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Message-ID: <CAMj1kXGSrEtoL2xztrr+LgNRxS6w6kY8i+GhjZsn+XNyPfKDXQ@mail.gmail.com>
Date: Thu, 3 Oct 2024 10:04:57 +0200
From: Ard Biesheuvel <ardb@...nel.org>
To: Koba Ko <kobak@...dia.com>
Cc: "Rafael J. Wysocki" <rafael@...nel.org>, Matt Ochs <mochs@...dia.com>, Len Brown <lenb@...nel.org>,
linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org,
Zhang Rui <rui.zhang@...el.com>, linux-efi <linux-efi@...r.kernel.org>
Subject: Re: [PATCH V5] acpi/prmt: find block with specific type
On Thu, 3 Oct 2024 at 05:45, Koba Ko <kobak@...dia.com> wrote:
>
>
> On 10/3/24 05:11, Ard Biesheuvel wrote:
> > External email: Use caution opening links or attachments
> >
> >
> > On Wed, 2 Oct 2024 at 20:06, Rafael J. Wysocki <rafael@...nel.org> wrote:
> >> On Wed, Sep 11, 2024 at 5:55 PM KobaK <kobak@...dia.com> wrote:
> >>> 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:
> >>> __efi_queue_work+0x11c/0x170
> >>> efi_call_acpi_prm_handler+0x68/0xd0
> >>> acpi_platformrt_space_handler+0x198/0x258
> >>> acpi_ev_address_space_dispatch+0x144/0x388
> >>> acpi_ex_access_region+0x9c/0x118
> >>> acpi_ex_write_serial_bus+0xc4/0x218
> >>> acpi_ex_write_data_to_field+0x168/0x218
> >>> acpi_ex_store_object_to_node+0x1a8/0x258
> >>> acpi_ex_store+0xec/0x330
> >>> acpi_ex_opcode_1A_1T_1R+0x15c/0x618
> >>> acpi_ds_exec_end_op+0x274/0x548
> >>> acpi_ps_parse_loop+0x10c/0x6b8
> >>> acpi_ps_parse_aml+0x140/0x3b0
> >>> acpi_ps_execute_method+0x12c/0x2a0
> >>> acpi_ns_evaluate+0x210/0x310
> >>> acpi_evaluate_object+0x178/0x358
> >>> acpi_proc_write+0x1a8/0x8a0 [acpi_call]
> >>> proc_reg_write+0xcc/0x150
> >>> vfs_write+0xd8/0x380
> >>> ksys_write+0x70/0x120
> >>> __arm64_sys_write+0x24/0x48
> >>> invoke_syscall.constprop.0+0x80/0xf8
> >>> do_el0_svc+0x50/0x110
> >>> el0_svc+0x48/0x1d0
> >>> el0t_64_sync_handler+0x15c/0x178
> >>> el0t_64_sync+0x1a8/0x1b0
> >>>
> >>> Find a block with specific type to fix this.
> >>> prmt find a block with EFI_RUNTIME_SERVICES_DATA for prm handler and
> >>> find a block with EFI_RUNTIME_SERVICES_CODE for prm context.
> >>> If no suitable block is found, a warning message will be prompted
> >>> but the procedue continues to manage the next prm handler.
> >>> However, if the prm handler is actullay 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.
> >>>
> >>> [1] https://uefi.org/sites/default/files/resources/UEFI_Spec_2_10_Aug29.pdf
> >> I need input from EFI people on this, so can you please resend the
> >> patch with a CC to linux-efi@...r.kernel.org?
> >>
> >>> Fixes: cefc7ca46235 ("ACPI: PRM: implement OperationRegion handler for the PlatformRtMechanism subtype")
> >>> Signed-off-by: KobaK <kobak@...dia.com>
> > Please use your full name.
> Hi Ardb,
> Sure, will update.
> >
> >>> Reviewed-by: Matthew R. Ochs <mochs@...dia.com>
> >>> ---
> >>> 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
> >>> ---
> >>> drivers/acpi/prmt.c | 49 +++++++++++++++++++++++++++++++--------------
> >>> 1 file changed, 34 insertions(+), 15 deletions(-)
> >>>
> >>> diff --git a/drivers/acpi/prmt.c b/drivers/acpi/prmt.c
> >>> index c78453c74ef5..cd4a7f5491d6 100644
> >>> --- a/drivers/acpi/prmt.c
> >>> +++ b/drivers/acpi/prmt.c
> >>> @@ -72,15 +72,17 @@ struct prm_module_info {
> >>> struct prm_handler_info handlers[] __counted_by(handler_count);
> >>> };
> >>>
> >>> -static u64 efi_pa_va_lookup(u64 pa)
> >>> +static u64 efi_pa_va_lookup(u64 pa, u32 type)
> >>> {
> >>> efi_memory_desc_t *md;
> >>> u64 pa_offset = pa & ~PAGE_MASK;
> >>> u64 page = pa & PAGE_MASK;
> >>>
> >>> for_each_efi_memory_desc(md) {
> >>> - if (md->phys_addr < pa && pa < md->phys_addr + PAGE_SIZE * md->num_pages)
> >>> + if ((md->type == type) &&
> >>> + (md->phys_addr < pa && pa < md->phys_addr + PAGE_SIZE * md->num_pages)) {
> >>> return pa_offset + md->virt_addr + page - md->phys_addr;
> >>> + }
> >>> }
> >>>
> >>> return 0;
> >>> @@ -148,9 +150,18 @@ acpi_parse_prmt(union acpi_subtable_headers *header, const unsigned long end)
> >>> th = &tm->handlers[cur_handler];
> >>>
> >>> guid_copy(&th->guid, (guid_t *)handler_info->handler_guid);
> >>> - th->handler_addr = (void *)efi_pa_va_lookup(handler_info->handler_address);
> >>> - th->static_data_buffer_addr = efi_pa_va_lookup(handler_info->static_data_buffer_address);
> >>> - th->acpi_param_buffer_addr = efi_pa_va_lookup(handler_info->acpi_param_buffer_address);
> >>> + th->handler_addr =
> >>> + (void *)efi_pa_va_lookup(handler_info->handler_address, EFI_RUNTIME_SERVICES_CODE);
> > Wouldn't it make more sense to test the EFI_MEMORY_RUNTIME attribute
> > rather than expecting/assuming a certain memory type in each case?
