KVM: x86 emulator: move interruptibility state tracking out of emulator

Emulator shouldn't access vcpu directly.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 17 insertions, 3 deletions

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 21d36081a9d..91bfe7771f5 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3838,12 +3838,26 @@ static void cache_all_regs(struct kvm_vcpu *vcpu)
         vcpu->arch.regs_dirty = ~0;
 }
 
+static void toggle_interruptibility(struct kvm_vcpu *vcpu, u32 mask)
+{
+        u32 int_shadow = kvm_x86_ops->get_interrupt_shadow(vcpu, mask);
+        /*
+         * an sti; sti; sequence only disable interrupts for the first
+         * instruction. So, if the last instruction, be it emulated or
+         * not, left the system with the INT_STI flag enabled, it
+         * means that the last instruction is an sti. We should not
+         * leave the flag on in this case. The same goes for mov ss
+         */
+        if (!(int_shadow & mask))
+                kvm_x86_ops->set_interrupt_shadow(vcpu, mask);
+}
+
 int emulate_instruction(struct kvm_vcpu *vcpu,
                         unsigned long cr2,
                         u16 error_code,
                         int emulation_type)
 {
-        int r, shadow_mask;
+        int r;
         struct decode_cache *c = &vcpu->arch.emulate_ctxt.decode;
 
         kvm_clear_exception_queue(vcpu);
@@ -3871,6 +3885,7 @@ int emulate_instruction(struct kvm_vcpu *vcpu,
                         ? X86EMUL_MODE_PROT32 : X86EMUL_MODE_PROT16;
                 memset(c, 0, sizeof(struct decode_cache));
                 memcpy(c->regs, vcpu->arch.regs, sizeof c->regs);
+                vcpu->arch.emulate_ctxt.interruptibility = 0;
 
                 r = x86_decode_insn(&vcpu->arch.emulate_ctxt, &emulate_ops);
                 trace_kvm_emulate_insn_start(vcpu);
@@ -3938,8 +3953,7 @@ restart:
                 return EMULATE_FAIL;
         }
 
-        shadow_mask = vcpu->arch.emulate_ctxt.interruptibility;
-        kvm_x86_ops->set_interrupt_shadow(vcpu, shadow_mask);
+        toggle_interruptibility(vcpu, vcpu->arch.emulate_ctxt.interruptibility);
         kvm_x86_ops->set_rflags(vcpu, vcpu->arch.emulate_ctxt.eflags);
         memcpy(vcpu->arch.regs, c->regs, sizeof c->regs);
         kvm_rip_write(vcpu, vcpu->arch.emulate_ctxt.eip);