[PATCH 32/54] KVM: Generalize exception injection mechanism

[Avi Kivity <avi@qumranet.com>]

Instead of each subarch doing its own thing, add an API for queuing an
injection, and manage failed exception injection centerally (i.e., if
an inject failed due to a shadow page fault, we need to requeue it).

Signed-off-by: Avi Kivity <avi@qumranet.com>
---
 drivers/kvm/svm.c |   21 +++++++++++++++++++++
 drivers/kvm/vmx.c |   20 ++++++++++++++++++++
 drivers/kvm/x86.c |   33 ++++++++++++++++++++++++++++++++-
 drivers/kvm/x86.h |   13 +++++++++++++
 4 files changed, 86 insertions(+), 1 deletions(-)

diff --git a/drivers/kvm/svm.c b/drivers/kvm/svm.c
index 04e6b39..f4c61c8 100644
--- a/drivers/kvm/svm.c
+++ b/drivers/kvm/svm.c
@@ -188,6 +188,25 @@ static void svm_set_efer(struct kvm_vcpu *vcpu, u64 efer)
 	vcpu->shadow_efer = efer;
 }
 
+static void svm_queue_exception(struct kvm_vcpu *vcpu, unsigned nr,
+				bool has_error_code, u32 error_code)
+{
+	struct vcpu_svm *svm = to_svm(vcpu);
+
+	svm->vmcb->control.event_inj = nr
+		| SVM_EVTINJ_VALID
+		| (has_error_code ? SVM_EVTINJ_VALID_ERR : 0)
+		| SVM_EVTINJ_TYPE_EXEPT;
+	svm->vmcb->control.event_inj_err = error_code;
+}
+
+static bool svm_exception_injected(struct kvm_vcpu *vcpu)
+{
+	struct vcpu_svm *svm = to_svm(vcpu);
+
+	return !(svm->vmcb->control.exit_int_info & SVM_EXITINTINFO_VALID);
+}
+
 static void svm_inject_gp(struct kvm_vcpu *vcpu, unsigned error_code)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
@@ -1712,6 +1731,8 @@ static struct kvm_x86_ops svm_x86_ops = {
 	.patch_hypercall = svm_patch_hypercall,
 	.get_irq = svm_get_irq,
 	.set_irq = svm_set_irq,
+	.queue_exception = svm_queue_exception,
+	.exception_injected = svm_exception_injected,
 	.inject_pending_irq = svm_intr_assist,
 	.inject_pending_vectors = do_interrupt_requests,
 
diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c
index 8e43feb..1ec1c28 100644
--- a/drivers/kvm/vmx.c
+++ b/drivers/kvm/vmx.c
@@ -595,6 +595,24 @@ static void skip_emulated_instruction(struct kvm_vcpu *vcpu)
 	vcpu->interrupt_window_open = 1;
 }
 
+static void vmx_queue_exception(struct kvm_vcpu *vcpu, unsigned nr,
+				bool has_error_code, u32 error_code)
+{
+	vmcs_write32(VM_ENTRY_INTR_INFO_FIELD,
+		     nr | INTR_TYPE_EXCEPTION
+		     | (has_error_code ? INTR_INFO_DELIEVER_CODE_MASK : 0)
+		     | INTR_INFO_VALID_MASK);
+	if (has_error_code)
+		vmcs_write32(VM_ENTRY_EXCEPTION_ERROR_CODE, error_code);
+}
+
+static bool vmx_exception_injected(struct kvm_vcpu *vcpu)
+{
+	struct vcpu_vmx *vmx = to_vmx(vcpu);
+
+	return !(vmx->idt_vectoring_info & VECTORING_INFO_VALID_MASK);
+}
+
 static void vmx_inject_gp(struct kvm_vcpu *vcpu, unsigned error_code)
 {
 	printk(KERN_DEBUG "inject_general_protection: rip 0x%lx\n",
@@ -2641,6 +2659,8 @@ static struct kvm_x86_ops vmx_x86_ops = {
 	.patch_hypercall = vmx_patch_hypercall,
 	.get_irq = vmx_get_irq,
 	.set_irq = vmx_inject_irq,
+	.queue_exception = vmx_queue_exception,
+	.exception_injected = vmx_exception_injected,
 	.inject_pending_irq = vmx_intr_assist,
 	.inject_pending_vectors = do_interrupt_requests,
 
diff --git a/drivers/kvm/x86.c b/drivers/kvm/x86.c
index c9e4b67..11440d1 100644
--- a/drivers/kvm/x86.c
+++ b/drivers/kvm/x86.c
@@ -133,6 +133,32 @@ static void inject_gp(struct kvm_vcpu *vcpu)
 	kvm_x86_ops->inject_gp(vcpu, 0);
 }
 
