x86/speculation/srbds: Update SRBDS mitigation selection

[mirror_ubuntu-jammy-kernel.git] / arch / x86 / kernel / cpu / bugs.c

diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 6f627855f46cf363d95451cfc76ed53cb2424007..75ccea211696df445a40d9106241a4f72aab059d 100644 (file)
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -595,11 +595,13 @@ static void __init srbds_select_mitigation(void)
                return;
 
        /*
-        * Check to see if this is one of the MDS_NO systems supporting
-        * TSX that are only exposed to SRBDS when TSX is enabled.
+        * Check to see if this is one of the MDS_NO systems supporting TSX that
+        * are only exposed to SRBDS when TSX is enabled or when CPU is affected
+        * by Processor MMIO Stale Data vulnerability.
         */
        ia32_cap = x86_read_arch_cap_msr();
-       if ((ia32_cap & ARCH_CAP_MDS_NO) && !boot_cpu_has(X86_FEATURE_RTM))
+       if ((ia32_cap & ARCH_CAP_MDS_NO) && !boot_cpu_has(X86_FEATURE_RTM) &&
+           !boot_cpu_has_bug(X86_BUG_MMIO_STALE_DATA))
                srbds_mitigation = SRBDS_MITIGATION_TSX_OFF;
        else if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
                srbds_mitigation = SRBDS_MITIGATION_HYPERVISOR;