Message-Id: <20240812224820.34826-19-rick.p.edgecombe@intel.com>
Date: Mon, 12 Aug 2024 15:48:13 -0700
From: Rick Edgecombe <rick.p.edgecombe@...el.com>
To: seanjc@...gle.com,
	pbonzini@...hat.com,
	kvm@...r.kernel.org
Cc: kai.huang@...el.com,
	isaku.yamahata@...il.com,
	tony.lindgren@...ux.intel.com,
	xiaoyao.li@...el.com,
	linux-kernel@...r.kernel.org,
	rick.p.edgecombe@...el.com,
	Isaku Yamahata <isaku.yamahata@...el.com>,
	Sean Christopherson <sean.j.christopherson@...el.com>
Subject: [PATCH 18/25] KVM: TDX: Do TDX specific vcpu initialization

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

TD guest vcpu needs TDX specific initialization before running.  Repurpose
KVM_MEMORY_ENCRYPT_OP to vcpu-scope, add a new sub-command
KVM_TDX_INIT_VCPU, and implement the callback for it.

Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
Signed-off-by: Isaku Yamahata <isaku.yamahata@...el.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@...el.com>
---
uAPI breakout v1:
 - Support FEATURES0_TOPOLOGY_ENUM
 - Update for the wrapper functions for SEAMCALLs. (Sean)
 - Remove WARN_ON_ONCE() in tdx_vcpu_free().
   WARN_ON_ONCE(vcpu->cpu != -1), WARN_ON_ONCE(tdx->tdvpx_pa),
   WARN_ON_ONCE(tdx->tdvpr_pa)
 - Remove KVM_BUG_ON() in tdx_vcpu_reset().
 - Remove duplicate "tdx->tdvpr_pa=" lines
 - Rename tdvpx to tdcx as it is confusing, follow spec change for same
   reason (Isaku)
 - Updates from seamcall overhaul (Kai)
 - Rename error->hw_error
 - Change using tdx_info to using exported 'tdx_sysinfo' pointer in
   tdx_td_vcpu_init().
 - Remove code to the old (non-existing) tdx_module_setup().
 - Use a new wrapper tdx_sysinfo_nr_tdcx_pages() to replace
   tdx_info->nr_tdcx_pages.
 - Combine the two for loops in tdx_td_vcpu_init() (Chao)
 - Add more line breaks into tdx_td_vcpu_init() for readability (Tony)
 - Drop Drop local tdcx_pa in tdx_td_vcpu_init() (Rick)
 - Drop Drop local tdvpr_pa in tdx_td_vcpu_init() (Rick)

v18:
 - Use tdh_sys_rd() instead of struct tdsysinfo_struct.
 - Rename tdx_reclaim_td_page() => tdx_reclaim_control_page()
 - Remove the change of tools/arch/x86/include/uapi/asm/kvm.h.
---
 arch/x86/include/asm/kvm-x86-ops.h |   1 +
 arch/x86/include/asm/kvm_host.h    |   1 +
 arch/x86/include/uapi/asm/kvm.h    |   1 +
 arch/x86/kvm/vmx/main.c            |   9 ++
 arch/x86/kvm/vmx/tdx.c             | 193 ++++++++++++++++++++++++++++-
 arch/x86/kvm/vmx/tdx.h             |   6 +
 arch/x86/kvm/vmx/tdx_arch.h        |   2 +
 arch/x86/kvm/vmx/x86_ops.h         |   4 +
 arch/x86/kvm/x86.c                 |   6 +
 9 files changed, 221 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h
index 12ee66bc9026..5dd7955376e3 100644
--- a/arch/x86/include/asm/kvm-x86-ops.h
+++ b/arch/x86/include/asm/kvm-x86-ops.h
@@ -126,6 +126,7 @@ KVM_X86_OP(enable_smi_window)
 #endif
 KVM_X86_OP_OPTIONAL(dev_get_attr)
 KVM_X86_OP(mem_enc_ioctl)
+KVM_X86_OP_OPTIONAL(vcpu_mem_enc_ioctl)
 KVM_X86_OP_OPTIONAL(mem_enc_register_region)
 KVM_X86_OP_OPTIONAL(mem_enc_unregister_region)
 KVM_X86_OP_OPTIONAL(vm_copy_enc_context_from)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 188cd684bffb..e3094c843556 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1829,6 +1829,7 @@ struct kvm_x86_ops {
 
