From: Paolo Bonzini <pbonzini@redhat.com>
To: speck@linutronix.de
Subject: [MODERATED] [qemu PATCH] mds
Date: Mon, 4 Mar 2019 12:04:47 +0100 [thread overview]
Message-ID: <20190304110447.28961-1-pbonzini@redhat.com> (raw)
md-clear is a new CPUID bit which is set when microcode provides the
mechanism to invoke a flush of various exploitable CPU buffers by invoking
the VERW instruction. Add the new feature, and pass it down to
Hypervisor.framework guests.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
The last hunk is only needed for OS X, but anyway this is going
to be the patch that will be committed upstream.
target/i386/cpu.c | 2 +-
target/i386/cpu.h | 1 +
target/i386/hvf/x86_cpuid.c | 3 ++-
3 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index d990070c59..16da90562c 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -1075,7 +1075,7 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
.feat_names = {
NULL, NULL, "avx512-4vnniw", "avx512-4fmaps",
NULL, NULL, NULL, NULL,
- NULL, NULL, NULL, NULL,
+ NULL, NULL, "md-clear", NULL,
NULL, NULL, NULL, NULL,
NULL, NULL, NULL, NULL,
NULL, NULL, NULL, NULL,
diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index 26412f15eb..cbfab1a421 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -692,6 +692,7 @@ typedef uint32_t FeatureWordArray[FEATURE_WORDS];
#define CPUID_7_0_EDX_AVX512_4VNNIW (1U << 2) /* AVX512 Neural Network Instructions */
#define CPUID_7_0_EDX_AVX512_4FMAPS (1U << 3) /* AVX512 Multiply Accumulation Single Precision */
+#define CPUID_7_0_EDX_MD_CLEAR (1U << 10) /* Microarchitectural Data Clear */
#define CPUID_7_0_EDX_SPEC_CTRL (1U << 26) /* Speculation Control */
#define CPUID_7_0_EDX_ARCH_CAPABILITIES (1U << 29) /*Arch Capabilities*/
#define CPUID_7_0_EDX_SPEC_CTRL_SSBD (1U << 31) /* Speculative Store Bypass Disable */
diff --git a/target/i386/hvf/x86_cpuid.c b/target/i386/hvf/x86_cpuid.c
index 9874a46e92..f76ba50424 100644
--- a/target/i386/hvf/x86_cpuid.c
+++ b/target/i386/hvf/x86_cpuid.c
@@ -103,7 +103,8 @@ uint32_t hvf_get_supported_cpuid(uint32_t func, uint32_t idx,
}
ecx &= CPUID_7_0_ECX_AVX512BMI | CPUID_7_0_ECX_AVX512_VPOPCNTDQ;
- edx &= CPUID_7_0_EDX_AVX512_4VNNIW | CPUID_7_0_EDX_AVX512_4FMAPS;
+ edx &= CPUID_7_0_EDX_AVX512_4VNNIW | CPUID_7_0_EDX_AVX512_4FMAPS | \
+ CPUID_7_0_EDX_MD_CLEAR;
} else {
ebx = 0;
ecx = 0;
--
2.20.1
reply other threads:[~2019-03-04 11:04 UTC|newest]
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