On Tue, Jun 18, 2024 at 05:49:58AM -0400, Michael S. Tsirkin wrote:
> On Mon, Jun 17, 2024 at 03:39:45PM -0700, Nicolin Chen wrote:
> > The IORT doc defines "Number of IDs" ("id_count" in the virt-acpi-build)
> > to be "the number of IDs in the range minus one". Otherwise, Linux kernel
> > reports "conflicting mapping for input ID" FW_BUG at the overlapped ID.
> >
> > Fixes: 42e0f050e3a5 ("hw/arm/virt-acpi-build: Add IORT support to bypass
> > SMMUv3")
> > Signed-off-by: Nicolin Chen <nicol...@nvidia.com>
> > ---
> > Changelog
> > v2:
> > * Moved "-1" to the same line of id_count calculation
> > * Added "+1" to the next_range.input_base calculation
> > v1:
> > https://lore.kernel.org/all/20240613234802.828265-1-nicol...@nvidia.com/
> >
> > hw/arm/virt-acpi-build.c | 9 ++++++---
> > 1 file changed, 6 insertions(+), 3 deletions(-)
> >
> > diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
> > index c3ccfef026..631f2c6d04 100644
> > --- a/hw/arm/virt-acpi-build.c
> > +++ b/hw/arm/virt-acpi-build.c
> > @@ -243,7 +243,8 @@ iort_host_bridges(Object *obj, void *opaque)
> >
> > AcpiIortIdMapping idmap = {
> > .input_base = min_bus << 8,
> > - .id_count = (max_bus - min_bus + 1) << 8,
> > + /* id_count is the number of IDs in the range minus one */
> > + .id_count = ((max_bus - min_bus + 1) << 8) - 1,
> > };
> > g_array_append_val(idmap_blob, idmap);
> > }
> > @@ -298,11 +299,13 @@ build_iort(GArray *table_data, BIOSLinker *linker,
> > VirtMachineState *vms)
> > idmap = &g_array_index(smmu_idmaps, AcpiIortIdMapping, i);
> >
> > if (next_range.input_base < idmap->input_base) {
> > - next_range.id_count = idmap->input_base -
> > next_range.input_base;
> > + /* id_count is the number of IDs in the range minus one */
> > + next_range.id_count = idmap->input_base -
> > + next_range.input_base - 1;
> > g_array_append_val(its_idmaps, next_range);
>
>
> What about other places where id_count is set?
There are only three places where id_count could be set:
hw/arm/virt-acpi-build.c:296: .id_count = ((max_bus - min_bus +
1) << 8) - 1,
hw/arm/virt-acpi-build.c:422: next_range.id_count =
idmap->input_base -
hw/arm/virt-acpi-build.c:435: next_range.id_count = 0xFFFF -
next_range.input_base;
This patch fixes two, while the last one is correct using 0xFFFF.
> > }
> >
> > - next_range.input_base = idmap->input_base + idmap->id_count;
> > + next_range.input_base = idmap->input_base + idmap->id_count +
> > 1;
> > }
> >
>
> Given this was different previously, did you actually test with multiple
> ranges?
Tested by creating 5 buses: input_base increases by 0x400 while
id_count=0x2ff (0x300 - 1). ITS results look correct to me:
--------------build_iort: smmu_idmaps
DEBUG: build_iort_id_mapping: input_base=0xec00, id_count=0x2ff, out_ref=0x48,
flags=0
DEBUG: build_iort_id_mapping: input_base=0xf000, id_count=0x2ff, out_ref=0xa0,
flags=0
DEBUG: build_iort_id_mapping: input_base=0xf400, id_count=0x2ff, out_ref=0xf8,
flags=0
DEBUG: build_iort_id_mapping: input_base=0xf800, id_count=0x2ff, out_ref=0x150,
flags=0
DEBUG: build_iort_id_mapping: input_base=0xfc00, id_count=0x2ff, out_ref=0x1a8,
flags=0
--------------build_iort: its_idmaps
DEBUG: build_iort_id_mapping: input_base=0x0, id_count=0xebff, out_ref=0x30,
flags=0
DEBUG: build_iort_id_mapping: input_base=0xef00, id_count=0xff, out_ref=0x30,
flags=0
DEBUG: build_iort_id_mapping: input_base=0xf300, id_count=0xff, out_ref=0x30,
flags=0
DEBUG: build_iort_id_mapping: input_base=0xf700, id_count=0xff, out_ref=0x30,
flags=0
DEBUG: build_iort_id_mapping: input_base=0xfb00, id_count=0xff, out_ref=0x30,
flags=0
DEBUG: build_iort_id_mapping: input_base=0xff00, id_count=0xff, out_ref=0x30,
flags=0
Thanks
Nicolin
