Re: [PATCH 1/4] OvmfPkg: introduce ACPI Test Support data structure and GUID

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

Hi Laszlo,

On 25/11/18 11:01, Laszlo Ersek wrote:
> QEMU's test suite includes a set of cases called "BIOS tables test". Among
> other things, it locates the RSD PTR ACPI table in guest RAM, and then
> (chasing pointers to other ACPI tables) performs various sanity checks on
> the QEMU-generated and firmware-installed tables.
> 
> Currently this set of test cases doesn't work with UEFI guests, because
> the ACPI spec's definition for locating the RSD PTR in UEFI guests is a
> lot harder to implement from the hypervisor side -- just with raw guest
> memory access -- than it is when scraping the memory of BIOS guests.
> 
> Introduce a signature GUID, and a small, MB-aligned structure, identified
> by the GUID. The hypervisor should loop over all MB-aligned pages in guest
> RAM until one matches the signature GUID at offset 0, at which point the
> hypervisor can fetch the RSDP address field(s) from the structure.
> 
> QEMU's test logic currently spins on a pre-determined guest address, until
> that address assumes a magic value. The method described in this patch is
> conceptually the same ("busy loop until match is found"), except there is
> no hard-coded address. This plays a lot more nicely with UEFI guest
> firmware (we'll be able to use the normal page allocation UEFI service).
> Given the size of EFI_GUID (16 bytes -- 128 bits), mismatches should be
> astronomically unlikely. In addition, given the typical guest RAM size for
> such tests (128 MB), there are 128 locations to check in one iteration of
> the "outer" loop, which shouldn't introduce an intolerable delay after the
> guest stores the RSDP address(es), and then the GUID.

I applied/build your series, but keep failing trying to test it with QEMU :/
I modified a bit tests/bios-tables-test.c to use the OVMF.fd build for
the Q35 machine tests, but still pass the "OnRootBridgesConnected: root
bridges have been connected, installing ACPI tables".

Do you have a QEMU companion patch for this series?

> 
> The GUID that the hypervisor should search for is
> 
>   AB87A6B1-2034-BDA0-71BD-375007757785
> 
> Expressed as a byte array:
> 
>   {
>     0xb1, 0xa6, 0x87, 0xab,
>     0x34, 0x20,
>     0xa0, 0xbd,
>     0x71, 0xbd, 0x37, 0x50, 0x07, 0x75, 0x77, 0x85
>   }