On 14.01.21 20:40, Josh Poimboeuf wrote:
It's kernel policy to not have (unannotated) indirect jumps because of Spectre v2. This one's probably harmless, but better safe than sorry. Convert it to a retpoline.Cc: Boris Ostrovsky <boris.ostrov...@oracle.com> Cc: Juergen Gross <jgr...@suse.com> Signed-off-by: Josh Poimboeuf <jpoim...@redhat.com> --- arch/x86/platform/pvh/head.S | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/platform/pvh/head.S b/arch/x86/platform/pvh/head.S index 43b4d864817e..d87cebd08d32 100644 --- a/arch/x86/platform/pvh/head.S +++ b/arch/x86/platform/pvh/head.S @@ -16,6 +16,7 @@ #include <asm/boot.h> #include <asm/processor-flags.h> #include <asm/msr.h> +#include <asm/nospec-branch.h> #include <xen/interface/elfnote.h>__HEAD@@ -105,7 +106,7 @@ SYM_CODE_START_LOCAL(pvh_start_xen) /* startup_64 expects boot_params in %rsi. */ mov $_pa(pvh_bootparams), %rsi mov $_pa(startup_64), %rax - jmp *%rax + JMP_NOSPEC rax
I'd rather have it annotated only. Using ALTERNATIVE in very early boot code is just adding needless clutter, as the retpoline variant won't ever be active. Juergen
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