diff options
author | Sean Christopherson <seanjc@google.com> | 2022-12-13 06:09:12 +0000 |
---|---|---|
committer | Sean Christopherson <seanjc@google.com> | 2023-01-24 10:36:41 -0800 |
commit | 11df586d774f4aab1835144fd2a8dc3cb2add8d4 (patch) | |
tree | 17e072c09eaeff43a5423d88f6e1cd2ba54bcb67 /arch/x86 | |
parent | 4f76e86f7e0dc33af14256d30177bf65de2f9cab (diff) | |
download | linux-11df586d774f4aab1835144fd2a8dc3cb2add8d4.tar.gz linux-11df586d774f4aab1835144fd2a8dc3cb2add8d4.tar.bz2 linux-11df586d774f4aab1835144fd2a8dc3cb2add8d4.zip |
KVM: VMX: Handle NMI VM-Exits in noinstr region
Move VMX's handling of NMI VM-Exits into vmx_vcpu_enter_exit() so that
the NMI is handled prior to leaving the safety of noinstr. Handling the
NMI after leaving noinstr exposes the kernel to potential ordering
problems as an instrumentation-induced fault, e.g. #DB, #BP, #PF, etc.
will unblock NMIs when IRETing back to the faulting instruction.
Reported-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20221213060912.654668-8-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'arch/x86')
-rw-r--r-- | arch/x86/kvm/vmx/vmcs.h | 4 | ||||
-rw-r--r-- | arch/x86/kvm/vmx/vmenter.S | 8 | ||||
-rw-r--r-- | arch/x86/kvm/vmx/vmx.c | 34 | ||||
-rw-r--r-- | arch/x86/kvm/x86.h | 6 |
4 files changed, 30 insertions, 22 deletions
diff --git a/arch/x86/kvm/vmx/vmcs.h b/arch/x86/kvm/vmx/vmcs.h index ac290a44a693..7c1996b433e2 100644 --- a/arch/x86/kvm/vmx/vmcs.h +++ b/arch/x86/kvm/vmx/vmcs.h @@ -75,7 +75,7 @@ struct loaded_vmcs { struct vmcs_controls_shadow controls_shadow; }; -static inline bool is_intr_type(u32 intr_info, u32 type) +static __always_inline bool is_intr_type(u32 intr_info, u32 type) { const u32 mask = INTR_INFO_VALID_MASK | INTR_INFO_INTR_TYPE_MASK; @@ -146,7 +146,7 @@ static inline bool is_icebp(u32 intr_info) return is_intr_type(intr_info, INTR_TYPE_PRIV_SW_EXCEPTION); } -static inline bool is_nmi(u32 intr_info) +static __always_inline bool is_nmi(u32 intr_info) { return is_intr_type(intr_info, INTR_TYPE_NMI_INTR); } diff --git a/arch/x86/kvm/vmx/vmenter.S b/arch/x86/kvm/vmx/vmenter.S index f0519f0f738c..f550540ed54e 100644 --- a/arch/x86/kvm/vmx/vmenter.S +++ b/arch/x86/kvm/vmx/vmenter.S @@ -299,6 +299,10 @@ SYM_INNER_LABEL(vmx_vmexit, SYM_L_GLOBAL) SYM_FUNC_END(__vmx_vcpu_run) +SYM_FUNC_START(vmx_do_nmi_irqoff) + VMX_DO_EVENT_IRQOFF call asm_exc_nmi_kvm_vmx +SYM_FUNC_END(vmx_do_nmi_irqoff) + .section .text, "ax" @@ -353,10 +357,6 @@ SYM_FUNC_START(vmread_error_trampoline) SYM_FUNC_END(vmread_error_trampoline) #endif -SYM_FUNC_START(vmx_do_nmi_irqoff) - VMX_DO_EVENT_IRQOFF call asm_exc_nmi_kvm_vmx -SYM_FUNC_END(vmx_do_nmi_irqoff) - SYM_FUNC_START(vmx_do_interrupt_irqoff) VMX_DO_EVENT_IRQOFF CALL_NOSPEC _ASM_ARG1 SYM_FUNC_END(vmx_do_interrupt_irqoff) diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 1d9e3fd6584e..664994e3e909 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -5170,8 +5170,13 @@ static int handle_exception_nmi(struct kvm_vcpu *vcpu) vect_info = vmx->idt_vectoring_info; intr_info = vmx_get_intr_info(vcpu); + /* + * Machine checks are handled by handle_exception_irqoff(), or by + * vmx_vcpu_run() if a #MC occurs on VM-Entry. NMIs are handled by + * vmx_vcpu_enter_exit(). + */ if (is_machine_check(intr_info) || is_nmi(intr_info)) - return 1; /* handled by handle_exception_nmi_irqoff() */ + return 1; /* * Queue the exception here instead of in handle_nm_fault_irqoff(). @@ -6884,7 +6889,7 @@ static void handle_nm_fault_irqoff(struct kvm_vcpu *vcpu) rdmsrl(MSR_IA32_XFD_ERR, vcpu->arch.guest_fpu.xfd_err); } -static void handle_exception_nmi_irqoff(struct vcpu_vmx *vmx) +static void handle_exception_irqoff(struct vcpu_vmx *vmx) { u32 intr_info = vmx_get_intr_info(&vmx->vcpu); @@ -6897,12 +6902,6 @@ static void handle_exception_nmi_irqoff(struct vcpu_vmx *vmx) /* Handle machine checks before interrupts are enabled */ else if (is_machine_check(intr_info)) kvm_machine_check(); - /* We need to handle NMIs before interrupts are enabled */ - else if (is_nmi(intr_info)) { - kvm_before_interrupt(&vmx->vcpu, KVM_HANDLING_NMI); - vmx_do_nmi_irqoff(); - kvm_after_interrupt(&vmx->vcpu); - } } static void handle_external_interrupt_irqoff(struct kvm_vcpu *vcpu) @@ -6932,7 +6931,7 @@ static void vmx_handle_exit_irqoff(struct kvm_vcpu *vcpu) if (vmx->exit_reason.basic == EXIT_REASON_EXTERNAL_INTERRUPT) handle_external_interrupt_irqoff(vcpu); else if (vmx->exit_reason.basic == EXIT_REASON_EXCEPTION_NMI) - handle_exception_nmi_irqoff(vmx); + handle_exception_irqoff(vmx); } /* @@ -7194,6 +7193,18 @@ static noinstr void vmx_vcpu_enter_exit(struct kvm_vcpu *vcpu, vmx_enable_fb_clear(vmx); + if (unlikely(vmx->fail)) + vmx->exit_reason.full = 0xdead; + else + vmx->exit_reason.full = vmcs_read32(VM_EXIT_REASON); + + if ((u16)vmx->exit_reason.basic == EXIT_REASON_EXCEPTION_NMI && + is_nmi(vmx_get_intr_info(vcpu))) { + kvm_before_interrupt(vcpu, KVM_HANDLING_NMI); + vmx_do_nmi_irqoff(); + kvm_after_interrupt(vcpu); + } + guest_state_exit_irqoff(); } @@ -7335,12 +7346,9 @@ static fastpath_t vmx_vcpu_run(struct kvm_vcpu *vcpu) vmx->idt_vectoring_info = 0; - if (unlikely(vmx->fail)) { - vmx->exit_reason.full = 0xdead; + if (unlikely(vmx->fail)) return EXIT_FASTPATH_NONE; - } - vmx->exit_reason.full = vmcs_read32(VM_EXIT_REASON); if (unlikely((u16)vmx->exit_reason.basic == EXIT_REASON_MCE_DURING_VMENTRY)) kvm_machine_check(); diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h index 9de72586f406..44d1827f0a30 100644 --- a/arch/x86/kvm/x86.h +++ b/arch/x86/kvm/x86.h @@ -382,13 +382,13 @@ enum kvm_intr_type { KVM_HANDLING_NMI, }; -static inline void kvm_before_interrupt(struct kvm_vcpu *vcpu, - enum kvm_intr_type intr) +static __always_inline void kvm_before_interrupt(struct kvm_vcpu *vcpu, + enum kvm_intr_type intr) { WRITE_ONCE(vcpu->arch.handling_intr_from_guest, (u8)intr); } -static inline void kvm_after_interrupt(struct kvm_vcpu *vcpu) +static __always_inline void kvm_after_interrupt(struct kvm_vcpu *vcpu) { WRITE_ONCE(vcpu->arch.handling_intr_from_guest, 0); } |