On Fri, 02 Aug 2024 12:51:15 -0700, Sean Christopherson wrote: > This series was prompted by observations of HLT-exiting when debugging > a throughput issue related to posted interrupts. When KVM is running in > a nested scenario, a rather surprising number of HLT exits occur with an > unmasked interrupt already pending. I didn't debug too deeply into the > guest side of things, but I suspect what is happening is that it's fairly > easy for L2 to be interrupted (by L1 or L0) between checking if it (the > CPU) should enter an idle state and actually executing STI;HLT. > > [...] Applied to kvm-x86 misc, I gave myself enough confidence the fastpath fix is correct with a selftest update[*] (which I'll get applied next week). [*] https://lore.kernel.org/all/20240830044448.130449-1-seanjc@xxxxxxxxxx [1/5] KVM: x86: Re-enter guest if WRMSR(X2APIC_ICR) fastpath is successful https://github.com/kvm-x86/linux/commit/0dd45f2cd8cc [2/5] KVM: x86: Dedup fastpath MSR post-handling logic https://github.com/kvm-x86/linux/commit/ea60229af7fb [3/5] KVM: x86: Exit to userspace if fastpath triggers one on instruction skip https://github.com/kvm-x86/linux/commit/f7f39c50edb9 [4/5] KVM: x86: Reorganize code in x86.c to co-locate vCPU blocking/running helpers https://github.com/kvm-x86/linux/commit/70cdd2385106 [5/5] KVM: x86: Add fastpath handling of HLT VM-Exits https://github.com/kvm-x86/linux/commit/1876dd69dfe8 -- https://github.com/kvm-x86/linux/tree/next
