On Fri, 28 Feb 2025 17:36:08 +0800
Jonathan Cameron <Jonathan.Cameron@huawei.com> wrote:
> On Thu, 27 Feb 2025 17:00:56 +0100
> Mauro Carvalho Chehab <mchehab+huawei@kernel.org> wrote:
>
> > While the HEST layout didn't change, there are some internal
> > changes related to how offsets are calculated and how memory error
> > events are triggered.
> >
> > Update specs to reflect such changes.
> >
> > Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
> One minor editorial suggestion. With that or similar tidy up,
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
with nit below fixed,
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
>
> > ---
> > docs/specs/acpi_hest_ghes.rst | 28 +++++++++++++++++-----------
> > 1 file changed, 17 insertions(+), 11 deletions(-)
> >
> > diff --git a/docs/specs/acpi_hest_ghes.rst b/docs/specs/acpi_hest_ghes.rst
> > index c3e9f8d9a702..4311a9536b21 100644
> > --- a/docs/specs/acpi_hest_ghes.rst
> > +++ b/docs/specs/acpi_hest_ghes.rst
> > @@ -89,12 +89,21 @@ Design Details
> > addresses in the "error_block_address" fields with a pointer to the
> > respective "Error Status Data Block" in the "etc/hardware_errors" blob.
> >
> > -(8) QEMU defines a third and write-only fw_cfg blob which is called
> > - "etc/hardware_errors_addr". Through that blob, the firmware can send back
> > - the guest-side allocation addresses to QEMU. The "etc/hardware_errors_addr"
> > - blob contains a 8-byte entry. QEMU generates a single WRITE_POINTER command
> > - for the firmware. The firmware will write back the start address of
> > - "etc/hardware_errors" blob to the fw_cfg file "etc/hardware_errors_addr".
> > +(8) QEMU defines a third and write-only fw_cfg blob to store the location
> > + where the error block offsets, read ack registers and CPER records are
> > + stored.
> > +
> > + Up to QEMU 9.2, the location was at "etc/hardware_errors_addr", and
> > + contains a GPA for the beginning of "etc/hardware_errors".
> > +
> > + Newer versions place the location at "etc/acpi_table_hest_addr",
> > + pointing to the GPA of the HEST table.
> > +
> > + Through that such GPA values, the firmware can send back the guest-side
> This confuses me.
> Via those GPA values...? (maybe?)
it's not GPA here, it should be fwcfg.
Maybe something like this
"Using above mentioned 'fwcfg' files,"
>
> > + allocation addresses to QEMU. They contain a 8-byte entry. QEMU generates
> > + a single WRITE_POINTER command for the firmware. The firmware will write
> > + back the start address of either "etc/hardware_errors" or HEST table at
> > + the corresponding fw_cfg file.
> >
> > (9) When QEMU gets a SIGBUS from the kernel, QEMU writes CPER into corresponding
> > "Error Status Data Block", guest memory, and then injects platform specific
> > @@ -105,8 +114,5 @@ Design Details
> > kernel, on receiving notification, guest APEI driver could read the CPER error
> > and take appropriate action.
> >
> > -(11) kvm_arch_on_sigbus_vcpu() uses source_id as index in "etc/hardware_errors" to
> > - find out "Error Status Data Block" entry corresponding to error source. So supported
> > - source_id values should be assigned here and not be changed afterwards to make sure
> > - that guest will write error into expected "Error Status Data Block" even if guest was
> > - migrated to a newer QEMU.
> > +(11) kvm_arch_on_sigbus_vcpu() report RAS errors via a SEA notifications,
> > + when a SIGBUS event is triggered.
>