linux.git/arch/x86/kernel/cpu/microcode, branch v4.18

x86/microcode/intel: Fix memleak in save_microcode_patch()

2018-06-22T12:42:59+00:00

Free useless ucode_patch entry when it's replaced.

[ bp: Drop the memfree_patch() two-liner. ]

Signed-off-by: Zhenzhong Duan 
Signed-off-by: Borislav Petkov 
Signed-off-by: Thomas Gleixner 
Cc: Srinivas REDDY Eeda 
Link: http://lkml.kernel.org/r/888102f0-fd22-459d-b090-a1bd8a00cb2b@default

x86/microcode: Make the late update update_lock a raw lock for RT

2018-05-27T19:50:09+00:00

__reload_late() is called from stop_machine context and thus cannot
acquire a non-raw spinlock on PREEMPT_RT.

Signed-off-by: Scott Wood 
Signed-off-by: Borislav Petkov 
Signed-off-by: Thomas Gleixner 
Acked-by: Thomas Gleixner 
Cc: Ashok Raj 
Cc: Clark Williams 
Cc: Pei Zhang 
Cc: x86-ml 
Link: http://lkml.kernel.org/r/20180524154420.24455-1-swood@redhat.com

x86/microcode: Do not exit early from __reload_late()

2018-04-24T07:48:22+00:00

Vitezslav reported a case where the

  "Timeout during microcode update!"

panic would hit. After a deeper look, it turned out that his .config had
CONFIG_HOTPLUG_CPU disabled which practically made save_mc_for_early() a
no-op.

When that happened, the discovered microcode patch wasn't saved into the
cache and the late loading path wouldn't find any.

This, then, lead to early exit from __reload_late() and thus CPUs waiting
until the timeout is reached, leading to the panic.

In hindsight, that function should have been written so it does not return
before the post-synchronization. Oh well, I know better now...

Fixes: bb8c13d61a62 ("x86/microcode: Fix CPU synchronization routine")
Reported-by: Vitezslav Samel 
Signed-off-by: Borislav Petkov 
Signed-off-by: Thomas Gleixner 
Tested-by: Vitezslav Samel 
Tested-by: Ashok Raj 
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/20180418081140.GA2439@pc11.op.pod.cz
Link: https://lkml.kernel.org/r/20180421081930.15741-2-bp@alien8.de

x86/microcode/intel: Save microcode patch unconditionally

2018-04-24T07:48:22+00:00

save_mc_for_early() was a no-op on !CONFIG_HOTPLUG_CPU but the
generic_load_microcode() path saves the microcode patches it has found into
the cache of patches which is used for late loading too. Regardless of
whether CPU hotplug is used or not.

Make the saving unconditional so that late loading can find the proper
patch.

Reported-by: Vitezslav Samel 
Signed-off-by: Borislav Petkov 
Signed-off-by: Thomas Gleixner 
Tested-by: Vitezslav Samel 
Tested-by: Ashok Raj 
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/20180418081140.GA2439@pc11.op.pod.cz
Link: https://lkml.kernel.org/r/20180421081930.15741-1-bp@alien8.de

Documentation: Fix early-microcode.txt references after file rename

2018-03-27T07:51:23+00:00

The file Documentation/x86/early-microcode.txt was renamed to
Documentation/x86/microcode.txt in 0e3258753f81, but it was still
referenced by its old name in a three places:

* Documentation/x86/00-INDEX
* arch/x86/Kconfig
* arch/x86/kernel/cpu/microcode/amd.c

This commit updates these references accordingly.

