[Xen-devel] [PATCH v3 4/4] iommu / pci: re-implement XEN_DOMCTL_get_device_group...

[Paul Durrant <paul.durrant@citrix.com>]

... using the new iommu_group infrastructure.

Because 'sibling' devices are now members of the same iommu_group,
implement the domctl by looking up the iommu_group of the pdev with the
matching SBDF and then finding all the assigned pdevs that are in the
group.

Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
---
Cc: Jan Beulich <jbeulich@suse.com>

v3:
 - Make 'max_sdevs' parameter in iommu_get_device_group() unsigned.
 - Add missing check of max_sdevs to avoid buffer overflow.

v2:
 - Re-implement in the absence of a per-group devs list.
 - Make use of pci_sbdf_t.
---
 xen/drivers/passthrough/groups.c | 46 ++++++++++++++++++++++++++++++++++++
 xen/drivers/passthrough/pci.c    | 51 ++--------------------------------------
 xen/include/xen/iommu.h          |  3 +++
 3 files changed, 51 insertions(+), 49 deletions(-)

diff --git a/xen/drivers/passthrough/groups.c b/xen/drivers/passthrough/groups.c
index c6d00980b6..4e6e8022c1 100644
--- a/xen/drivers/passthrough/groups.c
+++ b/xen/drivers/passthrough/groups.c
@@ -12,8 +12,12 @@
  * GNU General Public License for more details.
  */
 
+#include <xen/guest_access.h>
 #include <xen/iommu.h>
+#include <xen/pci.h>
 #include <xen/radix-tree.h>
+#include <xen/sched.h>
+#include <xsm/xsm.h>
 
 struct iommu_group {
     unsigned int id;
@@ -81,6 +85,48 @@ int iommu_group_assign(struct pci_dev *pdev, void *arg)
     return 0;
 }
 
+int iommu_get_device_group(struct domain *d, pci_sbdf_t sbdf,
+                           XEN_GUEST_HANDLE_64(uint32) buf,
+                           unsigned int max_sdevs)
+{
+    struct iommu_group *grp = NULL;
+    struct pci_dev *pdev;
+    unsigned int i = 0;
+
+    pcidevs_lock();
+
+    for_each_pdev ( d, pdev )
+    {
+        if ( pdev->sbdf.sbdf == sbdf.sbdf )
+        {
+            grp = pdev->grp;
+            break;
+        }
+    }
+
+    if ( !grp )
+        goto out;
+
+    for_each_pdev ( d, pdev )
+    {
+        if ( xsm_get_device_group(XSM_HOOK, pdev->sbdf.sbdf) ||
+             pdev->grp != grp )
+            continue;
+
+        if ( i < max_sdevs &&
+             unlikely(copy_to_guest_offset(buf, i++, &pdev->sbdf.sbdf, 1)) )
+        {
+            pcidevs_unlock();
+            return -EFAULT;
+        }
+    }
+
+ out:
+    pcidevs_unlock();
+
+    return i;
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/xen/drivers/passthrough/pci.c b/xen/drivers/passthrough/pci.c
index 4bb9996049..7171b50557 100644
--- a/xen/drivers/passthrough/pci.c
+++ b/xen/drivers/passthrough/pci.c
@@ -1564,53 +1564,6 @@ int deassign_device(struct domain *d, u16 seg, u8 bus, u8 devfn)
     return ret;
 }
 
-static int iommu_get_device_group(
-    struct domain *d, u16 seg, u8 bus, u8 devfn,
-    XEN_GUEST_HANDLE_64(uint32) buf, int max_sdevs)
-{
-    const struct domain_iommu *hd = dom_iommu(d);
-    struct pci_dev *pdev;
-    int group_id, sdev_id;
-    u32 bdf;
-    int i = 0;
-    const struct iommu_ops *ops = hd->platform_ops;
-
-    if ( !iommu_enabled || !ops || !ops->get_device_group_id )
-        return 0;
-
-    group_id = ops->get_device_group_id(seg, bus, devfn);
-
-    pcidevs_lock();
-    for_each_pdev( d, pdev )
-    {
-        if ( (pdev->seg != seg) ||
-             ((pdev->bus == bus) && (pdev->devfn == devfn)) )
-            continue;
-
-        if ( xsm_get_device_group(XSM_HOOK, (seg << 16) | (pdev->bus << 8) | pdev->devfn) )
-            continue;
-
-        sdev_id = ops->get_device_group_id(seg, pdev->bus, pdev->devfn);
-        if ( (sdev_id == group_id) && (i < max_sdevs) )
-        {
-            bdf = 0;
-            bdf |= (pdev->bus & 0xff) << 16;
-            bdf |= (pdev->devfn & 0xff) << 8;
-
-            if ( unlikely(copy_to_guest_offset(buf, i, &bdf, 1)) )
-            {
-                pcidevs_unlock();
-                return -1;
-            }
-            i++;
-        }
-    }
-
-    pcidevs_unlock();
-
-    return i;
-}
-
 void iommu_dev_iotlb_flush_timeout(struct domain *d, struct pci_dev *pdev)
 {
     pcidevs_lock();
@@ -1667,11 +1620,11 @@ int iommu_do_pci_domctl(
         max_sdevs = domctl->u.get_device_group.max_sdevs;
         sdevs = domctl->u.get_device_group.sdev_array;
 
-        ret = iommu_get_device_group(d, seg, bus, devfn, sdevs, max_sdevs);
+        ret = iommu_get_device_group(d, PCI_SBDF3(seg, bus, devfn), sdevs,
+                                     max_sdevs);
         if ( ret < 0 )
         {
             dprintk(XENLOG_ERR, "iommu_get_device_group() failed!\n");
-            ret = -EFAULT;
             domctl->u.get_device_group.num_sdevs = 0;
         }
         else
diff --git a/xen/include/xen/iommu.h b/xen/include/xen/iommu.h
index c93f580fdc..6301833219 100644
--- a/xen/include/xen/iommu.h
+++ b/xen/include/xen/iommu.h
@@ -321,6 +321,9 @@ extern struct page_list_head iommu_pt_cleanup_list;
 
 void iommu_groups_init(void);
 int iommu_group_assign(struct pci_dev *pdev, void *arg);
+int iommu_get_device_group(struct domain *d, pci_sbdf_t sbdf,
+                           XEN_GUEST_HANDLE_64(uint32) buf,
+                           unsigned int max_sdevs);
 
 #endif /* CONFIG_HAS_PCI */
 
-- 
2.11.0


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