 	int (*dev_get_attr)(u32 group, u64 attr, u64 *val);
 	int (*mem_enc_ioctl)(struct kvm *kvm, void __user *argp);
+	int (*vcpu_mem_enc_ioctl)(struct kvm_vcpu *vcpu, void __user *argp);
 	int (*mem_enc_register_region)(struct kvm *kvm, struct kvm_enc_region *argp);
 	int (*mem_enc_unregister_region)(struct kvm *kvm, struct kvm_enc_region *argp);
 	int (*vm_copy_enc_context_from)(struct kvm *kvm, unsigned int source_fd);
diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h
index 95ae2d4a4697..b4f12997052d 100644
--- a/arch/x86/include/uapi/asm/kvm.h
+++ b/arch/x86/include/uapi/asm/kvm.h
@@ -930,6 +930,7 @@ struct kvm_hyperv_eventfd {
 enum kvm_tdx_cmd_id {
 	KVM_TDX_CAPABILITIES = 0,
 	KVM_TDX_INIT_VM,
+	KVM_TDX_INIT_VCPU,
 
 	KVM_TDX_CMD_NR_MAX,
 };
diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
index d40de73d2bd3..e34cb476cc78 100644
--- a/arch/x86/kvm/vmx/main.c
+++ b/arch/x86/kvm/vmx/main.c
@@ -116,6 +116,14 @@ static int vt_mem_enc_ioctl(struct kvm *kvm, void __user *argp)
 	return tdx_vm_ioctl(kvm, argp);
 }
 
+static int vt_vcpu_mem_enc_ioctl(struct kvm_vcpu *vcpu, void __user *argp)
+{
+	if (!is_td_vcpu(vcpu))
+		return -EINVAL;
+
+	return tdx_vcpu_ioctl(vcpu, argp);
+}
+
 #define VMX_REQUIRED_APICV_INHIBITS				\
 	(BIT(APICV_INHIBIT_REASON_DISABLED) |			\
 	 BIT(APICV_INHIBIT_REASON_ABSENT) |			\
@@ -268,6 +276,7 @@ struct kvm_x86_ops vt_x86_ops __initdata = {
 	.get_untagged_addr = vmx_get_untagged_addr,
 
 	.mem_enc_ioctl = vt_mem_enc_ioctl,
+	.vcpu_mem_enc_ioctl = vt_vcpu_mem_enc_ioctl,
 };
 
 struct kvm_x86_init_ops vt_init_ops __initdata = {
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index 18738cacbc87..ba7b436fae86 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -89,6 +89,11 @@ static __always_inline hpa_t set_hkid_to_hpa(hpa_t pa, u16 hkid)
 	return pa | ((hpa_t)hkid << boot_cpu_data.x86_phys_bits);
 }
 
+static inline bool is_td_vcpu_created(struct vcpu_tdx *tdx)
+{
+	return tdx->td_vcpu_created;
+}
+
 static inline bool is_td_created(struct kvm_tdx *kvm_tdx)
 {
 	return kvm_tdx->tdr_pa;
@@ -105,6 +110,11 @@ static inline bool is_hkid_assigned(struct kvm_tdx *kvm_tdx)
 	return kvm_tdx->hkid > 0;
 }
 
+static inline bool is_td_finalized(struct kvm_tdx *kvm_tdx)
+{
+	return kvm_tdx->finalized;
+}
+
 static void tdx_clear_page(unsigned long page_pa)
 {
 	const void *zero_page = (const void *) __va(page_to_phys(ZERO_PAGE(0)));
@@ -293,6 +303,15 @@ static inline u8 tdx_sysinfo_nr_tdcs_pages(void)
 	return tdx_sysinfo->td_ctrl.tdcs_base_size / PAGE_SIZE;
 }
 
