Message-Id: <22eed5c3e61c8a05a8870f2b40f89f954a8112ef.1678643052.git.isaku.yamahata@intel.com>
Date:   Sun, 12 Mar 2023 10:55:44 -0700
From:   isaku.yamahata@...el.com
To:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     isaku.yamahata@...el.com, isaku.yamahata@...il.com,
        Paolo Bonzini <pbonzini@...hat.com>, erdemaktas@...gle.com,
        Sean Christopherson <seanjc@...gle.com>,
        Sagi Shahar <sagis@...gle.com>,
        David Matlack <dmatlack@...gle.com>,
        Kai Huang <kai.huang@...el.com>,
        Zhi Wang <zhi.wang.linux@...il.com>,
        Xiaoyao Li <xiaoyao.li@...el.com>
Subject: [PATCH v13 020/113] KVM: TDX: initialize VM with TDX specific parameters

From: Isaku Yamahata <isaku.yamahata@...el.com>

TDX requires additional parameters for TDX VM for confidential execution to
protect its confidentiality of its memory contents and its CPU state from
any other software, including VMM. When creating guest TD VM before
creating vcpu, the number of vcpu, TSC frequency (that is same among
vcpus. and it can't be changed.)  CPUIDs which is emulated by the TDX
module. It means guest can trust those CPUIDs. and sha384 values for
measurement.

Add new subcommand, KVM_TDX_INIT_VM, to pass parameters for TDX guest.  It
assigns encryption key to the TDX guest for memory encryption.  TDX
encrypts memory per-guest bases.  It assigns device model passes per-VM
parameters for the TDX guest.  The maximum number of vcpus, tsc frequency
(TDX guest has fised VM-wide TSC frequency. not per-vcpu.  The TDX guest
can not change it.), attributes (production or debug), available extended
features (which is reflected into guest XCR0, IA32_XSS MSR), cpuids, sha384
measurements, and etc.

This subcommand is called before creating vcpu and KVM_SET_CPUID2, i.e.
cpuids configurations aren't available yet.  So CPUIDs configuration values
needs to be passed in struct kvm_tdx_init_vm.  It's device model
responsibility to make this cpuid config for KVM_TDX_INIT_VM and
KVM_SET_CPUID2.

Signed-off-by: Xiaoyao Li <xiaoyao.li@...el.com>
Signed-off-by: Isaku Yamahata <isaku.yamahata@...el.com>
---
Changes from v11 to v12
- ABI change. Changes struct kvm_tdx_init_vm layout
---
 arch/x86/include/asm/tdx.h            |   3 +
 arch/x86/include/uapi/asm/kvm.h       |  24 +++
 arch/x86/kvm/cpuid.c                  |   7 +
 arch/x86/kvm/cpuid.h                  |   2 +
 arch/x86/kvm/vmx/tdx.c                | 247 ++++++++++++++++++++++++--
 arch/x86/kvm/vmx/tdx.h                |  18 ++
 tools/arch/x86/include/uapi/asm/kvm.h |  33 ++++
 7 files changed, 324 insertions(+), 10 deletions(-)

diff --git a/arch/x86/include/asm/tdx.h b/arch/x86/include/asm/tdx.h
index 05870e5ed131..bd09b03d7edd 100644
--- a/arch/x86/include/asm/tdx.h
+++ b/arch/x86/include/asm/tdx.h
@@ -101,6 +101,9 @@ static inline long tdx_kvm_hypercall(unsigned int nr, unsigned long p1,
 #endif /* CONFIG_INTEL_TDX_GUEST && CONFIG_KVM_GUEST */
 
