[Spice-devel] [PATCH qxl-win32 v2] miniport/qxl: FillVideoMode: only allow word aligned strides

[Alon Levy]

The title is wrong, I'll change it to "only allow word aligned strides" before push, since now this patch affects more then just miniport/qxl.c .

> This is a pixman requirement. If it isn't enforced spice crashes,
> qemu
> with it. That should be fixed, but there is no simple way to allow
> for
> non word aligned strides, and the only down side is that for 16 bit
> modes we will require even widths. And we already have the same
> implementation detail in the X driver, only there it is a multiple of
> 8,
> not 4.
> 
> The SurfaceCreate command's stride is computed in one place:
>  miniport:FillVidModeInfo sets ScreenStride as word aligned
>  display:pdev->stride is set from ScreenStride
> 
> A third change at GetSurfaceMemory fixes the stride used for GDI
> allocated surface, but since surface 0 has a fixed larger then
> required
> area this isn't required for the bug fix, just for consistency.
> ---
>  display/driver.c | 7 ++++---
>  display/res.c    | 2 +-
>  miniport/qxl.c   | 4 +++-
>  3 files changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/display/driver.c b/display/driver.c
> index 90c52c5..d7fdbf7 100644
> --- a/display/driver.c
> +++ b/display/driver.c
> @@ -620,13 +620,13 @@ static VOID HideMouse(PDev *pdev)
>  }
>  
>  static VOID CreatePrimarySurface(PDev *pdev, UINT32 depth, UINT32
>  format,
> -                                 UINT32 width, UINT32 height,
> +                                 UINT32 width, UINT32 height, INT32
> stride,
>                                   QXLPHYSICAL phys_mem)
>  {
>      pdev->primary_surface_create->format = format;
>      pdev->primary_surface_create->width = width;
>      pdev->primary_surface_create->height = height;
> -    pdev->primary_surface_create->stride = -(INT32)width * (depth /
> 8);
> +    pdev->primary_surface_create->stride = -stride;
>      pdev->primary_surface_create->mem = phys_mem;
>  
>      pdev->primary_surface_create->flags = 0;
> @@ -898,7 +898,8 @@ VOID EnableQXLPrimarySurface(PDev *pdev)
>      };
>  
>      CreatePrimarySurface(pdev, depth, format,
> -                         pdev->resolution.cx, pdev->resolution.cy,
> pdev->surf_phys);
> +                         pdev->resolution.cx, pdev->resolution.cy,
> +                         pdev->stride, pdev->surf_phys);
>      pdev->surf_enable = TRUE;
>  }
>  
> diff --git a/display/res.c b/display/res.c
> index e9c301e..e494271 100644
> --- a/display/res.c
> +++ b/display/res.c
> @@ -698,7 +698,7 @@ _inline void GetSurfaceMemory(PDev *pdev, UINT32
> x, UINT32 y, UINT32 depth, INT3
>          ASSERT(pdev, x * y * depth /8 <= pdev->primary_memory_size);
>          *base_mem = pdev->primary_memory_start;
>          *phys_mem = PA(pdev, *base_mem, pdev->main_mem_slot);
> -        *stride = x * depth / 8;
> +        *stride = (x * depth / 8 + 3) & ~0x3; /* Pixman requires 4
> byte aligned stride */
>          break;
>      case DEVICE_BITMAP_ALLOCATION_TYPE_DEVRAM:
>          *stride = x * depth / 8;
> diff --git a/miniport/qxl.c b/miniport/qxl.c
> index 55e55d3..58ba15e 100644
> --- a/miniport/qxl.c
> +++ b/miniport/qxl.c
> @@ -469,6 +469,8 @@ VP_STATUS FillVidModeInfo(VIDEO_MODE_INFORMATION
> *pMode, ULONG xres, ULONG yres,
>  /* Fills given video mode structure */
>  VP_STATUS FillVidModeInfo(VIDEO_MODE_INFORMATION *pMode, ULONG xres,
>  ULONG yres, ULONG bpp, ULONG index)
>  {
> +    unsigned bytes_pp = (bpp + 7) / 8;
> +
>      if (xres <= 0 || yres <= 0)
>          return ERROR_INVALID_DATA;
>  
> @@ -479,7 +481,7 @@ VP_STATUS FillVidModeInfo(VIDEO_MODE_INFORMATION
> *pMode, ULONG xres, ULONG yres,
>      pMode->ModeIndex                    = index;
>      pMode->VisScreenWidth               = xres;
>      pMode->VisScreenHeight              = yres;
> -    pMode->ScreenStride                 = xres * ((bpp + 7) / 8);
> +    pMode->ScreenStride                 = (xres * bytes_pp + 3) &
> ~0x3; /* Pixman requirement */
>      pMode->NumberOfPlanes               = 1;
>      pMode->BitsPerPlane                 = bpp;
>      pMode->Frequency                    = 60;
> --
> 1.7.12.1
> 
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