From: Xin Li <xin3.li@xxxxxxxxx> Set VMX nested exception bit in the VM-entry interruption information VMCS field when injecting a nested exception using FRED event delivery to ensure: 1) The nested exception is injected on a correct stack level. 2) The nested bit defined in FRED stack frame is set. The event stack level used by FRED event delivery depends on whether the event was a nested exception encountered during delivery of another event, because a nested exception is "regarded" as happening on ring 0. E.g., when #PF is configured to use stack level 1 in IA32_FRED_STKLVLS MSR: - nested #PF will be delivered on stack level 1 when encountered in ring 3. - normal #PF will be delivered on stack level 0 when encountered in ring 3. The VMX nested-exception support ensures the correct event stack level is chosen when a VM entry injects a nested exception. Signed-off-by: Xin Li <xin3.li@xxxxxxxxx> [ Sean: reworked kvm_requeue_exception() to simply the code changes ] Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx> Signed-off-by: Xin Li (Intel) <xin@xxxxxxxxx> Tested-by: Shan Kang <shan.kang@xxxxxxxxx> --- Change since v2: * Rework kvm_requeue_exception() to simply the code changes (Sean Christopherson). Change since v1: * Set the nested flag when there is an original interrupt (Chao Gao). --- arch/x86/include/asm/kvm_host.h | 4 +++- arch/x86/include/asm/vmx.h | 5 ++++- arch/x86/kvm/svm/svm.c | 2 +- arch/x86/kvm/vmx/vmx.c | 6 +++++- arch/x86/kvm/x86.c | 14 +++++++++++++- arch/x86/kvm/x86.h | 1 + 6 files changed, 27 insertions(+), 5 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index b9b82aaea9a3..3830084b569b 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -736,6 +736,7 @@ struct kvm_queued_exception { u32 error_code; unsigned long payload; bool has_payload; + bool nested; u64 event_data; }; @@ -2114,7 +2115,8 @@ void kvm_queue_exception(struct kvm_vcpu *vcpu, unsigned nr); void kvm_queue_exception_e(struct kvm_vcpu *vcpu, unsigned nr, u32 error_code); void kvm_queue_exception_p(struct kvm_vcpu *vcpu, unsigned nr, unsigned long payload); void kvm_requeue_exception(struct kvm_vcpu *vcpu, unsigned int nr, - bool has_error_code, u32 error_code, u64 event_data); + bool has_error_code, u32 error_code, bool nested, + u64 event_data); void kvm_inject_page_fault(struct kvm_vcpu *vcpu, struct x86_exception *fault); void kvm_inject_emulated_page_fault(struct kvm_vcpu *vcpu, struct x86_exception *fault); diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h index 3696e763c231..06c52fee5dcd 100644 --- a/arch/x86/include/asm/vmx.h +++ b/arch/x86/include/asm/vmx.h @@ -137,6 +137,7 @@ #define VMX_BASIC_DUAL_MONITOR_TREATMENT BIT_ULL(49) #define VMX_BASIC_INOUT BIT_ULL(54) #define VMX_BASIC_TRUE_CTLS BIT_ULL(55) +#define VMX_BASIC_NESTED_EXCEPTION BIT_ULL(58) static inline u32 vmx_basic_vmcs_revision_id(u64 vmx_basic) { @@ -416,13 +417,15 @@ enum vmcs_field { #define INTR_INFO_INTR_TYPE_MASK 0x700 /* 10:8 */ #define INTR_INFO_DELIVER_CODE_MASK 0x800 /* 11 */ #define INTR_INFO_UNBLOCK_NMI 0x1000 /* 12 */ +#define INTR_INFO_NESTED_EXCEPTION_MASK 0x2000 /* 13 */ #define INTR_INFO_VALID_MASK 0x80000000 /* 31 */ -#define INTR_INFO_RESVD_BITS_MASK 0x7ffff000 +#define INTR_INFO_RESVD_BITS_MASK 0x7fffd000 #define VECTORING_INFO_VECTOR_MASK INTR_INFO_VECTOR_MASK #define VECTORING_INFO_TYPE_MASK INTR_INFO_INTR_TYPE_MASK #define VECTORING_INFO_DELIVER_CODE_MASK INTR_INFO_DELIVER_CODE_MASK #define VECTORING_INFO_VALID_MASK INTR_INFO_VALID_MASK +#define VECTORING_INFO_NESTED_EXCEPTION_MASK INTR_INFO_NESTED_EXCEPTION_MASK #define INTR_TYPE_EXT_INTR (EVENT_TYPE_EXTINT << 8) /* external interrupt */ #define INTR_TYPE_RESERVED (EVENT_TYPE_RESERVED << 8) /* reserved */ diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 7fa8f842f116..e479e0208efe 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -4126,7 +4126,7 @@ static void svm_complete_interrupts(struct kvm_vcpu *vcpu) kvm_requeue_exception(vcpu, vector, exitintinfo & SVM_EXITINTINFO_VALID_ERR, - error_code, 0); + error_code, false, 0); break; } case SVM_EXITINTINFO_TYPE_INTR: diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index d81144bd648f..03f42b218554 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -1910,8 +1910,11 @@ void vmx_inject_exception(struct kvm_vcpu *vcpu) vmcs_write32(VM_ENTRY_INSTRUCTION_LEN, vmx->vcpu.arch.event_exit_inst_len); intr_info |= INTR_TYPE_SOFT_EXCEPTION; - } else + } else { intr_info |= INTR_TYPE_HARD_EXCEPTION; + if (ex->nested) + intr_info |= INTR_INFO_NESTED_EXCEPTION_MASK; + } vmcs_write32(VM_ENTRY_INTR_INFO_FIELD, intr_info); @@ -7290,6 +7293,7 @@ static void __vmx_complete_interrupts(struct kvm_vcpu *vcpu, kvm_requeue_exception(vcpu, vector, idt_vectoring_info & VECTORING_INFO_DELIVER_CODE_MASK, error_code, + idt_vectoring_info & VECTORING_INFO_NESTED_EXCEPTION_MASK, event_data); break; } diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 7a55c1eb5297..8546629166e9 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -874,6 +874,11 @@ static void kvm_multiple_exception(struct kvm_vcpu *vcpu, unsigned int nr, vcpu->arch.exception.pending = true; vcpu->arch.exception.injected = false; + vcpu->arch.exception.nested = vcpu->arch.exception.nested || + (is_fred_enabled(vcpu) && + (vcpu->arch.nmi_injected || + vcpu->arch.interrupt.injected)); + vcpu->arch.exception.has_error_code = has_error; vcpu->arch.exception.vector = nr; vcpu->arch.exception.error_code = error_code; @@ -903,8 +908,13 @@ static void kvm_multiple_exception(struct kvm_vcpu *vcpu, unsigned int nr, vcpu->arch.exception.injected = false; vcpu->arch.exception.pending = false; + /* #DF is NOT a nested event, per its definition. */ + vcpu->arch.exception.nested = false; + kvm_queue_exception_e(vcpu, DF_VECTOR, 0); } else { + vcpu->arch.exception.nested = is_fred_enabled(vcpu); + /* replace previous exception with a new one in a hope that instruction re-execution will regenerate lost exception */ @@ -933,7 +943,8 @@ static void kvm_queue_exception_e_p(struct kvm_vcpu *vcpu, unsigned nr, } void kvm_requeue_exception(struct kvm_vcpu *vcpu, unsigned int nr, - bool has_error_code, u32 error_code, u64 event_data) + bool has_error_code, u32 error_code, bool nested, + u64 event_data) { /* @@ -958,6 +969,7 @@ void kvm_requeue_exception(struct kvm_vcpu *vcpu, unsigned int nr, vcpu->arch.exception.error_code = error_code; vcpu->arch.exception.has_payload = false; vcpu->arch.exception.payload = 0; + vcpu->arch.exception.nested = nested; vcpu->arch.exception.event_data = event_data; } EXPORT_SYMBOL_GPL(kvm_requeue_exception); diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h index 578fea05ff18..992e73ee2ec5 100644 --- a/arch/x86/kvm/x86.h +++ b/arch/x86/kvm/x86.h @@ -134,6 +134,7 @@ static inline void kvm_clear_exception_queue(struct kvm_vcpu *vcpu) { vcpu->arch.exception.pending = false; vcpu->arch.exception.injected = false; + vcpu->arch.exception.nested = false; vcpu->arch.exception_vmexit.pending = false; } -- 2.46.2