 #ifdef CONFIG_INTEL_TDX_HOST
+
+/* -1 indicates CPUID leaf with no sub-leaves. */
+#define TDX_CPUID_NO_SUBLEAF	((u32)-1)
 struct tdx_cpuid_config {
 	u32	leaf;
 	u32	sub_leaf;
diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h
index af4c5bd0af1c..68e8d544afe5 100644
--- a/arch/x86/include/uapi/asm/kvm.h
+++ b/arch/x86/include/uapi/asm/kvm.h
@@ -565,6 +565,7 @@ struct kvm_pmu_event_filter {
 /* Trust Domain eXtension sub-ioctl() commands. */
 enum kvm_tdx_cmd_id {
 	KVM_TDX_CAPABILITIES = 0,
+	KVM_TDX_INIT_VM,
 
 	KVM_TDX_CMD_NR_MAX,
 };
@@ -610,4 +611,27 @@ struct kvm_tdx_capabilities {
 	struct kvm_tdx_cpuid_config cpuid_configs[0];
 };
 
+struct kvm_tdx_init_vm {
+	__u64 attributes;
+	__u64 mrconfigid[6];	/* sha384 digest */
+	__u64 mrowner[6];	/* sha384 digest */
+	__u64 mrownerconfig[6];	/* sha348 digest */
+	/*
+	 * For future extensibility to make sizeof(struct kvm_tdx_init_vm) = 8KB.
+	 * This should be enough given sizeof(TD_PARAMS) = 1024.
+	 * 8KB was chosen given because
+	 * sizeof(struct kvm_cpuid_entry2) * KVM_MAX_CPUID_ENTRIES(=256) = 8KB.
+	 */
+	__u64 reserved[1004];
+
+	/*
+	 * KVM_TDX_INIT_VM is called before vcpu creation, thus before
+	 * KVM_SET_CPUID2.
+	 * This configuration supersedes KVM_SET_CPUID2s for VCPUs. The user
+	 * space VMM, e.g. qemu, should make KVM_SET_CPUID2 consistent with this
+	 * values.
+	 */
+	struct kvm_cpuid2 cpuid;
+};
+
 #endif /* _ASM_X86_KVM_H */
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 599aebec2d52..9cda9a3a558a 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -1386,6 +1386,13 @@ int kvm_dev_ioctl_get_cpuid(struct kvm_cpuid2 *cpuid,
 	return r;
 }
 
+struct kvm_cpuid_entry2 *kvm_find_cpuid_entry2( struct kvm_cpuid2 *cpuid,
+						u32 function, u32 index)
+{
+	return cpuid_entry2_find(cpuid->entries, cpuid->nent, function, index);
+}
+EXPORT_SYMBOL_GPL(kvm_find_cpuid_entry2);
+
 struct kvm_cpuid_entry2 *kvm_find_cpuid_entry_index(struct kvm_vcpu *vcpu,
 						    u32 function, u32 index)
 {
diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h
index b1658c0de847..a0e799297629 100644
--- a/arch/x86/kvm/cpuid.h
+++ b/arch/x86/kvm/cpuid.h
@@ -13,6 +13,8 @@ void kvm_set_cpu_caps(void);
 
 void kvm_update_cpuid_runtime(struct kvm_vcpu *vcpu);
 void kvm_update_pv_runtime(struct kvm_vcpu *vcpu);
+struct kvm_cpuid_entry2 *kvm_find_cpuid_entry2(struct kvm_cpuid2 *cpuid,
+					       u32 function, u32 index);
 struct kvm_cpuid_entry2 *kvm_find_cpuid_entry_index(struct kvm_vcpu *vcpu,
 						    u32 function, u32 index);
 struct kvm_cpuid_entry2 *kvm_find_cpuid_entry(struct kvm_vcpu *vcpu,
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index 3ede8a726b47..496410ec6334 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -6,7 +6,6 @@
 #include "capabilities.h"
 #include "x86_ops.h"
 #include "tdx.h"
-#include "tdx_ops.h"
 #include "x86.h"
 
 #undef pr_fmt
@@ -303,18 +302,21 @@ static int tdx_do_tdh_mng_key_config(void *param)
 	return 0;
 }
 
