On Sun, 25 Aug 2024 05:29:23 +0200 Mauro Carvalho Chehab <mchehab+hua...@kernel.org> wrote:
> Em Mon, 19 Aug 2024 14:51:36 +0200 > Igor Mammedov <imamm...@redhat.com> escreveu: > > > > + read_ack = 1; > > > + cpu_physical_memory_write(read_ack_start_addr, > > > + &read_ack, (uint64_t)); > > we don't do this for SEV so, why are you setting it to 1 here? > > According with: > https://uefi.org/specs/ACPI/6.5/18_Platform_Error_Interfaces.html#generic-hardware-error-source-version-2-ghesv2-type-10 > > "These are the steps the OS must take once detecting an error from a > particular GHESv2 error source: > > OSPM detects error (via interrupt/exception or polling the block status) > > OSPM copies the error status block > > OSPM clears the block status field of the error status block > > OSPM acknowledges the error via Read Ack register. For example: > > OSPM reads the Read Ack register –> X > > OSPM writes –> (( X & ReadAckPreserve) | ReadAckWrite)" > > > So, basically the guest OS takes some time to detect that an error > is raised. When it detects, it needs to mark that the error was > handled. what you are doing here by setting read_ack = 1, is making ack on behalf of OSPM when OSPM haven't handled existing error yet. Essentially making HW/FW do the job of OSPM. That looks wrong to me. From HW/FW side read_ack register should be thought as read-only. > > IMO, this is needed, independently of the notification mechanism. > > Regards, > Mauro >
