From 9a0bf05430699dc94b7ced940f6270c7cf1d77ef Mon Sep 17 00:00:00 2001 From: Suravee Suthikulpanit Date: Thu, 14 Nov 2019 14:15:14 -0600 Subject: svm: Deactivate AVIC when launching guest with nested SVM support Since AVIC does not currently work w/ nested virtualization, deactivate AVIC for the guest if setting CPUID Fn80000001_ECX[SVM] (i.e. indicate support for SVM, which is needed for nested virtualization). Also, introduce a new APICV_INHIBIT_REASON_NESTED bit to be used for this reason. Suggested-by: Alexander Graf Signed-off-by: Suravee Suthikulpanit Signed-off-by: Paolo Bonzini --- arch/x86/include/asm/kvm_host.h | 1 + arch/x86/kvm/svm.c | 11 ++++++++++- 2 files changed, 11 insertions(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 90bfe8becc56..ce19dea5f2dd 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -877,6 +877,7 @@ enum kvm_irqchip_mode { #define APICV_INHIBIT_REASON_DISABLE 0 #define APICV_INHIBIT_REASON_HYPERV 1 +#define APICV_INHIBIT_REASON_NESTED 2 struct kvm_arch { unsigned long n_used_mmu_pages; diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 3b87ccd320d1..af90f83d7123 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -5988,6 +5988,14 @@ static void svm_cpuid_update(struct kvm_vcpu *vcpu) return; guest_cpuid_clear(vcpu, X86_FEATURE_X2APIC); + + /* + * Currently, AVIC does not work with nested virtualization. + * So, we disable AVIC when cpuid for SVM is set in the L1 guest. + */ + if (nested && guest_cpuid_has(vcpu, X86_FEATURE_SVM)) + kvm_request_apicv_update(vcpu->kvm, false, + APICV_INHIBIT_REASON_NESTED); } #define F feature_bit @@ -7319,7 +7327,8 @@ static bool svm_apic_init_signal_blocked(struct kvm_vcpu *vcpu) static bool svm_check_apicv_inhibit_reasons(ulong bit) { ulong supported = BIT(APICV_INHIBIT_REASON_DISABLE) | - BIT(APICV_INHIBIT_REASON_HYPERV); + BIT(APICV_INHIBIT_REASON_HYPERV) | + BIT(APICV_INHIBIT_REASON_NESTED); return supported & BIT(bit); } -- cgit v1.2.3