On Fri, 19 Jul 2024 16:50:57 -0700, Sean Christopherson wrote:
> I made the mistake of expanding my testing to run with and without AVIC
> enabled, and to my surprise (wow, sarcasm), x2AVIC failed hard on the
> xapic_state_test due to ICR issues.
>
> AFAICT, the issue is that AMD splits the 64-bit ICR into the legacy ICR
> and ICR2 fields when storing the ICR in the vAPIC (apparently "it's a
> single 64-bit register" is open to intepretation). Aside from causing
> the selftest failure and potential live migration issues, botching the
> format is quite bad, as KVM will mishandle incomplete virtualized IPIs,
> e.g. generate IRQs to the wrong vCPU, drop IRQs, etc.
>
> [...]
Applied to kvm-x86 misc, thanks!
[01/10] KVM: x86: Enforce x2APIC's must-be-zero reserved ICR bits
https://github.com/kvm-x86/linux/commit/71bf395a276f
[02/10] KVM: x86: Move x2APIC ICR helper above kvm_apic_write_nodecode()
https://github.com/kvm-x86/linux/commit/d33234342f8b
[03/10] KVM: x86: Re-split x2APIC ICR into ICR+ICR2 for AMD (x2AVIC)
https://github.com/kvm-x86/linux/commit/73b42dc69be8
[04/10] KVM: selftests: Open code vcpu_run() equivalent in guest_printf test
https://github.com/kvm-x86/linux/commit/d1c2cdca5a08
[05/10] KVM: selftests: Report unhandled exceptions on x86 as regular guest asserts
https://github.com/kvm-x86/linux/commit/ed24ba6c2c34
[06/10] KVM: selftests: Add x86 helpers to play nice with x2APIC MSR #GPs
https://github.com/kvm-x86/linux/commit/f2e91e874179
[07/10] KVM: selftests: Skip ICR.BUSY test in xapic_state_test if x2APIC is enabled
https://github.com/kvm-x86/linux/commit/faf06a238254
[08/10] KVM: selftests: Test x2APIC ICR reserved bits
https://github.com/kvm-x86/linux/commit/3426cb48adb4
[09/10] KVM: selftests: Verify the guest can read back the x2APIC ICR it wrote
https://github.com/kvm-x86/linux/commit/0cb26ec32085
[10/10] KVM: selftests: Play nice with AMD's AVIC errata
https://github.com/kvm-x86/linux/commit/5a7c7d148e48
--
https://github.com/kvm-x86/linux/tree/next
