On Sun, 12 Mar 2023 10:55:44 -0700
isaku.yamahata@xxxxxxxxx wrote:
> From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
>
> 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
^ This sentence seems broken. "
> 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@xxxxxxxxx>
> Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
> ---
> 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.
^
It would be nice to have one more sentence to talk about the
consequence if QEMU configures different CPUIDs in KVM_TDX_INIT_VM and the later
SET_CPUID2.
> + */
> + 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 */
