[PATCH] KVM: nSVM/nVMX: Implement vmexit on INIT assertion

[Jan Kiszka <jan.kiszka@web.de>]

From: Jan Kiszka <jan.kiszka@siemens.com>

On Intel, raising INIT causing an unconditional vmexit. On AMD, this is
controlled by the interception mask.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---

Sorry for double-posting, failed to CC the list on first try.

 arch/x86/include/asm/kvm_host.h |    1 +
 arch/x86/include/asm/vmx.h      |    2 ++
 arch/x86/kvm/svm.c              |   16 ++++++++++++++++
 arch/x86/kvm/vmx.c              |   15 +++++++++++++++
 arch/x86/kvm/x86.c              |    6 ++++++
 5 files changed, 40 insertions(+), 0 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 635a74d..5b0534a 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -681,6 +681,7 @@ struct kvm_x86_ops {
  	void (*run)(struct kvm_vcpu *vcpu);
 	int (*handle_exit)(struct kvm_vcpu *vcpu);
+	bool (*handle_init_received)(struct kvm_vcpu *vcpu);
 	void (*skip_emulated_instruction)(struct kvm_vcpu *vcpu);
 	void (*set_interrupt_shadow)(struct kvm_vcpu *vcpu, int mask);
 	u32 (*get_interrupt_shadow)(struct kvm_vcpu *vcpu, int mask);
diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h
index 5c9dbad..40f7f74 100644
--- a/arch/x86/include/asm/vmx.h
+++ b/arch/x86/include/asm/vmx.h
@@ -30,6 +30,7 @@
 #define EXIT_REASON_EXCEPTION_NMI       0
 #define EXIT_REASON_EXTERNAL_INTERRUPT  1
 #define EXIT_REASON_TRIPLE_FAULT        2
+#define EXIT_REASON_INIT_SIGNAL         3
  #define EXIT_REASON_PENDING_INTERRUPT   7
 #define EXIT_REASON_NMI_WINDOW          8
@@ -74,6 +75,7 @@
 	{ EXIT_REASON_EXCEPTION_NMI,         "EXCEPTION_NMI" }, \
 	{ EXIT_REASON_EXTERNAL_INTERRUPT,    "EXTERNAL_INTERRUPT" }, \
 	{ EXIT_REASON_TRIPLE_FAULT,          "TRIPLE_FAULT" }, \
+	{ EXIT_REASON_INIT_SIGNAL,           "INIT_SIGNAL" }, \
 	{ EXIT_REASON_PENDING_INTERRUPT,     "PENDING_INTERRUPT" }, \
 	{ EXIT_REASON_NMI_WINDOW,            "NMI_WINDOW" }, \
 	{ EXIT_REASON_TASK_SWITCH,           "TASK_SWITCH" }, \
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index e1b1ce2..1118631 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -2390,6 +2390,21 @@ static int nested_svm_vmexit(struct vcpu_svm *svm)
 	return 0;
 }
 +static bool nested_svm_handle_init_received(struct kvm_vcpu *vcpu)
+{
+	struct vcpu_svm *svm = to_svm(vcpu);
+
+	if (!is_guest_mode(vcpu) ||
+	    !(svm->nested.intercept & (1ULL << INTERCEPT_INIT)))
+		return false;
+
+	svm->vmcb->control.exit_code     = SVM_EXIT_INIT;
+	svm->vmcb->control.exit_int_info = 0;
+	nested_svm_vmexit(svm);
+
+	return true;
+}
+
 static bool nested_svm_vmrun_msrpm(struct vcpu_svm *svm)
 {
 	/*
@@ -4295,6 +4310,7 @@ static struct kvm_x86_ops svm_x86_ops = {
  	.run = svm_vcpu_run,
 	.handle_exit = handle_exit,
+	.handle_init_received = nested_svm_handle_init_received,
 	.skip_emulated_instruction = skip_emulated_instruction,
 	.set_interrupt_shadow = svm_set_interrupt_shadow,
 	.get_interrupt_shadow = svm_get_interrupt_shadow,
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index ccb6456..6830d26 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -7538,6 +7538,20 @@ static void nested_vmx_vmexit(struct kvm_vcpu *vcpu)
 		nested_vmx_succeed(vcpu);
 }
 +static bool nested_vmx_handle_init_received(struct kvm_vcpu *vcpu)
+{
+	struct vmcs12 *vmcs12 = get_vmcs12(vcpu);
+
+	if (!is_guest_mode(vcpu))
+		return false;
+
+	nested_vmx_vmexit(vcpu);
+	vmcs12->vm_exit_reason = EXIT_REASON_INIT_SIGNAL;
+	vmcs12->vm_exit_intr_info = 0;
+
+	return true;
+}
+
 /*
  * L1's failure to enter L2 is a subset of a normal exit, as explained in
  * 23.7 "VM-entry failures during or after loading guest state" (this also
@@ -7610,6 +7624,7 @@ static struct kvm_x86_ops vmx_x86_ops = {
  	.run = vmx_vcpu_run,
 	.handle_exit = vmx_handle_exit,
+	.handle_init_received = nested_vmx_handle_init_received,
 	.skip_emulated_instruction = skip_emulated_instruction,
 	.set_interrupt_shadow = vmx_set_interrupt_shadow,
 	.get_interrupt_shadow = vmx_get_interrupt_shadow,
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 3c5bb6f..28dba95 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6977,6 +6977,12 @@ void kvm_arch_flush_shadow_memslot(struct kvm *kvm,
  int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu)
 {
+	if (vcpu->arch.mp_state == KVM_MP_STATE_INIT_RECEIVED &&
+	    kvm_x86_ops->handle_init_received(vcpu)) {
+		/* nested vmexit, L1 is runnable now */
+		vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
+		return 1;
+	}
 	return (vcpu->arch.mp_state == KVM_MP_STATE_RUNNABLE &&
 		!vcpu->arch.apf.halted)
 		|| !list_empty_careful(&vcpu->async_pf.done)
-- 
1.7.3.4