Il 07/05/2014 15:29, Michael S. Tsirkin ha scritto:
It seems that it's easy to implement the EOI assist on top of the PV EOI feature: simply convert the page address to the format expected by PV EOI.Notes: -"No EOI required" is set only if interrupt injected is edge triggered; this is true because level interrupts are going through IOAPIC which disables PV EOI. In any case, if guest triggers EOI the bit will get cleared on exit. -For migration, set of HV_X64_MSR_APIC_ASSIST_PAGE sets KVM_PV_EOI_EN internally, so restoring HV_X64_MSR_APIC_ASSIST_PAGE seems sufficient In any case, bit is cleared on exit so worst case it's never re-enabled -no handling of PV EOI data is performed at HV_X64_MSR_EOI write; HV_X64_MSR_EOI is a separate optimization - it's an X2APIC replacement that lets you do EOI with an MSR and not IO. Signed-off-by: Michael S. Tsirkin <m...@redhat.com> --- patch is unchanged from RFC except for documenting the design points in the commit log, do address Marcelo's comments. This passed basic testing. Migration was not tested. I think at this point it's a good idea to merge this so it can get tested and used by more people. diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 8ae1ff5..d84d750fc 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1890,6 +1890,8 @@ static int set_msr_hyperv(struct kvm_vcpu *vcpu, u32 msr, u64 data) if (!(data & HV_X64_MSR_APIC_ASSIST_PAGE_ENABLE)) { vcpu->arch.hv_vapic = data; + if (kvm_lapic_enable_pv_eoi(vcpu, 0)) + return 1; break; } gfn = data >> HV_X64_MSR_APIC_ASSIST_PAGE_ADDRESS_SHIFT; @@ -1900,6 +1902,8 @@ static int set_msr_hyperv(struct kvm_vcpu *vcpu, u32 msr, u64 data) return 1; vcpu->arch.hv_vapic = data; mark_page_dirty(vcpu->kvm, gfn); + if (kvm_lapic_enable_pv_eoi(vcpu, gfn_to_gpa(gfn) | KVM_MSR_ENABLED)) + return 1; break; } case HV_X64_MSR_EOI:
Applying to kvm/queue, thanks. Paolo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
