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

[Malcolm Crossley <malcolm.crossley@citrix.com>]

On 12/05/14 16:18, Ian Jackson wrote:
> Malcolm Crossley writes ("[PATCH] hw/passthrough: Prevent QEMU from mapping PCI option ROM at address 0"):
>> 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.
> 
> Is this just for qemu-xen-traditional ?  Is there a corresponding
> patch to qemu-upstream ?
> 
It is just for qemu-xen-traditional, I've just submitted a v4 patch
which expands the masking of the bottom bits up to 4k.

MMIO regions are handled differently in qemu-upstream and so a
corresponding patch is not required.

Malcolm

> Ian.
>