[Xen-changelog] [xen master] IOMMU: prevent VT-d device IOTLB operations on wrong IOMMU

[patchbot@xxxxxxx]

commit 84c340ba4c3eb99278b6ba885616bb183b88ad67
Author:     Malcolm Crossley <malcolm.crossley@xxxxxxxxxx>
AuthorDate: Wed Jun 18 15:50:02 2014 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Wed Jun 18 15:50:02 2014 +0200

    IOMMU: prevent VT-d device IOTLB operations on wrong IOMMU
    
    PCIe ATS allows for devices to contain IOTLBs, the VT-d code was iterating
    around all ATS capable devices and issuing IOTLB operations for all IOMMUs,
    even though each ATS device is only accessible via one particular IOMMU.
    
    Issuing an IOMMU operation to a device not accessible via that IOMMU results
    in an IOMMU timeout because the device does not reply. VT-d IOMMU timeouts
    result in a Xen panic.
    
    Therefore this bug prevents any Intel system with 2 or more ATS enabled 
IOMMUs,
    each with an ATS device connected to them, from booting Xen.
    
    The patch adds a IOMMU pointer to the ATS device struct so the VT-d code can
    ensure it does not issue IOMMU ATS operations on the wrong IOMMU. A void
    pointer has to be used because AMD and Intel IOMMU implementations do not 
have
    a common IOMMU structure or indexing mechanism.
    
    Signed-off-by: Malcolm Crossley <malcolm.crossley@xxxxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Acked-by: Kevin Tian <kevin.tian@xxxxxxxxx>
    Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/drivers/passthrough/amd/pci_amd_iommu.c |    2 +-
 xen/drivers/passthrough/ats.h               |    3 ++-
 xen/drivers/passthrough/vtd/iommu.c         |    4 ++--
 xen/drivers/passthrough/vtd/x86/ats.c       |    4 ++++
 xen/drivers/passthrough/x86/ats.c           |    3 ++-
 5 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/xen/drivers/passthrough/amd/pci_amd_iommu.c 
b/xen/drivers/passthrough/amd/pci_amd_iommu.c
index 44e7693..0b301b3 100644
--- a/xen/drivers/passthrough/amd/pci_amd_iommu.c
+++ b/xen/drivers/passthrough/amd/pci_amd_iommu.c
@@ -164,7 +164,7 @@ static void amd_iommu_setup_domain_device(
          !pci_ats_enabled(iommu->seg, bus, pdev->devfn) )
     {
         if ( devfn == pdev->devfn )
-            enable_ats_device(iommu->seg, bus, devfn);
+            enable_ats_device(iommu->seg, bus, devfn, iommu);
 
         amd_iommu_flush_iotlb(devfn, pdev, INV_IOMMU_ALL_PAGES_ADDRESS, 0);
     }
diff --git a/xen/drivers/passthrough/ats.h b/xen/drivers/passthrough/ats.h
index cf649d4..000e76d 100644
--- a/xen/drivers/passthrough/ats.h
+++ b/xen/drivers/passthrough/ats.h
@@ -24,6 +24,7 @@ struct pci_ats_dev {
     u8 bus;
     u8 devfn;
     u16 ats_queue_depth;    /* ATS device invalidation queue depth */
+    const void *iommu;      /* No common IOMMU struct so use void pointer */
 };
 
 #define ATS_REG_CAP    4
@@ -34,7 +35,7 @@ struct pci_ats_dev {
 extern struct list_head ats_devices;
 extern bool_t ats_enabled;
 
-int enable_ats_device(int seg, int bus, int devfn);
+int enable_ats_device(int seg, int bus, int devfn, const void *iommu);
 void disable_ats_device(int seg, int bus, int devfn);
 struct pci_ats_dev *get_ats_device(int seg, int bus, int devfn);
 
diff --git a/xen/drivers/passthrough/vtd/iommu.c 
b/xen/drivers/passthrough/vtd/iommu.c
index 431adb4..500fc3b 100644
--- a/xen/drivers/passthrough/vtd/iommu.c
+++ b/xen/drivers/passthrough/vtd/iommu.c
@@ -1442,7 +1442,7 @@ static int domain_context_mapping(
         ret = domain_context_mapping_one(domain, drhd->iommu, bus, devfn,
                                          pdev);
         if ( !ret && devfn == pdev->devfn && ats_device(pdev, drhd) > 0 )
-            enable_ats_device(seg, bus, devfn);
+            enable_ats_device(seg, bus, devfn, drhd->iommu);
 
         break;
 
@@ -1930,7 +1930,7 @@ static int intel_iommu_enable_device(struct pci_dev *pdev)
     if ( ret <= 0 )
         return ret;
 
-    ret = enable_ats_device(pdev->seg, pdev->bus, pdev->devfn);
+    ret = enable_ats_device(pdev->seg, pdev->bus, pdev->devfn, drhd->iommu);
 
     return ret >= 0 ? 0 : ret;
 }
diff --git a/xen/drivers/passthrough/vtd/x86/ats.c 
b/xen/drivers/passthrough/vtd/x86/ats.c
index f3b8c2d..ea57d7d 100644
--- a/xen/drivers/passthrough/vtd/x86/ats.c
+++ b/xen/drivers/passthrough/vtd/x86/ats.c
@@ -120,6 +120,10 @@ int dev_invalidate_iotlb(struct iommu *iommu, u16 did,
     {
         sid = (pdev->bus << 8) | pdev->devfn;
 
+        /* Only invalidate devices that belong to this IOMMU */
+        if ( pdev->iommu != iommu )
+            continue;
+
         switch ( type ) {
         case DMA_TLB_DSI_FLUSH:
             if ( !device_in_domain(iommu, pdev, did) )
diff --git a/xen/drivers/passthrough/x86/ats.c 
b/xen/drivers/passthrough/x86/ats.c
index bb7ee9a..1e3e03a 100644
--- a/xen/drivers/passthrough/x86/ats.c
+++ b/xen/drivers/passthrough/x86/ats.c
@@ -23,7 +23,7 @@ LIST_HEAD(ats_devices);
 bool_t __read_mostly ats_enabled = 1;
 boolean_param("ats", ats_enabled);
 
-int enable_ats_device(int seg, int bus, int devfn)
+int enable_ats_device(int seg, int bus, int devfn, const void *iommu)
 {
     struct pci_ats_dev *pdev = NULL;
     u32 value;
@@ -66,6 +66,7 @@ int enable_ats_device(int seg, int bus, int devfn)
         pdev->seg = seg;
         pdev->bus = bus;
         pdev->devfn = devfn;
+        pdev->iommu = iommu;
         value = pci_conf_read16(seg, bus, PCI_SLOT(devfn),
                                 PCI_FUNC(devfn), pos + ATS_REG_CAP);
         pdev->ats_queue_depth = value & ATS_QUEUE_DEPTH_MASK ?:
--
generated by git-patchbot for /home/xen/git/xen.git#master

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