Re: [Xen-devel] [PATCH] hw/passthrough: Prevent QEMU from mapping PCI option ROM at address 0

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Mon, 2014-05-12 at 14:31 +0100, Malcolm Crossley wrote:
> On 12/05/14 14:17, Ian Campbell wrote:
> > On Mon, 2014-05-12 at 13:42 +0100, Malcolm Crossley wrote:
> >> The PCI option ROM BAR uses the LSB to indicate if the BAR is enabled.
> >> The AMD graphics driver sets the address bit's of the BAR to 0 but leaves 
> >> the
> >> LSB set to 1. Whilst this is not good practice, QEMU should be ignoring the
> >> non address parts of the BAR.
> >>
> >> This patch adds masking of the non address parts of the BAR before 
> >> comparing
> >> the address to 0.
> > 
> > Since you CC Ian J I assume this is against the qemu-xen-traditional
> > tree. Is the same fix needed against upstream qemu?
> > 
> 
> The fix is only required on qemu-xen-traditional tree.
> 
> I have not tested qemu-upstream but it looks fine from code inspection
> (line 436 in hw/xen/xen_pt.c has the correct masking on BAR address).

Great, thanks for confirming.

Ian.



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