Em Tue, 3 Dec 2024 12:51:43 +0100
Igor Mammedov <imamm...@redhat.com> escreveu:
> On Fri, 22 Nov 2024 10:11:30 +0100
> Mauro Carvalho Chehab <mchehab+hua...@kernel.org> wrote:
>
> > Currently, CPER address location is calculated as an offset of
> > the hardware_errors table. It is also badly named, as the
> > offset actually used is the address where the CPER data starts,
> > and not the beginning of the error source.
> >
> > Move the logic which calculates such offset to a separate
> > function, in preparation for a patch that will be changing the
> > logic to calculate it from the HEST table.
> >
> > While here, properly name the variable which stores the cper
> > address.
> >
> > Signed-off-by: Mauro Carvalho Chehab <mchehab+hua...@kernel.org>
> > Reviewed-by: Jonathan Cameron <jonathan.came...@huawei.com>
> > ---
> > hw/acpi/ghes.c | 41 ++++++++++++++++++++++++++++++++---------
> > 1 file changed, 32 insertions(+), 9 deletions(-)
> >
> > diff --git a/hw/acpi/ghes.c b/hw/acpi/ghes.c
> > index 87fd3feedd2a..d99697b20164 100644
> > --- a/hw/acpi/ghes.c
> > +++ b/hw/acpi/ghes.c
> > @@ -364,10 +364,37 @@ void acpi_ghes_add_fw_cfg(AcpiGhesState *ags,
> > FWCfgState *s,
> > ags->present = true;
> > }
> >
> > +static void get_hw_error_offsets(uint64_t ghes_addr,
> > + uint64_t *cper_addr,
> > + uint64_t *read_ack_register_addr)
> > +{
>
>
> > + if (!ghes_addr) {
> > + return;
> > + }
>
> why do we need this check?
It is a safeguard measure to avoid crashes and OOM access. If fw_cfg
callback doesn't fill it properly, this will be zero.
> > +
> > + /*
> > + * non-HEST version supports only one source, so no need to change
> > + * the start offset based on the source ID. Also, we can't validate
> > + * the source ID, as it is stored inside the HEST table.
> > + */
> > +
> > + cpu_physical_memory_read(ghes_addr, cper_addr,
> > + sizeof(*cper_addr));
> > +
> > + *cper_addr = le64_to_cpu(*cper_addr);
> 1st bits flip, and then see later
>
> > +
> > + /*
> > + * As the current version supports only one source, the ack offset is
> > + * just sizeof(uint64_t).
> > + */
> > + *read_ack_register_addr = ghes_addr +
> > + ACPI_GHES_ERROR_SOURCE_COUNT * sizeof(uint64_t);
> > +}
> > +
> > void ghes_record_cper_errors(const void *cper, size_t len,
> > uint16_t source_id, Error **errp)
> > {
> > - uint64_t error_block_addr, read_ack_register_addr, read_ack_register =
> > 0;
> > + uint64_t cper_addr = 0, read_ack_register_addr = 0, read_ack_register;
> >
>
> if get_hw_error_offsets() isn't supposed to fail, then we do not need to
> initialize
> above. So this hunk doesn't belong to this patch.
It may fail due to:
if (!ghes_addr) {
return;
}
>
> > uint64_t start_addr;
> > AcpiGedState *acpi_ged_state;
> > AcpiGhesState *ags;
> > @@ -389,18 +416,14 @@ void ghes_record_cper_errors(const void *cper, size_t
> > len,
> >
> > start_addr += source_id * sizeof(uint64_t);
> >
> > - cpu_physical_memory_read(start_addr, &error_block_addr,
> > - sizeof(error_block_addr));
> > + get_hw_error_offsets(start_addr, &cper_addr, &read_ack_register_addr);
> >
> > - error_block_addr = le64_to_cpu(error_block_addr);
> > - if (!error_block_addr) {
> > + cper_addr = le64_to_cpu(cper_addr);
> ^^^^ 2nd bits flip turning it back to guest byte order
> again
>
> suggest to keep only one of them in get_hw_error_offsets()
Ok, I'll drop this one.
> > + if (!cper_addr) {
> > error_setg(errp, "can not find Generic Error Status Block");
> > return;
> > }
> >
> > - read_ack_register_addr = start_addr +
> > - ACPI_GHES_ERROR_SOURCE_COUNT *
> > sizeof(uint64_t);
> > -
> > cpu_physical_memory_read(read_ack_register_addr,
> > &read_ack_register,
> > sizeof(read_ack_register));
> >
> > @@ -421,7 +444,7 @@ void ghes_record_cper_errors(const void *cper, size_t
> > len,
> > &read_ack_register, sizeof(uint64_t));
> >
> > /* Write the generic error data entry into guest memory */
> > - cpu_physical_memory_write(error_block_addr, cper, len);
> > + cpu_physical_memory_write(cper_addr, cper, len);
> >
> > return;
> > }
>
Thanks,
Mauro
