From e40ff1d6608dd9a5e07d7bc3079c64d9d676fe15 Mon Sep 17 00:00:00 2001 From: Liran Alon Date: Wed, 21 Mar 2018 02:50:31 +0200 Subject: KVM: nVMX: Do not load EOI-exitmap while running L2 When L1 IOAPIC redirection-table is written, a request of KVM_REQ_SCAN_IOAPIC is set on all vCPUs. This is done such that all vCPUs will now recalc their IOAPIC handled vectors and load it to their EOI-exitmap. However, it could be that one of the vCPUs is currently running L2. In this case, load_eoi_exitmap() will be called which would write to vmcs02->eoi_exit_bitmap, which is wrong because vmcs02->eoi_exit_bitmap should always be equal to vmcs12->eoi_exit_bitmap. Furthermore, at this point KVM_REQ_SCAN_IOAPIC was already consumed and therefore we will never update vmcs01->eoi_exit_bitmap. This could lead to remote_irr of some IOAPIC level-triggered entry to remain set forever. Fix this issue by delaying the load of EOI-exitmap to when vCPU is running L1. One may wonder why not just delay entire KVM_REQ_SCAN_IOAPIC processing to when vCPU is running L1. This is done in order to handle correctly the case where LAPIC & IO-APIC of L1 is pass-throughed into L2. In this case, vmcs12->virtual_interrupt_delivery should be 0. In current nVMX implementation, that results in vmcs02->virtual_interrupt_delivery to also be 0. Thus, vmcs02->eoi_exit_bitmap is not used. Therefore, every L2 EOI cause a #VMExit into L0 (either on MSR_WRITE to x2APIC MSR or APIC_ACCESS/APIC_WRITE/EPT_MISCONFIG to APIC MMIO page). In order for such L2 EOI to be broadcasted, if needed, from LAPIC to IO-APIC, vcpu->arch.ioapic_handled_vectors must be updated while L2 is running. Therefore, patch makes sure to delay only the loading of EOI-exitmap but not the update of vcpu->arch.ioapic_handled_vectors. Reviewed-by: Arbel Moshe Reviewed-by: Krish Sadhukhan Signed-off-by: Liran Alon Signed-off-by: Paolo Bonzini --- arch/x86/include/asm/kvm_host.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'arch/x86/include/asm/kvm_host.h') diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 8fb60287d987..c72891dd7d78 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -73,6 +73,7 @@ #define KVM_REQ_HV_RESET KVM_ARCH_REQ(20) #define KVM_REQ_HV_EXIT KVM_ARCH_REQ(21) #define KVM_REQ_HV_STIMER KVM_ARCH_REQ(22) +#define KVM_REQ_LOAD_EOI_EXITMAP KVM_ARCH_REQ(23) #define CR0_RESERVED_BITS \ (~(unsigned long)(X86_CR0_PE | X86_CR0_MP | X86_CR0_EM | X86_CR0_TS \ @@ -498,6 +499,7 @@ struct kvm_vcpu_arch { u64 apic_base; struct kvm_lapic *apic; /* kernel irqchip context */ bool apicv_active; + bool load_eoi_exitmap_pending; DECLARE_BITMAP(ioapic_handled_vectors, 256); unsigned long apic_attention; int32_t apic_arb_prio; -- cgit v1.2.3