qemu-kvm/kvm-i386-tdx-Add-supported-CPUID-bits-related-to-TD-Attr.patch

From d228f2ad7fb96be3ec1fa3256ee0404cf7e2b094 Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Fri, 18 Jul 2025 18:03:48 +0200
Subject: [PATCH 075/115] i386/tdx: Add supported CPUID bits related to TD
 Attributes

RH-Author: Paolo Bonzini <pbonzini@redhat.com>
RH-MergeRequest: 391: TDX support, including attestation and device assignment
RH-Jira: RHEL-15710 RHEL-20798 RHEL-49728
RH-Acked-by: Yash Mankad <None>
RH-Acked-by: Peter Xu <peterx@redhat.com>
RH-Acked-by: David Hildenbrand <david@redhat.com>
RH-Commit: [75/115] 095f42329711d2cb7f147856ebf2775a522fd8e3 (bonzini/rhel-qemu-kvm)

For TDX, some CPUID feature bit is configured via TD attributes. They
are not covered by tdx_caps.cpuid (which only contians the directly
configurable CPUID bits), but they are actually supported when the
related attributre bit is supported.

Note, LASS and KeyLocker are not supported by KVM for TDX, nor does
QEMU support it (see TDX_SUPPORTED_TD_ATTRS). They are defined in
tdx_attrs_maps[] for the completeness of the existing TD Attribute
bits that are related with CPUID features.

Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Link: https://lore.kernel.org/r/20250508150002.689633-47-xiaoyao.li@intel.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit 31df29c532a9ef473c6efd497950a620099bf1da)
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 target/i386/cpu.h     |  4 +++
 target/i386/kvm/tdx.c | 60 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 64 insertions(+)

diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index 529f24df00..e02cb75619 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -903,6 +903,8 @@ 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 */
@@ -963,6 +965,8 @@ 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 6fa30c3ec4..60dd239c05 100644
--- a/target/i386/kvm/tdx.c
+++ b/target/i386/kvm/tdx.c
@@ -458,6 +458,34 @@ 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 struct kvm_cpuid_entry2 *find_in_supported_entry(uint32_t function,
                                                         uint32_t index)
 {
@@ -494,6 +522,37 @@ static void tdx_add_supported_cpuid_by_fixed1_bits(void)
     }
 }
 
+static void tdx_add_supported_cpuid_by_attrs(void)
+{
+    struct kvm_cpuid_entry2 *e;
+    TdxAttrsMap *map;
+    int i;
+
+    for (i = 0; i < ARRAY_SIZE(tdx_attrs_maps); i++) {
+        map = &tdx_attrs_maps[i];
+        if (!((1ULL << map->attr_index) & tdx_caps->supported_attrs)) {
+            continue;
+        }
+
+        e = find_in_supported_entry(map->cpuid_leaf, map->cpuid_subleaf);
+
+        switch(map->cpuid_reg) {
+        case R_EAX:
+            e->eax |= map->feat_mask;
+            break;
+        case R_EBX:
+            e->ebx |= map->feat_mask;
+            break;
+        case R_ECX:
+            e->ecx |= map->feat_mask;
+            break;
+        case R_EDX:
+            e->edx |= map->feat_mask;
+            break;
+        }
+    }
+}
+
 static void tdx_setup_supported_cpuid(void)
 {
     if (tdx_supported_cpuid) {
@@ -508,6 +567,7 @@ static void tdx_setup_supported_cpuid(void)
     tdx_supported_cpuid->nent = tdx_caps->cpuid.nent;
 
     tdx_add_supported_cpuid_by_fixed1_bits();
+    tdx_add_supported_cpuid_by_attrs();
 }
 
 static int tdx_kvm_init(ConfidentialGuestSupport *cgs, Error **errp)
-- 
2.50.1