Re: [PATCH 0/3] KVM: x86: Fix Intel PT Host/Guest mode when host tracing also

[Adrian Hunter]

On 6/09/24 16:00, Adrian Hunter wrote:
> Hi
> 
> There is a long-standing problem whereby running Intel PT on host and guest
> in Host/Guest mode, causes VM-Entry failure.
> 
> The motivation for this patch set is to provide a fix for stable kernels
> prior to the advent of the "Mediated Passthrough vPMU" patch set:
> 
> 	https://lore.kernel.org/kvm/20240801045907.4010984-1-mizhang@xxxxxxxxxx/
> 
> which would render a large part of the fix unnecessary but likely not be
> suitable for backport to stable due to its size and complexity.
> 
> Ideally, this patch set would be applied before "Mediated Passthrough vPMU"
> 
> Note that the fix does not conflict with "Mediated Passthrough vPMU", it
> is just that "Mediated Passthrough vPMU" will make the code to stop and
> restart Intel PT unnecessary.

Any comments?

> 
> 
> Adrian Hunter (3):
>       KVM: x86: Fix Intel PT IA32_RTIT_CTL MSR validation
>       KVM: x86: Fix Intel PT Host/Guest mode when host tracing also
>       KVM: selftests: Add guest Intel PT test
> 
>  arch/x86/events/intel/pt.c                         | 131 ++++++-
>  arch/x86/events/intel/pt.h                         |  10 +
>  arch/x86/include/asm/intel_pt.h                    |   4 +
>  arch/x86/kvm/vmx/vmx.c                             |  26 +-
>  arch/x86/kvm/vmx/vmx.h                             |   1 -
>  tools/testing/selftests/kvm/Makefile               |   1 +
>  .../selftests/kvm/include/x86_64/processor.h       |   1 +
>  tools/testing/selftests/kvm/x86_64/intel_pt.c      | 381 +++++++++++++++++++++
>  8 files changed, 532 insertions(+), 23 deletions(-)
>  create mode 100644 tools/testing/selftests/kvm/x86_64/intel_pt.c
> 
> base-commit: d45aab436cf06544abeeffc607110f559a3af3b4
> 
> 
> Regards
> Adrian