KVM: VMX: Add invalid guest state handler

This adds the invalid guest state handler function which invokes the x86
emulator until getting the guest to a VMX-friendly state.

[avi: leave atomic context if scheduling]
[guillaume: return to atomic context correctly]

Signed-off-by: Laurent Vivier <laurent.vivier@bull.net>
Signed-off-by: Guillaume Thouvenin <guillaume.thouvenin@ext.bull.net>
Signed-off-by: Mohammed Gamal <m.gamal005@gmail.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

1 files changed, 37 insertions, 0 deletions

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 7c5f611e1a94..eae1f2c64f97 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2892,6 +2892,43 @@ static int handle_nmi_window(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
         return 1;
 }
 
+static void handle_invalid_guest_state(struct kvm_vcpu *vcpu,
+                                struct kvm_run *kvm_run)
+{
+        struct vcpu_vmx *vmx = to_vmx(vcpu);
+        int err;
+
+        preempt_enable();
+        local_irq_enable();
+
+        while (!guest_state_valid(vcpu)) {
+                err = emulate_instruction(vcpu, kvm_run, 0, 0, 0);
+
+                switch (err) {
+                        case EMULATE_DONE:
+                                break;
+                        case EMULATE_DO_MMIO:
+                                kvm_report_emulation_failure(vcpu, "mmio");
+                                /* TODO: Handle MMIO */
+                                return;
+                        default:
+                                kvm_report_emulation_failure(vcpu, "emulation failure");
+                                return;
+                }
+
+                if (signal_pending(current))
+                        break;
+                if (need_resched())
+                        schedule();
+        }
+
+        local_irq_disable();
+        preempt_disable();
+
+        /* Guest state should be valid now, no more emulation should be needed */
+        vmx->emulation_required = 0;
+}
+
 /*
  * The exit handlers return 1 if the exit was handled fully and guest execution
  * may resume.  Otherwise they set the kvm_run parameter to indicate what needs