[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 0/11] Xen PCI Passthrough security fixes
On Wed, 17 Jun 2015, Ian Campbell wrote: > On Tue, 2015-06-02 at 16:47 +0100, Ian Campbell wrote: > > ping? The QEMU patch series is already upstream in QEMU and qemu-xen, so I think we can apply this patch to libxl now. > > On Tue, 2015-06-02 at 16:08 +0100, Stefano Stabellini wrote: > > > the following is a collection of QEMU security fixes for PCI Passthrough > > > on Xen. > > > > Part of this locks down the PCI cfg space emulation, which means we now > > need a way for people to request the old "permissive" behaviour for > > devices which need it. Per the xl docs: > > It is recommended to enable this option only for trusted VMs > > under administrator control. > > > > The toolstack (libxl, xl etc) already support a permissive flag in the > > domain cfg, and this series adds a new device property. All we need to > > do is tie them together. > > > > The simple version is below. I also have an incremental update which > > uses the QMP device-list-properties command to probe for the presence of > > this property (so things can automatically work with unpatches qemu). I > > think it's not really necessary in this case. > > > > Ian. > > > > -----8>--------- > > > > From c395657b03a1e2b7616d987e7078694874981979 Mon Sep 17 00:00:00 2001 > > From: Ian Campbell <ian.campbell@xxxxxxxxxx> > > Date: Mon, 1 Jun 2015 11:32:23 +0100 > > Subject: [PATCH] tools: libxl: allow permissive qemu-upstream pci > > passthrough. > > > > EMBARGOED UNTIL 2015-06-02 12:00 (WITH XSA-131 ET AL) > > > > Since XSA-131 qemu-xen now restricts access to PCI cfg by default. In > > order to allow local configuration of the existing libxl_device_pci > > "permissive" flag needs to be plumbed through via the new QMP property > > added by the XSA-131 patches. > > > > Versions of QEMU prior to XSA-131 did not support this permissive > > property, so we only pass it if it is true. Older versions only > > supported permissive mode. > > > > qemu-xen-traditional already supports the permissive mode setting via > > xenstore. > > > > Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx> > > Cc: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx> > > Cc: Anthony PERARD <anthony.perard@xxxxxxxxxx> > > --- > > v2: Only set argument if permissive==true. > > --- > > tools/libxl/libxl_qmp.c | 12 ++++++++++++ > > 1 file changed, 12 insertions(+) > > > > diff --git a/tools/libxl/libxl_qmp.c b/tools/libxl/libxl_qmp.c > > index 9aa7e2e..6484f5e 100644 > > --- a/tools/libxl/libxl_qmp.c > > +++ b/tools/libxl/libxl_qmp.c > > @@ -849,6 +849,18 @@ int libxl__qmp_pci_add(libxl__gc *gc, int domid, > > libxl_device_pci *pcidev) > > QMP_PARAMETERS_SPRINTF(&args, "addr", "%x.%x", > > PCI_SLOT(pcidev->vdevfn), > > PCI_FUNC(pcidev->vdevfn)); > > } > > + /* > > + * Version of QEMU prior to the XSA-131 fix did not support this > > + * property and were effectively always in permissive mode. The > > + * fix for XSA-131 switched the default to be restricted by > > + * default and added the permissive property. > > + * > > + * Therefore in order to support both old and new QEMU we only set > > + * the permissive flag if it is true. Users of older QEMU have no > > + * reason to set the flag so this is ok. > > + */ > > + if (pcidev->permissive) > > + qmp_parameters_add_bool(gc, &args, "permissive", true); > > > > rc = qmp_synchronous_send(qmp, "device_add", args, > > NULL, NULL, qmp->timeout); > > _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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