[Qemu-devel] [PATCH v3 1/4] ACPI: Add APEI GHES Table Generation support

[Laszlo Ersek]

On 05/22/17 16:23, Laszlo Ersek wrote:
> Keeping some context:
> 
> On 05/12/17 23:00, Laszlo Ersek wrote:
>> On 04/30/17 07:35, Dongjiu Geng wrote:

> (68) In the code below, you are not taking an "OVMF header probe
> suppressor" into account.
> 
> But, we have already planned to replace that quirk with a separate,
> dedicated allocation hint or command, so I'm not going to describe what
> an "OVMF header probe suppressor" is; instead, I'll describe the
> replacement for it.
> 
> [...]

So, the NOACPI allocation hint is a no-go at the moment, based on the
discussion in the following threads:

http://mid.mail-archive.com/20170601112241.2580-1-ard.biesheuvel@linaro.org

http://mid.mail-archive.com/c76b36de-ebf9-c662-d454-0a95b43901e8@redhat.com

Therefore the header probe suppression remains necessary.

In this case, it is not hard to do, you just have to reorder the
following two ADD_POINTER additions a bit:

>>> +
>>> +        bios_linker_loader_add_pointer(linker, GHES_ERRORS_FW_CFG_FILE,
>>> +                                sizeof(uint64_t) * i, sizeof(uint64_t),
>>> +                                GHES_ERRORS_FW_CFG_FILE,
>>> +                                MAX_ERROR_SOURCE_COUNT_V6 * sizeof(uint64_t) +
>>> +                                i * MAX_RAW_DATA_LENGTH);

This one should be moved out to a separate loop, after the current loop.

>>> +        bios_linker_loader_add_pointer(linker, ACPI_BUILD_TABLE_FILE,
>>> +                    address_registers_offset
>>> +                    + i * sizeof(AcpiGenericHardwareErrorSource),
>>> +                    sizeof(uint32_t), GHES_ERRORS_FW_CFG_FILE,
>>> +                    i * sizeof(uint64_t));

This one should be kept in the first (i.e., current) loop.

The idea is, when you first point the HEST/GHES_n entries in
ACPI_BUILD_TABLE_FILE to the "address registers" in
GHES_ERRORS_FW_CFG_FILE, all those address registers will still be
zero-filled. This will fail the ACPI table header probe in
OvmfPkg/AcpiPlatformDxe, which is what we want.

After this is done, the address registers in GHES_ERRORS_FW_CFG_FILE
should be pointed to the error status data blocks in the same fw_cfg
blob, in a separate loop. (Those error status data blocks will again be
zero-filled, so no ACPI table headers will be mistakenly recognized in
them.)

Thanks
Laszlo