On 27. 02. 24, 9:00, Pawan Gupta wrote:
commit baf8361e54550a48a7087b603313ad013cc13386 upstream.
...
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -194,6 +194,17 @@
#endif
.endm
+/*
+ * Macro to execute VERW instruction that mitigate transient data sampling
+ * attacks such as MDS. On affected systems a microcode update overloaded VERW
+ * instruction to also clear the CPU buffers. VERW clobbers CFLAGS.ZF.
+ *
+ * Note: Only the memory operand variant of VERW clears the CPU buffers.
+ */
+.macro CLEAR_CPU_BUFFERS
+ ALTERNATIVE "", __stringify(verw mds_verw_sel), X86_FEATURE_CLEAR_CPU_BUF
The same here. Except 6.1 (I didn't check stable-6.1) does not have:
commit 270a69c4485d7d07516d058bcc0473c90ee22185
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Date: Wed Feb 8 18:10:52 2023 +0100
x86/alternative: Support relocations in alternatives
yet. You likely need to backport that too.
regards,
--
js
suse labs
