[PATCH v2] drm/qxl: fix qxl can't use in arm64

[David Airlie]

I'd like to make sure this has no side effects on x86 guests, it
probably is safe, but keep an eye for regression reports.

Reviewed-by: Dave Airlie <airlied at redhat.com>
Dave.

On Wed, Mar 30, 2022 at 8:20 PM Cong Liu <liucong2 at kylinos.cn> wrote:
>
> any suggestions or extra test I can do now?
>
> Regards,
> Cong
>
> On 2022/3/25 15:45, Christian König wrote:
> > Am 24.03.22 um 11:49 schrieb Cong Liu:
> >> qxl use ioremap to map ram_header and rom, in the arm64 implementation,
> >> the device is mapped as DEVICE_nGnRE, it can not support unaligned
> >> access. and qxl is a virtual device, it can be treated more like RAM
> >> than actual MMIO registers. use ioremap_wc() replace it.
> >>
> >> Signed-off-by: Cong Liu <liucong2 at kylinos.cn>
> >
> > Looks sane to me, but I'm really not involved enough to fully judge.
> >
> > Acked-by: Christian König <christian.koenig at amd.com>
> >
> >> ---
> >>   drivers/gpu/drm/qxl/qxl_kms.c | 4 ++--
> >>   drivers/gpu/drm/qxl/qxl_ttm.c | 4 ++--
> >>   2 files changed, 4 insertions(+), 4 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/qxl/qxl_kms.c
> >> b/drivers/gpu/drm/qxl/qxl_kms.c
> >> index 4dc5ad13f12c..a054e4a00fe8 100644
> >> --- a/drivers/gpu/drm/qxl/qxl_kms.c
> >> +++ b/drivers/gpu/drm/qxl/qxl_kms.c
> >> @@ -165,7 +165,7 @@ int qxl_device_init(struct qxl_device *qdev,
> >>            (int)qdev->surfaceram_size / 1024,
> >>            (sb == 4) ? "64bit" : "32bit");
> >> -    qdev->rom = ioremap(qdev->rom_base, qdev->rom_size);
> >> +    qdev->rom = ioremap_wc(qdev->rom_base, qdev->rom_size);
> >>       if (!qdev->rom) {
> >>           pr_err("Unable to ioremap ROM\n");
> >>           r = -ENOMEM;
> >> @@ -183,7 +183,7 @@ int qxl_device_init(struct qxl_device *qdev,
> >>           goto rom_unmap;
> >>       }
> >> -    qdev->ram_header = ioremap(qdev->vram_base +
> >> +    qdev->ram_header = ioremap_wc(qdev->vram_base +
> >>                      qdev->rom->ram_header_offset,
> >>                      sizeof(*qdev->ram_header));
> >>       if (!qdev->ram_header) {
> >> diff --git a/drivers/gpu/drm/qxl/qxl_ttm.c
> >> b/drivers/gpu/drm/qxl/qxl_ttm.c
> >> index b2e33d5ba5d0..95df5750f47f 100644
> >> --- a/drivers/gpu/drm/qxl/qxl_ttm.c
> >> +++ b/drivers/gpu/drm/qxl/qxl_ttm.c
> >> @@ -82,13 +82,13 @@ int qxl_ttm_io_mem_reserve(struct ttm_device *bdev,
> >>       case TTM_PL_VRAM:
> >>           mem->bus.is_iomem = true;
> >>           mem->bus.offset = (mem->start << PAGE_SHIFT) + qdev->vram_base;
> >> -        mem->bus.caching = ttm_cached;
> >> +        mem->bus.caching = ttm_write_combined;
> >>           break;
> >>       case TTM_PL_PRIV:
> >>           mem->bus.is_iomem = true;
> >>           mem->bus.offset = (mem->start << PAGE_SHIFT) +
> >>               qdev->surfaceram_base;
> >> -        mem->bus.caching = ttm_cached;
> >> +        mem->bus.caching = ttm_write_combined;
> >>           break;
> >>       default:
> >>           return -EINVAL;
> >
>