Re: [Xen-devel] [PATCH v4] xen: fix handling framebuffer located above 4GB

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 16.05.19 at 17:46, <marmarek@xxxxxxxxxxxxxxxxxxxxxx> wrote:
> On some machines (for example Thinkpad P52), UEFI GOP reports
> framebuffer located above 4GB (0x4000000000 on that machine). This
> address does not fit in {xen,dom0}_vga_console_info.u.vesa_lfb.lfb_base
> field, which is 32bit. The overflow here cause all kind of memory
> corruption when anything tries to write something on the screen,
> starting with zeroing the whole framebuffer in vesa_init().
> 
> Fix this similar to how it's done in Linux: add ext_lfb_base field at
> the end of the structure, to hold upper 32bits of the address. Since the
> field is added at the end of the structure, it will work with older
> Linux versions too (other than using possibly truncated address - no
> worse than without this change). Thanks to ABI containing size of the
> structure (start_info.console.dom0.info_size), Linux can detect when
> this field is present and use it appropriately then.
> 
> Since this change public interface and use __XEN_INTERFACE_VERSION__,
> bump __XEN_LATEST_INTERFACE_VERSION__.
> 
> Note: if/when backporting this change to Xen <= 4.12, #if in xen.h needs
> to be extended with " || defined(__XEN__)".
> 
> Signed-off-by: Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>

Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel