6.17-stable review patch. If anyone has any objections, please let me know.
------------------
From: David Kaplan david.kaplan@amd.com
[ Upstream commit 5799d5d8a6c877f03ad5b5a640977053be45059a ]
Use attack vector controls to select whether VMSCAPE requires mitigation, similar to other bugs.
Signed-off-by: David Kaplan david.kaplan@amd.com Signed-off-by: Borislav Petkov (AMD) bp@alien8.de Signed-off-by: Sasha Levin sashal@kernel.org --- .../admin-guide/hw-vuln/attack_vector_controls.rst | 1 + arch/x86/kernel/cpu/bugs.c | 14 ++++++++++---- 2 files changed, 11 insertions(+), 4 deletions(-)
diff --git a/Documentation/admin-guide/hw-vuln/attack_vector_controls.rst b/Documentation/admin-guide/hw-vuln/attack_vector_controls.rst index 5964901d66e31..d0bdbd81dcf9f 100644 --- a/Documentation/admin-guide/hw-vuln/attack_vector_controls.rst +++ b/Documentation/admin-guide/hw-vuln/attack_vector_controls.rst @@ -218,6 +218,7 @@ SRSO X X X X SSB X TAA X X X X * (Note 2) TSA X X X X +VMSCAPE X =============== ============== ============ ============= ============== ============ ========
Notes: diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 9750ce448e626..c6bb8e76eb984 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -434,6 +434,9 @@ static bool __init should_mitigate_vuln(unsigned int bug) case X86_BUG_SPEC_STORE_BYPASS: return cpu_attack_vector_mitigated(CPU_MITIGATE_USER_USER);
+ case X86_BUG_VMSCAPE: + return cpu_attack_vector_mitigated(CPU_MITIGATE_GUEST_HOST); + default: WARN(1, "Unknown bug %x\n", bug); return false; @@ -3308,15 +3311,18 @@ early_param("vmscape", vmscape_parse_cmdline);
static void __init vmscape_select_mitigation(void) { - if (cpu_mitigations_off() || - !boot_cpu_has_bug(X86_BUG_VMSCAPE) || + if (!boot_cpu_has_bug(X86_BUG_VMSCAPE) || !boot_cpu_has(X86_FEATURE_IBPB)) { vmscape_mitigation = VMSCAPE_MITIGATION_NONE; return; }
- if (vmscape_mitigation == VMSCAPE_MITIGATION_AUTO) - vmscape_mitigation = VMSCAPE_MITIGATION_IBPB_EXIT_TO_USER; + if (vmscape_mitigation == VMSCAPE_MITIGATION_AUTO) { + if (should_mitigate_vuln(X86_BUG_VMSCAPE)) + vmscape_mitigation = VMSCAPE_MITIGATION_IBPB_EXIT_TO_USER; + else + vmscape_mitigation = VMSCAPE_MITIGATION_NONE; + } }
static void __init vmscape_update_mitigation(void)