Re: [PATCH V9] acpi/prmt: find block with specific type

[Koba Ko]

On 10/13/24 03:46, Ard Biesheuvel wrote:
> External email: Use caution opening links or attachments
>
>
> On Sat, 12 Oct 2024 at 21:42, KobaK <kobak@xxxxxxxxxx> wrote:
> > From: Koba Ko <kobak@xxxxxxxxxx>
> >
> > PRMT needs to find the correct type of block to
> > translate the PA-VA mapping for EFI runtime services.
> >
> > The issue arises because the PRMT is finding a block of
> > type EFI_CONVENTIONAL_MEMORY, which is not appropriate for
> > runtime services as described in Section 2.2.2 (Runtime
> > Services) of the UEFI Specification [1]. Since the PRM handler is
> > a type of runtime service, this causes an exception
> > when the PRM handler is called.
> >
> >      [Firmware Bug]: Unable to handle paging request in EFI runtime service
> >      WARNING: CPU: 22 PID: 4330 at drivers/firmware/efi/runtime-wrappers.c:341
> >          __efi_queue_work+0x11c/0x170
> >      Call trace:
> >
> > Find a block with specific type to fix this.
> > PRMT find a block with EFI_MEMORY_RUNTIME for PRM handler and PRM context.
> > If no suitable block is found, a warning message will be prompted
> > but the procedure continues to manage the next PRM handler.
> > However, if the PRM handler is actually called without proper allocation,
> > it would result in a failure during error handling.
> >
> > By using the correct memory types for runtime services,
> > ensure that the PRM handler and the context are
> > properly mapped in the virtual address space during runtime,
> > preventing the paging request error.
> >
> > The issue is really that only memory that has been remapped for
> > runtime by the firmware can be used by the PRM handler, and so the
> > region needs to have the EFI_MEMORY_RUNTIME attribute.
> >
> > [1] https://uefi.org/sites/default/files/resources/UEFI_Spec_2_10_Aug29.pdf
> > Fixes: cefc7ca46235 ("ACPI: PRM: implement OperationRegion handler for the PlatformRtMechanism subtype")
> > cc: stable@xxxxxxxxxxxxxxx
> > Signed-off-by: Koba Ko <kobak@xxxxxxxxxx>
> > Reviewed-by: Matthew R. Ochs <mochs@xxxxxxxxxx>
> > Reviewed-by: Zhang Rui <rui.zhang@xxxxxxxxx>
> > Reviewed-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
> > ---
> > V2:
> > 1. format the changelog and add more about error handling.
> > 2. replace goto
> > V3: Warn if parts of handler are missed during va-pa translating.
> > V4: Fix the 0day
> > V5: Fix typo and pr_warn warning
> > V6: use EFI_MOMOERY_RUNTIME to find block and split goto refactor as a single
> > patch
> > V7:
> > 1. refine the codes and commit description as per comments
> > 2. drop goto refacotr
> > V8: Fix 0day and cc to stable
> > V9: Describe 0day fix
> > cast PA as (void *) in pr_warn
> Sigh.
>
> Please read to the end of my previous email and fix the other thing too.
Sorry, I lost that.