command-line "-cpu
> host,+kvm-hint-dedicated", then in KVM,
> "kvm_hint_has_feature(KVM_HINTS_DEDICATED)" will be true, am I right?
Yes, but it d
On 27/05/19 12:30, Peter Zijlstra wrote:
>> This patch adds support for UMONITOR, UMWAIT and TPAUSE instructions
>> in kvm, and by default dont't expose it to kvm and provide a capability
>> to enable it.
>
> I'm thinking this should be conditional on the guest being a 1:1 guest,
> and I also seem
On 24/05/19 09:56, Tao Xu wrote:
> +7.19 KVM_CAP_ENABLE_USR_WAIT_PAUSE
> +
> +Architectures: x86
> +Parameters: args[0] whether feature should be enabled or not
> +
> +With this capability enabled, a VM can use UMONITOR, UMWAIT and TPAUSE
> +instructions. If the instruction causes a delay, the amou
> diff --git a/include/xen/balloon.h b/include/xen/balloon.h
> index 4914b93a23f2..a72ef3f88b39 100644
> --- a/include/xen/balloon.h
> +++ b/include/xen/balloon.h
> @@ -28,14 +28,6 @@ int alloc_xenballooned_pages(int nr_pages, struct page
> **pages);
> void free_xenballooned_pages(int nr_pages,
On Fri, May 24, 2019 at 5:07 PM Peter Oskolkov wrote:
> Linux CPU scheduling tail latency is a well-known issue and a major
> pain point in some workloads:
> https://www.google.com/search?q=linux+cpu+scheduling+tail+latency
>
> Even assuming that nobody noticed this particular cause
> of CPU sched
On Tue, May 28, 2019 at 03:00:07PM -0400, Joel Fernandes wrote:
> On Tue, May 28, 2019 at 05:24:47AM -0700, Paul E. McKenney wrote:
> > On Sat, May 25, 2019 at 02:14:07PM -0400, Joel Fernandes wrote:
> > > On Sat, May 25, 2019 at 08:50:35AM -0700, Paul E. McKenney wrote:
> > > > On Sat, May 25, 201
On Tue, May 28, 2019 at 05:24:47AM -0700, Paul E. McKenney wrote:
> On Sat, May 25, 2019 at 02:14:07PM -0400, Joel Fernandes wrote:
> > On Sat, May 25, 2019 at 08:50:35AM -0700, Paul E. McKenney wrote:
> > > On Sat, May 25, 2019 at 10:19:54AM -0400, Joel Fernandes wrote:
> > > > On Sat, May 25, 201
On Tue, May 28, 2019 at 06:32:57PM +0200, Marco Elver wrote:
> This is a pre-requisite for enabling bitops instrumentation. Some bitops
> may safely be used with instrumentation in uaccess regions.
>
> For example, on x86, `test_bit` is used to test a CPU-feature in a
> uaccess region: arch/x86/
Hi,
On Tue, May 28, 2019 at 06:32:56PM +0200, Marco Elver wrote:
> +static noinline void __init kasan_bitops(void)
> +{
> + long bits = 0;
> + const long bit = sizeof(bits) * 8;
You can use BITS_PER_LONG here.
Thanks,
Mark.
On Tue, May 28, 2019 at 06:32:58PM +0200, Marco Elver wrote:
> This adds a new header to asm-generic to allow optionally instrumenting
> architecture-specific asm implementations of bitops.
>
> This change includes the required change for x86 as reference and
> changes the kernel API doc to point
INQUIRY_4178916..xlsx
Description: Binary data
This adds a new header to asm-generic to allow optionally instrumenting
architecture-specific asm implementations of bitops.
This change includes the required change for x86 as reference and
changes the kernel API doc to point to bitops-instrumented.h instead.
Rationale: the functions in x86's bit
This is a pre-requisite for enabling bitops instrumentation. Some bitops
may safely be used with instrumentation in uaccess regions.
For example, on x86, `test_bit` is used to test a CPU-feature in a
uaccess region: arch/x86/ia32/ia32_signal.c:361
Signed-off-by: Marco Elver
---
tools/objtool/
This adds bitops tests to the test_kasan module. In a follow-up patch,
support for bitops instrumentation will be added.
Signed-off-by: Marco Elver
---
lib/test_kasan.c | 73 ++--
1 file changed, 70 insertions(+), 3 deletions(-)
diff --git a/lib/test_
> > >
> > > This puts a probe on vfs_read with argument1 and 2, and
> > > enable the new event.
> > >
> > > Signed-off-by: Masami Hiramatsu
> >
> > I built an arm64 kernel from todays linux-next tag next-20190528 and
> > ran in to this is
; > interface, but use ',' and ';' instead of ' ' and '\n'
> > respectively. e.g.
> >
> > kprobe_event=p,vfs_read,$arg1,$arg2
> >
> > This puts a probe on vfs_read with argument1 and 2, and
> > enable the new event.
> &g
On Sat, May 25, 2019 at 02:14:07PM -0400, Joel Fernandes wrote:
> On Sat, May 25, 2019 at 08:50:35AM -0700, Paul E. McKenney wrote:
> > On Sat, May 25, 2019 at 10:19:54AM -0400, Joel Fernandes wrote:
> > > On Sat, May 25, 2019 at 07:08:26AM -0400, Steven Rostedt wrote:
> > > > On Sat, 25 May 2019 0
#x27;\n'
> respectively. e.g.
>
> kprobe_event=p,vfs_read,$arg1,$arg2
>
> This puts a probe on vfs_read with argument1 and 2, and
> enable the new event.
>
> Signed-off-by: Masami Hiramatsu
I built an arm64 kernel from todays linux-next tag next-20190528 and
ran in to thi
On 28/05/2019 14:11, Wanpeng Li wrote:
On Tue, 28 May 2019 at 13:16, Tao Xu wrote:
On 27/05/2019 18:30, Peter Zijlstra wrote:
On Fri, May 24, 2019 at 03:56:35PM +0800, Tao Xu wrote:
This patch adds support for UMONITOR, UMWAIT and TPAUSE instructions
in kvm, and by default dont't expose i
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