KVM: VMX: Handle NMIs, #MCs and async #PFs in common irqs-disabled fn

Per commit 1b6269db3f833 ("KVM: VMX: Handle NMIs before enabling
interrupts and preemption"), NMIs are handled directly in vmx_vcpu_run()
to "make sure we handle NMI on the current cpu, and that we don't
service maskable interrupts before non-maskable ones".  The other
exceptions handled by complete_atomic_exit(), e.g. async #PF and #MC,
have similar requirements, and are located there to avoid extra VMREADs
since VMX bins hardware exceptions and NMIs into a single exit reason.

Clean up the code and eliminate the vaguely named complete_atomic_exit()
by moving the interrupts-disabled exception and NMI handling into the
existing handle_external_intrs() callback, and rename the callback to
a more appropriate name.  Rename VMexit handlers throughout so that the
atomic and non-atomic counterparts have similar names.

In addition to improving code readability, this also ensures the NMI
handler is run with the host's debug registers loaded in the unlikely
event that the user is debugging NMIs.  Accuracy of the last_guest_tsc
field is also improved when handling NMIs (and #MCs) as the handler
will run after updating said field.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
[Naming cleanups. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 35e7937cc9acd74d1038af490956d6be10221b83..f46a12a5cf2e0156f958b594ff0e84c730fb89b6 100644 (file)
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1117,7 +1117,7 @@ struct kvm_x86_ops {
        int (*check_intercept)(struct kvm_vcpu *vcpu,
                               struct x86_instruction_info *info,
                               enum x86_intercept_stage stage);
-       void (*handle_external_intr)(struct kvm_vcpu *vcpu);
+       void (*handle_exit_irqoff)(struct kvm_vcpu *vcpu);
        bool (*mpx_supported)(void);
        bool (*xsaves_supported)(void);
        bool (*umip_emulated)(void);

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index acc09e9fc173a220e45875d40d7f24906c909de0..bbc31f7213ed81b2ffcb21c8f8d184a5559b1ee2 100644 (file)
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -6172,7 +6172,7 @@ out:
        return ret;
 }
 
-static void svm_handle_external_intr(struct kvm_vcpu *vcpu)
+static void svm_handle_exit_irqoff(struct kvm_vcpu *vcpu)
 {
        kvm_before_interrupt(vcpu);
        local_irq_enable();
@@ -7268,7 +7268,7 @@ static struct kvm_x86_ops svm_x86_ops __ro_after_init = {
        .set_tdp_cr3 = set_tdp_cr3,
 
        .check_intercept = svm_check_intercept,
-       .handle_external_intr = svm_handle_external_intr,
+       .handle_exit_irqoff = svm_handle_exit_irqoff,
 
        .request_immediate_exit = __kvm_request_immediate_exit,
 

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 963c8c409223a95924f245c950835c9a92cf5545..2b182f58c1263c790582f87e57565c495e760d04 100644 (file)
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -4437,11 +4437,11 @@ static void kvm_machine_check(void)
 
 static int handle_machine_check(struct kvm_vcpu *vcpu)
 {
-       /* already handled by vcpu_run */
+       /* handled by vmx_vcpu_run() */
        return 1;
 }
 
-static int handle_exception(struct kvm_vcpu *vcpu)
+static int handle_exception_nmi(struct kvm_vcpu *vcpu)
 {
        struct vcpu_vmx *vmx = to_vmx(vcpu);
        struct kvm_run *kvm_run = vcpu->run;
@@ -4454,7 +4454,7 @@ static int handle_exception(struct kvm_vcpu *vcpu)
        intr_info = vmx->exit_intr_info;
 
        if (is_machine_check(intr_info) || is_nmi(intr_info))
-               return 1;  /* already handled by vmx_complete_atomic_exit */
+               return 1; /* handled by handle_exception_nmi_irqoff() */
 
        if (is_invalid_opcode(intr_info))
                return handle_ud(vcpu);
@@ -5462,7 +5462,7 @@ static int handle_encls(struct kvm_vcpu *vcpu)
  * to be done to userspace and return 0.
  */
 static int (*kvm_vmx_exit_handlers[])(struct kvm_vcpu *vcpu) = {
-       [EXIT_REASON_EXCEPTION_NMI]           = handle_exception,
+       [EXIT_REASON_EXCEPTION_NMI]           = handle_exception_nmi,
        [EXIT_REASON_EXTERNAL_INTERRUPT]      = handle_external_interrupt,
        [EXIT_REASON_TRIPLE_FAULT]            = handle_triple_fault,
        [EXIT_REASON_NMI_WINDOW]              = handle_nmi_window,
@@ -6100,11 +6100,8 @@ static void vmx_apicv_post_state_restore(struct kvm_vcpu *vcpu)
        memset(vmx->pi_desc.pir, 0, sizeof(vmx->pi_desc.pir));
 }
 
