From b611931d4f70b9a3e49e39c405c63b3b5e9c0df1 Mon Sep 17 00:00:00 2001 From: Tao Su Date: Tue, 21 Jan 2025 10:06:48 +0800 Subject: [PATCH] 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 Signed-off-by: Tao Su Reviewed-by: Zhao Liu Link: https://lore.kernel.org/r/20250121020650.1899618-3-tao1.su@linux.intel.com Signed-off-by: Paolo Bonzini --- target/i386/cpu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) 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, }, -- 2.30.2