Re: [Xen-devel] [v3][PATCH 16/16] xen/vtd: prevent from assign the device with shared rmrr

["Chen, Tiejun" <tiejun.chen@xxxxxxxxx>]

On 2015/6/17 18:28, Jan Beulich wrote:
> > > > On 11.06.15 at 03:15, <tiejun.chen@xxxxxxxxx> wrote:
> > --- a/xen/drivers/passthrough/vtd/iommu.c
> > +++ b/xen/drivers/passthrough/vtd/iommu.c
> > @@ -2277,13 +2277,37 @@ static int intel_iommu_assign_device(
> >       if ( list_empty(&acpi_drhd_units) )
> >           return -ENODEV;
> >
> > +    seg = pdev->seg;
> > +    bus = pdev->bus;
> > +    /*
> > +     * In rare cases one given rmrr is shared by multiple devices but
> > +     * obviously this would put the security of a system at risk. So
> > +     * we should prevent from this sort of device assignment.
> > +     *
> > +     * TODO: actually we can group these devices which shared rmrr, and
> > +     * then allow all devices within a group to be assigned to same domain.
> > +     */
> > +    for_each_rmrr_device( rmrr, bdf, i )
> > +    {
> > +        if ( rmrr->segment == seg &&
> > +             PCI_BUS(bdf) == bus &&
> > +             PCI_DEVFN2(bdf) == devfn )
> > +        {
> > +            if ( rmrr->scope.devices_cnt > 1 )
> > +            {
> > +                ret = -EPERM;
> > +                printk(XENLOG_G_ERR VTDPREFIX
> > +                       " cannot assign this device with shared RMRR for Dom%d 
> > (%d)\n",
> > +                       d->domain_id, ret);
> > +                return ret;
> return -EPERM. No need to assign the value to ret, and no need to
> add the constant error code to the log entry. What's missing otoh
> is what "this device" is - you should print SBDF instead.
Right.

                printk(XENLOG_G_ERR VTDPREFIX
                       " cannot assign %04x:%02x:%02x.%u"
                       " with shared RMRR for Dom%d.\n",
                       seg, bus, PCI_SLOT(devfn), PCI_FUNC(devfn),
                       d->domain_id);
                return -EPERM;


Thanks
Tiejun

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