[RFC PATCH v4 01/10] KVM: x86: Add is_vm_type_supported callback

[isaku . yamahata]

From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>

For TDX, allow the backend can override the supported vm type.  Add
KVM_X86_TDX_VM to reserve the bit.

Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>

---
Changes v3 -> v4:
- Added KVM_X86_SNP_VM

Changes v2 -> v3:
- no change
- didn't bother to rename KVM_X86_PROTECTED_VM to KVM_X86_SW_PROTECTED_VM

Changes v1 -> v2
- no change
---
 arch/x86/include/asm/kvm-x86-ops.h |  1 +
 arch/x86/include/asm/kvm_host.h    |  1 +
 arch/x86/include/uapi/asm/kvm.h    |  2 ++
 arch/x86/kvm/svm/svm.c             |  7 +++++++
 arch/x86/kvm/vmx/vmx.c             |  7 +++++++
 arch/x86/kvm/x86.c                 | 12 +++++++++++-
 arch/x86/kvm/x86.h                 |  2 ++
 7 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h
index 13bc212cd4bc..c0143906fe6d 100644
--- a/arch/x86/include/asm/kvm-x86-ops.h
+++ b/arch/x86/include/asm/kvm-x86-ops.h
@@ -20,6 +20,7 @@ KVM_X86_OP(hardware_disable)
 KVM_X86_OP(hardware_unsetup)
 KVM_X86_OP(has_emulated_msr)
 KVM_X86_OP(vcpu_after_set_cpuid)
+KVM_X86_OP(is_vm_type_supported)
 KVM_X86_OP(vm_init)
 KVM_X86_OP_OPTIONAL(vm_destroy)
 KVM_X86_OP_OPTIONAL_RET0(vcpu_precreate)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index bbefd79b7950..2c9350aa0da4 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1543,6 +1543,7 @@ struct kvm_x86_ops {
 	bool (*has_emulated_msr)(struct kvm *kvm, u32 index);
 	void (*vcpu_after_set_cpuid)(struct kvm_vcpu *vcpu);
 
+	bool (*is_vm_type_supported)(unsigned long vm_type);
 	unsigned int vm_size;
 	int (*vm_init)(struct kvm *kvm);
 	void (*vm_destroy)(struct kvm *kvm);
diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h
index a448d0964fc0..aa7a56a47564 100644
--- a/arch/x86/include/uapi/asm/kvm.h
+++ b/arch/x86/include/uapi/asm/kvm.h
@@ -564,5 +564,7 @@ struct kvm_pmu_event_filter {
 
 #define KVM_X86_DEFAULT_VM	0
 #define KVM_X86_SW_PROTECTED_VM	1
+#define KVM_X86_TDX_VM		2
+#define KVM_X86_SNP_VM		3
 
 #endif /* _ASM_X86_KVM_H */
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index d381ad424554..d681dd7ad397 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -4768,6 +4768,12 @@ static void svm_vm_destroy(struct kvm *kvm)
 	sev_vm_destroy(kvm);
 }
 
+static bool svm_is_vm_type_supported(unsigned long type)
+{
+	/* FIXME: Check if CPU is capable of SEV-SNP. */
+	return __kvm_is_vm_type_supported(type);
+}
+
 static int svm_vm_init(struct kvm *kvm)
 {
 	if (!pause_filter_count || !pause_filter_thresh)
@@ -4796,6 +4802,7 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
 	.vcpu_free = svm_vcpu_free,
 	.vcpu_reset = svm_vcpu_reset,
 
+	.is_vm_type_supported = svm_is_vm_type_supported,
 	.vm_size = sizeof(struct kvm_svm),
 	.vm_init = svm_vm_init,
 	.vm_destroy = svm_vm_destroy,
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 946380b53cf5..693f07b80966 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7511,6 +7511,12 @@ static int vmx_vcpu_create(struct kvm_vcpu *vcpu)
 	return err;
 }
 
+static bool vmx_is_vm_type_supported(unsigned long type)
+{
+	/* TODO: Check if TDX is supported. */
+	return __kvm_is_vm_type_supported(type);
+}
+
 #define L1TF_MSG_SMT "L1TF CPU bug present and SMT on, data leak possible. See CVE-2018-3646 and https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/l1tf.html for details.\n"
 #define L1TF_MSG_L1D "L1TF CPU bug present and virtualization mitigation disabled, data leak possible. See CVE-2018-3646 and https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/l1tf.html for details.\n"
 
@@ -8180,6 +8186,7 @@ static struct kvm_x86_ops vmx_x86_ops __initdata = {
 	.hardware_disable = vmx_hardware_disable,
 	.has_emulated_msr = vmx_has_emulated_msr,
 
+	.is_vm_type_supported = vmx_is_vm_type_supported,
 	.vm_size = sizeof(struct kvm_vmx),
 	.vm_init = vmx_vm_init,
 	.vm_destroy = vmx_vm_destroy,
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index de195ad83ec0..fd6c05d1883c 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4427,12 +4427,18 @@ static int kvm_ioctl_get_supported_hv_cpuid(struct kvm_vcpu *vcpu,
 	return 0;
 }
 
-static bool kvm_is_vm_type_supported(unsigned long type)
+bool __kvm_is_vm_type_supported(unsigned long type)
 {
 	return type == KVM_X86_DEFAULT_VM ||
 	       (type == KVM_X86_SW_PROTECTED_VM &&
 		IS_ENABLED(CONFIG_KVM_SW_PROTECTED_VM) && tdp_enabled);
 }
+EXPORT_SYMBOL_GPL(__kvm_is_vm_type_supported);
+
+static bool kvm_is_vm_type_supported(unsigned long type)
+{
+	return static_call(kvm_x86_is_vm_type_supported)(type);
+}
 
 int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 {
@@ -4628,6 +4634,10 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 		r = BIT(KVM_X86_DEFAULT_VM);
 		if (kvm_is_vm_type_supported(KVM_X86_SW_PROTECTED_VM))
 			r |= BIT(KVM_X86_SW_PROTECTED_VM);
+		if (kvm_is_vm_type_supported(KVM_X86_TDX_VM))
+			r |= BIT(KVM_X86_TDX_VM);
+		if (kvm_is_vm_type_supported(KVM_X86_SNP_VM))
+			r |= BIT(KVM_X86_SNP_VM);
 		break;
 	default:
 		break;
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index 82e3dafc5453..7de3a45f655a 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -9,6 +9,8 @@
 #include "kvm_cache_regs.h"
 #include "kvm_emulate.h"
 
+bool __kvm_is_vm_type_supported(unsigned long type);
+
 struct kvm_caps {
 	/* control of guest tsc rate supported? */
 	bool has_tsc_control;
-- 
2.25.1