KVM: Replace ->drop_interrupt_shadow() by ->set_interrupt_shadow()

This patch replaces drop_interrupt_shadow with the more
general set_interrupt_shadow, that can either drop or raise
it, depending on its parameter.  It also adds ->get_interrupt_shadow()
for future use.

Signed-off-by: Glauber Costa <glommer@redhat.com>
CC: H. Peter Anvin <hpa@zytor.com>
CC: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

5 files changed, 63 insertions, 26 deletions

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index ab7de4a11955..16d1481aa231 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -508,6 +508,8 @@ struct kvm_x86_ops {
         void (*run)(struct kvm_vcpu *vcpu, struct kvm_run *run);
         int (*handle_exit)(struct kvm_run *run, struct kvm_vcpu *vcpu);
         void (*skip_emulated_instruction)(struct kvm_vcpu *vcpu);
+        void (*set_interrupt_shadow)(struct kvm_vcpu *vcpu, int mask);
+        u32 (*get_interrupt_shadow)(struct kvm_vcpu *vcpu, int mask);
         void (*patch_hypercall)(struct kvm_vcpu *vcpu,
                                 unsigned char *hypercall_addr);
         void (*set_irq)(struct kvm_vcpu *vcpu, int vec);
@@ -519,7 +521,6 @@ struct kvm_x86_ops {
         void (*enable_nmi_window)(struct kvm_vcpu *vcpu);
         void (*enable_irq_window)(struct kvm_vcpu *vcpu);
         void (*update_cr8_intercept)(struct kvm_vcpu *vcpu, int tpr, int irr);
-        void (*drop_interrupt_shadow)(struct kvm_vcpu *vcpu);
         int (*set_tss_addr)(struct kvm *kvm, unsigned int addr);
         int (*get_tdp_level)(void);
         u64 (*get_mt_mask)(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio);
diff --git a/arch/x86/include/asm/kvm_x86_emulate.h b/arch/x86/include/asm/kvm_x86_emulate.h
index 6a159732881a..be40d6e2b6bb 100644
--- a/arch/x86/include/asm/kvm_x86_emulate.h
+++ b/arch/x86/include/asm/kvm_x86_emulate.h
@@ -143,6 +143,9 @@ struct decode_cache {
         struct fetch_cache fetch;
 };
 
+#define X86_SHADOW_INT_MOV_SS  1
+#define X86_SHADOW_INT_STI     2
+
 struct x86_emulate_ctxt {
         /* Register state before/after emulation. */
         struct kvm_vcpu *vcpu;
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index f994c6df78be..8b5ffbd55c11 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -202,6 +202,27 @@ static int is_external_interrupt(u32 info)
         return info == (SVM_EVTINJ_VALID | SVM_EVTINJ_TYPE_INTR);
 }
 
+static u32 svm_get_interrupt_shadow(struct kvm_vcpu *vcpu, int mask)
+{
+        struct vcpu_svm *svm = to_svm(vcpu);
+        u32 ret = 0;
+
+        if (svm->vmcb->control.int_state & SVM_INTERRUPT_SHADOW_MASK)
+                ret |= X86_SHADOW_INT_STI | X86_SHADOW_INT_MOV_SS;
+        return ret & mask;
+}
+
+static void svm_set_interrupt_shadow(struct kvm_vcpu *vcpu, int mask)
+{
+        struct vcpu_svm *svm = to_svm(vcpu);
+
+        if (mask == 0)
+                svm->vmcb->control.int_state &= ~SVM_INTERRUPT_SHADOW_MASK;
+        else
+                svm->vmcb->control.int_state |= SVM_INTERRUPT_SHADOW_MASK;
+
+}
+
 static void skip_emulated_instruction(struct kvm_vcpu *vcpu)
 {
         struct vcpu_svm *svm = to_svm(vcpu);
@@ -215,7 +236,7 @@ static void skip_emulated_instruction(struct kvm_vcpu *vcpu)
                        __func__, kvm_rip_read(vcpu), svm->next_rip);
 
         kvm_rip_write(vcpu, svm->next_rip);
-        svm->vmcb->control.int_state &= ~SVM_INTERRUPT_SHADOW_MASK;
+        svm_set_interrupt_shadow(vcpu, 0);
 }
 
 static int has_svm(void)
@@ -2259,12 +2280,6 @@ static void pre_svm_run(struct vcpu_svm *svm)
                 new_asid(svm, svm_data);
 }
 
-static void svm_drop_interrupt_shadow(struct kvm_vcpu *vcpu)
-{
-        struct vcpu_svm *svm = to_svm(vcpu);
-        svm->vmcb->control.int_state &= ~SVM_INTERRUPT_SHADOW_MASK;
-}
-
 static void svm_inject_nmi(struct kvm_vcpu *vcpu)
 {
         struct vcpu_svm *svm = to_svm(vcpu);
@@ -2667,6 +2682,8 @@ static struct kvm_x86_ops svm_x86_ops = {
         .run = svm_vcpu_run,
         .handle_exit = handle_exit,
         .skip_emulated_instruction = skip_emulated_instruction,
+        .set_interrupt_shadow = svm_set_interrupt_shadow,
+        .get_interrupt_shadow = svm_get_interrupt_shadow,
         .patch_hypercall = svm_patch_hypercall,
         .set_irq = svm_set_irq,
         .set_nmi = svm_inject_nmi,
@@ -2676,7 +2693,6 @@ static struct kvm_x86_ops svm_x86_ops = {
         .enable_nmi_window = enable_nmi_window,
         .enable_irq_window = enable_irq_window,
         .update_cr8_intercept = update_cr8_intercept,
-        .drop_interrupt_shadow = svm_drop_interrupt_shadow,
 
