KVM: x86: Update Xen TSC leaves during CPUID emulation

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The Xen emulation in KVM modifies certain CPUID leaves to expose
TSC information to the guest.

Previously, these CPUID leaves were updated whenever guest time changed,
but this conflicts with KVM_SET_CPUID/KVM_SET_CPUID2 ioctls which reject
changes to CPUID entries on running vCPUs.

Fix this by updating the TSC information directly in the CPUID emulation
handler instead of modifying the vCPU's CPUID entries.

Signed-off-by: Fred Griffoul <fgriffo@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
Reviewed-by: David Woodhouse <dwmw@amazon.co.uk>
Link: https://lore.kernel.org/r/20250124150539.69975-1-fgriffo@amazon.co.uk
Signed-off-by: Sean Christopherson <seanjc@google.com>

...

This commit is contained in:

Fred Griffoul 2025-01-24 15:05:39 +00:00 • committed by Sean Christopherson

parent 26e228ec16

commit a2b00f85d7

5 changed files with 29 additions and 27 deletions

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16

arch/x86/kvm/cpuid.c

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3

arch/x86/kvm/x86.c

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1

arch/x86/kvm/x86.h

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23

arch/x86/kvm/xen.c

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arch/x86/kvm/xen.h

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