On 12/2/24 14:12, Alex Williamson wrote: > On Sun, 1 Dec 2024 22:11:29 -0700 > Alex Williamson <alex.william...@redhat.com> wrote: > >> On Mon, 2 Dec 2024 00:09:31 +0800 >> Tomita Moeko <tomitamo...@gmail.com> wrote: >> >>> Both intel documentation [1][2] and i915 driver shows GGMS represents >>> GTT stolen memory size in multiple of 1MB, not 2MB starting from gen 8. >>> >>> [1] >>> https://www.intel.com/content/dam/www/public/us/en/documents/datasheets/3rd-gen-core-desktop-vol-2-datasheet.pdf >>> [2] >>> https://www.intel.com/content/dam/www/public/us/en/documents/datasheets/4th-gen-core-family-desktop-vol-2-datasheet.pdf >>> >>> Signed-off-by: Tomita Moeko <tomitamo...@gmail.com> >>> --- >>> hw/vfio/igd.c | 4 ++-- >>> 1 file changed, 2 insertions(+), 2 deletions(-) >>> >>> diff --git a/hw/vfio/igd.c b/hw/vfio/igd.c >>> index 4047f4f071..e40e601026 100644 >>> --- a/hw/vfio/igd.c >>> +++ b/hw/vfio/igd.c >>> @@ -268,7 +268,7 @@ static int vfio_igd_gtt_max(VFIOPCIDevice *vdev) >>> >>> gmch = vfio_pci_read_config(&vdev->pdev, IGD_GMCH, sizeof(gmch)); >>> ggms = (gmch >> (gen < 8 ? 8 : 6)) & 0x3; >>> - if (gen > 6) { >>> + if (gen > 7) { >>> ggms = 1 << ggms; >>> } >>> >>> @@ -678,7 +678,7 @@ void vfio_probe_igd_bar4_quirk(VFIOPCIDevice *vdev, int >>> nr) >>> >>> /* Determine the size of stolen memory needed for GTT */ >>> ggms_mb = (gmch >> (gen < 8 ? 8 : 6)) & 0x3; >>> - if (gen > 6) { >>> + if (gen > 7) { >>> ggms_mb = 1 << ggms_mb; >>> } >>> >> >> I'd argue this should be rolled into patch 4. It's not really fixing >> anything because igd_gen() can't return anything between 6 and 8. This >> only allows for several device versions that we currently consider to >> be gen 6 to align with i915 kernel driver generation by calling them >> generation 7. We'd previously lumped them into generation 6 because >> there's no functional difference we care about here between 6 & 7. >> >> In the next patch you replace this '1 << ggms_mb' with '*= 2', which >> would be equivalent to 'ggms_mb << 1' and matches your description that >> the increment is doubled. Is there a separate bug fix that needs to be >> pulled out here?
Sorry this was a mistake when I composing my patches. At this time, there was no gen 7, original condition won't cause any issue. It is more suitable to be included in patch 4. I will drop this one in v2. >> Also, please send a cover letter for any series longer than a single >> patch and please configure your tools to thread the series. Thanks, > > Disregard this latter comment, I just wasn't copied on the cover letter > and didn't have it in my inbox to root the thread. Thanks, > > Alex CC of cover letter is not generated by get_mainainer.pl hook. Sorry for not checking it before sending, I will manually set correct CC in v2.
