KVM: TDX: Add a place holder to handle TDX VM exit

Wire up handle_exit and handle_exit_irqoff methods and add a place holder to handle VM exit. Add helper functions to get exit info, exit qualification, etc. Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
intel · Dec 16, 2021 · 23fe81f995e342b4152daa56cad4105a72277d4f · 23fe81f
1 parent d89c79e
commit 23fe81f995e342b4152daa56cad4105a72277d4f
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Showing 4 changed files with 125 additions and 3 deletions.
diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
@@ -150,6 +150,23 @@ static void vt_vcpu_put(struct kvm_vcpu *vcpu)
 	return vmx_vcpu_put(vcpu);
 }
 
+static int vt_handle_exit(struct kvm_vcpu *vcpu,
+			     enum exit_fastpath_completion fastpath)
+{
+	if (is_td_vcpu(vcpu))
+		return tdx_handle_exit(vcpu, fastpath);
+
+	return vmx_handle_exit(vcpu, fastpath);
+}
+
+static void vt_handle_exit_irqoff(struct kvm_vcpu *vcpu)
+{
+	if (is_td_vcpu(vcpu))
+		return tdx_handle_exit_irqoff(vcpu);
+
+	vmx_handle_exit_irqoff(vcpu);
+}
+
 static void vt_apicv_post_state_restore(struct kvm_vcpu *vcpu)
 {
 	if (is_td_vcpu(vcpu))
@@ -278,6 +295,18 @@ static void vt_request_immediate_exit(struct kvm_vcpu *vcpu)
 	vmx_request_immediate_exit(vcpu);
 }
 
+static void vt_get_exit_info(struct kvm_vcpu *vcpu, u32 *reason,
+			u64 *info1, u64 *info2, u32 *intr_info, u32 *error_code)
+{
+	if (is_td_vcpu(vcpu)) {
+		tdx_get_exit_info(vcpu, reason, info1, info2, intr_info,
+				error_code);
+		return;
+	}
+
+	vmx_get_exit_info(vcpu, reason, info1, info2, intr_info, error_code);
+}
+
 static int vt_pre_block(struct kvm_vcpu *vcpu)
 {
 	if (pi_pre_block(vcpu))
@@ -374,7 +403,7 @@ struct kvm_x86_ops vt_x86_ops __initdata = {
 	.tlb_flush_guest = vt_flush_tlb_guest,
 
 	.run = vt_vcpu_run,
-	.handle_exit = vmx_handle_exit,
+	.handle_exit = vt_handle_exit,
 	.skip_emulated_instruction = vmx_skip_emulated_instruction,
 	.update_emulated_instruction = vmx_update_emulated_instruction,
 	.set_interrupt_shadow = vt_set_interrupt_shadow,
@@ -408,7 +437,7 @@ struct kvm_x86_ops vt_x86_ops __initdata = {
 	.set_identity_map_addr = vmx_set_identity_map_addr,
 	.get_mt_mask = vmx_get_mt_mask,
 
-	.get_exit_info = vmx_get_exit_info,
+	.get_exit_info = vt_get_exit_info,
 
 	.vcpu_after_set_cpuid = vmx_vcpu_after_set_cpuid,
 
@@ -422,7 +451,7 @@ struct kvm_x86_ops vt_x86_ops __initdata = {
 	.load_mmu_pgd = vt_load_mmu_pgd,
 
 	.check_intercept = vmx_check_intercept,
-	.handle_exit_irqoff = vmx_handle_exit_irqoff,
+	.handle_exit_irqoff = vt_handle_exit_irqoff,
 
 	.request_immediate_exit = vt_request_immediate_exit,
 

diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
@@ -119,6 +119,26 @@ static struct tdx_uret_msr tdx_uret_msrs[] = {
 	{.msr = MSR_TSC_AUX,},
 };
 
+static __always_inline unsigned long tdexit_exit_qual(struct kvm_vcpu *vcpu)
+{
+	return kvm_rcx_read(vcpu);
+}
+
+static __always_inline unsigned long tdexit_ext_exit_qual(struct kvm_vcpu *vcpu)
+{
+	return kvm_rdx_read(vcpu);
+}
+
+static __always_inline unsigned long tdexit_gpa(struct kvm_vcpu *vcpu)
+{
+	return kvm_r8_read(vcpu);
+}
+
+static __always_inline unsigned long tdexit_intr_info(struct kvm_vcpu *vcpu)
+{
+	return kvm_r9_read(vcpu);
+}
+
 static inline bool is_td_vcpu_created(struct vcpu_tdx *tdx)
 {
 	return tdx->tdvpr.added;
@@ -798,6 +818,25 @@ fastpath_t tdx_vcpu_run(struct kvm_vcpu *vcpu)
 	return EXIT_FASTPATH_NONE;
 }
 
