Re: [Qemu-devel] [RFC][PATCH 06/45] msix: Prevent bogus mask updates on MMIO accesses

[Jan Kiszka]

On 2011-10-17 13:57, Michael S. Tsirkin wrote:
> On Mon, Oct 17, 2011 at 01:23:46PM +0200, Jan Kiszka wrote:
>> On 2011-10-17 13:10, Michael S. Tsirkin wrote:
>>> On Mon, Oct 17, 2011 at 11:27:40AM +0200, Jan Kiszka wrote:
>>>> Only accesses to the MSI-X table must trigger a call to
>>>> msix_handle_mask_update or a notifier invocation.
>>>>
>>>> Signed-off-by: Jan Kiszka <address@hidden>
>>>
>>> Why would msix_mmio_write be called on an access
>>> outside the table?
>>
>> Because it handles both the table and the PBA.
> 
> Hmm. Interesting. Is there a bug in how we handle PBA
> updates then? If yes I'd like a separate patch for that
> to apply to the stable tree.

I first thought it was a serious bug, but it just triggers if the guest
write to PBA (which is very uncommon) and that actually triggers any
spurious out-of-bounds vector injection. Highly unlikely.

> 
> BTW, this code will go away if PBA can get stored separately?

Hmm - yeah, true. Likely it's moot to discuss this change then.

Jan

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