-static int __tdx_td_init(struct kvm *kvm);
-
 int tdx_vm_init(struct kvm *kvm)
 {
+	/*
+	 * This function initializes only KVM software construct.  It doesn't
+	 * initialize TDX stuff, e.g. TDCS, TDR, TDCX, HKID etc.
+	 * It is handled by KVM_TDX_INIT_VM, __tdx_td_init().
+	 */
+
 	/*
 	 * TDX has its own limit of the number of vcpus in addition to
 	 * KVM_MAX_VCPUS.
 	 */
 	kvm->max_vcpus = min(kvm->max_vcpus, TDX_MAX_VCPUS);
 
-	/* Place holder for TDX specific logic. */
-	return __tdx_td_init(kvm);
+	return 0;
 }
 
 int tdx_dev_ioctl(void __user *argp)
@@ -368,9 +370,162 @@ int tdx_dev_ioctl(void __user *argp)
 	return 0;
 }
 
-static int __tdx_td_init(struct kvm *kvm)
+static void setup_tdparams_eptp_controls(struct kvm_cpuid2 *cpuid, struct td_params *td_params)
+{
+	const struct kvm_cpuid_entry2 *entry;
+	int max_pa = 36;
+
+	entry = kvm_find_cpuid_entry2(cpuid, 0x80000008, 0);
+	if (entry)
+		max_pa = entry->eax & 0xff;
+
+	td_params->eptp_controls = VMX_EPTP_MT_WB;
+	/*
+	 * No CPU supports 4-level && max_pa > 48.
+	 * "5-level paging and 5-level EPT" section 4.1 4-level EPT
+	 * "4-level EPT is limited to translating 48-bit guest-physical
+	 *  addresses."
+	 * cpu_has_vmx_ept_5levels() check is just in case.
+	 */
+	if (cpu_has_vmx_ept_5levels() && max_pa > 48) {
+		td_params->eptp_controls |= VMX_EPTP_PWL_5;
+		td_params->exec_controls |= TDX_EXEC_CONTROL_MAX_GPAW;
+	} else {
+		td_params->eptp_controls |= VMX_EPTP_PWL_4;
+	}
+}
+
+static void setup_tdparams_cpuids(const struct tdsysinfo_struct *tdsysinfo,
+				  struct kvm_cpuid2 *cpuid,
+				  struct td_params *td_params)
+{
+	int i;
+
+	/*
+	 * td_params.cpuid_values: The number and the order of cpuid_value must
+	 * be same to the one of struct tdsysinfo.{num_cpuid_config, cpuid_configs}
+	 * It's assumed that td_params was zeroed.
+	 */
+	for (i = 0; i < tdsysinfo->num_cpuid_config; i++) {
+		const struct tdx_cpuid_config *config = &tdsysinfo->cpuid_configs[i];
+		/* TDX_CPUID_NO_SUBLEAF in TDX CPUID_CONFIG means index = 0. */
+		u32 index = config->sub_leaf == TDX_CPUID_NO_SUBLEAF ? 0: config->sub_leaf;
+		const struct kvm_cpuid_entry2 *entry =
+			kvm_find_cpuid_entry2(cpuid, config->leaf, index);
+		struct tdx_cpuid_value *value = &td_params->cpuid_values[i];
+
+		if (!entry)
+			continue;
+
+		/*
+		 * tdsysinfo.cpuid_configs[].{eax, ebx, ecx, edx}
+		 * bit 1 means it can be configured to zero or one.
+		 * bit 0 means it must be zero.
+		 * Mask out non-configurable bits.
+		 */
+		value->eax = entry->eax & config->eax;
+		value->ebx = entry->ebx & config->ebx;
+		value->ecx = entry->ecx & config->ecx;
+		value->edx = entry->edx & config->edx;
+	}
+}
+
+static int setup_tdparams_xfam(struct kvm_cpuid2 *cpuid, struct td_params *td_params)
+{
+	const struct kvm_cpuid_entry2 *entry;
+	u64 guest_supported_xcr0;
+	u64 guest_supported_xss;
+
+	/* Setup td_params.xfam */