+static inline u8 tdx_sysinfo_nr_tdcx_pages(void)
+{
+	/*
+	 * TDVPS = TDVPR(4K page) + TDCX(multiple 4K pages).
+	 * -1 for TDVPR.
+	 */
+	return tdx_sysinfo->td_ctrl.tdvps_base_size / PAGE_SIZE - 1;
+}
+
 void tdx_vm_free(struct kvm *kvm)
 {
 	struct kvm_tdx *kvm_tdx = to_kvm_tdx(kvm);
@@ -405,7 +424,29 @@ int tdx_vcpu_create(struct kvm_vcpu *vcpu)
 
 void tdx_vcpu_free(struct kvm_vcpu *vcpu)
 {
-	/* This is stub for now.  More logic will come. */
+	struct vcpu_tdx *tdx = to_tdx(vcpu);
+	int i;
+
+	/*
+	 * This methods can be called when vcpu allocation/initialization
+	 * failed. So it's possible that hkid, tdvpx and tdvpr are not assigned
+	 * yet.
+	 */
+	if (is_hkid_assigned(to_kvm_tdx(vcpu->kvm)))
+		return;
+
+	if (tdx->tdcx_pa) {
+		for (i = 0; i < tdx_sysinfo_nr_tdcx_pages(); i++) {
+			if (tdx->tdcx_pa[i])
+				tdx_reclaim_control_page(tdx->tdcx_pa[i]);
+		}
+		kfree(tdx->tdcx_pa);
+		tdx->tdcx_pa = NULL;
+	}
+	if (tdx->tdvpr_pa) {
+		tdx_reclaim_control_page(tdx->tdvpr_pa);
+		tdx->tdvpr_pa = 0;
+	}
 }
 
 void tdx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
@@ -414,8 +455,13 @@ void tdx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
 	/* Ignore INIT silently because TDX doesn't support INIT event. */
 	if (init_event)
 		return;
+	if (is_td_vcpu_created(to_tdx(vcpu)))
+		return;
 
-	/* This is stub for now. More logic will come here. */
+	/*
+	 * Don't update mp_state to runnable because more initialization
+	 * is needed by TDX_VCPU_INIT.
+	 */
 }
 
 static int tdx_get_capabilities(struct kvm_tdx_cmd *cmd)
@@ -884,6 +930,149 @@ int tdx_vm_ioctl(struct kvm *kvm, void __user *argp)
 	return r;
 }
 
