Re: [PATCH] fix XSA-46 regression with xend/xm

[Gordan Bobic <gordan@bobich.net>]

On 05/21/2013 09:56 AM, Ian Campbell wrote:
> On Tue, 2013-05-21 at 09:40 +0100, Jan Beulich wrote:
>> The hypervisor side changes for XSA-46 require the tool stack to now
>> always map the guest pIRQ before granting access permission to the
>> underlying host IRQ (GSI). This in particular requires that pciif.py
>> no longer can skip this step (assuming qemu would do it) for HVM
>> guests.
>>
>> This in turn exposes, however, an inconsistency between xend and qemu:
>> The former wants to always establish 1:1 mappings between pIRQ and host
>> IRQ (for non-MSI only of course), while the latter always wants to
>> allocate an arbitrary mapping. Since the whole tool stack obviously
>> should always agree on the mapping model, make libxc enforce the 1:1
>> mapping as the more natural one (as well as being the one that allows
>> for easier debugging, since there no need to find out the extra
>> mapping). Users of libxc that want to establish a particular (rather
>> than an allocated) mapping are still free to do so, as well as tool
>> stacks not based on libxc wanting to implement an allocation based
>> model (which is why it's not the hypervisor that's being changed to
>> enforce either model).
>>
>> Since libxl, like xend, already uses a 1:1 model, it's unaffected by
>> the libxc change (and it being unaffected by the original hypervisor
>> side changes is - afaict - simply due to qemu getting spawned at a
>> later point in time compared to the xend event flow).
>>
>> Signed-off-by: Jan Beulich <jbeulich@suse.com>
>> Tested-by: Andreas Falck <falck.andreas.lists@gmail.com> (on 4.1)
>> Tested-by: Gordan Bobic <gordan@bobich.net> (on 4.2)
>
> In both cases tested with xend rather than xl or both?

I can confirm that my VMs start fine with xl with this patch applied.

Gordan