5.10-stable review patch. If anyone has any objections, please let me know.
------------------
From: Borislav Petkov (AMD) <bp@xxxxxxxxx>
commit 6405b72e8d17bd1875a56ae52d23ec3cd51b9d66 upstream.
Specify how is SRSO mitigated when SMT is disabled. Also, correct the
SMT check for that.
Fixes: e9fbc47b818b ("x86/srso: Disable the mitigation on unaffected configurations")
Suggested-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Acked-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230814200813.p5czl47zssuej7nv@treble
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/cpu/bugs.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -2328,8 +2328,7 @@ static void __init srso_select_mitigatio
* Zen1/2 with SMT off aren't vulnerable after the right
* IBPB microcode has been applied.
*/
- if ((boot_cpu_data.x86 < 0x19) &&
- (!cpu_smt_possible() || (cpu_smt_control == CPU_SMT_DISABLED))) {
+ if (boot_cpu_data.x86 < 0x19 && !cpu_smt_possible()) {
setup_force_cpu_cap(X86_FEATURE_SRSO_NO);
return;
}
@@ -2619,7 +2618,7 @@ static ssize_t gds_show_state(char *buf)
static ssize_t srso_show_state(char *buf)
{
if (boot_cpu_has(X86_FEATURE_SRSO_NO))
- return sysfs_emit(buf, "Not affected\n");
+ return sysfs_emit(buf, "Mitigation: SMT disabled\n");
return sysfs_emit(buf, "%s%s\n",
srso_strings[srso_mitigation],
