target/i386: Add VNMI and automatic IBRS feature bits

Add the following featute bits.

vnmi: Virtual NMI (VNMI) allows the hypervisor to inject the NMI into the
      guest without using Event Injection mechanism meaning not required to
      track the guest NMI and intercepting the IRET.
      The presence of this feature is indicated via the CPUID function
      0x8000000A_EDX[25].

automatic-ibrs :
      The AMD Zen4 core supports a new feature called Automatic IBRS.
      It is a "set-and-forget" feature that means that, unlike e.g.,
      s/w-toggled SPEC_CTRL.IBRS, h/w manages its IBRS mitigation
      resources automatically across CPL transitions.
      The presence of this feature is indicated via the CPUID function
      0x80000021_EAX[8].

The documention for the features are available in the links below.
a. Processor Programming Reference (PPR) for AMD Family 19h Model 01h,
   Revision B1 Processors
b. AMD64 Architecture Programmer’s Manual Volumes 1–5 Publication No. Revision
   40332 4.05 Date October 2022

Signed-off-by: Santosh Shukla <santosh.shukla@amd.com>
Signed-off-by: Kim Phillips <kim.phillips@amd.com>
Signed-off-by: Babu Moger <babu.moger@amd.com>
Link: https://www.amd.com/system/files/TechDocs/55898_B1_pub_0.50.zip
Link: https://www.amd.com/system/files/TechDocs/40332_4.05.pdf
Message-Id: <20230504205313.225073-7-babu.moger@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

target/i386/cpu.c

@@ -809,7 +809,7 @@ FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
             "pfthreshold", "avic", NULL, "v-vmsave-vmload",
             "vgif", NULL, NULL, NULL,
             NULL, NULL, NULL, NULL,
-            NULL, NULL, NULL, NULL,
+            NULL, "vnmi", NULL, NULL,
             "svme-addr-chk", NULL, NULL, NULL,
         },
         .cpuid = { .eax = 0x8000000A, .reg = R_EDX, },
@@ -947,7 +947,7 @@ FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
         .feat_names = {
             "no-nested-data-bp", NULL, "lfence-always-serializing", NULL,
             NULL, NULL, "null-sel-clr-base", NULL,
-            NULL, NULL, NULL, NULL,
+            "auto-ibrs", NULL, NULL, NULL,
             NULL, NULL, NULL, NULL,
             NULL, NULL, NULL, NULL,
             NULL, NULL, NULL, NULL,

target/i386/cpu.h

@@ -774,6 +774,7 @@ uint64_t x86_cpu_get_supported_feature_word(FeatureWord w,
 #define CPUID_SVM_AVIC            (1U << 13)
 #define CPUID_SVM_V_VMSAVE_VMLOAD (1U << 15)
 #define CPUID_SVM_VGIF            (1U << 16)
+#define CPUID_SVM_VNMI            (1U << 25)
 #define CPUID_SVM_SVME_ADDR_CHK   (1U << 28)
 
 /* Support RDFSBASE/RDGSBASE/WRFSBASE/WRGSBASE */
@@ -960,6 +961,8 @@ uint64_t x86_cpu_get_supported_feature_word(FeatureWord w,
 #define CPUID_8000_0021_EAX_LFENCE_ALWAYS_SERIALIZING    (1U << 2)
 /* Null Selector Clears Base */
 #define CPUID_8000_0021_EAX_NULL_SEL_CLR_BASE    (1U << 6)
+/* Automatic IBRS */
+#define CPUID_8000_0021_EAX_AUTO_IBRS   (1U << 8)
 
 #define CPUID_XSAVE_XSAVEOPT   (1U << 0)
 #define CPUID_XSAVE_XSAVEC     (1U << 1)