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[PATCH v2 01/30] include/qemu/cpuid: Introduce xgetbv_low
From: |
Richard Henderson |
Subject: |
[PATCH v2 01/30] include/qemu/cpuid: Introduce xgetbv_low |
Date: |
Wed, 15 Feb 2023 16:57:10 -1000 |
Replace the two uses of asm to expand xgetbv with an inline function.
Since one of the two has been using the mnemonic, assume that the
comment about "older versions of the assember" is obsolete, as even
that is 4 years old.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
include/qemu/cpuid.h | 7 +++++++
util/bufferiszero.c | 3 +--
tcg/i386/tcg-target.c.inc | 11 ++++-------
3 files changed, 12 insertions(+), 9 deletions(-)
diff --git a/include/qemu/cpuid.h b/include/qemu/cpuid.h
index 7adb12d320..1451e8ef2f 100644
--- a/include/qemu/cpuid.h
+++ b/include/qemu/cpuid.h
@@ -71,4 +71,11 @@
#define bit_LZCNT (1 << 5)
#endif
+static inline unsigned xgetbv_low(unsigned c)
+{
+ unsigned a, d;
+ asm("xgetbv" : "=a"(a), "=d"(d) : "c"(c));
+ return a;
+}
+
#endif /* QEMU_CPUID_H */
diff --git a/util/bufferiszero.c b/util/bufferiszero.c
index 1790ded7d4..1886bc5ba4 100644
--- a/util/bufferiszero.c
+++ b/util/bufferiszero.c
@@ -258,8 +258,7 @@ static void __attribute__((constructor))
init_cpuid_cache(void)
/* We must check that AVX is not just available, but usable. */
if ((c & bit_OSXSAVE) && (c & bit_AVX) && max >= 7) {
- int bv;
- __asm("xgetbv" : "=a"(bv), "=d"(d) : "c"(0));
+ unsigned bv = xgetbv_low(0);
__cpuid_count(7, 0, a, b, c, d);
if ((bv & 0x6) == 0x6 && (b & bit_AVX2)) {
cache |= CACHE_AVX2;
diff --git a/tcg/i386/tcg-target.c.inc b/tcg/i386/tcg-target.c.inc
index 883ced8168..028ece62a0 100644
--- a/tcg/i386/tcg-target.c.inc
+++ b/tcg/i386/tcg-target.c.inc
@@ -4156,12 +4156,9 @@ static void tcg_target_init(TCGContext *s)
/* There are a number of things we must check before we can be
sure of not hitting invalid opcode. */
if (c & bit_OSXSAVE) {
- unsigned xcrl, xcrh;
- /* The xgetbv instruction is not available to older versions of
- * the assembler, so we encode the instruction manually.
- */
- asm(".byte 0x0f, 0x01, 0xd0" : "=a" (xcrl), "=d" (xcrh) : "c" (0));
- if ((xcrl & 6) == 6) {
+ unsigned bv = xgetbv_low(0);
+
+ if ((bv & 6) == 6) {
have_avx1 = (c & bit_AVX) != 0;
have_avx2 = (b7 & bit_AVX2) != 0;
@@ -4172,7 +4169,7 @@ static void tcg_target_init(TCGContext *s)
* check that OPMASK and all extended ZMM state are enabled
* even if we're not using them -- the insns will fault.
*/
- if ((xcrl & 0xe0) == 0xe0
+ if ((bv & 0xe0) == 0xe0
&& (b7 & bit_AVX512F)
&& (b7 & bit_AVX512VL)) {
have_avx512vl = true;
--
2.34.1
- [PATCH v2 00/30] tcg: Improve atomicity support, Richard Henderson, 2023/02/15
- [PATCH v2 01/30] include/qemu/cpuid: Introduce xgetbv_low,
Richard Henderson <=
- [PATCH v2 02/30] include/exec/memop: Add bits describing atomicity, Richard Henderson, 2023/02/15
- [PATCH v2 03/30] accel/tcg: Add cpu_in_serial_context, Richard Henderson, 2023/02/15
- [PATCH v2 04/30] accel/tcg: Introduce tlb_read_idx, Richard Henderson, 2023/02/15
- [PATCH v2 05/30] accel/tcg: Reorg system mode load helpers, Richard Henderson, 2023/02/15
- [PATCH v2 06/30] accel/tcg: Reorg system mode store helpers, Richard Henderson, 2023/02/15
- [PATCH v2 07/30] accel/tcg: Honor atomicity of loads, Richard Henderson, 2023/02/15