[Xen-changelog] [xen master] xen/vtd: prevent from assign the device with shared rmrr

[patchbot@xxxxxxx]

commit 6457dae9960bf6f31cef928a6997b6b5b6386a6d
Author:     Tiejun Chen <tiejun.chen@xxxxxxxxx>
AuthorDate: Wed Jul 22 01:39:58 2015 +0000
Commit:     Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
CommitDate: Thu Jul 23 13:45:26 2015 +0100

    xen/vtd: prevent from assign the device with shared rmrr
    
    Currently we're intending to cover this kind of devices
    with shared RMRR simply since the case of shared RMRR is
    a rare case according to our previous experiences. But
    late we can group these devices which shared rmrr, and
    then allow all devices within a group to be assigned to
    same domain.
    
    CC: Yang Zhang <yang.z.zhang@xxxxxxxxx>
    CC: Kevin Tian <kevin.tian@xxxxxxxxx>
    Signed-off-by: Tiejun Chen <tiejun.chen@xxxxxxxxx>
    Acked-by: Kevin Tian <kevin.tian@xxxxxxxxx>
---
 xen/drivers/passthrough/vtd/iommu.c |   30 +++++++++++++++++++++++++++---
 1 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/xen/drivers/passthrough/vtd/iommu.c 
b/xen/drivers/passthrough/vtd/iommu.c
index 8a8d763..ce5c295 100644
--- a/xen/drivers/passthrough/vtd/iommu.c
+++ b/xen/drivers/passthrough/vtd/iommu.c
@@ -2293,13 +2293,37 @@ 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: in the future we can introduce group device assignment
+     * interface to make sure devices sharing RMRR are assigned to the
+     * same domain together.
+     */
+    for_each_rmrr_device( rmrr, bdf, i )
+    {
+        if ( rmrr->segment == seg &&
+             PCI_BUS(bdf) == bus &&
+             PCI_DEVFN2(bdf) == devfn &&
+             rmrr->scope.devices_cnt > 1 )
+        {
+            printk(XENLOG_G_ERR VTDPREFIX
+                   " cannot assign %04x:%02x:%02x.%u"
+                   " with shared RMRR at %"PRIx64" for Dom%d.\n",
+                   seg, bus, PCI_SLOT(devfn), PCI_FUNC(devfn),
+                   rmrr->base_address, d->domain_id);
+            return -EPERM;
+        }
+    }
+
     ret = reassign_device_ownership(hardware_domain, d, devfn, pdev);
     if ( ret )
         return ret;
 
-    seg = pdev->seg;
-    bus = pdev->bus;
-
     /* Setup rmrr identity mapping */
     for_each_rmrr_device( rmrr, bdf, i )
     {
--
generated by git-patchbot for /home/xen/git/xen.git#master

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