x86,bugs: Unconditionally allow spectre_v2=retpoline,amd

Currently Linux prevents usage of retpoline,amd on !AMD hardware, this
is unfriendly and gets in the way of testing. Remove this restriction.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Tested-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/r/20211026120310.487348118@infradead.org

diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index ecfca3bbcd96866c8666accd32947656b10f7159..ba43597f1027cf7f463a2a2d1e0b6415a5d7381d 100644 (file)
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -882,13 +882,6 @@ static enum spectre_v2_mitigation_cmd __init spectre_v2_parse_cmdline(void)
                return SPECTRE_V2_CMD_AUTO;
        }
 
-       if (cmd == SPECTRE_V2_CMD_RETPOLINE_AMD &&
-           boot_cpu_data.x86_vendor != X86_VENDOR_HYGON &&
-           boot_cpu_data.x86_vendor != X86_VENDOR_AMD) {
-               pr_err("retpoline,amd selected but CPU is not AMD. Switching to AUTO select\n");
-               return SPECTRE_V2_CMD_AUTO;
-       }
-
        spec_v2_print_cond(mitigation_options[i].option,
                           mitigation_options[i].secure);
        return cmd;