target/i386: remove PCOMMIT from TCG, deprecate property
The PCOMMIT instruction was never included in any physical processor.
TCG implements it as a no-op instruction, but its utility is debatable
to say the least. Drop it from the decoder since it is only available
with "-cpu max", which does not guarantee migration compatibility
across versions, and deprecate the property just in case someone is
using it as "pcommit=off".
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst
index 5c3ca47..40585ca 100644
--- a/docs/about/deprecated.rst
+++ b/docs/about/deprecated.rst
@@ -432,6 +432,14 @@
CPU device properties
'''''''''''''''''''''
+``pcommit`` on x86 (since 9.1)
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+The PCOMMIT instruction was never included in any physical processor.
+It was implemented as a no-op instruction in TCG up to QEMU 9.0, but
+only with ``-cpu max`` (which does not guarantee migration compatibility
+across versions).
+
``pmu-num=n`` on RISC-V CPUs (since 8.2)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 1058b68..79372de 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -713,7 +713,7 @@
#endif
#define TCG_7_0_EBX_FEATURES (CPUID_7_0_EBX_SMEP | CPUID_7_0_EBX_SMAP | \
CPUID_7_0_EBX_BMI1 | CPUID_7_0_EBX_BMI2 | CPUID_7_0_EBX_ADX | \
- CPUID_7_0_EBX_PCOMMIT | CPUID_7_0_EBX_CLFLUSHOPT | \
+ CPUID_7_0_EBX_CLFLUSHOPT | \
CPUID_7_0_EBX_CLWB | CPUID_7_0_EBX_MPX | CPUID_7_0_EBX_FSGSBASE | \
CPUID_7_0_EBX_ERMS | CPUID_7_0_EBX_AVX2 | CPUID_7_0_EBX_RDSEED | \
CPUID_7_0_EBX_SHA_NI | CPUID_7_0_EBX_KERNEL_FEATURES)
diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index 1e0d2c9..ccccb62 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -816,8 +816,6 @@
#define CPUID_7_0_EBX_SMAP (1U << 20)
/* AVX-512 Integer Fused Multiply Add */
#define CPUID_7_0_EBX_AVX512IFMA (1U << 21)
-/* Persistent Commit */
-#define CPUID_7_0_EBX_PCOMMIT (1U << 22)
/* Flush a Cache Line Optimized */
#define CPUID_7_0_EBX_CLFLUSHOPT (1U << 23)
/* Cache Line Write Back */
diff --git a/target/i386/tcg/translate.c b/target/i386/tcg/translate.c
index 3842b29..7d9f6b5 100644
--- a/target/i386/tcg/translate.c
+++ b/target/i386/tcg/translate.c
@@ -4487,17 +4487,7 @@
}
goto unknown_op;
- case 0xf8: /* sfence / pcommit */
- if (prefixes & PREFIX_DATA) {
- /* pcommit */
- if (!(s->cpuid_7_0_ebx_features & CPUID_7_0_EBX_PCOMMIT)
- || (prefixes & PREFIX_LOCK)) {
- goto illegal_op;
- }
- break;
- }
- /* fallthru */
- case 0xf9 ... 0xff: /* sfence */
+ case 0xf8 ... 0xff: /* sfence */
if (!(s->cpuid_features & CPUID_SSE)
|| (prefixes & PREFIX_LOCK)) {
goto illegal_op;