+	entry = kvm_find_cpuid_entry2(cpuid, 0xd, 0);
+	if (entry)
+		guest_supported_xcr0 = (entry->eax | ((u64)entry->edx << 32));
+	else
+		guest_supported_xcr0 = 0;
+	guest_supported_xcr0 &= kvm_caps.supported_xcr0;
+
+	entry = kvm_find_cpuid_entry2(cpuid, 0xd, 1);
+	if (entry)
+		guest_supported_xss = (entry->ecx | ((u64)entry->edx << 32));
+	else
+		guest_supported_xss = 0;
+	/* PT can be exposed to TD guest regardless of KVM's XSS support */
+	guest_supported_xss &= (kvm_caps.supported_xss | XFEATURE_MASK_PT);
+
+	td_params->xfam = guest_supported_xcr0 | guest_supported_xss;
+	if (td_params->xfam & XFEATURE_MASK_LBR) {
+		/*
+		 * TODO: once KVM supports LBR(save/restore LBR related
+		 * registers around TDENTER), remove this guard.
+		 */
+		pr_warn("TD doesn't support LBR yet. KVM needs to save/restore "
+			"IA32_LBR_DEPTH properly.\n");
+		return -EOPNOTSUPP;
+	}
+
+	if (td_params->xfam & XFEATURE_MASK_XTILE) {
+		/*
+		 * TODO: once KVM supports AMX(save/restore AMX related
+		 * registers around TDENTER), remove this guard.
+		 */
+		pr_warn("TD doesn't support AMX yet. KVM needs to save/restore "
+			"IA32_XFD, IA32_XFD_ERR properly.\n");
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+static int setup_tdparams(struct kvm *kvm, struct td_params *td_params,
+			struct kvm_tdx_init_vm *init_vm)
+{
+	struct kvm_cpuid2 *cpuid = &init_vm->cpuid;
+	const struct tdsysinfo_struct *tdsysinfo;
+	int ret;
+
+	tdsysinfo = tdx_get_sysinfo();
+	if (!tdsysinfo)
+		return -ENOTSUPP;
+	if (kvm->created_vcpus)
+		return -EBUSY;
+
+	if (td_params->attributes & TDX_TD_ATTRIBUTE_PERFMON) {
+		/*
+		 * TODO: save/restore PMU related registers around TDENTER.
+		 * Once it's done, remove this guard.
+		 */
+		pr_warn("TD doesn't support perfmon yet. KVM needs to save/restore "
+			"host perf registers properly.\n");
+		return -EOPNOTSUPP;
+	}
+
+	td_params->max_vcpus = kvm->max_vcpus;
+	td_params->attributes = init_vm->attributes;
+	td_params->tsc_frequency = TDX_TSC_KHZ_TO_25MHZ(kvm->arch.default_tsc_khz);
+
+	setup_tdparams_eptp_controls(cpuid, td_params);
+	setup_tdparams_cpuids(tdsysinfo, cpuid, td_params);
+	ret = setup_tdparams_xfam(cpuid, td_params);
+	if (ret)
+		return ret;
+
+#define MEMCPY_SAME_SIZE(dst, src)				\
+	do {							\
+		BUILD_BUG_ON(sizeof(dst) != sizeof(src));	\
+		memcpy((dst), (src), sizeof(dst));		\
+	} while (0)
+
+	MEMCPY_SAME_SIZE(td_params->mrconfigid, init_vm->mrconfigid);
+	MEMCPY_SAME_SIZE(td_params->mrowner, init_vm->mrowner);
+	MEMCPY_SAME_SIZE(td_params->mrownerconfig, init_vm->mrownerconfig);
+
+	return 0;
+}
+
+static int __tdx_td_init(struct kvm *kvm, struct td_params *td_params)
 {
 	struct kvm_tdx *kvm_tdx = to_kvm_tdx(kvm);
+	struct tdx_module_output out;
 	cpumask_var_t packages;
 	unsigned long *tdcs_pa = NULL;
 	unsigned long tdr_pa = 0;
@@ -484,10 +639,13 @@ static int __tdx_td_init(struct kvm *kvm)
 		}
 	}
 
