Re: [PATCH v19 034/130] KVM: TDX: Get system-wide info about TDX module on initialization

Binbin Wu <binbin.wu@xxxxxxxxxxxxxxx> · Thu, 14 Mar 2024 23:06:09 +0800

On 2/26/2024 4:25 PM, isaku.yamahata@xxxxxxxxx wrote:
From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>

TDX KVM needs system-wide information about the TDX module, store it in
struct tdx_info.

Nit: Maybe you can add some description about hardware_unsetup()?

Reviewed-by: Binbin Wu <binbin.wu@xxxxxxxxxxxxxxx>

Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
---
v19:
- Added features0
- Use tdx_sys_metadata_read()
- Fix error recovery path by Yuan

Change v18:
- Newly Added

Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
---
  arch/x86/include/uapi/asm/kvm.h | 11 +++++
  arch/x86/kvm/vmx/main.c         |  9 +++-
  arch/x86/kvm/vmx/tdx.c          | 80 ++++++++++++++++++++++++++++++++-
  arch/x86/kvm/vmx/x86_ops.h      |  2 +
  4 files changed, 100 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h
index aa7a56a47564..45b2c2304491 100644
--- a/arch/x86/include/uapi/asm/kvm.h
+++ b/arch/x86/include/uapi/asm/kvm.h
@@ -567,4 +567,15 @@ struct kvm_pmu_event_filter {
  #define KVM_X86_TDX_VM		2
  #define KVM_X86_SNP_VM		3
  
+#define KVM_TDX_CPUID_NO_SUBLEAF	((__u32)-1)
+
+struct kvm_tdx_cpuid_config {
+	__u32 leaf;
+	__u32 sub_leaf;
+	__u32 eax;
+	__u32 ebx;
+	__u32 ecx;
+	__u32 edx;
+};
+
  #endif /* _ASM_X86_KVM_H */
diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
index fa19682b366c..a948a6959ac7 100644
--- a/arch/x86/kvm/vmx/main.c
+++ b/arch/x86/kvm/vmx/main.c
@@ -32,6 +32,13 @@ static __init int vt_hardware_setup(void)
  	return 0;
  }
  
+static void vt_hardware_unsetup(void)
+{
+	if (enable_tdx)
+		tdx_hardware_unsetup();
+	vmx_hardware_unsetup();
+}
+
  static int vt_vm_init(struct kvm *kvm)
  {
  	if (is_td(kvm))
@@ -54,7 +61,7 @@ struct kvm_x86_ops vt_x86_ops __initdata = {
  
  	.check_processor_compatibility = vmx_check_processor_compat,
  
-	.hardware_unsetup = vmx_hardware_unsetup,
+	.hardware_unsetup = vt_hardware_unsetup,
  
  	/* TDX cpu enablement is done by tdx_hardware_setup(). */
  	.hardware_enable = vmx_hardware_enable,
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index dce21f675155..5edfb99abb89 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -40,6 +40,21 @@ static void __used tdx_guest_keyid_free(int keyid)
  	ida_free(&tdx_guest_keyid_pool, keyid);
  }
  
+struct tdx_info {
+	u64 features0;
+	u64 attributes_fixed0;
+	u64 attributes_fixed1;
+	u64 xfam_fixed0;
+	u64 xfam_fixed1;
+
+	u16 num_cpuid_config;
+	/* This must the last member. */
+	DECLARE_FLEX_ARRAY(struct kvm_tdx_cpuid_config, cpuid_configs);
+};
+
+/* Info about the TDX module. */
+static struct tdx_info *tdx_info;
+
  #define TDX_MD_MAP(_fid, _ptr)			\
  	{ .fid = MD_FIELD_ID_##_fid,		\
  	  .ptr = (_ptr), }
@@ -66,7 +81,7 @@ static size_t tdx_md_element_size(u64 fid)
  	}
  }
  
-static int __used tdx_md_read(struct tdx_md_map *maps, int nr_maps)
+static int tdx_md_read(struct tdx_md_map *maps, int nr_maps)
  {
  	struct tdx_md_map *m;
  	int ret, i;
@@ -84,9 +99,26 @@ static int __used tdx_md_read(struct tdx_md_map *maps, int nr_maps)
  	return 0;
  }
  
