Re: [PATCH RESEND v2] x86: introduce ioremap_wc()

["Roger Pau Monné" <roger.pau@citrix.com>]

On Thu, Feb 17, 2022 at 04:57:41PM +0100, Jan Beulich wrote:
> On 17.02.2022 16:50, Roger Pau Monné wrote:
> > On Thu, Feb 17, 2022 at 04:02:39PM +0100, Jan Beulich wrote:
> >> On 17.02.2022 15:47, Roger Pau Monné wrote:
> >>> On Thu, Feb 17, 2022 at 12:01:08PM +0100, Jan Beulich wrote:
> >>>> --- a/xen/drivers/video/vga.c
> >>>> +++ b/xen/drivers/video/vga.c
> >>>> @@ -79,7 +79,7 @@ void __init video_init(void)
> >>>>      {
> >>>>      case XEN_VGATYPE_TEXT_MODE_3:
> >>>>          if ( page_is_ram_type(paddr_to_pfn(0xB8000), RAM_TYPE_CONVENTIONAL) ||
> >>>> -             ((video = ioremap(0xB8000, 0x8000)) == NULL) )
> >>>> +             ((video = ioremap_wc(0xB8000, 0x8000)) == NULL) )
> >>>>              return;
> >>>>          outw(0x200a, 0x3d4); /* disable cursor */
> >>>>          columns = vga_console_info.u.text_mode_3.columns;
> >>>> @@ -164,7 +164,11 @@ void __init video_endboot(void)
> >>>>      {
> >>>>      case XEN_VGATYPE_TEXT_MODE_3:
> >>>>          if ( !vgacon_keep )
> >>>> +        {
> >>>>              memset(video, 0, columns * lines * 2);
> >>>> +            iounmap(video);
> >>>> +            video = ZERO_BLOCK_PTR;
> >>>> +        }
> >>>>          break;
> >>>>      case XEN_VGATYPE_VESA_LFB:
> >>>>      case XEN_VGATYPE_EFI_LFB:
> >>>
> >>> I think in vesa_endboot you also need to iounmap the framebuffer
> >>> iomem?
> >>
> >> Again part of the full series. I guess I was a little inconsistent
> >> with leaving the VGA unmap in here, but breaking out the VESA part.
> >> It's been a long time, but I guess I did so because the VESA part
> >> needs to touch two files.
> > 
> > I think you are hesitant to include the chunks for the above items? (or
> > maybe I'm not properly accounting for their complexity).
> 
> There's no complexity, it's really just that the zapping of the pointer
> needs to be done in a different place from where the unmap is. See below.
> 
> Jan
> 
> video/vesa: unmap frame buffer when relinquishing console
> 
> There's no point in keeping the VA space occupied when no further output
> will occur.
> 
> Signed-off-by: Jan Beulich <jbeulich@suse.com>

Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>

For both patches, the one inline here and "x86: introduce
ioremap_wc()".

While at it, I think you should also push "video/vesa: drop
"vesa-mtrr" command line option".

Thanks, Roger.