-	/*
-	 * Note, TDH_MNG_INIT cannot be invoked here.  TDH_MNG_INIT requires a dedicated
-	 * ioctl() to define the configure CPUID values for the TD.
-	 */
+	err = tdh_mng_init(kvm_tdx->tdr_pa, __pa(td_params), &out);
+	if (WARN_ON_ONCE(err)) {
+		pr_tdx_error(TDH_MNG_INIT, err, &out);
+		ret = -EIO;
+		goto teardown;
+	}
+
 	return 0;
 
 	/*
@@ -522,6 +680,72 @@ static int __tdx_td_init(struct kvm *kvm)
 	return ret;
 }
 
+static int tdx_td_init(struct kvm *kvm, struct kvm_tdx_cmd *cmd)
+{
+	struct kvm_tdx *kvm_tdx = to_kvm_tdx(kvm);
+	struct kvm_tdx_init_vm *init_vm = NULL;
+	struct td_params *td_params = NULL;
+	int ret;
+
+	BUILD_BUG_ON(sizeof(*init_vm) != 8 * 1024);
+	BUILD_BUG_ON(sizeof(struct td_params) != 1024);
+
+	if (is_hkid_assigned(kvm_tdx))
+		return -EINVAL;
+
+	if (cmd->flags)
+		return -EINVAL;
+
+	init_vm = kzalloc(sizeof(*init_vm) +
+			  sizeof(init_vm->cpuid.entries[0]) * KVM_MAX_CPUID_ENTRIES,
+			  GFP_KERNEL);
+	if (!init_vm)
+		return -ENOMEM;
+	if (copy_from_user(init_vm, (void __user *)cmd->data, sizeof(*init_vm))) {
+		ret = -EFAULT;
+		goto out;
+	}
+	if (init_vm->cpuid.nent > KVM_MAX_CPUID_ENTRIES) {
+		ret = -E2BIG;
+		goto out;
+	}
+	if (copy_from_user(init_vm->cpuid.entries,
+			   (void __user *)cmd->data + sizeof(*init_vm),
+			   sizeof(init_vm->cpuid.entries[0]) * init_vm->cpuid.nent)) {
+		ret = -EFAULT;
+		goto out;
+	}
+
+	if (init_vm->cpuid.padding) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	td_params = kzalloc(sizeof(struct td_params), GFP_KERNEL);
+	if (!td_params) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	ret = setup_tdparams(kvm, td_params, init_vm);
+	if (ret)
+		goto out;
+
+	ret = __tdx_td_init(kvm, td_params);
+	if (ret)
+		goto out;
+
+	kvm_tdx->tsc_offset = td_tdcs_exec_read64(kvm_tdx, TD_TDCS_EXEC_TSC_OFFSET);
+	kvm_tdx->attributes = td_params->attributes;
+	kvm_tdx->xfam = td_params->xfam;
+
+out:
+	/* kfree() accepts NULL. */
+	kfree(init_vm);
+	kfree(td_params);
+	return ret;
+}
+
 int tdx_vm_ioctl(struct kvm *kvm, void __user *argp)
 {
 	struct kvm_tdx_cmd tdx_cmd;
@@ -535,6 +759,9 @@ int tdx_vm_ioctl(struct kvm *kvm, void __user *argp)
 	mutex_lock(&kvm->lock);
 
