Re: Patch "x86/pm: Introduce quirk framework to save/restore extra MSR registers around suspend/resume" has been added to the 4.4-stable tree

From: Greg KH
Date: Wed Aug 28 2019 - 04:43:59 EST

On Wed, Aug 28, 2019 at 12:12:39AM -0400, Sasha Levin wrote:
> This is a note to let you know that I've just added the patch titled
> x86/pm: Introduce quirk framework to save/restore extra MSR registers around suspend/resume
> to the 4.4-stable tree which can be found at:
> The filename of the patch is:
> x86-pm-introduce-quirk-framework-to-save-restore-ext.patch
> and it can be found in the queue-4.4 subdirectory.
> If you, or anyone else, feels it should not be added to the stable tree,
> please let <stable@xxxxxxxxxxxxxxx> know about it.
> commit d63273440aa0fdebc30d0c931f15f79beb213134
> Author: Chen Yu <yu.c.chen@xxxxxxxxx>
> Date: Wed Nov 25 01:03:41 2015 +0800
> x86/pm: Introduce quirk framework to save/restore extra MSR registers around suspend/resume
> A bug was reported that on certain Broadwell platforms, after
> resuming from S3, the CPU is running at an anomalously low
> speed.
> It turns out that the BIOS has modified the value of the
> THERM_CONTROL register during S3, and changed it from 0 to 0x10,
> thus enabled clock modulation(bit4), but with undefined CPU Duty
> Cycle(bit1:3) - which causes the problem.
> Here is a simple scenario to reproduce the issue:
> 1. Boot up the system
> 2. Get MSR 0x19a, it should be 0
> 3. Put the system into sleep, then wake it up
> 4. Get MSR 0x19a, it shows 0x10, while it should be 0
> Although some BIOSen want to change the CPU Duty Cycle during
> S3, in our case we don't want the BIOS to do any modification.
> Fix this issue by introducing a more generic x86 framework to
> save/restore specified MSR registers(THERM_CONTROL in this case)
> for suspend/resume. This allows us to fix similar bugs in a much
> simpler way in the future.
> When the kernel wants to protect certain MSRs during suspending,
> we simply add a quirk entry in msr_save_dmi_table, and customize
> the MSR registers inside the quirk callback, for example:
> u32 msr_id_need_to_save[] = {MSR_ID0, MSR_ID1, MSR_ID2...};
> and the quirk mechanism ensures that, once resumed from suspend,
> the MSRs indicated by these IDs will be restored to their
> original, pre-suspend values.
> Since both 64-bit and 32-bit kernels are affected, this patch
> covers the common 64/32-bit suspend/resume code path. And
> because the MSRs specified by the user might not be available or
> readable in any situation, we use rdmsrl_safe() to safely save
> these MSRs.
> Reported-and-tested-by: Marcin Kaszewski <marcin.kaszewski@xxxxxxxxx>
> Signed-off-by: Chen Yu <yu.c.chen@xxxxxxxxx>
> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> Acked-by: Pavel Machek <pavel@xxxxxx>
> Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
> Cc: Borislav Petkov <bp@xxxxxxxxx>
> Cc: Brian Gerst <brgerst@xxxxxxxxx>
> Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
> Cc: H. Peter Anvin <hpa@xxxxxxxxx>
> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: bp@xxxxxxx
> Cc: len.brown@xxxxxxxxx
> Cc: linux@xxxxxxxxxxx
> Cc: luto@xxxxxxxxxx
> Cc: rjw@xxxxxxxxxxxxx
> Link:
> [ More edits to the naming of data structures. ]
> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>

No git id of the patch in Linus's tree, or your signed-off-by?

Sasha, did your scripts trigger this unintentionally somehow?


greg k-h