From 5d133dd839e80e48702916b629c8b396e28611c8 Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Tue, 25 Oct 2022 18:40:48 +1000 Subject: [PATCH] include/qemu/cpuid: Introduce xgetbv_low MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 Since one of the two has been using the mnemonic, assume that the comment about "older versions of the assember" is obsolete, as even that is 4 years old.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 Signed-off-by: Richard Henderson --- include/qemu/cpuid.h | 7 +++++++ tcg/i386/tcg-target.c.inc | 11 ++++------- util/bufferiszero.c | 3 +-- 3 files changed, 12 insertions(+), 9 deletions(-) diff --git a/include/qemu/cpuid.h b/include/qemu/cpuid.h index 7adb12d3202..1451e8ef2fe 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/tcg/i386/tcg-target.c.inc b/tcg/i386/tcg-target.c.inc index 883ced81683..028ece62a04 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; diff --git a/util/bufferiszero.c b/util/bufferiszero.c index 1790ded7d42..1886bc5ba43 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; -- 2.39.5