[PATCH v14 025/113] KVM: TDX: Do TDX specific vcpu initialization

From: isaku . yamahata
Date: Mon May 29 2023 - 00:23:04 EST

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From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>

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@xxxxxxxxx>
Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
---
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 | 180 +++++++++++++++++++++++++-
arch/x86/kvm/vmx/tdx.h | 7 +
arch/x86/kvm/vmx/x86_ops.h | 4 +
arch/x86/kvm/x86.c | 6 +
tools/arch/x86/include/uapi/asm/kvm.h | 1 +
9 files changed, 208 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h
index 54fe5baf99ed..a08df1368ad7 100644
--- a/arch/x86/include/asm/kvm-x86-ops.h
+++ b/arch/x86/include/asm/kvm-x86-ops.h
@@ -125,6 +125,7 @@ KVM_X86_OP(leave_smm)
KVM_X86_OP(enable_smi_window)
#endif
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 f5a861c8b88b..e13794608dcc 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1714,6 +1714,7 @@ struct kvm_x86_ops {
#endif

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 1d2be13e845f..b8af133dd195 100644
--- a/arch/x86/include/uapi/asm/kvm.h
+++ b/arch/x86/include/uapi/asm/kvm.h
@@ -569,6 +569,7 @@ struct kvm_pmu_event_filter {
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 612f3eb9e422..a04d575ec50e 100644
--- a/arch/x86/kvm/vmx/main.c
+++ b/arch/x86/kvm/vmx/main.c
@@ -142,6 +142,14 @@ 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_DISABLE)| \
@@ -300,6 +308,7 @@ struct kvm_x86_ops vt_x86_ops __initdata = {
.vcpu_deliver_sipi_vector = kvm_vcpu_deliver_sipi_vector,

.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 2903b37c0c28..3118b4f52911 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -48,6 +48,7 @@ int tdx_vm_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap)

struct tdx_info {
u8 nr_tdcs_pages;
+ u8 nr_tdvpx_pages;
};

/* Info about the TDX module. */
@@ -70,6 +71,11 @@ 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->tdvpr_pa;
+}
+
static inline bool is_td_created(struct kvm_tdx *kvm_tdx)
{
return kvm_tdx->tdr_pa;
@@ -86,6 +92,11 @@ 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)));
@@ -346,7 +357,32 @@ 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))) {
+ WARN_ON_ONCE(tdx->tdvpx_pa);
+ WARN_ON_ONCE(tdx->tdvpr_pa);
+ return;
+ }
+
+ if (tdx->tdvpx_pa) {
+ for (i = 0; i < tdx_info.nr_tdvpx_pages; i++) {
+ if (tdx->tdvpx_pa[i])
+ tdx_reclaim_td_page(tdx->tdvpx_pa[i]);
+ }
+ kfree(tdx->tdvpx_pa);
+ tdx->tdvpx_pa = NULL;
+ }
+ if (tdx->tdvpr_pa) {
+ tdx_reclaim_td_page(tdx->tdvpr_pa);
+ tdx->tdvpr_pa = 0;
+ }
}

