> -----Original Message----- > From: Lorenzo Pieralisi [mailto:lpieralisi@xxxxxxxxxx] > Sent: 18 July 2023 08:52 > To: Guanghui Feng <guanghuifeng@xxxxxxxxxxxxxxxxx> > Cc: Guohanjun (Hanjun Guo) <guohanjun@xxxxxxxxxx>; > sudeep.holla@xxxxxxx; rafael@xxxxxxxxxx; linux-acpi@xxxxxxxxxxxxxxx; > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > baolin.wang@xxxxxxxxxxxxxxxxx; alikernel-developer@xxxxxxxxxxxxxxxxx; > will@xxxxxxxxxx; catalin.marinas@xxxxxxx; Shameerali Kolothum Thodi > <shameerali.kolothum.thodi@xxxxxxxxxx> > Subject: Re: [PATCH v3] ACPI/IORT: Remove erroneous id_count check in > iort_node_get_rmr_info() > > [+Catalin, Will, Shameer] > > On Mon, Jul 17, 2023 at 07:33:45PM +0800, Guanghui Feng wrote: > > According to the ARM IORT specifications DEN 0049 issue E, > > the "Number of IDs" field in the ID mapping format reports > > the number of IDs in the mapping range minus one. > > > > In iort_node_get_rmr_info(), we erroneously skip ID mappings > > whose "Number of IDs" equal to 0, resulting in valid mapping > > nodes with a single ID to map being skipped, which is wrong. > > > > Fix iort_node_get_rmr_info() by removing the bogus id_count > > check. > > > > Fixes: 491cf4a6735a ("ACPI/IORT: Add support to retrieve IORT RMR > reserved regions") > > Signed-off-by: Guanghui Feng <guanghuifeng@xxxxxxxxxxxxxxxxx> > > --- > > drivers/acpi/arm64/iort.c | 3 --- > > 1 file changed, 3 deletions(-) > > > > diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c > > index 3631230..56d8873 100644 > > --- a/drivers/acpi/arm64/iort.c > > +++ b/drivers/acpi/arm64/iort.c > > @@ -1007,9 +1007,6 @@ static void iort_node_get_rmr_info(struct > acpi_iort_node *node, > > for (i = 0; i < node->mapping_count; i++, map++) { > > struct acpi_iort_node *parent; > > > > - if (!map->id_count) > > - continue; > > - > > parent = ACPI_ADD_PTR(struct acpi_iort_node, iort_table, > > map->output_reference); > > if (parent != iommu) > > Shameer, I know this may look like overkill since the hunk we are > removing is buggy but can you please test this patch on platforms > with RMR to make sure we are not triggering regressions by removing > it (by the specs that's what should be done but current firmware > is always something to reckon with) ? Yes, that is a valid fix. Unlikely it will be a problem. Anyway, I have requested Hanjun to help with the testing as I don't have a test setup with me now. Hanjun, please help. Thanks, Shameer
