[PULL 02/25] target/i386: Enable fdp-excptn-only and zero-fcs-fds

Paolo Bonzini posted 25 patches 1 week ago
There is a newer version of this series
[PULL 02/25] target/i386: Enable fdp-excptn-only and zero-fcs-fds
Posted by Paolo Bonzini 1 week ago
From: Xiaoyao Li <xiaoyao.li@intel.com>

- CPUID.(EAX=07H,ECX=0H):EBX[bit 6]: x87 FPU Data Pointer updated only
  on x87 exceptions if 1.

- CPUID.(EAX=07H,ECX=0H):EBX[bit 13]: Deprecates FPU CS and FPU DS
  values if 1. i.e., X87 FCS and FDS are always zero.

Define names for them so that they can be exposed to guest with -cpu host.

Also define the bit field MACROs so that named cpu models can add it as
well in the future.

Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Link: https://lore.kernel.org/r/20240814075431.339209-3-xiaoyao.li@intel.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 target/i386/cpu.h | 4 ++++
 target/i386/cpu.c | 4 ++--
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index 4c63e7b0459..4c84cd41fd5 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -820,6 +820,8 @@ uint64_t x86_cpu_get_supported_feature_word(X86CPU *cpu, FeatureWord w);
 #define CPUID_7_0_EBX_HLE               (1U << 4)
 /* Intel Advanced Vector Extensions 2 */
 #define CPUID_7_0_EBX_AVX2              (1U << 5)
+/* FPU data pointer updated only on x87 exceptions */
+#define CPUID_7_0_EBX_FDP_EXCPTN_ONLY (1u << 6)
 /* Supervisor-mode Execution Prevention */
 #define CPUID_7_0_EBX_SMEP              (1U << 7)
 /* 2nd Group of Advanced Bit Manipulation Extensions */
@@ -830,6 +832,8 @@ uint64_t x86_cpu_get_supported_feature_word(X86CPU *cpu, FeatureWord w);
 #define CPUID_7_0_EBX_INVPCID           (1U << 10)
 /* Restricted Transactional Memory */
 #define CPUID_7_0_EBX_RTM               (1U << 11)
+/* Zero out FPU CS and FPU DS */
+#define CPUID_7_0_EBX_ZERO_FCS_FDS      (1U << 13)
 /* Memory Protection Extension */
 #define CPUID_7_0_EBX_MPX               (1U << 14)
 /* AVX-512 Foundation */
diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 0d30191482e..089b651591b 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -1054,9 +1054,9 @@ FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
         .type = CPUID_FEATURE_WORD,
         .feat_names = {
             "fsgsbase", "tsc-adjust", "sgx", "bmi1",
-            "hle", "avx2", NULL, "smep",
+            "hle", "avx2", "fdp-excptn-only", "smep",
             "bmi2", "erms", "invpcid", "rtm",
-            NULL, NULL, "mpx", NULL,
+            NULL, "zero-fcs-fds", "mpx", NULL,
             "avx512f", "avx512dq", "rdseed", "adx",
             "smap", "avx512ifma", "pcommit", "clflushopt",
             "clwb", "intel-pt", "avx512pf", "avx512er",
-- 
2.46.2