 	switch (tdx_cmd.id) {
+	case KVM_TDX_INIT_VM:
+		r = tdx_td_init(kvm, &tdx_cmd);
+		break;
 	default:
 		r = -EINVAL;
 		goto out;
diff --git a/arch/x86/kvm/vmx/tdx.h b/arch/x86/kvm/vmx/tdx.h
index 4b790503e43e..1e00e75b1c5e 100644
--- a/arch/x86/kvm/vmx/tdx.h
+++ b/arch/x86/kvm/vmx/tdx.h
@@ -12,7 +12,11 @@ struct kvm_tdx {
 	unsigned long tdr_pa;
 	unsigned long *tdcs_pa;
 
+	u64 attributes;
+	u64 xfam;
 	int hkid;
+
+	u64 tsc_offset;
 };
 
 struct vcpu_tdx {
@@ -39,6 +43,20 @@ static inline struct vcpu_tdx *to_tdx(struct kvm_vcpu *vcpu)
 {
 	return container_of(vcpu, struct vcpu_tdx, vcpu);
 }
+
+static __always_inline u64 td_tdcs_exec_read64(struct kvm_tdx *kvm_tdx, u32 field)
+{
+	struct tdx_module_output out;
+	u64 err;
+
+	err = tdh_mng_rd(kvm_tdx->tdr_pa, TDCS_EXEC(field), &out);
+	if (unlikely(err)) {
+		pr_err("TDH_MNG_RD[EXEC.0x%x] failed: 0x%llx\n", field, err);
+		return 0;
+	}
+	return out.r8;
+}
+
 #else
 struct kvm_tdx {
 	struct kvm kvm;
diff --git a/tools/arch/x86/include/uapi/asm/kvm.h b/tools/arch/x86/include/uapi/asm/kvm.h
index af4c5bd0af1c..c0f011384934 100644
--- a/tools/arch/x86/include/uapi/asm/kvm.h
+++ b/tools/arch/x86/include/uapi/asm/kvm.h
@@ -565,6 +565,7 @@ struct kvm_pmu_event_filter {
 /* Trust Domain eXtension sub-ioctl() commands. */
 enum kvm_tdx_cmd_id {
 	KVM_TDX_CAPABILITIES = 0,
+	KVM_TDX_INIT_VM,
 
 	KVM_TDX_CMD_NR_MAX,
 };
@@ -610,4 +611,36 @@ struct kvm_tdx_capabilities {
 	struct kvm_tdx_cpuid_config cpuid_configs[0];
 };
 
+struct kvm_tdx_init_vm {
+	__u64 attributes;
+	__u32 max_vcpus;
+	__u32 padding;
+	__u64 mrconfigid[6];    /* sha384 digest */
+	__u64 mrowner[6];       /* sha384 digest */
+	__u64 mrownerconfig[6]; /* sha348 digest */
+	union {
+		/*
+		 * KVM_TDX_INIT_VM is called before vcpu creation, thus before
+		 * KVM_SET_CPUID2.  CPUID configurations needs to be passed.
+		 *
+		 * This configuration supersedes KVM_SET_CPUID{,2}.
+		 * The user space VMM, e.g. qemu, should make them consistent
+		 * with this values.
+		 * sizeof(struct kvm_cpuid_entry2) * KVM_MAX_CPUID_ENTRIES(256)
+		 * = 8KB.
+		 */
+		struct {
+			struct kvm_cpuid2 cpuid;
+			/* 8KB with KVM_MAX_CPUID_ENTRIES. */
+			struct kvm_cpuid_entry2 entries[];
+		};
+		/*
+		 * For future extensibility.
+		 * The size(struct kvm_tdx_init_vm) = 16KB.
+		 * This should be enough given sizeof(TD_PARAMS) = 1024
+		 */
+		__u64 reserved[2028];
+	};
+};
+
 #endif /* _ASM_X86_KVM_H */
-- 
2.25.1

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