[GIT PULL] KVM fixes for 4.10 merge window

[GIT PULL] KVM fixes for 4.10 merge window

[Paolo Bonzini]

Linus,

The following changes since commit cdb98c2698b4af287925abcba4d77d92af82a0c3:

  Revert "nvme: add support for the Write Zeroes command" (2016-12-13 19:53:37 -0800)

are available in the git repository at:

  git://git.kernel.org/pub/scm/virt/kvm/kvm.git tags/for-linus

for you to fetch changes up to b94c3698b4b043a7b3aae8c3c88f60dd29565b90:

  Revert "x86/kvm: Support the vCPU preemption check" (2016-12-16 17:53:40 +0100)

----------------------------------------------------------------
Early fixes for x86, most notably a lockdep/might_sleep splat
introduced during the merge window.

----------------------------------------------------------------
GanShun (1):
      kvm: nVMX: Correct a VMX instruction error code for VMPTRLD

Paolo Bonzini (2):
      KVM: hyperv: fix locking of struct kvm_hv fields
      Revert "x86/kvm: Support the vCPU preemption check"

Yi Sun (1):
      KVM: x86: Expose Intel AVX512IFMA/AVX512VBMI/SHA features to guest.

 Documentation/virtual/kvm/locking.txt |  8 ++++++--
 arch/x86/include/asm/kvm_host.h       |  1 +
 arch/x86/include/uapi/asm/kvm_para.h  |  4 +---
 arch/x86/kvm/cpuid.c                  |  9 +++++----
 arch/x86/kvm/hyperv.c                 | 24 +++++++++++++++---------
 arch/x86/kvm/vmx.c                    |  2 +-
 arch/x86/kvm/x86.c                    | 17 +----------------
 7 files changed, 30 insertions(+), 35 deletions(-)

Re: [GIT PULL] KVM fixes for 4.10 merge window

[Linus Torvalds]

On Fri, Dec 16, 2016 at 8:57 AM, Paolo Bonzini <pbonzini@redhat.com> wrote:
>
>   git://git.kernel.org/pub/scm/virt/kvm/kvm.git tags/for-linus

This piece-of-shit branch has obviously never been even compile-tested:

  arch/x86/kernel/kvm.c: In function ‘__kvm_vcpu_is_preempted’:
  arch/x86/kernel/kvm.c:596:14: error: ‘struct kvm_steal_time’ has no
member named ‘preempted’

where commit b94c3698b4b0 ("Revert "x86/kvm: Support the vCPU
preemption check"") removed the "preempted" field from struct
kvm_steal_time, but you left this in place:

  __visible bool __kvm_vcpu_is_preempted(int cpu)
  {
          struct kvm_steal_time *src = &per_cpu(steal_time, cpu);

          return !!src->preempted;
  }

And no, that is not a merge artifact in my tree (although that
function did come in from Ingo). That compile failure comes from your
very own branch.

Am I upset? You bet I am. Get your act together. You can't just
randomly revert things without checking the end result.

             Linus

Re: [GIT PULL] KVM fixes for 4.10 merge window

[Pan Xinhui]

在 2016/12/17 03:42, Linus Torvalds 写道:
> On Fri, Dec 16, 2016 at 8:57 AM, Paolo Bonzini <pbonzini@redhat.com> wrote:
>>
>>   git://git.kernel.org/pub/scm/virt/kvm/kvm.git tags/for-linus
>
> This piece-of-shit branch has obviously never been even compile-tested:
>
>   arch/x86/kernel/kvm.c: In function ‘__kvm_vcpu_is_preempted’:
>   arch/x86/kernel/kvm.c:596:14: error: ‘struct kvm_steal_time’ has no
> member named ‘preempted’
>
hi, Linus
	oh, my bad also. I introduce this struct member and use it in same patch.
Better to separate tem into two patches. I make one fix patch below. sorry again.

Hi, Paolo
	I have known where is th problem, I think if we can set this ->preempted later after preempted_enable()
or just introduce something like write_guest_nosleep (per cpu memory section in guest, so there is no page_fault or any other cannot sleep problems)?

thanks
xinhui
-----------------
 From d4fa3ea0b8b6f3e5ff511604a4a6665d1cbb74c3 Mon Sep 17 00:00:00 2001
From: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Date: Sat, 17 Dec 2016 02:56:33 -0500
Subject: [PATCH] kvm: fix compile issue

we revert commit 0b9f6c4615c993d2b552e0d2bd1ade49b56e5beb which calls
sleep function while preempt_disable on host part. But we remove struct
kvm_steal_time::preempted too. This casues compile problem as both guest
and host code use it.

Fix it by adding struct kvm_steal_time::preempted back.