+#define TDX_INFO_MAP(_field_id, _member)			\
+	TD_SYSINFO_MAP(_field_id, struct tdx_info, _member)
+
  static int __init tdx_module_setup(void)
  {
+	u16 num_cpuid_config;
  	int ret;
+	u32 i;
+
+	struct tdx_md_map mds[] = {
+		TDX_MD_MAP(NUM_CPUID_CONFIG, &num_cpuid_config),
+	};
+
+	struct tdx_metadata_field_mapping fields[] = {
+		TDX_INFO_MAP(FEATURES0, features0),
+		TDX_INFO_MAP(ATTRS_FIXED0, attributes_fixed0),
+		TDX_INFO_MAP(ATTRS_FIXED1, attributes_fixed1),
+		TDX_INFO_MAP(XFAM_FIXED0, xfam_fixed0),
+		TDX_INFO_MAP(XFAM_FIXED1, xfam_fixed1),
+	};
  
  	ret = tdx_enable();
  	if (ret) {
@@ -94,7 +126,48 @@ static int __init tdx_module_setup(void)
  		return ret;
  	}
  
+	ret = tdx_md_read(mds, ARRAY_SIZE(mds));
+	if (ret)
+		return ret;
+
+	tdx_info = kzalloc(sizeof(*tdx_info) +
+			   sizeof(*tdx_info->cpuid_configs) * num_cpuid_config,
+			   GFP_KERNEL);
+	if (!tdx_info)
+		return -ENOMEM;
+	tdx_info->num_cpuid_config = num_cpuid_config;
+
+	ret = tdx_sys_metadata_read(fields, ARRAY_SIZE(fields), tdx_info);
+	if (ret)
+		goto error_out;
+
+	for (i = 0; i < num_cpuid_config; i++) {
+		struct kvm_tdx_cpuid_config *c = &tdx_info->cpuid_configs[i];
+		u64 leaf, eax_ebx, ecx_edx;
+		struct tdx_md_map cpuids[] = {
+			TDX_MD_MAP(CPUID_CONFIG_LEAVES + i, &leaf),
+			TDX_MD_MAP(CPUID_CONFIG_VALUES + i * 2, &eax_ebx),
+			TDX_MD_MAP(CPUID_CONFIG_VALUES + i * 2 + 1, &ecx_edx),
+		};
+
+		ret = tdx_md_read(cpuids, ARRAY_SIZE(cpuids));
+		if (ret)
+			goto error_out;
+
+		c->leaf = (u32)leaf;
+		c->sub_leaf = leaf >> 32;
+		c->eax = (u32)eax_ebx;
+		c->ebx = eax_ebx >> 32;
+		c->ecx = (u32)ecx_edx;
+		c->edx = ecx_edx >> 32;
+	}
+
  	return 0;
+
+error_out:
+	/* kfree() accepts NULL. */
+	kfree(tdx_info);
+	return ret;
  }
  
  bool tdx_is_vm_type_supported(unsigned long type)
@@ -162,3 +235,8 @@ int __init tdx_hardware_setup(struct kvm_x86_ops *x86_ops)
  out:
  	return r;
  }
+
+void tdx_hardware_unsetup(void)
+{
+	kfree(tdx_info);
+}
diff --git a/arch/x86/kvm/vmx/x86_ops.h b/arch/x86/kvm/vmx/x86_ops.h
index f4da88a228d0..e8cb4ae81cf1 100644
--- a/arch/x86/kvm/vmx/x86_ops.h
+++ b/arch/x86/kvm/vmx/x86_ops.h
@@ -136,9 +136,11 @@ void vmx_setup_mce(struct kvm_vcpu *vcpu);
  
  #ifdef CONFIG_INTEL_TDX_HOST
  int __init tdx_hardware_setup(struct kvm_x86_ops *x86_ops);
+void tdx_hardware_unsetup(void);
  bool tdx_is_vm_type_supported(unsigned long type);
  #else
  static inline int tdx_hardware_setup(struct kvm_x86_ops *x86_ops) { return -EOPNOTSUPP; }
+static inline void tdx_hardware_unsetup(void) {}
  static inline bool tdx_is_vm_type_supported(unsigned long type) { return false; }
  #endif
  








