From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gordan Bobic Subject: Re: [PATCH] fix XSA-46 regression with xend/xm Date: Wed, 22 May 2013 21:51:07 +0100 Message-ID: <519D2FBB.7000309@bobich.net> References: <519B4F1102000078000D789D@nat28.tlf.novell.com> <1369126587.21246.32.camel@zakaz.uk.xensource.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1369126587.21246.32.camel@zakaz.uk.xensource.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Ian Campbell Cc: Steven Haigh , Ian Jackson , Andreas Falck , xen-devel , Stefano Stabellini , Jan Beulich List-Id: xen-devel@lists.xenproject.org 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 >> Tested-by: Andreas Falck (on 4.1) >> Tested-by: Gordan Bobic (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