> > That attribute is precisely what controls whether or not a region has
> > been remapped into the firmware's page tables.
> Please see the below
> >
> >>> + th->static_data_buffer_addr =
> >>> + efi_pa_va_lookup(handler_info->static_data_buffer_address, EFI_RUNTIME_SERVICES_DATA);
> >>> + th->acpi_param_buffer_addr =
> >>> + efi_pa_va_lookup(handler_info->acpi_param_buffer_address, EFI_RUNTIME_SERVICES_DATA);
> >>> +
> >>> + if (!th->handler_addr || !th->static_data_buffer_addr || !th->acpi_param_buffer_addr)
> >>> + pr_warn(
> >>> + "Idx: %llu, Parts of handler(GUID: %pUL) are missed, handler_addr %p, data_addr %p, param_addr %p",
> > Please improve this diagnostic: 'are missed' is not very helpful.
>
> Are these good for you
>
I /think/ it looks ok but please resend it as a proper patch - the
whitespace got mangled and it is difficult to read.
> ```
>
> -static u64 efi_pa_va_lookup(u64 pa, u32 type)
> +static u64 efi_pa_va_lookup(u64 pa)
> {
> efi_memory_desc_t *md;
> u64 pa_offset = pa & ~PAGE_MASK;
> u64 page = pa & PAGE_MASK;
>
> for_each_efi_memory_desc(md) {
> - if ((md->type == type) &&
> + if ((md->attribute & EFI_MEMORY_RUNTIME) &&
> (md->phys_addr < pa && pa < md->phys_addr +
> PAGE_SIZE * md->num_pages)) {
> return pa_offset + md->virt_addr + page -
> md->phys_addr;
> }
> @@ -150,18 +150,20 @@ acpi_parse_prmt(union acpi_subtable_headers
> *header, const unsigned long end)
> th = &tm->handlers[cur_handler];
>
> guid_copy(&th->guid, (guid_t *)handler_info->handler_guid);
> - th->handler_addr =
> - (void
> *)efi_pa_va_lookup(handler_info->handler_address,
> EFI_RUNTIME_SERVICES_CODE);
> - th->static_data_buffer_addr =
> - efi_pa_va_lookup(handler_info->static_data_buffer_address,
> EFI_RUNTIME_SERVICES_DATA);
> - th->acpi_param_buffer_addr =
> - efi_pa_va_lookup(handler_info->acpi_param_buffer_address,
> EFI_RUNTIME_SERVICES_DATA);
> -
> - if (!th->handler_addr || !th->static_data_buffer_addr ||
> !th->acpi_param_buffer_addr)
> - pr_warn(
> - "Idx: %llu, Parts of handler(GUID: %pUL)
> are missed, handler_addr %p, data_addr %p, param_addr %p",
> - cur_handler, &th->guid, th->handler_addr,
> - (void *)th->static_data_buffer_addr,
> (void *)th->acpi_param_buffer_addr);
> + th->handler_addr = (void
> *)efi_pa_va_lookup(handler_info->handler_address);
> + if (!th->handler_addr)
> + pr_warn( "Idx: %llu, failed to find VA for
> handler_addr(GUID: %pUL, PA: %p)",
> + cur_handler, &th->guid, th->handler_addr);
> +
> + th->static_data_buffer_addr =
> efi_pa_va_lookup(handler_info->static_data_buffer_address);
> + if (!th->static_data_buffer_addr)
> + pr_warn( "Idx: %llu, failed to find VA for
> data_addr(PA: %p)",
> + cur_handler, &th->guid, (void
> *)th->static_data_buffer_addr);
> +
> + th->acpi_param_buffer_addr =
> efi_pa_va_lookup(handler_info->acpi_param_buffer_address);
> + if (!th->acpi_param_buffer_addr)
> + pr_warn( "Idx: %llu, failed to find VA for
> param_addr(PA: %p)",
> + cur_handler, &th->guid, (void
> *)th->acpi_param_buffer_addr);
>
> ```
>
...
> >>> @@ -274,8 +293,10 @@ static acpi_status acpi_platformrt_space_handler(u32 function,
> >>> case PRM_CMD_START_TRANSACTION:
> >>>
> >>> module = find_prm_module(&buffer->handler_guid);
> >>> - if (!module)
> >>> - goto invalid_guid;
> >>> + if (!module) {
> >>> + buffer->prm_status = PRM_HANDLER_GUID_NOT_FOUND;
> >>> + return AE_OK;
> >>> + }
> > What is the reason for this change, and the ones down below?
> As per Rui's comment, goto can be replaced with return.
> So I modified them with return and PRM_HANDLER_GUID_NOT_FOUND.
I don't think this change is necessary, but it should be a separate
patch at the very least.
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