         .set_tss_addr = svm_set_tss_addr,
         .get_tdp_level = get_npt_level,
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index e8a5649f9c15..f3ab27b5a6b2 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -736,23 +736,45 @@ static void vmx_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags)
         vmcs_writel(GUEST_RFLAGS, rflags);
 }
 
+static u32 vmx_get_interrupt_shadow(struct kvm_vcpu *vcpu, int mask)
+{
+        u32 interruptibility = vmcs_read32(GUEST_INTERRUPTIBILITY_INFO);
+        int ret = 0;
+
+        if (interruptibility & GUEST_INTR_STATE_STI)
+                ret |= X86_SHADOW_INT_STI;
+        if (interruptibility & GUEST_INTR_STATE_MOV_SS)
+                ret |= X86_SHADOW_INT_MOV_SS;
+
+        return ret & mask;
+}
+
+static void vmx_set_interrupt_shadow(struct kvm_vcpu *vcpu, int mask)
+{
+        u32 interruptibility_old = vmcs_read32(GUEST_INTERRUPTIBILITY_INFO);
+        u32 interruptibility = interruptibility_old;
+
+        interruptibility &= ~(GUEST_INTR_STATE_STI | GUEST_INTR_STATE_MOV_SS);
+
+        if (mask & X86_SHADOW_INT_MOV_SS)
+                interruptibility |= GUEST_INTR_STATE_MOV_SS;
+        if (mask & X86_SHADOW_INT_STI)
+                interruptibility |= GUEST_INTR_STATE_STI;
+
+        if ((interruptibility != interruptibility_old))
+                vmcs_write32(GUEST_INTERRUPTIBILITY_INFO, interruptibility);
+}
+
 static void skip_emulated_instruction(struct kvm_vcpu *vcpu)
 {
         unsigned long rip;
-        u32 interruptibility;
 
         rip = kvm_rip_read(vcpu);
         rip += vmcs_read32(VM_EXIT_INSTRUCTION_LEN);
         kvm_rip_write(vcpu, rip);
 
-        /*
-         * We emulated an instruction, so temporary interrupt blocking
-         * should be removed, if set.
-         */
-        interruptibility = vmcs_read32(GUEST_INTERRUPTIBILITY_INFO);
-        if (interruptibility & 3)
-                vmcs_write32(GUEST_INTERRUPTIBILITY_INFO,
-                             interruptibility & ~3);
+        /* skipping an emulated instruction also counts */
+        vmx_set_interrupt_shadow(vcpu, 0);
 }
 
 static void vmx_queue_exception(struct kvm_vcpu *vcpu, unsigned nr,
@@ -2400,12 +2422,6 @@ out:
         return ret;
 }
 
-void vmx_drop_interrupt_shadow(struct kvm_vcpu *vcpu)
-{
-        vmcs_clear_bits(GUEST_INTERRUPTIBILITY_INFO,
-                        GUEST_INTR_STATE_STI | GUEST_INTR_STATE_MOV_SS);
-}
-
 static void enable_irq_window(struct kvm_vcpu *vcpu)
 {
         u32 cpu_based_vm_exec_control;
@@ -3649,6 +3665,8 @@ static struct kvm_x86_ops vmx_x86_ops = {
         .run = vmx_vcpu_run,
         .handle_exit = vmx_handle_exit,
         .skip_emulated_instruction = skip_emulated_instruction,
+        .set_interrupt_shadow = vmx_set_interrupt_shadow,
+        .get_interrupt_shadow = vmx_get_interrupt_shadow,
         .patch_hypercall = vmx_patch_hypercall,
         .set_irq = vmx_inject_irq,
         .set_nmi = vmx_inject_nmi,
@@ -3658,7 +3676,6 @@ static struct kvm_x86_ops vmx_x86_ops = {
         .enable_nmi_window = enable_nmi_window,
         .enable_irq_window = enable_irq_window,
         .update_cr8_intercept = update_cr8_intercept,
-        .drop_interrupt_shadow = vmx_drop_interrupt_shadow,
 
         .set_tss_addr = vmx_set_tss_addr,
         .get_tdp_level = get_ept_level,
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 3c4c327490af..7475b029b2ad 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3178,7 +3178,7 @@ static void inject_pending_irq(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
                 kvm_run->request_interrupt_window;
 
         if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)
-                kvm_x86_ops->drop_interrupt_shadow(vcpu);
+                kvm_x86_ops->set_interrupt_shadow(vcpu, 0);
 
         inject_irq(vcpu);