-static void vmx_complete_atomic_exit(struct vcpu_vmx *vmx)
+static void handle_exception_nmi_irqoff(struct vcpu_vmx *vmx)
 {
-       if (vmx->exit_reason != EXIT_REASON_EXCEPTION_NMI)
-               return;
-
        vmx->exit_intr_info = vmcs_read32(VM_EXIT_INTR_INFO);
 
        /* if exit due to PF check for async PF */
@@ -6123,7 +6120,7 @@ static void vmx_complete_atomic_exit(struct vcpu_vmx *vmx)
        }
 }
 
-static void vmx_handle_external_intr(struct kvm_vcpu *vcpu)
+static void handle_external_interrupt_irqoff(struct kvm_vcpu *vcpu)
 {
        unsigned int vector;
        unsigned long entry;
@@ -6133,9 +6130,6 @@ static void vmx_handle_external_intr(struct kvm_vcpu *vcpu)
        gate_desc *desc;
        u32 intr_info;
 
-       if (to_vmx(vcpu)->exit_reason != EXIT_REASON_EXTERNAL_INTERRUPT)
-               return;
-
        intr_info = vmcs_read32(VM_EXIT_INTR_INFO);
        if (WARN_ONCE(!is_external_intr(intr_info),
            "KVM: unexpected VM-Exit interrupt info: 0x%x", intr_info))
@@ -6170,7 +6164,17 @@ static void vmx_handle_external_intr(struct kvm_vcpu *vcpu)
 
        kvm_after_interrupt(vcpu);
 }
-STACK_FRAME_NON_STANDARD(vmx_handle_external_intr);
+STACK_FRAME_NON_STANDARD(handle_external_interrupt_irqoff);
+
+static void vmx_handle_exit_irqoff(struct kvm_vcpu *vcpu)
+{
+       struct vcpu_vmx *vmx = to_vmx(vcpu);
+
+       if (vmx->exit_reason == EXIT_REASON_EXTERNAL_INTERRUPT)
+               handle_external_interrupt_irqoff(vcpu);
+       else if (vmx->exit_reason == EXIT_REASON_EXCEPTION_NMI)
+               handle_exception_nmi_irqoff(vmx);
+}
 
 static bool vmx_has_emulated_msr(int index)
 {
@@ -6540,7 +6544,6 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu)
        vmx->loaded_vmcs->launched = 1;
        vmx->idt_vectoring_info = vmcs_read32(IDT_VECTORING_INFO_FIELD);
 
-       vmx_complete_atomic_exit(vmx);
        vmx_recover_nmi_blocking(vmx);
        vmx_complete_interrupts(vmx);
 }
@@ -7694,7 +7697,7 @@ static struct kvm_x86_ops vmx_x86_ops __ro_after_init = {
        .set_tdp_cr3 = vmx_set_cr3,
 
        .check_intercept = vmx_check_intercept,
-       .handle_external_intr = vmx_handle_external_intr,
+       .handle_exit_irqoff = vmx_handle_exit_irqoff,
        .mpx_supported = vmx_mpx_supported,
        .xsaves_supported = vmx_xsaves_supported,
        .umip_emulated = vmx_umip_emulated,

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 9ff3a670d2b34359e5f0780d1171ff17069ed246..848ca0335b597efc7ed999bec639aad603684a03 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7999,7 +7999,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
        vcpu->mode = OUTSIDE_GUEST_MODE;
        smp_wmb();
 
-       kvm_x86_ops->handle_external_intr(vcpu);
+       kvm_x86_ops->handle_exit_irqoff(vcpu);
 
        ++vcpu->stat.exits;