diff options
| author | Thomas Gleixner <[email protected]> | 2023-10-02 13:59:56 +0200 |
|---|---|---|
| committer | Borislav Petkov (AMD) <[email protected]> | 2023-10-24 15:05:54 +0200 |
| commit | 634ac23ad609b3ddd9e0e478bd5afbf49d3a2556 (patch) | |
| tree | b67c0fab5a46a5fa3f0dd9a7a37aa4f105ca026d /arch/x86/kernel/cpu/microcode/amd.c | |
| parent | ba48aa32388ac652256baa8d0a6092d350160da0 (diff) | |
x86/microcode: Handle "nosmt" correctly
On CPUs where microcode loading is not NMI-safe the SMT siblings which
are parked in one of the play_dead() variants still react to NMIs.
So if an NMI hits while the primary thread updates the microcode the
resulting behaviour is undefined. The default play_dead() implementation on
modern CPUs is using MWAIT which is not guaranteed to be safe against
a microcode update which affects MWAIT.
Take the cpus_booted_once_mask into account to detect this case and
refuse to load late if the vendor specific driver does not advertise
that late loading is NMI safe.
AMD stated that this is safe, so mark the AMD driver accordingly.
This requirement will be partially lifted in later changes.
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Borislav Petkov (AMD) <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Diffstat (limited to 'arch/x86/kernel/cpu/microcode/amd.c')
| -rw-r--r-- | arch/x86/kernel/cpu/microcode/amd.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c index 99aa5a88d668..102aebcdb766 100644 --- a/arch/x86/kernel/cpu/microcode/amd.c +++ b/arch/x86/kernel/cpu/microcode/amd.c @@ -917,10 +917,11 @@ static void microcode_fini_cpu_amd(int cpu) } static struct microcode_ops microcode_amd_ops = { - .request_microcode_fw = request_microcode_amd, - .collect_cpu_info = collect_cpu_info_amd, - .apply_microcode = apply_microcode_amd, - .microcode_fini_cpu = microcode_fini_cpu_amd, + .request_microcode_fw = request_microcode_amd, + .collect_cpu_info = collect_cpu_info_amd, + .apply_microcode = apply_microcode_amd, + .microcode_fini_cpu = microcode_fini_cpu_amd, + .nmi_safe = true, }; struct microcode_ops * __init init_amd_microcode(void) |