1 files changed, 72 insertions, 16 deletions

diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c
index 2d204fd45972..c55635ddf426 100644
--- a/drivers/kvm/vmx.c
+++ b/drivers/kvm/vmx.c
@@ -263,6 +263,7 @@ static void skip_emulated_instruction(struct kvm_vcpu *vcpu)
         if (interruptibility & 3)
                 vmcs_write32(GUEST_INTERRUPTIBILITY_INFO,
                              interruptibility & ~3);
+        vcpu->interrupt_window_open = 1;
 }
 
 static void vmx_inject_gp(struct kvm_vcpu *vcpu, unsigned error_code)
@@ -1214,21 +1215,34 @@ static void kvm_do_inject_irq(struct kvm_vcpu *vcpu)
                         irq | INTR_TYPE_EXT_INTR | INTR_INFO_VALID_MASK);
 }
 
-static void kvm_try_inject_irq(struct kvm_vcpu *vcpu)
+
+static void do_interrupt_requests(struct kvm_vcpu *vcpu,
+                                       struct kvm_run *kvm_run)
 {
-        if ((vmcs_readl(GUEST_RFLAGS) & X86_EFLAGS_IF)
-            && (vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) & 3) == 0)
+        u32 cpu_based_vm_exec_control;
+
+        vcpu->interrupt_window_open =
+                ((vmcs_readl(GUEST_RFLAGS) & X86_EFLAGS_IF) &&
+                 (vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) & 3) == 0);
+
+        if (vcpu->interrupt_window_open &&
+            vcpu->irq_summary &&
+            !(vmcs_read32(VM_ENTRY_INTR_INFO_FIELD) & INTR_INFO_VALID_MASK))
                 /*
-                 * Interrupts enabled, and not blocked by sti or mov ss. Good.
+                 * If interrupts enabled, and not blocked by sti or mov ss. Good.
                  */
                 kvm_do_inject_irq(vcpu);
-        else
+
+        cpu_based_vm_exec_control = vmcs_read32(CPU_BASED_VM_EXEC_CONTROL);
+        if (!vcpu->interrupt_window_open &&
+            (vcpu->irq_summary || kvm_run->request_interrupt_window))
                 /*
                  * Interrupts blocked.  Wait for unblock.
                  */
-                vmcs_write32(CPU_BASED_VM_EXEC_CONTROL,
-                             vmcs_read32(CPU_BASED_VM_EXEC_CONTROL)
-                             | CPU_BASED_VIRTUAL_INTR_PENDING);
+                cpu_based_vm_exec_control |= CPU_BASED_VIRTUAL_INTR_PENDING;
+        else
+                cpu_based_vm_exec_control &= ~CPU_BASED_VIRTUAL_INTR_PENDING;
+        vmcs_write32(CPU_BASED_VM_EXEC_CONTROL, cpu_based_vm_exec_control);
 }
 
 static void kvm_guest_debug_pre(struct kvm_vcpu *vcpu)
@@ -1565,23 +1579,41 @@ static int handle_wrmsr(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
         return 1;
 }
 
+static void post_kvm_run_save(struct kvm_vcpu *vcpu,
+                              struct kvm_run *kvm_run)
+{
+        kvm_run->if_flag = (vmcs_readl(GUEST_RFLAGS) & X86_EFLAGS_IF) != 0;
+        kvm_run->cr8 = vcpu->cr8;
+        kvm_run->apic_base = vcpu->apic_base;
+        kvm_run->ready_for_interrupt_injection = (vcpu->interrupt_window_open &&
+                                                  vcpu->irq_summary == 0);
+}
+
 static int handle_interrupt_window(struct kvm_vcpu *vcpu,
                                    struct kvm_run *kvm_run)
 {
-        /* Turn off interrupt window reporting. */
-        vmcs_write32(CPU_BASED_VM_EXEC_CONTROL,
-                     vmcs_read32(CPU_BASED_VM_EXEC_CONTROL)
-                     & ~CPU_BASED_VIRTUAL_INTR_PENDING);
+        /*
+         * If the user space waits to inject interrupts, exit as soon as
+         * possible
+         */
+        if (kvm_run->request_interrupt_window &&
+            !vcpu->irq_summary &&
+            (vmcs_readl(GUEST_RFLAGS) & X86_EFLAGS_IF)) {
+                kvm_run->exit_reason = KVM_EXIT_IRQ_WINDOW_OPEN;
+                ++kvm_stat.irq_window_exits;
+                return 0;
+        }
         return 1;
 }
 
 static int handle_halt(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 {
         skip_emulated_instruction(vcpu);
-        if (vcpu->irq_summary && (vmcs_readl(GUEST_RFLAGS) & X86_EFLAGS_IF))
+        if (vcpu->irq_summary)
                 return 1;
 
         kvm_run->exit_reason = KVM_EXIT_HLT;
+        ++kvm_stat.halt_exits;
         return 0;
 }
 
@@ -1632,6 +1664,21 @@ static int kvm_handle_exit(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
         return 0;
 }
 
+/*
+ * Check if userspace requested an interrupt window, and that the
+ * interrupt window is open.
+ *
+ * No need to exit to userspace if we already have an interrupt queued.
+ */
+static int dm_request_for_irq_injection(struct kvm_vcpu *vcpu,
+                                          struct kvm_run *kvm_run)
+{
+        return (!vcpu->irq_summary &&
+                kvm_run->request_interrupt_window &&
+                vcpu->interrupt_window_open &&
+                (vmcs_readl(GUEST_RFLAGS) & X86_EFLAGS_IF));
+}
+
 static int vmx_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 {
         u8 fail;
@@ -1663,9 +1710,7 @@ again:
         vmcs_writel(HOST_GS_BASE, segment_base(gs_sel));
 #endif
 
-        if (vcpu->irq_summary &&
-            !(vmcs_read32(VM_ENTRY_INTR_INFO_FIELD) & INTR_INFO_VALID_MASK))
-                kvm_try_inject_irq(vcpu);
+        do_interrupt_requests(vcpu, kvm_run);
 
         if (vcpu->guest_debug.enabled)
                 kvm_guest_debug_pre(vcpu);
@@ -1802,6 +1847,7 @@ again:
 
         fx_save(vcpu->guest_fx_image);
         fx_restore(vcpu->host_fx_image);
+        vcpu->interrupt_window_open = (vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) & 3) == 0;
 
 #ifndef CONFIG_X86_64
         asm ("mov %0, %%ds; mov %0, %%es" : : "r"(__USER_DS));
@@ -1834,12 +1880,22 @@ again:
                         /* Give scheduler a change to reschedule. */
                         if (signal_pending(current)) {
                                 ++kvm_stat.signal_exits;
+                                post_kvm_run_save(vcpu, kvm_run);
+                                return -EINTR;
+                        }
+
+                        if (dm_request_for_irq_injection(vcpu, kvm_run)) {
+                                ++kvm_stat.request_irq_exits;
+                                post_kvm_run_save(vcpu, kvm_run);
                                 return -EINTR;
                         }
+
                         kvm_resched(vcpu);
                         goto again;
                 }
         }
+
+        post_kvm_run_save(vcpu, kvm_run);
         return 0;
 }