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-rw-r--r--arch/x86/include/uapi/asm/kvm.h1
-rw-r--r--arch/x86/kvm/vmx/tdx.c191
-rw-r--r--arch/x86/kvm/vmx/tdx_arch.h5
-rw-r--r--arch/x86/kvm/vmx/tdx_errno.h1
4 files changed, 198 insertions, 0 deletions
diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h
index 9316afbd4a88..cd55484e3f0c 100644
--- a/arch/x86/include/uapi/asm/kvm.h
+++ b/arch/x86/include/uapi/asm/kvm.h
@@ -932,6 +932,7 @@ enum kvm_tdx_cmd_id {
KVM_TDX_CAPABILITIES = 0,
KVM_TDX_INIT_VM,
KVM_TDX_INIT_VCPU,
+ KVM_TDX_GET_CPUID,
KVM_TDX_CMD_NR_MAX,
};
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index 4ba46ac3b9af..2ac925ecccd5 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -3,6 +3,7 @@
#include <asm/cpufeature.h>
#include <asm/tdx.h>
#include "capabilities.h"
+#include "mmu.h"
#include "x86_ops.h"
#include "lapic.h"
#include "tdx.h"
@@ -849,6 +850,103 @@ free_hkid:
return ret;
}
+static u64 tdx_td_metadata_field_read(struct kvm_tdx *tdx, u64 field_id,
+ u64 *data)
+{
+ u64 err;
+
+ err = tdh_mng_rd(&tdx->td, field_id, data);
+
+ return err;
+}
+
+#define TDX_MD_UNREADABLE_LEAF_MASK GENMASK(30, 7)
+#define TDX_MD_UNREADABLE_SUBLEAF_MASK GENMASK(31, 7)
+
+static int tdx_read_cpuid(struct kvm_vcpu *vcpu, u32 leaf, u32 sub_leaf,
+ bool sub_leaf_set, int *entry_index,
+ struct kvm_cpuid_entry2 *out)
+{
+ struct kvm_tdx *kvm_tdx = to_kvm_tdx(vcpu->kvm);
+ u64 field_id = TD_MD_FIELD_ID_CPUID_VALUES;
+ u64 ebx_eax, edx_ecx;
+ u64 err = 0;
+
+ if (sub_leaf > 0b1111111)
+ return -EINVAL;
+
+ if (*entry_index >= KVM_MAX_CPUID_ENTRIES)
+ return -EINVAL;
+
+ if (leaf & TDX_MD_UNREADABLE_LEAF_MASK ||
+ sub_leaf & TDX_MD_UNREADABLE_SUBLEAF_MASK)
+ return -EINVAL;
+
+ /*
+ * bit 23:17, REVSERVED: reserved, must be 0;
+ * bit 16, LEAF_31: leaf number bit 31;
+ * bit 15:9, LEAF_6_0: leaf number bits 6:0, leaf bits 30:7 are
+ * implicitly 0;
+ * bit 8, SUBLEAF_NA: sub-leaf not applicable flag;
+ * bit 7:1, SUBLEAF_6_0: sub-leaf number bits 6:0. If SUBLEAF_NA is 1,
+ * the SUBLEAF_6_0 is all-1.
+ * sub-leaf bits 31:7 are implicitly 0;
+ * bit 0, ELEMENT_I: Element index within field;
+ */
+ field_id |= ((leaf & 0x80000000) ? 1 : 0) << 16;
+ field_id |= (leaf & 0x7f) << 9;
+ if (sub_leaf_set)
+ field_id |= (sub_leaf & 0x7f) << 1;
+ else
+ field_id |= 0x1fe;
+
+ err = tdx_td_metadata_field_read(kvm_tdx, field_id, &ebx_eax);
+ if (err) //TODO check for specific errors
+ goto err_out;
+
+ out->eax = (u32) ebx_eax;
+ out->ebx = (u32) (ebx_eax >> 32);
+
+ field_id++;
+ err = tdx_td_metadata_field_read(kvm_tdx, field_id, &edx_ecx);
+ /*
+ * It's weird that reading edx_ecx fails while reading ebx_eax
+ * succeeded.
+ */
+ if (WARN_ON_ONCE(err))
+ goto err_out;
+
+ out->ecx = (u32) edx_ecx;
+ out->edx = (u32) (edx_ecx >> 32);
+
+ out->function = leaf;
+ out->index = sub_leaf;
+ out->flags |= sub_leaf_set ? KVM_CPUID_FLAG_SIGNIFCANT_INDEX : 0;
+
+ /*
+ * Work around missing support on old TDX modules, fetch
+ * guest maxpa from gfn_direct_bits.
+ */
+ if (leaf == 0x80000008) {
+ gpa_t gpa_bits = gfn_to_gpa(kvm_gfn_direct_bits(vcpu->kvm));
+ unsigned int g_maxpa = __ffs(gpa_bits) + 1;
+
+ out->eax = tdx_set_guest_phys_addr_bits(out->eax, g_maxpa);
+ }
+
+ (*entry_index)++;
+
+ return 0;
+
+err_out:
+ out->eax = 0;
+ out->ebx = 0;
+ out->ecx = 0;
+ out->edx = 0;
+
+ return -EIO;
+}
+
static int tdx_td_init(struct kvm *kvm, struct kvm_tdx_cmd *cmd)
{
struct kvm_tdx *kvm_tdx = to_kvm_tdx(kvm);
@@ -1043,6 +1141,96 @@ free_tdvpr:
return ret;
}
+/* Sometimes reads multipple subleafs. Return how many enties were written. */
+static int tdx_vcpu_get_cpuid_leaf(struct kvm_vcpu *vcpu, u32 leaf, int *entry_index,
+ struct kvm_cpuid_entry2 *output_e)
+{
+ int sub_leaf = 0;
+ int ret;
+
+ /* First try without a subleaf */
+ ret = tdx_read_cpuid(vcpu, leaf, 0, false, entry_index, output_e);
+
+ /* If success, or invalid leaf, just give up */
+ if (ret != -EIO)
+ return ret;
+
+ /*
+ * If the try without a subleaf failed, try reading subleafs until
+ * failure. The TDX module only supports 6 bits of subleaf index.
