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[0/2] KVM: x86: Convey the exit reason to user-space on emulation failure

Message ID 20210628173152.2062988-1-david.edmondson@oracle.com (mailing list archive)
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Series KVM: x86: Convey the exit reason to user-space on emulation failure | expand

Message

David Edmondson June 28, 2021, 5:31 p.m. UTC 
To aid in debugging failures in the field, when instruction emulation
fails, report the VM exit reason to userspace in order that it can be
recorded.

The changes are on top of Aaron's patches from
https://lore.kernel.org/r/20210510144834.658457-1-aaronlewis@google.com
which are in the KVM queue, but not yet upstream.

David Edmondson (2):
  KVM: x86: Add kvm_x86_ops.get_exit_reason
  KVM: x86: On emulation failure, convey the exit reason to userspace

 arch/x86/include/asm/kvm-x86-ops.h |  1 +
 arch/x86/include/asm/kvm_host.h    |  1 +
 arch/x86/kvm/svm/svm.c             |  6 ++++++
 arch/x86/kvm/vmx/vmx.c             |  6 ++++++
 arch/x86/kvm/x86.c                 | 23 +++++++++++++++++------
 include/uapi/linux/kvm.h           |  2 ++
 6 files changed, 33 insertions(+), 6 deletions(-)

Comments

David Matlack June 30, 2021, 4:33 p.m. UTC | #1 
On Mon, Jun 28, 2021 at 06:31:50PM +0100, David Edmondson wrote:
> To aid in debugging failures in the field, when instruction emulation

What do you mean by a "debugging failure"?

> fails, report the VM exit reason to userspace in order that it can be
> recorded.

What is the benefit of seeing the VM-exit reason that led to an
emulation failure?

> 
> The changes are on top of Aaron's patches from
> https://lore.kernel.org/r/20210510144834.658457-1-aaronlewis@google.com
> which are in the KVM queue, but not yet upstream.
> 
> David Edmondson (2):
>   KVM: x86: Add kvm_x86_ops.get_exit_reason
>   KVM: x86: On emulation failure, convey the exit reason to userspace
> 
>  arch/x86/include/asm/kvm-x86-ops.h |  1 +
>  arch/x86/include/asm/kvm_host.h    |  1 +
>  arch/x86/kvm/svm/svm.c             |  6 ++++++
>  arch/x86/kvm/vmx/vmx.c             |  6 ++++++
>  arch/x86/kvm/x86.c                 | 23 +++++++++++++++++------
>  include/uapi/linux/kvm.h           |  2 ++
>  6 files changed, 33 insertions(+), 6 deletions(-)
> 
> -- 
> 2.30.2
>
David Matlack June 30, 2021, 5:08 p.m. UTC | #2 
On Wed, Jun 30, 2021 at 9:33 AM David Matlack <dmatlack@google.com> wrote:
>
> On Mon, Jun 28, 2021 at 06:31:50PM +0100, David Edmondson wrote:
> > To aid in debugging failures in the field, when instruction emulation
>
> What do you mean by a "debugging failure"?

Oh! Sorry I misread this as "*debugging failures*" rather than
"debugging *failures*". I know what you mean here :-).

>
> > fails, report the VM exit reason to userspace in order that it can be
> > recorded.
>
> What is the benefit of seeing the VM-exit reason that led to an
> emulation failure?
>
> >
> > The changes are on top of Aaron's patches from
> > https://lore.kernel.org/r/20210510144834.658457-1-aaronlewis@google.com
> > which are in the KVM queue, but not yet upstream.
> >
> > David Edmondson (2):
> >   KVM: x86: Add kvm_x86_ops.get_exit_reason
> >   KVM: x86: On emulation failure, convey the exit reason to userspace
> >
> >  arch/x86/include/asm/kvm-x86-ops.h |  1 +
> >  arch/x86/include/asm/kvm_host.h    |  1 +
> >  arch/x86/kvm/svm/svm.c             |  6 ++++++
> >  arch/x86/kvm/vmx/vmx.c             |  6 ++++++
> >  arch/x86/kvm/x86.c                 | 23 +++++++++++++++++------
> >  include/uapi/linux/kvm.h           |  2 ++
> >  6 files changed, 33 insertions(+), 6 deletions(-)
> >
> > --
> > 2.30.2
> >