Re: [PATCH v18 030/121] KVM: TDX: Do TDX specific vcpu initialization
From: Binbin Wu
Date: Thu Jan 25 2024 - 02:57:16 EST
On 1/23/2024 7:53 AM, isaku.yamahata@xxxxxxxxx wrote:
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>
---
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 | 184 ++++++++++++++++++++++++++++-
arch/x86/kvm/vmx/tdx.h | 8 ++
arch/x86/kvm/vmx/x86_ops.h | 4 +
arch/x86/kvm/x86.c | 6 +
8 files changed, 211 insertions(+), 3 deletions(-)
diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h
index 1b8fe1502bde..cfa505dd7a98 100644
--- a/arch/x86/include/asm/kvm-x86-ops.h
+++ b/arch/x86/include/asm/kvm-x86-ops.h
@@ -129,6 +129,7 @@ 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 ba68f63958db..b54e0bdb77eb 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1776,6 +1776,7 @@ 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 9ac0246bd974..4000a2e087a8 100644
--- a/arch/x86/include/uapi/asm/kvm.h
+++ b/arch/x86/include/uapi/asm/kvm.h
@@ -571,6 +571,7 @@ 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 c2f1dc2000c5..de4b6f924a36 100644
--- a/arch/x86/kvm/vmx/main.c
+++ b/arch/x86/kvm/vmx/main.c
@@ -146,6 +146,14 @@ 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)| \
BIT(APICV_INHIBIT_REASON_ABSENT) | \
@@ -305,6 +313,7 @@ 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 8330f448ab8e..245be29721b4 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -93,6 +93,7 @@ struct tdx_info {
u64 xfam_fixed1;
u8 nr_tdcs_pages;
+ u8 nr_tdvpx_pages;
u16 num_cpuid_config;
/* This must the last member. */
@@ -148,6 +149,11 @@ 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;
@@ -165,6 +171,11 @@ 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)));
@@ -447,7 +458,32 @@ 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_control_page(tdx->tdvpx_pa[i]);
+ }
+ kfree(tdx->tdvpx_pa);
+ tdx->tdvpx_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)
@@ -456,8 +492,13 @@ 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)
@@ -951,15 +992,147 @@ 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 */
vcpu_free() interface is called by two sites.
One is the error handling path of kvm_vm_ioctl_create_vcpu() when vcpu
creation.
The other is during kvm_destroy_vm().
What about the error occurs in KVM_TDX_INIT_VCPU?
Let's assume TDR and some of tdvpx pages are donated to TDX, and the next
call of tdh_vp_addcx() failed. The comment says "vcpu_free method frees
TDVPX
and TDR donated to TDX", but if it happens, it seems that vcpu_free() would
not be called? Memory leakage?
+ 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;
+ tdx->td_vcpu_created = true;
+ 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)
+ 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)
{
- u16 num_cpuid_config, tdcs_base_size;
+ u16 num_cpuid_config, tdcs_base_size, tdvps_base_size;
int ret;
u32 i;
struct tdx_md_map mds[] = {
TDX_MD_MAP(NUM_CPUID_CONFIG, &num_cpuid_config),
TDX_MD_MAP(TDCS_BASE_SIZE, &tdcs_base_size),
+ TDX_MD_MAP(TDVPS_BASE_SIZE, &tdvps_base_size),
};
#define TDX_INFO_MAP(_field_id, _member) \
@@ -1015,6 +1188,11 @@ static int __init tdx_module_setup(void)
}
tdx_info->nr_tdcs_pages = tdcs_base_size / PAGE_SIZE;
+ /*
+ * TDVPS = TDVPR(4K page) + TDVPX(multiple 4K pages).
+ * -1 for TDVPR.
+ */
+ tdx_info->nr_tdvpx_pages = 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 173ed19207fb..d3077151252c 100644
--- a/arch/x86/kvm/vmx/tdx.h
+++ b/arch/x86/kvm/vmx/tdx.h
@@ -17,12 +17,20 @@ 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 td_vcpu_created;
+
+ 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 1ea532dfaf2a..5f8ee1c93cd1 100644
--- a/arch/x86/kvm/vmx/x86_ops.h
+++ b/arch/x86/kvm/vmx/x86_ops.h
@@ -150,6 +150,8 @@ 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 -EOPNOTSUPP; }
static inline void tdx_hardware_unsetup(void) {}
@@ -169,6 +171,8 @@ 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 e0027134454c..eee63b08f14f 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6248,6 +6248,12 @@ 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;
}