Signed-off-by: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
---
  arch/x86/include/uapi/asm/kvm_para.h | 4 +++-
  1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/uapi/asm/kvm_para.h b/arch/x86/include/uapi/asm/kvm_para.h
index 94dc8ca..1421a65 100644
--- a/arch/x86/include/uapi/asm/kvm_para.h
+++ b/arch/x86/include/uapi/asm/kvm_para.h
@@ -45,7 +45,9 @@ struct kvm_steal_time {
  	__u64 steal;
  	__u32 version;
  	__u32 flags;
-	__u32 pad[12];
+	__u8  preempted;
+	__u8  u8_pad[3];
+	__u32 pad[11];
  };
  
  #define KVM_STEAL_ALIGNMENT_BITS 5
-- 
2.4.11

> where commit b94c3698b4b0 ("Revert "x86/kvm: Support the vCPU
> preemption check"") removed the "preempted" field from struct
> kvm_steal_time, but you left this in place:
>
>   __visible bool __kvm_vcpu_is_preempted(int cpu)
>   {
>           struct kvm_steal_time *src = &per_cpu(steal_time, cpu);
>
>           return !!src->preempted;
>   }
>
> And no, that is not a merge artifact in my tree (although that
> function did come in from Ingo). That compile failure comes from your
> very own branch.
>
> Am I upset? You bet I am. Get your act together. You can't just
> randomly revert things without checking the end result.
>
>              Linus
>

Re: [GIT PULL] KVM fixes for 4.10 merge window

[Paolo Bonzini]

> On Fri, Dec 16, 2016 at 8:57 AM, Paolo Bonzini <pbonzini@redhat.com> wrote:
> >
> >   git://git.kernel.org/pub/scm/virt/kvm/kvm.git tags/for-linus
> 
> This piece-of-shit branch has obviously never been even compile-tested:
> 
>   arch/x86/kernel/kvm.c: In function ‘__kvm_vcpu_is_preempted’:
>   arch/x86/kernel/kvm.c:596:14: error: ‘struct kvm_steal_time’ has no
> member named ‘preempted’
> 
> where commit b94c3698b4b0 ("Revert "x86/kvm: Support the vCPU
> preemption check"") removed the "preempted" field from struct
> kvm_steal_time, but you left this in place:
> 
>   __visible bool __kvm_vcpu_is_preempted(int cpu)
>   {
>           struct kvm_steal_time *src = &per_cpu(steal_time, cpu);
> 
>           return !!src->preempted;
>   }
> 
> And no, that is not a merge artifact in my tree (although that
> function did come in from Ingo). That compile failure comes from your
> very own branch.

Yes, it does.  Well, to be honest I did test this (not just compile-test
it) but I didn't have KVM guest support turned on, only KVM host support.

Sorry, I'll resend it and make sure I do a "make allmodconfig" in the
future (and not send pull requests at 6 PM on Friday).

Paolo

Re: [GIT PULL] KVM fixes for 4.10 merge window

[Paolo Bonzini]

----- Original Message -----
> From: "Pan Xinhui" <xinhui@linux.vnet.ibm.com>
> To: "Linus Torvalds" <torvalds@linux-foundation.org>, "Paolo Bonzini" <pbonzini@redhat.com>
> Cc: "Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>, "Radim Krčmář" <rkrcmar@redhat.com>, "KVM list"
> <kvm@vger.kernel.org>
> Sent: Saturday, December 17, 2016 4:09:16 AM
> Subject: Re: [GIT PULL] KVM fixes for 4.10 merge window
> 
> 
> 
> 在 2016/12/17 03:42, Linus Torvalds 写道:
> > On Fri, Dec 16, 2016 at 8:57 AM, Paolo Bonzini <pbonzini@redhat.com> wrote:
> >>
> >>   git://git.kernel.org/pub/scm/virt/kvm/kvm.git tags/for-linus
> >
> > This piece-of-shit branch has obviously never been even compile-tested:
> >
> >   arch/x86/kernel/kvm.c: In function ‘__kvm_vcpu_is_preempted’:
> >   arch/x86/kernel/kvm.c:596:14: error: ‘struct kvm_steal_time’ has no
> > member named ‘preempted’
> >
> hi, Linus
> 	oh, my bad also. I introduce this struct member and use it in same patch.
> Better to separate tem into two patches. I make one fix patch below. sorry
> again.

Hi Xinhui, don't worry it's purely my fault. :)

> 	I have known where is th problem, I think if we can set this ->preempted
> 	later after preempted_enable()
> or just introduce something like write_guest_nosleep (per cpu memory section
> in guest, so there is no page_fault or any other cannot sleep problems)?

Yes there is already kvm_read_guest_inatomic, we can add an equivalent one
for writes.  It will be for 4.11 anyway, so there's time.

Paolo