+void kvm_queue_exception(struct kvm_vcpu *vcpu, unsigned nr)
+{
+	WARN_ON(vcpu->exception.pending);
+	vcpu->exception.pending = true;
+	vcpu->exception.has_error_code = false;
+	vcpu->exception.nr = nr;
+}
+EXPORT_SYMBOL_GPL(kvm_queue_exception);
+
+void kvm_queue_exception_e(struct kvm_vcpu *vcpu, unsigned nr, u32 error_code)
+{
+	WARN_ON(vcpu->exception.pending);
+	vcpu->exception.pending = true;
+	vcpu->exception.has_error_code = true;
+	vcpu->exception.nr = nr;
+	vcpu->exception.error_code = error_code;
+}
+EXPORT_SYMBOL_GPL(kvm_queue_exception_e);
+
+static void __queue_exception(struct kvm_vcpu *vcpu)
+{
+	kvm_x86_ops->queue_exception(vcpu, vcpu->exception.nr,
+				     vcpu->exception.has_error_code,
+				     vcpu->exception.error_code);
+}
+
 /*
  * Load the pae pdptrs.  Return true is they are all valid.
  */
@@ -2370,7 +2396,9 @@ again:
 		goto out;
 	}
 
-	if (irqchip_in_kernel(vcpu->kvm))
+	if (vcpu->exception.pending)
+		__queue_exception(vcpu);
+	else if (irqchip_in_kernel(vcpu->kvm))
 		kvm_x86_ops->inject_pending_irq(vcpu);
 	else
 		kvm_x86_ops->inject_pending_vectors(vcpu, kvm_run);
@@ -2409,6 +2437,9 @@ again:
 		profile_hit(KVM_PROFILING, (void *)vcpu->rip);
 	}
 
+	if (vcpu->exception.pending && kvm_x86_ops->exception_injected(vcpu))
+		vcpu->exception.pending = false;
+
 	r = kvm_x86_ops->handle_exit(kvm_run, vcpu);
 
 	if (r > 0) {
diff --git a/drivers/kvm/x86.h b/drivers/kvm/x86.h
index eed7964..1e71668 100644
--- a/drivers/kvm/x86.h
+++ b/drivers/kvm/x86.h
@@ -139,6 +139,13 @@ struct kvm_vcpu {
 	struct kvm_pio_request pio;
 	void *pio_data;
 
+	struct kvm_queued_exception {
+		bool pending;
+		bool has_error_code;
+		u8 nr;
+		u32 error_code;
+	} exception;
+
 	struct {
 		int active;
 		u8 save_iopl;
@@ -224,6 +231,9 @@ struct kvm_x86_ops {
 				unsigned char *hypercall_addr);
 	int (*get_irq)(struct kvm_vcpu *vcpu);
 	void (*set_irq)(struct kvm_vcpu *vcpu, int vec);
+	void (*queue_exception)(struct kvm_vcpu *vcpu, unsigned nr,
+				bool has_error_code, u32 error_code);
+	bool (*exception_injected)(struct kvm_vcpu *vcpu);
 	void (*inject_pending_irq)(struct kvm_vcpu *vcpu);
 	void (*inject_pending_vectors)(struct kvm_vcpu *vcpu,
 				       struct kvm_run *run);
@@ -294,6 +304,9 @@ void kvm_get_cs_db_l_bits(struct kvm_vcpu *vcpu, int *db, int *l);
 int kvm_get_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata);
 int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data);
 
+void kvm_queue_exception(struct kvm_vcpu *vcpu, unsigned nr);
+void kvm_queue_exception_e(struct kvm_vcpu *vcpu, unsigned nr, u32 error_code);
+
 void fx_init(struct kvm_vcpu *vcpu);
 
 int emulator_read_std(unsigned long addr,
-- 
1.5.3.7