KVM requires userspace to pass XFAM configuration via CPUID 0xD leaves.

Convert tdx_caps->xfam_fixed0/1 into corresponding
tdx_cpuid_lookup[].tdx_fixed0/1 field of CPUID 0xD leaves. Thus the
requirement can be applied naturally.

Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
---
 target/i386/cpu.c     |  3 ---
 target/i386/cpu.h     |  3 +++
 target/i386/kvm/tdx.c | 24 ++++++++++++++++++++++++
 3 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 358d9c0a655a..128b01054ff3 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -1575,9 +1575,6 @@ static const X86RegisterInfo32 x86_reg_info_32[CPU_NB_REGS32] = {
 };
 #undef REGISTER
 
-/* CPUID feature bits available in XSS */
-#define CPUID_XSTATE_XSS_MASK    (XSTATE_ARCH_LBR_MASK)
-
 ExtSaveArea x86_ext_save_areas[XSAVE_STATE_AREA_COUNT] = {
     [XSTATE_FP_BIT] = {
         /* x87 FP state component is always enabled if XSAVE is supported */
diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index bd9151d3bcaa..d0b7ba5d113e 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -588,6 +588,9 @@ typedef enum X86Seg {
                                  XSTATE_Hi16_ZMM_MASK | XSTATE_PKRU_MASK | \
                                  XSTATE_XTILE_CFG_MASK | XSTATE_XTILE_DATA_MASK)
 
+/* CPUID feature bits available in XSS */
+#define CPUID_XSTATE_XSS_MASK    (XSTATE_ARCH_LBR_MASK)
+
 /* CPUID feature words */
 typedef enum FeatureWord {
     FEAT_1_EDX,         /* CPUID[1].EDX */
diff --git a/target/i386/kvm/tdx.c b/target/i386/kvm/tdx.c
index 7fa86858de58..be7771bd97d7 100644
--- a/target/i386/kvm/tdx.c
+++ b/target/i386/kvm/tdx.c
@@ -400,6 +400,30 @@ static void update_tdx_cpuid_lookup_by_tdx_caps(void)
         entry->tdx_fixed0 &= ~config;
         entry->tdx_fixed1 &= ~config;
     }
+
+    /*
+     * Because KVM gets XFAM settings via CPUID leaves 0xD,  map
+     * tdx_caps->xfam_fixed{0, 1} into tdx_cpuid_lookup[].tdx_fixed{0, 1}.
+     *
+     * Then the enforment applies in tdx_get_configurable_cpuid() naturally.
+     */
+    tdx_cpuid_lookup[FEAT_XSAVE_XCR0_LO].tdx_fixed0 =
+            (uint32_t)~tdx_caps->xfam_fixed0 & CPUID_XSTATE_XCR0_MASK;
+    tdx_cpuid_lookup[FEAT_XSAVE_XCR0_LO].tdx_fixed1 =
+            (uint32_t)tdx_caps->xfam_fixed1 & CPUID_XSTATE_XCR0_MASK;
+    tdx_cpuid_lookup[FEAT_XSAVE_XCR0_HI].tdx_fixed0 =
+            (~tdx_caps->xfam_fixed0 & CPUID_XSTATE_XCR0_MASK) >> 32;
+    tdx_cpuid_lookup[FEAT_XSAVE_XCR0_HI].tdx_fixed1 =
+            (tdx_caps->xfam_fixed1 & CPUID_XSTATE_XCR0_MASK) >> 32;
+
+    tdx_cpuid_lookup[FEAT_XSAVE_XSS_LO].tdx_fixed0 =
+            (uint32_t)~tdx_caps->xfam_fixed0 & CPUID_XSTATE_XSS_MASK;
+    tdx_cpuid_lookup[FEAT_XSAVE_XSS_LO].tdx_fixed1 =
+            (uint32_t)tdx_caps->xfam_fixed1 & CPUID_XSTATE_XSS_MASK;
+    tdx_cpuid_lookup[FEAT_XSAVE_XSS_HI].tdx_fixed0 =
+            (~tdx_caps->xfam_fixed0 & CPUID_XSTATE_XSS_MASK) >> 32;
+    tdx_cpuid_lookup[FEAT_XSAVE_XSS_HI].tdx_fixed1 =
+            (tdx_caps->xfam_fixed1 & CPUID_XSTATE_XSS_MASK) >> 32;
 }
 
 int tdx_kvm_init(MachineState *ms, Error **errp)
-- 
2.34.1