You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
72 lines
2.7 KiB
72 lines
2.7 KiB
From 0d056d6da9e4147d5965bf3507f6d6d6a413924d Mon Sep 17 00:00:00 2001
|
|
From: Emanuele Giuseppe Esposito <eesposit@redhat.com>
|
|
Date: Wed, 24 May 2023 06:52:43 -0400
|
|
Subject: [PATCH 2/5] target/i386: add support for FB_CLEAR feature
|
|
|
|
RH-Author: Emanuele Giuseppe Esposito <eesposit@redhat.com>
|
|
RH-MergeRequest: 167: target/i386: add support for FB_CLEAR feature
|
|
RH-Bugzilla: 2216201
|
|
RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
|
|
RH-Commit: [2/2] 5f191964ba25754107a06ef907f4ac614280aaa1 (eesposit/qemu-kvm)
|
|
|
|
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2216201
|
|
|
|
commit 22e1094ca82d5518c1b69aff3e87c550776ae1eb
|
|
Author: Emanuele Giuseppe Esposito <eesposit@redhat.com>
|
|
Date: Wed Feb 1 08:57:59 2023 -0500
|
|
|
|
target/i386: add support for FB_CLEAR feature
|
|
|
|
As reported by the Intel's doc:
|
|
"FB_CLEAR: The processor will overwrite fill buffer values as part of
|
|
MD_CLEAR operations with the VERW instruction.
|
|
On these processors, L1D_FLUSH does not overwrite fill buffer values."
|
|
|
|
If this cpu feature is present in host, allow QEMU to choose whether to
|
|
show it to the guest too.
|
|
One disadvantage of not exposing it is that the guest will report
|
|
a non existing vulnerability in
|
|
/sys/devices/system/cpu/vulnerabilities/mmio_stale_data
|
|
because the mitigation is present only when the cpu has
|
|
(FLUSH_L1D and MD_CLEAR) or FB_CLEAR
|
|
features enabled.
|
|
|
|
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
|
|
Message-Id: <20230201135759.555607-3-eesposit@redhat.com>
|
|
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
|
|
|
|
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
|
|
---
|
|
target/i386/cpu.c | 2 +-
|
|
target/i386/cpu.h | 1 +
|
|
2 files changed, 2 insertions(+), 1 deletion(-)
|
|
|
|
diff --git a/target/i386/cpu.c b/target/i386/cpu.c
|
|
index caf6338cc0..839706b430 100644
|
|
--- a/target/i386/cpu.c
|
|
+++ b/target/i386/cpu.c
|
|
@@ -1012,7 +1012,7 @@ FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
|
|
"ssb-no", "mds-no", "pschange-mc-no", "tsx-ctrl",
|
|
"taa-no", NULL, NULL, NULL,
|
|
NULL, NULL, NULL, NULL,
|
|
- NULL, NULL, NULL, NULL,
|
|
+ NULL, "fb-clear", NULL, 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 74fa649b60..c28b9df217 100644
|
|
--- a/target/i386/cpu.h
|
|
+++ b/target/i386/cpu.h
|
|
@@ -989,6 +989,7 @@ uint64_t x86_cpu_get_supported_feature_word(FeatureWord w,
|
|
#define MSR_ARCH_CAP_PSCHANGE_MC_NO (1U << 6)
|
|
#define MSR_ARCH_CAP_TSX_CTRL_MSR (1U << 7)
|
|
#define MSR_ARCH_CAP_TAA_NO (1U << 8)
|
|
+#define MSR_ARCH_CAP_FB_CLEAR (1U << 17)
|
|
|
|
#define MSR_CORE_CAP_SPLIT_LOCK_DETECT (1U << 5)
|
|
|
|
--
|
|
2.39.3
|
|
|