+/* VMM can pass one 64bit auxiliary data to vcpu via RCX for guest BIOS. */
+static int tdx_td_vcpu_init(struct kvm_vcpu *vcpu, u64 vcpu_rcx)
+{
+	const struct tdx_sysinfo_module_info *modinfo = &tdx_sysinfo->module_info;
+	struct vcpu_tdx *tdx = to_tdx(vcpu);
+	unsigned long va;
+	int ret, i;
+	u64 err;
+
+	if (is_td_vcpu_created(tdx))
+		return -EINVAL;
+
+	/*
+	 * vcpu_free method frees allocated pages.  Avoid partial setup so
+	 * that the method can't handle it.
+	 */
+	va = __get_free_page(GFP_KERNEL_ACCOUNT);
+	if (!va)
+		return -ENOMEM;
+	tdx->tdvpr_pa = __pa(va);
+
+	tdx->tdcx_pa = kcalloc(tdx_sysinfo_nr_tdcx_pages(), sizeof(*tdx->tdcx_pa),
+			   GFP_KERNEL_ACCOUNT);
+	if (!tdx->tdcx_pa) {
+		ret = -ENOMEM;
+		goto free_tdvpr;
+	}
+
+	err = tdh_vp_create(tdx);
+	if (KVM_BUG_ON(err, vcpu->kvm)) {
+		tdx->tdvpr_pa = 0;
+		ret = -EIO;
+		pr_tdx_error(TDH_VP_CREATE, err);
+		goto free_tdvpx;
+	}
+
+	for (i = 0; i < tdx_sysinfo_nr_tdcx_pages(); i++) {
+		va = __get_free_page(GFP_KERNEL_ACCOUNT);
+		if (!va) {
+			ret = -ENOMEM;
+			goto free_tdvpx;
+		}
+		tdx->tdcx_pa[i] = __pa(va);
+
+		err = tdh_vp_addcx(tdx, tdx->tdcx_pa[i]);
+		if (KVM_BUG_ON(err, vcpu->kvm)) {
+			pr_tdx_error(TDH_VP_ADDCX, err);
+			/* vcpu_free method frees TDCX and TDR donated to TDX */
+			return -EIO;
+		}
+	}
+
+	if (modinfo->tdx_features0 & MD_FIELD_ID_FEATURES0_TOPOLOGY_ENUM)
+		err = tdh_vp_init_apicid(tdx, vcpu_rcx, vcpu->vcpu_id);
+	else
+		err = tdh_vp_init(tdx, vcpu_rcx);
+
+	if (KVM_BUG_ON(err, vcpu->kvm)) {
+		pr_tdx_error(TDH_VP_INIT, err);
+		return -EIO;
+	}
+
+	vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
+	tdx->td_vcpu_created = true;
+
+	return 0;
+
+free_tdvpx:
+	for (i = 0; i < tdx_sysinfo_nr_tdcx_pages(); i++) {
+		if (tdx->tdcx_pa[i])
+			free_page((unsigned long)__va(tdx->tdcx_pa[i]));
+		tdx->tdcx_pa[i] = 0;
+	}
+	kfree(tdx->tdcx_pa);
+	tdx->tdcx_pa = NULL;
+
+free_tdvpr:
+	if (tdx->tdvpr_pa)
+		free_page((unsigned long)__va(tdx->tdvpr_pa));
+	tdx->tdvpr_pa = 0;
+
+	return ret;
+}
+
+static int tdx_vcpu_init(struct kvm_vcpu *vcpu, struct kvm_tdx_cmd *cmd)
+{
+	struct msr_data apic_base_msr;
+	struct vcpu_tdx *tdx = to_tdx(vcpu);
+	int ret;
+
+	if (cmd->flags)
+		return -EINVAL;
+	if (tdx->initialized)
+		return -EINVAL;
+
+	/*
+	 * As TDX requires X2APIC, set local apic mode to X2APIC.  User space
+	 * VMM, e.g. qemu, is required to set CPUID[0x1].ecx.X2APIC=1 by
+	 * KVM_SET_CPUID2.  Otherwise kvm_set_apic_base() will fail.
+	 */
+	apic_base_msr = (struct msr_data) {
+		.host_initiated = true,
+		.data = APIC_DEFAULT_PHYS_BASE | LAPIC_MODE_X2APIC |
+		(kvm_vcpu_is_reset_bsp(vcpu) ? MSR_IA32_APICBASE_BSP : 0),
+	};
+	if (kvm_set_apic_base(vcpu, &apic_base_msr))
+		return -EINVAL;
+
+	ret = tdx_td_vcpu_init(vcpu, (u64)cmd->data);
+	if (ret)
+		return ret;
+
+	tdx->initialized = true;
+	return 0;
+}
+
+int tdx_vcpu_ioctl(struct kvm_vcpu *vcpu, void __user *argp)
+{
+	struct kvm_tdx *kvm_tdx = to_kvm_tdx(vcpu->kvm);
+	struct kvm_tdx_cmd cmd;
+	int ret;
+
+	if (!is_hkid_assigned(kvm_tdx) || is_td_finalized(kvm_tdx))
+		return -EINVAL;
+
+	if (copy_from_user(&cmd, argp, sizeof(cmd)))
+		return -EFAULT;
+
+	if (cmd.hw_error)
+		return -EINVAL;
+
+	switch (cmd.id) {
+	case KVM_TDX_INIT_VCPU:
+		ret = tdx_vcpu_init(vcpu, &cmd);
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+	return ret;
+}
+
 #define KVM_SUPPORTED_TD_ATTRS (TDX_TD_ATTR_SEPT_VE_DISABLE)
 
