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authorTao Su <tao1.su@linux.intel.com>2025-01-21 10:06:48 +0800
committerPaolo Bonzini <pbonzini@redhat.com>2025-01-23 11:50:53 +0100
commitb611931d4f70b9a3e49e39c405c63b3b5e9c0df1 (patch)
treea2325d52c1d97348cc2fc02a2b8b7c1377e30437
parentc597ff5339a9918b00d9f4160126db0ac2a423cc (diff)
downloadfocaccia-qemu-b611931d4f70b9a3e49e39c405c63b3b5e9c0df1.tar.gz
focaccia-qemu-b611931d4f70b9a3e49e39c405c63b3b5e9c0df1.zip
target/i386: Export BHI_NO bit to guests
Branch History Injection (BHI) is a CPU side-channel vulnerability, where
an attacker may manipulate branch history before transitioning from user
to supervisor mode or from VMX non-root/guest to root mode. CPUs that set
BHI_NO bit in MSR IA32_ARCH_CAPABILITIES to indicate no additional
mitigation is required to prevent BHI.

Make BHI_NO bit available to guests.

Tested-by: Xuelian Guo <xuelian.guo@intel.com>
Signed-off-by: Tao Su <tao1.su@linux.intel.com>
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Link: https://lore.kernel.org/r/20250121020650.1899618-3-tao1.su@linux.intel.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-rw-r--r--target/i386/cpu.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 6db8d6c9ba..33fb27a611 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -1364,7 +1364,7 @@ FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
             "taa-no", NULL, NULL, NULL,
             NULL, "sbdr-ssdp-no", "fbsdp-no", "psdp-no",
             NULL, "fb-clear", NULL, NULL,
-            NULL, NULL, NULL, NULL,
+            "bhi-no", NULL, NULL, NULL,
             "pbrsb-no", NULL, "gds-no", "rfds-no",
             "rfds-clear", NULL, NULL, NULL,
         },