Re: [Xen-devel] [PATCH 26/26] xl: Document VGA problems arising from lack of physmap dmop

[Wei Liu <wei.liu2@xxxxxxxxxx>]

On Mon, Oct 09, 2017 at 04:57:28PM +0100, Ian Jackson wrote:
> Ross reports that stdvga guests do not work, and cirrus guests are
> slow, because qemu tries to do xc_domain_add_to_physmap.  We will need
> another dmop to fix this properly.
> 
> For now, document the problem.
> 
> (In the cirrus case, the vram remains mapped at the old guest-physical
> addresses, while the guest runs.  We are not sure whether this is a
> correctness or security problem and we should advise against it.)
> 
> Signed-off-by: Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
> Reported-by: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>
> CC: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>
> CC: Wei Liu <wei.liu2@xxxxxxxxxx>
> CC: Paul Durrant <Paul.Durrant@xxxxxxxxxx>
> Signed-off-by: Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>

Acked-by: Wei Liu <wei.liu2@xxxxxxxxxx>

> ---
>  docs/man/xl.cfg.pod.5.in | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/docs/man/xl.cfg.pod.5.in b/docs/man/xl.cfg.pod.5.in
> index cb32d04..cf3fa0e 100644
> --- a/docs/man/xl.cfg.pod.5.in
> +++ b/docs/man/xl.cfg.pod.5.in
> @@ -2242,6 +2242,12 @@ For example, cdrom insert will fail.
>  
>  =item
>  
> +You should say C<vga="none">.
> +Domains with stdvga graphics cards to not work.
> +Domains with cirrus vga may seem to work.
> +
> +=item
> +
>  You must create user(s) for qemu to run as.
>  
>  Ideally, set aside a range of 32752 uids
> -- 
> 2.1.4
> 

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