KVM: Add kvm_inject_realmode_interrupt() wrapper

This adds a wrapper function kvm_inject_realmode_interrupt() around the
emulator function emulate_int_real() to allow real mode interrupt injection.

[avi: initialize operand and address sizes before emulating interrupts]
[avi: initialize rip for real mode interrupt injection]
[avi: clear interrupt pending flag after emulating interrupt injection]

Signed-off-by: Mohammed Gamal <m.gamal005@gmail.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

2 files changed, 30 insertions, 0 deletions

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 3adf6921e88e..7d2880500fa3 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4188,6 +4188,35 @@ static void init_emulate_ctxt(struct kvm_vcpu *vcpu)
         memcpy(c->regs, vcpu->arch.regs, sizeof c->regs);
 }
 
+int kvm_inject_realmode_interrupt(struct kvm_vcpu *vcpu, int irq)
+{
+        struct decode_cache *c = &vcpu->arch.emulate_ctxt.decode;
+        int ret;
+
+        init_emulate_ctxt(vcpu);
+
+        vcpu->arch.emulate_ctxt.decode.op_bytes = 2;
+        vcpu->arch.emulate_ctxt.decode.ad_bytes = 2;
+        vcpu->arch.emulate_ctxt.decode.eip = vcpu->arch.emulate_ctxt.eip;
+        ret = emulate_int_real(&vcpu->arch.emulate_ctxt, &emulate_ops, irq);
+
+        if (ret != X86EMUL_CONTINUE)
+                return EMULATE_FAIL;
+
+        vcpu->arch.emulate_ctxt.eip = c->eip;
+        memcpy(vcpu->arch.regs, c->regs, sizeof c->regs);
+        kvm_rip_write(vcpu, vcpu->arch.emulate_ctxt.eip);
+        kvm_x86_ops->set_rflags(vcpu, vcpu->arch.emulate_ctxt.eflags);
+
+        if (irq == NMI_VECTOR)
+                vcpu->arch.nmi_pending = false;
+        else
+                vcpu->arch.interrupt.pending = false;
+
+        return EMULATE_DONE;
+}
+EXPORT_SYMBOL_GPL(kvm_inject_realmode_interrupt);
+
 static int handle_emulation_failure(struct kvm_vcpu *vcpu)
 {
         ++vcpu->stat.insn_emulation_fail;
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index bf4dc2f40d7f..2cea414489f3 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -72,6 +72,7 @@ static inline int is_paging(struct kvm_vcpu *vcpu)
 
 void kvm_before_handle_nmi(struct kvm_vcpu *vcpu);
 void kvm_after_handle_nmi(struct kvm_vcpu *vcpu);
+int kvm_inject_realmode_interrupt(struct kvm_vcpu *vcpu, int irq);
 
 void kvm_write_tsc(struct kvm_vcpu *vcpu, u64 data);