+void tdx_handle_exit_irqoff(struct kvm_vcpu *vcpu)
+{
+	struct vcpu_tdx *tdx = to_tdx(vcpu);
+	u16 exit_reason = tdx->exit_reason.basic;
+
+	if (exit_reason == EXIT_REASON_EXCEPTION_NMI)
+		vmx_handle_exception_nmi_irqoff(vcpu, tdexit_intr_info(vcpu));
+	else if (exit_reason == EXIT_REASON_EXTERNAL_INTERRUPT)
+		vmx_handle_external_interrupt_irqoff(vcpu,
+						     tdexit_intr_info(vcpu));
+}
+
+static int tdx_handle_triple_fault(struct kvm_vcpu *vcpu)
+{
+	vcpu->run->exit_reason = KVM_EXIT_SHUTDOWN;
+	vcpu->mmio_needed = 0;
+	return 0;
+}
+
 void tdx_load_mmu_pgd(struct kvm_vcpu *vcpu, hpa_t root_hpa, int pgd_level)
 {
 	td_vmcs_write64(to_tdx(vcpu), SHARED_EPT_POINTER, root_hpa & PAGE_MASK);
@@ -999,6 +1038,50 @@ int tdx_deliver_posted_interrupt(struct kvm_vcpu *vcpu, int vector)
 	return 0;
 }
 
+int tdx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t fastpath)
+{
+	union tdx_exit_reason exit_reason = to_tdx(vcpu)->exit_reason;
+
+	if (unlikely(exit_reason.non_recoverable || exit_reason.error)) {
+		kvm_pr_unimpl("TD exit 0x%llx, %d qual 0x%lx ext 0x%lx gpa 0x%lx intr 0x%lx\n",
+			      exit_reason.full, exit_reason.basic,
+			      tdexit_exit_qual(vcpu),
+			      tdexit_ext_exit_qual(vcpu),
+			      tdexit_gpa(vcpu),
+			      tdexit_intr_info(vcpu));
+		if (exit_reason.basic == EXIT_REASON_TRIPLE_FAULT)
+			return tdx_handle_triple_fault(vcpu);
+
+		goto unhandled_exit;
+	}
+
+	WARN_ON_ONCE(fastpath != EXIT_FASTPATH_NONE);
+
+	switch (exit_reason.basic) {
+	default:
+		break;
+	}
+
+unhandled_exit:
+	vcpu->run->exit_reason = KVM_EXIT_UNKNOWN;
+	vcpu->run->hw.hardware_exit_reason = exit_reason.full;
+	return 0;
+}
+
+void tdx_get_exit_info(struct kvm_vcpu *vcpu, u32 *reason,
+		u64 *info1, u64 *info2, u32 *intr_info, u32 *error_code)
+{
+	struct vcpu_tdx *tdx = to_tdx(vcpu);
+
+	*reason = tdx->exit_reason.full;
+
+	*info1 = tdexit_exit_qual(vcpu);
+	*info2 = tdexit_ext_exit_qual(vcpu);
+
+	*intr_info = tdexit_intr_info(vcpu);
+	*error_code = 0;
+}
+
 int tdx_dev_ioctl(void __user *argp)
 {
 	struct kvm_tdx_capabilities __user *user_caps;

diff --git a/arch/x86/kvm/vmx/tdx_stubs.c b/arch/x86/kvm/vmx/tdx_stubs.c
@@ -14,9 +14,14 @@ fastpath_t tdx_vcpu_run(struct kvm_vcpu *vcpu) { return EXIT_FASTPATH_NONE; }
 void tdx_vcpu_load(struct kvm_vcpu *vcpu, int cpu) {}
 void tdx_vcpu_put(struct kvm_vcpu *vcpu) {}
 void tdx_prepare_switch_to_guest(struct kvm_vcpu *vcpu) {}
+void tdx_handle_exit_irqoff(struct kvm_vcpu *vcpu) {}
+int tdx_handle_exit(struct kvm_vcpu *vcpu,
+		enum exit_fastpath_completion fastpath) { return 0; }
 
 void tdx_apicv_post_state_restore(struct kvm_vcpu *vcpu) {}
 int tdx_deliver_posted_interrupt(struct kvm_vcpu *vcpu, int vector) { return 0; }
+void tdx_get_exit_info(struct kvm_vcpu *vcpu, u32 *reason,
+		u64 *info1, u64 *info2, u32 *intr_info, u32 *error_code) {}
 
 int tdx_dev_ioctl(void __user *argp) { return -EOPNOTSUPP; }
 int tdx_vm_ioctl(struct kvm *kvm, void __user *argp) { return -EOPNOTSUPP; }

diff --git a/arch/x86/kvm/vmx/x86_ops.h b/arch/x86/kvm/vmx/x86_ops.h
@@ -138,9 +138,14 @@ fastpath_t tdx_vcpu_run(struct kvm_vcpu *vcpu);
 void tdx_vcpu_load(struct kvm_vcpu *vcpu, int cpu);
 void tdx_vcpu_put(struct kvm_vcpu *vcpu);
 void tdx_prepare_switch_to_guest(struct kvm_vcpu *vcpu);
+void tdx_handle_exit_irqoff(struct kvm_vcpu *vcpu);
+int tdx_handle_exit(struct kvm_vcpu *vcpu,
+		enum exit_fastpath_completion fastpath);
 
 void tdx_apicv_post_state_restore(struct kvm_vcpu *vcpu);
 int tdx_deliver_posted_interrupt(struct kvm_vcpu *vcpu, int vector);
+void tdx_get_exit_info(struct kvm_vcpu *vcpu, u32 *reason,
+		u64 *info1, u64 *info2, u32 *intr_info, u32 *error_code);
 
 int tdx_dev_ioctl(void __user *argp);
 int tdx_vm_ioctl(struct kvm *kvm, void __user *argp);