void tdx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
@@ -355,8 +391,13 @@ 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 (KVM_BUG_ON(is_td_vcpu_created(to_tdx(vcpu)), vcpu->kvm))
+ 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)
@@ -818,6 +859,136 @@ 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)
+{
+ struct kvm_tdx *kvm_tdx = to_kvm_tdx(vcpu->kvm);
+ struct vcpu_tdx *tdx = to_tdx(vcpu);
+ unsigned long *tdvpx_pa = NULL;
+ unsigned long tdvpr_pa;
+ 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;
+ tdvpr_pa = __pa(va);
+
+ tdvpx_pa = kcalloc(tdx_info.nr_tdvpx_pages, sizeof(*tdx->tdvpx_pa),
+ GFP_KERNEL_ACCOUNT);
+ if (!tdvpx_pa) {
+ ret = -ENOMEM;
+ goto free_tdvpr;
+ }
+ for (i = 0; i < tdx_info.nr_tdvpx_pages; i++) {
+ va = __get_free_page(GFP_KERNEL_ACCOUNT);
+ if (!va) {
+ ret = -ENOMEM;
+ goto free_tdvpx;
+ }
+ tdvpx_pa[i] = __pa(va);
+ }
+
+ err = tdh_vp_create(kvm_tdx->tdr_pa, tdvpr_pa);
+ if (KVM_BUG_ON(err, vcpu->kvm)) {
+ ret = -EIO;
+ pr_tdx_error(TDH_VP_CREATE, err, NULL);
+ goto free_tdvpx;
+ }
+ tdx->tdvpr_pa = tdvpr_pa;
+
+ tdx->tdvpx_pa = tdvpx_pa;
+ for (i = 0; i < tdx_info.nr_tdvpx_pages; i++) {
+ err = tdh_vp_addcx(tdx->tdvpr_pa, tdvpx_pa[i]);
+ if (KVM_BUG_ON(err, vcpu->kvm)) {
+ pr_tdx_error(TDH_VP_ADDCX, err, NULL);
+ for (; i < tdx_info.nr_tdvpx_pages; i++) {
+ free_page((unsigned long)__va(tdvpx_pa[i]));
+ tdvpx_pa[i] = 0;
+ }
+ /* vcpu_free method frees TDVPX and TDR donated to TDX */
+ return -EIO;
+ }
+ }
+
+ err = tdh_vp_init(tdx->tdvpr_pa, vcpu_rcx);
+ if (KVM_BUG_ON(err, vcpu->kvm)) {
+ pr_tdx_error(TDH_VP_INIT, err, NULL);
+ return -EIO;
+ }
+
+ vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
+ return 0;
+
+free_tdvpx:
+ for (i = 0; i < tdx_info.nr_tdvpx_pages; i++) {
+ if (tdvpx_pa[i])
+ free_page((unsigned long)__va(tdvpx_pa[i]));
+ tdvpx_pa[i] = 0;
+ }
+ kfree(tdvpx_pa);
+ tdx->tdvpx_pa = NULL;
+free_tdvpr:
+ if (tdvpr_pa)
+ free_page((unsigned long)__va(tdvpr_pa));
+ tdx->tdvpr_pa = 0;
+
+ return ret;
+}
+
+int tdx_vcpu_ioctl(struct kvm_vcpu *vcpu, void __user *argp)
+{
+ struct msr_data apic_base_msr;
+ struct kvm_tdx *kvm_tdx = to_kvm_tdx(vcpu->kvm);
+ struct vcpu_tdx *tdx = to_tdx(vcpu);
+ struct kvm_tdx_cmd cmd;
+ int ret;
+
+ if (tdx->initialized)
+ return -EINVAL;
+
+ 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.error || cmd.unused)
+ return -EINVAL;
+
+ /* Currently only KVM_TDX_INTI_VCPU is defined for vcpu operation. */
+ if (cmd.flags || cmd.id != KVM_TDX_INIT_VCPU)
+ 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;
+}
+
static int __init tdx_module_setup(void)
{
const struct tdsysinfo_struct *tdsysinfo;
@@ -836,6 +1007,11 @@ static int __init tdx_module_setup(void)
WARN_ON(tdsysinfo->num_cpuid_config > TDX_MAX_NR_CPUID_CONFIGS);
tdx_info = (struct tdx_info) {
.nr_tdcs_pages = tdsysinfo->tdcs_base_size / PAGE_SIZE,
+ /*
+ * TDVPS = TDVPR(4K page) + TDVPX(multiple 4K pages).
+ * -1 for TDVPR.
+ */
+ .nr_tdvpx_pages = tdsysinfo->tdvps_base_size / PAGE_SIZE - 1,
};

return 0;
diff --git a/arch/x86/kvm/vmx/tdx.h b/arch/x86/kvm/vmx/tdx.h
index 5728820fed5e..5fa4d3198873 100644
--- a/arch/x86/kvm/vmx/tdx.h
+++ b/arch/x86/kvm/vmx/tdx.h
@@ -17,12 +17,19 @@ struct kvm_tdx {
u64 xfam;
int hkid;

+ bool finalized;
+
u64 tsc_offset;
};

struct vcpu_tdx {
struct kvm_vcpu vcpu;

+ unsigned long tdvpr_pa;
+ unsigned long *tdvpx_pa;
+
+ bool initialized;
+
/*
* Dummy to make pmu_intel not corrupt memory.
* TODO: Support PMU for TDX. Future work.
diff --git a/arch/x86/kvm/vmx/x86_ops.h b/arch/x86/kvm/vmx/x86_ops.h
index 8229277a8a54..1245fea67de9 100644
--- a/arch/x86/kvm/vmx/x86_ops.h
+++ b/arch/x86/kvm/vmx/x86_ops.h
@@ -151,6 +151,8 @@ 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_hardware_setup(struct kvm_x86_ops *x86_ops) { return -ENOSYS; }
static inline void tdx_hardware_unsetup(void) {}
@@ -167,6 +169,8 @@ 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 f0984f0aa18e..e87b280b64d3 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6062,6 +6062,12 @@ 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;
}
diff --git a/tools/arch/x86/include/uapi/asm/kvm.h b/tools/arch/x86/include/uapi/asm/kvm.h
index 187c364e3b37..043fcceb9fd8 100644
--- a/tools/arch/x86/include/uapi/asm/kvm.h
+++ b/tools/arch/x86/include/uapi/asm/kvm.h
@@ -569,6 +569,7 @@ struct kvm_pmu_event_filter {
enum kvm_tdx_cmd_id {
KVM_TDX_CAPABILITIES = 0,
KVM_TDX_INIT_VM,
+ KVM_TDX_INIT_VCPU,

KVM_TDX_CMD_NR_MAX,
};
--
2.25.1

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