i386/cpu: Cache EGPRs in CPUX86State

Expend general registers array "regs" of CPUX86State to cache entended
GPRs.

Tested-by: Xudong Hao <xudong.hao@intel.com>
Signed-off-by: Zide Chen <zide.chen@intel.com>
Co-developed-by: Zhao Liu <zhao1.liu@intel.com>
Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
Link: https://lore.kernel.org/r/20251211070942.3612547-4-zhao1.liu@intel.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

target/i386/cpu.h

@@ -1664,12 +1664,15 @@ typedef struct {
     uint64_t mask;
 } MTRRVar;
 
+#define CPU_NB_EREGS64 32
 #define CPU_NB_REGS64 16
 #define CPU_NB_REGS32 8
 
 #ifdef TARGET_X86_64
+#define CPU_NB_EREGS CPU_NB_EREGS64
 #define CPU_NB_REGS CPU_NB_REGS64
 #else
+#define CPU_NB_EREGS CPU_NB_REGS32
 #define CPU_NB_REGS CPU_NB_REGS32
 #endif
 
@@ -1901,7 +1904,7 @@ typedef struct CPUCaches {
 
 typedef struct CPUArchState {
     /* standard registers */
-    target_ulong regs[CPU_NB_REGS];
+    target_ulong regs[CPU_NB_EREGS];
     target_ulong eip;
     target_ulong eflags; /* eflags register. During CPU emulation, CC
                         flags and DF are set to zero because they are
@@ -1958,7 +1961,7 @@ typedef struct CPUArchState {
     float_status mmx_status; /* for 3DNow! float ops */
     float_status sse_status;
     uint32_t mxcsr;
-    ZMMReg xmm_regs[CPU_NB_REGS == 8 ? 8 : 32] QEMU_ALIGNED(16);
+    ZMMReg xmm_regs[CPU_NB_EREGS] QEMU_ALIGNED(16);
     ZMMReg xmm_t0 QEMU_ALIGNED(16);
     MMXReg mmx_t0;
 

target/i386/xsave_helper.c

@@ -140,6 +140,14 @@ void x86_cpu_xsave_all_areas(X86CPU *cpu, void *buf, uint32_t buflen)
 
         memcpy(tiledata, &env->xtiledata, sizeof(env->xtiledata));
     }
+
+    e = &x86_ext_save_areas[XSTATE_APX_BIT];
+    if (e->size && e->offset && buflen) {
+        XSaveAPX *apx = buf + e->offset;
+
+        memcpy(apx, &env->regs[CPU_NB_REGS],
+               sizeof(env->regs[CPU_NB_REGS]) * (CPU_NB_EREGS - CPU_NB_REGS));
+    }
 #endif
 }
 
@@ -275,5 +283,13 @@ void x86_cpu_xrstor_all_areas(X86CPU *cpu, const void *buf, uint32_t buflen)
 
         memcpy(&env->xtiledata, tiledata, sizeof(env->xtiledata));
     }
+
+    e = &x86_ext_save_areas[XSTATE_APX_BIT];
+    if (e->size && e->offset) {
+        const XSaveAPX *apx = buf + e->offset;
+
+        memcpy(&env->regs[CPU_NB_REGS], apx,
+               sizeof(env->regs[CPU_NB_REGS]) * (CPU_NB_EREGS - CPU_NB_REGS));
+    }
 #endif
 }