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x86/bugs: Add attack vector controls for BHI

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Use attack vector controls to determine if BHI mitigation is required.

Signed-off-by: David Kaplan <david.kaplan@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/20250707183316.1349127-15-david.kaplan@amd.com
This commit is contained in:
David Kaplan 2025-07-07 13:33:09 -05:00 committed by Borislav Petkov (AMD)
parent 07a659edcf
commit ddcd4d3cb3
1 changed files with 12 additions and 3 deletions
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15
arch/x86/kernel/cpu/bugs.c
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@ -2217,11 +2217,20 @@ early_param("spectre_bhi", spectre_bhi_parse_cmdline);
static void __init bhi_select_mitigation(void)
{
if (!boot_cpu_has(X86_BUG_BHI) || cpu_mitigations_off())
if (!boot_cpu_has(X86_BUG_BHI))
bhi_mitigation = BHI_MITIGATION_OFF;
if (bhi_mitigation == BHI_MITIGATION_AUTO)
bhi_mitigation = BHI_MITIGATION_ON;
if (bhi_mitigation != BHI_MITIGATION_AUTO)
return;
if (cpu_attack_vector_mitigated(CPU_MITIGATE_GUEST_HOST)) {
if (cpu_attack_vector_mitigated(CPU_MITIGATE_USER_KERNEL))
bhi_mitigation = BHI_MITIGATION_ON;
else
bhi_mitigation = BHI_MITIGATION_VMEXIT_ONLY;
} else {
bhi_mitigation = BHI_MITIGATION_OFF;
}
}
static void __init bhi_update_mitigation(void)