+ */
+ while (1) {
+ /* Keep reading subleafs until there is a failure. */
+ if (tdx_read_cpuid(vcpu, leaf, sub_leaf, true, entry_index, output_e))
+ return !sub_leaf;
+
+ sub_leaf++;
+ output_e++;
+ }
+
+ return 0;
+}
+
+static int tdx_vcpu_get_cpuid(struct kvm_vcpu *vcpu, struct kvm_tdx_cmd *cmd)
+{
+ struct kvm_cpuid2 __user *output, *td_cpuid;
+ int r = 0, i = 0, leaf;
+ u32 level;
+
+ output = u64_to_user_ptr(cmd->data);
+ td_cpuid = kzalloc(sizeof(*td_cpuid) +
+ sizeof(output->entries[0]) * KVM_MAX_CPUID_ENTRIES,
+ GFP_KERNEL);
+ if (!td_cpuid)
+ return -ENOMEM;
+
+ if (copy_from_user(td_cpuid, output, sizeof(*output))) {
+ r = -EFAULT;
+ goto out;
+ }
+
+ /* Read max CPUID for normal range */
+ if (tdx_vcpu_get_cpuid_leaf(vcpu, 0, &i, &td_cpuid->entries[i])) {
+ r = -EIO;
+ goto out;
+ }
+ level = td_cpuid->entries[0].eax;
+
+ for (leaf = 1; leaf <= level; leaf++)
+ tdx_vcpu_get_cpuid_leaf(vcpu, leaf, &i, &td_cpuid->entries[i]);
+
+ /* Read max CPUID for extended range */
+ if (tdx_vcpu_get_cpuid_leaf(vcpu, 0x80000000, &i, &td_cpuid->entries[i])) {
+ r = -EIO;
+ goto out;
+ }
+ level = td_cpuid->entries[i - 1].eax;
+
+ for (leaf = 0x80000001; leaf <= level; leaf++)
+ tdx_vcpu_get_cpuid_leaf(vcpu, leaf, &i, &td_cpuid->entries[i]);
+
+ if (td_cpuid->nent < i)
+ r = -E2BIG;
+ td_cpuid->nent = i;
+
+ if (copy_to_user(output, td_cpuid, sizeof(*output))) {
+ r = -EFAULT;
+ goto out;
+ }
+
+ if (r == -E2BIG)
+ goto out;
+
+ if (copy_to_user(output->entries, td_cpuid->entries,
+ td_cpuid->nent * sizeof(struct kvm_cpuid_entry2)))
+ r = -EFAULT;
+
+out:
+ kfree(td_cpuid);
+
+ return r;
+}
+
static int tdx_vcpu_init(struct kvm_vcpu *vcpu, struct kvm_tdx_cmd *cmd)
{
u64 apic_base;
@@ -1092,6 +1280,9 @@ int tdx_vcpu_ioctl(struct kvm_vcpu *vcpu, void __user *argp)
case KVM_TDX_INIT_VCPU:
ret = tdx_vcpu_init(vcpu, &cmd);
break;
+ case KVM_TDX_GET_CPUID:
+ ret = tdx_vcpu_get_cpuid(vcpu, &cmd);
+ break;
default:
ret = -EINVAL;
break;
diff --git a/arch/x86/kvm/vmx/tdx_arch.h b/arch/x86/kvm/vmx/tdx_arch.h
index 0e09188a8785..55a740f90e67 100644
--- a/arch/x86/kvm/vmx/tdx_arch.h
+++ b/arch/x86/kvm/vmx/tdx_arch.h
@@ -123,4 +123,9 @@ struct td_params {
#define MD_FIELD_ID_FEATURES0_TOPOLOGY_ENUM BIT_ULL(20)
+/*
+ * TD scope metadata field ID.
+ */
+#define TD_MD_FIELD_ID_CPUID_VALUES 0x9410000300000000ULL
+
#endif /* __KVM_X86_TDX_ARCH_H */
diff --git a/arch/x86/kvm/vmx/tdx_errno.h b/arch/x86/kvm/vmx/tdx_errno.h
index dc3fa2a58c2c..f9dbb3a065cc 100644
--- a/arch/x86/kvm/vmx/tdx_errno.h
+++ b/arch/x86/kvm/vmx/tdx_errno.h
@@ -23,6 +23,7 @@
#define TDX_FLUSHVP_NOT_DONE 0x8000082400000000ULL
#define TDX_EPT_WALK_FAILED 0xC0000B0000000000ULL
#define TDX_EPT_ENTRY_STATE_INCORRECT 0xC0000B0D00000000ULL
+#define TDX_METADATA_FIELD_NOT_READABLE 0xC0000C0200000000ULL
/*
* TDX module operand ID, appears in 31:0 part of error code as
generated by cgit v1.2.3 (git 2.46.0) at 2025-07-31 21:42:26 +0000