KVM: x86: Remove runtime Xen TSC frequency CPUID update

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Remove the code in kvm_cpuid() that dynamically updates the Xen TSC
info CPUID leaf at runtime, as KVM is updating the wrong sub-leaf anyway
(0x40000x03/2 EAX is the *host* TSC frequency per the Xen ABI, not the
guest frequency which belongs in 0x40000x03/0 ECX).

Simply drop the code instead of fixing it to fill the correct sub-leaf, as
modifying guest CPUID entries/output at runtime is generally undesirable,
and providing userspace the necessary data to fill the sub-leaf itself is
useful for other reasons, e.g. to fill the generic 0x40000010 timing leaf
and to provide exact scaling information to aid save/restore.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Link: https://patch.msgid.link/20260728144954.355376-23-dwmw2@infradead.org
[sean: tweak changelog to take this patch before the new uAPI]
Signed-off-by: Sean Christopherson <seanjc@google.com>

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David Woodhouse 2026-07-28 15:40:02 +01:00 • committed by Sean Christopherson

parent 36a8520064

commit 7d3bd21e45

2 changed files with 0 additions and 29 deletions

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16

arch/x86/kvm/cpuid.c

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13

arch/x86/kvm/xen.h

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