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>

1 files changed, 33 insertions, 16 deletions

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,