This patch series aims to lift long standing restriction of using AVIC only when nested virtualization is not exposed to the guest. Notes about specific patches: Patch 1 addresses the fact that AVIC appears to be disabled in CPUID on several Milan systems I am tesing on. This adds a workaround (with a big warning and a kernel taint) to enable it anyway if you really know what you are doing. It is possible that those systems have the AVIC disabled as a workaround for the AVIC errata #1235 which might be already fixed but OEM might not yet re-enabled it out of caution. Patch 6 adds the AVIC co-existance itself, and was tested with a modification of the ipi_stress unit test which I soon post upstream which made one of vCPUs enter nested guest and receive the IPI while nested guest is running. It was tested on a Zen3 (Milan) machine. On Zen2 machines I have errata #1235 makes my test fail quite fast. Best regards, Maxim Levitsky Maxim Levitsky (6): KVM: SVM: allow to force AVIC to be enabled KVM: x86: add a tracepoint for APICv/AVIC interrupt delivery KVM: SVM: fix AVIC race of host->guest IPI delivery vs AVIC inhibition KVM: SVM: fix races in the AVIC incomplete IPI delivery to vCPUs KVM: x86: never clear irr_pending in kvm_apic_update_apicv KVM: SVM: allow AVIC to co-exist with a nested guest running arch/x86/include/asm/kvm-x86-ops.h | 1 + arch/x86/include/asm/kvm_host.h | 7 +++++- arch/x86/kvm/lapic.c | 6 ++++- arch/x86/kvm/svm/avic.c | 35 +++++++++++++++++++++++----- arch/x86/kvm/svm/nested.c | 13 ++++++----- arch/x86/kvm/svm/svm.c | 37 +++++++++++++++++++----------- arch/x86/kvm/svm/svm.h | 1 + arch/x86/kvm/trace.h | 24 +++++++++++++++++++ arch/x86/kvm/x86.c | 17 ++++++++++++-- 9 files changed, 111 insertions(+), 30 deletions(-) -- 2.26.3
