[PATCH v7 43/52] i386/tdx: Mask off CPUID bits by unsupported TD Attributes

[Xiaoyao Li]

For TDX, some CPUID feature bit is configured via TD attributes. Adjust
the supported CPUID to mask off the bit if its matched attribute is
unsupported.

Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
---
 target/i386/cpu.h     |  4 ++++
 target/i386/kvm/tdx.c | 54 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 58 insertions(+)

diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index 8b63685e64e1..4890424c3a9e 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -905,6 +905,8 @@ uint64_t x86_cpu_get_supported_feature_word(X86CPU *cpu, 
FeatureWord w);
 #define CPUID_7_0_ECX_LA57              (1U << 16)
 /* Read Processor ID */
 #define CPUID_7_0_ECX_RDPID             (1U << 22)
+/* KeyLocker */
+#define CPUID_7_0_ECX_KeyLocker         (1U << 23)
 /* Bus Lock Debug Exception */
 #define CPUID_7_0_ECX_BUS_LOCK_DETECT   (1U << 24)
 /* Cache Line Demote Instruction */
@@ -957,6 +959,8 @@ uint64_t x86_cpu_get_supported_feature_word(X86CPU *cpu, 
FeatureWord w);
 #define CPUID_7_1_EAX_AVX_VNNI          (1U << 4)
 /* AVX512 BFloat16 Instruction */
 #define CPUID_7_1_EAX_AVX512_BF16       (1U << 5)
+/* Linear address space separation */
+#define CPUID_7_1_EAX_LASS              (1U << 6)
 /* CMPCCXADD Instructions */
 #define CPUID_7_1_EAX_CMPCCXADD         (1U << 7)
 /* Fast Zero REP MOVS */
diff --git a/target/i386/kvm/tdx.c b/target/i386/kvm/tdx.c
index 2d493a0dc1c6..3997a439f054 100644
--- a/target/i386/kvm/tdx.c
+++ b/target/i386/kvm/tdx.c
@@ -527,6 +527,58 @@ KvmCpuidInfo tdx_fixed1_bits = {
     },
 };
 
+typedef struct TdxAttrsMap {
+    uint32_t attr_index;
+    uint32_t cpuid_leaf;
+    uint32_t cpuid_subleaf;
+    int cpuid_reg;
+    uint32_t feat_mask;
+} TdxAttrsMap;
+
+static TdxAttrsMap tdx_attrs_maps[] = {
+    {.attr_index = 27,
+     .cpuid_leaf = 7,
+     .cpuid_subleaf = 1,
+     .cpuid_reg = R_EAX,
+     .feat_mask = CPUID_7_1_EAX_LASS},
+    {.attr_index = 30,
+     .cpuid_leaf = 7,
+     .cpuid_subleaf = 0,
+     .cpuid_reg = R_ECX,
+     .feat_mask = CPUID_7_0_ECX_PKS,},
+    {.attr_index = 31,
+     .cpuid_leaf = 7,
+     .cpuid_subleaf = 0,
+     .cpuid_reg = R_ECX,
+     .feat_mask = CPUID_7_0_ECX_KeyLocker,
+    },
+};
+
+static void tdx_mask_cpuid_by_attrs(uint32_t feature, uint32_t index,
+                                    int reg, uint32_t *value)
+{
+    TdxAttrsMap *map;
+    uint64_t unavail = 0;
+    int i;
+
+    for (i = 0; i < ARRAY_SIZE(tdx_attrs_maps); i++) {
+        map = &tdx_attrs_maps[i];
+
+        if (feature != map->cpuid_leaf || index != map->cpuid_subleaf ||
+            reg != map->cpuid_reg) {
+            continue;
+        }
+
+        if (!((1ULL << map->attr_index) & tdx_caps->supported_attrs)) {
+            unavail |= map->feat_mask;
+        }
+    }
+
+    if (unavail) {
+        *value &= ~unavail;
+    }
+}
+
 static uint32_t tdx_adjust_cpuid_features(X86ConfidentialGuest *cg,
                                           uint32_t feature, uint32_t index,
                                           int reg, uint32_t value)
@@ -560,6 +612,8 @@ static uint32_t 
tdx_adjust_cpuid_features(X86ConfidentialGuest *cg,
         break;
     }
 
+    tdx_mask_cpuid_by_attrs(feature, index, reg, &value);
+
     e = cpuid_find_entry(&tdx_fixed0_bits.cpuid, feature, index);
     if (e) {
         fixed0 = cpuid_entry_get_reg(e, reg);
-- 
2.34.1