[Qemu-devel][PATCH v5 2/4] x86/cpuid: Add XSAVES feature words and CET related state bits

[Yang Weijiang]

CET SHSTK/IBT MSRs can be saved/restored with XSAVES/XRSTORS, but
currently the related feature words are not supported, so add the
new entries. XSAVES/RSTORS always use compacted storage format, which
means the supervisor states' offsets are always 0, ignore them while
calculating stardard format storage size.

Signed-off-by: Zhang Yi <address@hidden>
Signed-off-by: Yang Weijiang <address@hidden>
---
 target/i386/cpu.c | 38 ++++++++++++++++++++++++++++++++++++--
 1 file changed, 36 insertions(+), 2 deletions(-)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 90ffc5f3b1..3174e05482 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -965,7 +965,7 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
         .type = CPUID_FEATURE_WORD,
         .feat_names = {
             NULL, "avx512vbmi", "umip", "pku",
-            NULL /* ospke */, "waitpkg", "avx512vbmi2", NULL,
+            NULL /* ospke */, "waitpkg", "avx512vbmi2", "shstk",
             "gfni", "vaes", "vpclmulqdq", "avx512vnni",
             "avx512bitalg", NULL, "avx512-vpopcntdq", NULL,
             "la57", NULL, NULL, NULL,
@@ -988,7 +988,7 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
             NULL, NULL, "md-clear", NULL,
             NULL, NULL, NULL, NULL,
             NULL, NULL, NULL /* pconfig */, NULL,
-            NULL, NULL, NULL, NULL,
+            "ibt", NULL, NULL, NULL,
             NULL, NULL, "spec-ctrl", "stibp",
             NULL, "arch-capabilities", "core-capability", "ssbd",
         },
@@ -1069,6 +1069,26 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] 
= {
         },
         .tcg_features = TCG_XSAVE_FEATURES,
     },
+    /* Below are xsaves feature words */
+    [FEAT_XSAVES_LO] = {
+        .type = CPUID_FEATURE_WORD,
+        .cpuid = {
+            .eax = 0xD,
+            .needs_ecx = true,
+            .ecx = 1,
+            .reg = R_ECX,
+        },
+        .migratable_flags = XSTATE_CET_U_MASK,
+    },
+    [FEAT_XSAVES_HI] = {
+        .type = CPUID_FEATURE_WORD,
+        .cpuid = {
+            .eax = 0xD,
+            .needs_ecx = true,
+            .ecx = 1,
+            .reg = R_EDX
+        },
+    },
     [FEAT_6_EAX] = {
         .type = CPUID_FEATURE_WORD,
         .feat_names = {
@@ -1455,6 +1475,14 @@ static const ExtSaveArea x86_ext_save_areas[] = {
           { .feature = FEAT_7_0_ECX, .bits = CPUID_7_0_ECX_PKU,
             .offset = offsetof(X86XSaveArea, pkru_state),
             .size = sizeof(XSavePKRU) },
+    [XSTATE_CET_U_BIT] = {
+            .feature = FEAT_7_0_ECX, .bits = CPUID_7_0_ECX_CET_SHSTK,
+            .offset = 0 /*supervisor mode component, offset = 0 */,
+            .size = sizeof(XSavesCETU) },
+    [XSTATE_CET_S_BIT] = {
+            .feature = FEAT_7_0_ECX, .bits = CPUID_7_0_ECX_CET_SHSTK,
+            .offset = 0 /*supervisor mode component, offset = 0 */,
+            .size = sizeof(XSavesCETS) },
 };
 
 static uint32_t xsave_area_size(uint64_t mask)
@@ -1465,6 +1493,9 @@ static uint32_t xsave_area_size(uint64_t mask)
     for (i = 0; i < ARRAY_SIZE(x86_ext_save_areas); i++) {
         const ExtSaveArea *esa = &x86_ext_save_areas[i];
         if ((mask >> i) & 1) {
+            if (i >= 2 && !esa->offset) {
+                continue;
+            }
             ret = MAX(ret, esa->offset + esa->size);
         }
     }
@@ -6008,6 +6039,9 @@ static void x86_cpu_reset(DeviceState *dev)
     }
     for (i = 2; i < ARRAY_SIZE(x86_ext_save_areas); i++) {
         const ExtSaveArea *esa = &x86_ext_save_areas[i];
+        if (!esa->offset) {
+            continue;
+        }
         if (env->features[esa->feature] & esa->bits) {
             xcr0 |= 1ull << i;
         }
-- 
2.17.2