Re: [Xen-devel] [PATCH] libxl: passthrough: avoid passing through devices not owned by pciback

["Hao, Xudong" <xudong.hao@xxxxxxxxx>]

> -----Original Message-----
> From: dunlapg@xxxxxxxxx [mailto:dunlapg@xxxxxxxxx] On Behalf Of George
> Dunlap
> Sent: Thursday, March 22, 2012 6:16 PM
> To: Hao, Xudong
> Cc: ian.jackson@xxxxxxxxxxxxx; xen-devel@xxxxxxxxxxxxxxxxxxx; Kay, Allen M
> Subject: Re: [Xen-devel] [PATCH] libxl: passthrough: avoid passing through
> devices not owned by pciback
> 
> On Thu, Mar 22, 2012 at 1:20 AM, Hao, Xudong <xudong.hao@xxxxxxxxx>
> wrote:
> > <Porting from Xen 4.1 tree.>
> >
> > libxl: passthrough: avoid passing through devices not owned by pciback
> >
> > This patch makes sure the passthrough device belongs to pciback before
> allow them passthrough to the guest.  There are still many other checks
> missing.
> >
> > xm terminates the guest startup process when this type of condition is
> found.  This patch just allows the guest to continue to boot but with no 
> device
> passthrough.
> 
> Thanks for the patch.  My one comment is that I think that xm's behavior is
> the correct one.  If I tell the computer "Do X with feature Y", I want the
> computer to either do X with feature Y, or to say, "I'm sorry, feature Y is 
> not
> available."  Then I can figure out if I want X without Y, or whether I want 
> to fix
> things so Y is available.  Saying, "Y is not available so I'll just to X" is 
> rarely the
> right thing.
> 
George, your theory is correct, but I think it's not much suitable for this 
patch. This patch just add an additional checking, it return ERROR_FAIL to its 
call function, but it can't control the behavior by the result of upper 
function libxl_device_pci_add().
 
> On a different (but related) note, it appears that libxl doesn't have the
> pci-quirks functionality that xend has.  Do you know if this is still needed, 
> if it's
> in the pvops tree and needs to be upstreamed?
> Is anyone at Intel working on libxl pci-quirks support for the 4.2 release?
> 
We did not see any Intel pci device need quirk in libxl till now, so maybe no 
plan for libxl pci-quirks support for the 4.2 release.

>  -George
> 
> >
> > Signed-off-by: Allen Kay <allen.m.kay@xxxxxxxxx>
> > Signed-off-by: Xudong Hao <xudong.hao@xxxxxxxxx>
> >
> > diff -r 4e1d091d10d8 tools/libxl/libxl_pci.c
> > --- a/tools/libxl/libxl_pci.c   Fri Mar 16 15:24:25 2012 +0000
> > +++ b/tools/libxl/libxl_pci.c   Thu Mar 22 00:43:14 2012 +0800
> > @@ -779,6 +779,24 @@ int libxl_device_pci_add(libxl_ctx *ctx,
> >     return rc;
> >  }
> >
> > +static int libxl_pcidev_assignable(libxl_ctx *ctx, libxl_device_pci
> > +*pcidev) {
> > +    libxl_device_pci *pcidevs;
> > +    int num, i;
> > +
> > +    pcidevs = libxl_device_pci_list_assignable(ctx, &num);
> > +    for (i = 0; i < num; i++) {
> > +        if (pcidevs[i].domain == pcidev->domain &&
> > +            pcidevs[i].bus == pcidev->bus &&
> > +            pcidevs[i].dev == pcidev->dev &&
> > +            pcidevs[i].func == pcidev->func)
> > +        {
> > +            return 1;
> > +        }
> > +    }
> > +    return 0;
> > +}
> > +
> >  int libxl__device_pci_add(libxl__gc *gc, uint32_t domid,
> > libxl_device_pci *pcidev, int starting)  {
> >     libxl_ctx *ctx = libxl__gc_owner(gc); @@ -789,6 +807,13 @@ int
> > libxl__device_pci_add(libxl__gc *gc,
> >
> >     rc = libxl__device_pci_setdefault(gc, pcidev);
> >     if (rc) goto out;
> > +
> > +    if (!libxl_pcidev_assignable(ctx, pcidev)) {
> > +        LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "PCI device %x:%x:%x.%x
> is
> > + not assignable",
> > +                   pcidev->domain, pcidev->bus, pcidev->dev,
> > + pcidev->func);
> > +        rc = ERROR_FAIL;
> > +        goto out;
> > +    }
> >
> >     rc = get_all_assigned_devices(gc, &assigned, &num_assigned);
> >     if ( rc ) {
> >
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@xxxxxxxxxxxxx
> > http://lists.xen.org/xen-devel

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