On 10/31/2024 3:00 AM, Rick Edgecombe wrote:
[...]
+
+#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, 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 & TDX_MD_UNREADABLE_LEAF_MASK ||
+ sub_leaf_set & TDX_MD_UNREADABLE_SUBLEAF_MASK)
+ return -EINVAL;
It looks weird.
Should be the following?
+ 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);
+ }
+
+ return 0;
+
+err_out:
+ out->eax = 0;
+ out->ebx = 0;
+ out->ecx = 0;
+ out->edx = 0;
+
+ return -EIO;
+}
+
[...]