 static int __init setup_kvm_tdx_caps(void)
diff --git a/arch/x86/kvm/vmx/tdx.h b/arch/x86/kvm/vmx/tdx.h
index ca948f26b755..8349b542836e 100644
--- a/arch/x86/kvm/vmx/tdx.h
+++ b/arch/x86/kvm/vmx/tdx.h
@@ -22,6 +22,8 @@ struct kvm_tdx {
 	u64 xfam;
 	int hkid;
 
+	bool finalized;
+
 	u64 tsc_offset;
 };
 
@@ -29,6 +31,10 @@ struct vcpu_tdx {
 	struct kvm_vcpu	vcpu;
 
 	unsigned long tdvpr_pa;
+	unsigned long *tdcx_pa;
+	bool td_vcpu_created;
+
+	bool initialized;
 
 	/*
 	 * Dummy to make pmu_intel not corrupt memory.
diff --git a/arch/x86/kvm/vmx/tdx_arch.h b/arch/x86/kvm/vmx/tdx_arch.h
index 413619dd92ef..d2d7f9cab740 100644
--- a/arch/x86/kvm/vmx/tdx_arch.h
+++ b/arch/x86/kvm/vmx/tdx_arch.h
@@ -155,4 +155,6 @@ struct td_params {
 #define TDX_MIN_TSC_FREQUENCY_KHZ		(100 * 1000)
 #define TDX_MAX_TSC_FREQUENCY_KHZ		(10 * 1000 * 1000)
 
+#define MD_FIELD_ID_FEATURES0_TOPOLOGY_ENUM	BIT_ULL(20)
+
 #endif /* __KVM_X86_TDX_ARCH_H */
diff --git a/arch/x86/kvm/vmx/x86_ops.h b/arch/x86/kvm/vmx/x86_ops.h
index e1d3276b0f60..55fd17fbfd19 100644
--- a/arch/x86/kvm/vmx/x86_ops.h
+++ b/arch/x86/kvm/vmx/x86_ops.h
@@ -129,6 +129,8 @@ int tdx_vm_ioctl(struct kvm *kvm, void __user *argp);
 int tdx_vcpu_create(struct kvm_vcpu *vcpu);
 void tdx_vcpu_free(struct kvm_vcpu *vcpu);
 void tdx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event);
+
+int tdx_vcpu_ioctl(struct kvm_vcpu *vcpu, void __user *argp);
 #else
 static inline int tdx_vm_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap)
 {
@@ -143,6 +145,8 @@ static inline int tdx_vm_ioctl(struct kvm *kvm, void __user *argp) { return -EOP
 static inline int tdx_vcpu_create(struct kvm_vcpu *vcpu) { return -EOPNOTSUPP; }
 static inline void tdx_vcpu_free(struct kvm_vcpu *vcpu) {}
 static inline void tdx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) {}
+
+static inline int tdx_vcpu_ioctl(struct kvm_vcpu *vcpu, void __user *argp) { return -EOPNOTSUPP; }
 #endif
 
 #endif /* __KVM_X86_VMX_X86_OPS_H */
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 9cee326f5e7a..3d43fa84c2b4 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6314,6 +6314,12 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
 	case KVM_SET_DEVICE_ATTR:
 		r = kvm_vcpu_ioctl_device_attr(vcpu, ioctl, argp);
 		break;
+	case KVM_MEMORY_ENCRYPT_OP:
+		r = -ENOTTY;
+		if (!kvm_x86_ops.vcpu_mem_enc_ioctl)
+			goto out;
+		r = kvm_x86_ops.vcpu_mem_enc_ioctl(vcpu, argp);
+		break;
 	default:
 		r = -EINVAL;
 	}
-- 
2.34.1

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