[Xen-changelog] [xen stable-4.2] VT-d: warn about Compatibility Format Interrupts being enabled by firmware

[patchbot@xxxxxxx]

commit 22ab16cefc04d4e8a0fc72dfff4edd00cc6841da
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Fri Sep 6 14:43:51 2013 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Fri Sep 6 14:43:51 2013 +0200

    VT-d: warn about Compatibility Format Interrupts being enabled by firmware
    
    ... as being insecure.
    
    Also drop the second (redundant) read DMAR_GSTS_REG from enable_intremap().
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Acked-by Xiantao Zhang <xiantao.zhang@xxxxxxxxx>
    master commit: c9c6abab583d27fdca1d979a7f1d18ae30f54e9b
    master date: 2013-08-21 16:44:58 +0200
---
 xen/drivers/passthrough/vtd/intremap.c |   16 ++++++++++------
 1 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/xen/drivers/passthrough/vtd/intremap.c 
b/xen/drivers/passthrough/vtd/intremap.c
index b6a4f95..8687311 100644
--- a/xen/drivers/passthrough/vtd/intremap.c
+++ b/xen/drivers/passthrough/vtd/intremap.c
@@ -695,8 +695,8 @@ int enable_intremap(struct iommu *iommu, int eim)
 
     if ( !platform_supports_intremap() )
     {
-        dprintk(XENLOG_ERR VTDPREFIX,
-                "Platform firmware does not support interrupt remapping\n");
+        printk(XENLOG_ERR VTDPREFIX
+               " Platform firmware does not support interrupt remapping\n");
         return -EINVAL;
     }
 
@@ -707,15 +707,19 @@ int enable_intremap(struct iommu *iommu, int eim)
     if ( (sts & DMA_GSTS_IRES) && ir_ctrl->iremap_maddr )
         return 0;
 
-    sts = dmar_readl(iommu->reg, DMAR_GSTS_REG);
     if ( !(sts & DMA_GSTS_QIES) )
     {
-        dprintk(XENLOG_ERR VTDPREFIX,
-                "Queued invalidation is not enabled, should not enable "
-                "interrupt remapping\n");
+        printk(XENLOG_ERR VTDPREFIX
+               " Queued invalidation is not enabled on IOMMU #%u:"
+               " Should not enable interrupt remapping\n", iommu->index);
         return -EINVAL;
     }
 
+    if ( !eim && (sts & DMA_GSTS_CFIS) )
+        printk(XENLOG_WARNING VTDPREFIX
+               " Compatibility Format Interrupts permitted on IOMMU #%u:"
+               " Device pass-through will be insecure\n", iommu->index);
+
     if ( ir_ctrl->iremap_maddr == 0 )
     {
         drhd = iommu_to_drhd(iommu);
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.2

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