diff options
| author | Andrew Cooper <andrew.cooper3@citrix.com> | 2022-10-03 10:10:33 -0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-10-07 09:16:56 +0200 |
| commit | d6a8a470dc22f7c5eb3affb3f1060d7ed6a5f58c (patch) | |
| tree | 82099a9ec38fd87cc8ddb628b2c6d73f46a23169 /arch/x86/kernel/cpu/common.c | |
| parent | 2edfa537f3b1dd3fbf2ff4fb70a4a408c1247693 (diff) | |
x86/cpu/amd: Enumerate BTC_NO
commit 26aae8ccbc1972233afd08fb3f368947c0314265 upstream.
BTC_NO indicates that hardware is not susceptible to Branch Type Confusion.
Zen3 CPUs don't suffer BTC.
Hypervisors are expected to synthesise BTC_NO when it is appropriate
given the migration pool, to prevent kernels using heuristics.
[ bp: Massage. ]
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/x86/kernel/cpu/common.c')
| -rw-r--r-- | arch/x86/kernel/cpu/common.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 4035581f61e0..0002dc62214d 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1259,8 +1259,10 @@ static void __init cpu_set_bug_bits(struct cpuinfo_x86 *c) setup_force_cpu_bug(X86_BUG_MMIO_UNKNOWN); } - if ((cpu_matches(cpu_vuln_blacklist, RETBLEED) || (ia32_cap & ARCH_CAP_RSBA))) - setup_force_cpu_bug(X86_BUG_RETBLEED); + if (!cpu_has(c, X86_FEATURE_BTC_NO)) { + if (cpu_matches(cpu_vuln_blacklist, RETBLEED) || (ia32_cap & ARCH_CAP_RSBA)) + setup_force_cpu_bug(X86_BUG_RETBLEED); + } if (cpu_matches(cpu_vuln_whitelist, NO_MELTDOWN)) return; |