RE: Bug in GnttabQueryReference

[Paul Durrant <xadimgnik@xxxxxxxxx>]

> -----Original Message-----
> From: win-pv-devel <win-pv-devel-bounces@xxxxxxxxxxxxxxxxxxxx> On Behalf Of 
> Connor Davis
> Sent: 22 May 2020 18:43
> To: win-pv-devel@xxxxxxxxxxxxxxxxxxxx
> Subject: Bug in GnttabQueryReference
> 
> Hi All,
> 
> There appears to be a bug in xenbus/src/xenbus/gnttab.c:GnttabQueryReference.
> The check for a ReadOnly entry uses
> 
>     (Context->Table[Reference].frame & GTF_readonly)
> 
> instead of
> 
>     (Context->Table[Reference].flags & GTF_readonly)
> 
> I grepped across all the PV drivers and it looks like this function is
> only used for the store and console references, which pass NULL to ReadOnly,
> so the bug hasn't actually manifested yet.

Yes, that is indeed a bug. Good spot! I'll send a patch to fix it shortly.

  Paul

> 
> Cheers,
> Connor Davis