Fixes: 0e3258753f81 ("x86/microcode: Document the three loading methods")
Signed-off-by: Jaak Ristioja 
Signed-off-by: Jiri Kosina

x86/microcode: Fix CPU synchronization routine

2018-03-16T19:55:51+00:00

Emanuel reported an issue with a hang during microcode update because my
dumb idea to use one atomic synchronization variable for both rendezvous
- before and after update - was simply bollocks:

  microcode: microcode_reload_late: late_cpus: 4
  microcode: __reload_late: cpu 2 entered
  microcode: __reload_late: cpu 1 entered
  microcode: __reload_late: cpu 3 entered
  microcode: __reload_late: cpu 0 entered
  microcode: __reload_late: cpu 1 left
  microcode: Timeout while waiting for CPUs rendezvous, remaining: 1

CPU1 above would finish, leave and the others will still spin waiting for
it to join.

So do two synchronization atomics instead, which makes the code a lot more
straightforward.

Also, since the update is serialized and it also takes quite some time per
microcode engine, increase the exit timeout by the number of CPUs on the
system.

That's ok because the moment all CPUs are done, that timeout will be cut
short.

Furthermore, panic when some of the CPUs timeout when returning from a
microcode update: we can't allow a system with not all cores updated.

Also, as an optimization, do not do the exit sync if microcode wasn't
updated.

Reported-by: Emanuel Czirai 
Signed-off-by: Borislav Petkov 
Signed-off-by: Thomas Gleixner 
Tested-by: Emanuel Czirai 
Tested-by: Ashok Raj 
Tested-by: Tom Lendacky 
Link: https://lkml.kernel.org/r/20180314183615.17629-2-bp@alien8.de

x86/microcode: Attempt late loading only when new microcode is present

2018-03-16T19:55:51+00:00

Return UCODE_NEW from the scanning functions to denote that new microcode
was found and only then attempt the expensive synchronization dance.

Reported-by: Emanuel Czirai 
Signed-off-by: Borislav Petkov 
Signed-off-by: Thomas Gleixner 
Tested-by: Emanuel Czirai 
Tested-by: Ashok Raj 
Tested-by: Tom Lendacky 
Link: https://lkml.kernel.org/r/20180314183615.17629-1-bp@alien8.de

x86/microcode: Synchronize late microcode loading

2018-03-08T09:19:26+00:00

Original idea by Ashok, completely rewritten by Borislav.

Before you read any further: the early loading method is still the
preferred one and you should always do that. The following patch is
improving the late loading mechanism for long running jobs and cloud use
cases.

Gather all cores and serialize the microcode update on them by doing it
one-by-one to make the late update process as reliable as possible and
avoid potential issues caused by the microcode update.

[ Borislav: Rewrite completely. ]

Co-developed-by: Borislav Petkov 
Signed-off-by: Ashok Raj 
Signed-off-by: Borislav Petkov 
Signed-off-by: Thomas Gleixner 
Tested-by: Tom Lendacky 
Tested-by: Ashok Raj 
Reviewed-by: Tom Lendacky 
Cc: Arjan Van De Ven 
Link: https://lkml.kernel.org/r/20180228102846.13447-8-bp@alien8.de

x86/microcode: Request microcode on the BSP

2018-03-08T09:19:26+00:00

... so that any newer version can land in the cache and can later be
fished out by the application functions. Do that before grabbing the
hotplug lock.

Signed-off-by: Borislav Petkov 
Signed-off-by: Thomas Gleixner 
Tested-by: Tom Lendacky 
Tested-by: Ashok Raj 
Reviewed-by: Tom Lendacky 
Cc: Arjan Van De Ven 
Link: https://lkml.kernel.org/r/20180228102846.13447-7-bp@alien8.de

x86/microcode/intel: Look into the patch cache first

2018-03-08T09:19:26+00:00

The cache might contain a newer patch - look in there first.

A follow-on change will make sure newest patches are loaded into the
cache of microcode patches.

Signed-off-by: Borislav Petkov 
Signed-off-by: Thomas Gleixner 
Tested-by: Tom Lendacky 
Tested-by: Ashok Raj 
Cc: Arjan Van De Ven 
Link: https://lkml.kernel.org/r/20180228102846.13447-6-bp@alien8.de