Re: [PATCH v2] KVM: TDX: Fix x2APIC MSR handling in tdx_has_emulated_msr()

[Sean Christopherson]

On Fri, 10 Apr 2026 16:26:54 -0700, Rick Edgecombe wrote:
> Rework tdx_has_emulated_msr() to explicitly enumerate the x2APIC MSRs
> that KVM can emulate, instead of trying to enumerate the MSRs that KVM
> cannot emulate. Drop the inner switch and list the emulatable x2APIC
> registers directly in the outer switch's "return true" block.
> 
> The old code had multiple bugs in the x2APIC range handling.
> X2APIC_MSR(APIC_ISR + APIC_ISR_NR) was incorrect because APIC_ISR_NR is
> 0x8, not 0x80, so the X2APIC_MSR() shift lost the lower bits, collapsing
> each range to a single MSR. IA32_X2APIC_SELF_IPI was also missing from
> the non-emulatable list.
> 
> [...]

Applied to kvm-x86 vmx, with a massaged comment as suggested by Binbin.  Thanks!

[1/1] KVM: TDX: Fix x2APIC MSR handling in tdx_has_emulated_msr()
      https://github.com/kvm-x86/linux/commit/1f3e69af5f93

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https://github.com/kvm-x86/linux/tree/next