[xen stable-4.12] VT-d: split domid map cleanup check into a function

[patchbot@xxxxxxx]

commit 5f3027e00666c248e8a25015b8e202cd321890ab
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Tue Apr 5 15:36:09 2022 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Apr 5 15:36:09 2022 +0200

    VT-d: split domid map cleanup check into a function
    
    This logic will want invoking from elsewhere.
    
    No functional change intended.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
    Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>
    master commit: 9fdc10abe9457e4c9879a266f82372cb08e88ffb
    master date: 2021-11-24 11:06:20 +0100
---
 xen/drivers/passthrough/vtd/iommu.c | 104 ++++++++++++++++++++++--------------
 1 file changed, 64 insertions(+), 40 deletions(-)

diff --git a/xen/drivers/passthrough/vtd/iommu.c 
b/xen/drivers/passthrough/vtd/iommu.c
index e7ba56e809..410dc216b2 100644
--- a/xen/drivers/passthrough/vtd/iommu.c
+++ b/xen/drivers/passthrough/vtd/iommu.c
@@ -152,6 +152,68 @@ static void __init free_intel_iommu(struct intel_iommu 
*intel)
     xfree(intel);
 }
 
+static void cleanup_domid_map(struct domain *domain, struct iommu *iommu)
+{
+    int iommu_domid = domain_iommu_domid(domain, iommu);
+
+    if ( iommu_domid >= 0 )
+    {
+        /*
+         * Update domid_map[] /before/ domid_bitmap[] to avoid a race with
+         * context_set_domain_id(), setting the slot to DOMID_INVALID for
+         * ->domid_map[] reads to produce a suitable value while the bit is
+         * still set.
+         */
+        iommu->domid_map[iommu_domid] = DOMID_INVALID;
+        clear_bit(iommu_domid, iommu->domid_bitmap);
+    }
+}
+
+static bool any_pdev_behind_iommu(const struct domain *d,
+                                  const struct pci_dev *exclude,
+                                  const struct iommu *iommu)
+{
+    const struct pci_dev *pdev;
+
+    for_each_pdev ( d, pdev )
+    {
+        const struct acpi_drhd_unit *drhd;
+
+        if ( pdev == exclude )
+            continue;
+
+        drhd = acpi_find_matched_drhd_unit(pdev);
+        if ( drhd && drhd->iommu == iommu )
+            return true;
+    }
+
+    return false;
+}
+
+/*
+ * If no other devices under the same iommu owned by this domain,
+ * clear iommu in iommu_bitmap and clear domain_id in domid_bitmap.
+ */
+static void check_cleanup_domid_map(struct domain *d,
+                                    const struct pci_dev *exclude,
+                                    struct iommu *iommu)
+{
+    bool found = any_pdev_behind_iommu(d, exclude, iommu);
+
+    /*
+     * Hidden devices are associated with DomXEN but usable by the hardware
+     * domain. Hence they need considering here as well.
+     */
+    if ( !found && is_hardware_domain(d) )
+        found = any_pdev_behind_iommu(dom_xen, exclude, iommu);
+
+    if ( !found )
+    {
+        clear_bit(iommu->index, &dom_iommu(d)->arch.iommu_bitmap);
+        cleanup_domid_map(d, iommu);
+    }
+}
+
 static int iommus_incoherent;
 
 static void sync_cache(const void *addr, unsigned int size)
@@ -1671,7 +1733,6 @@ static int domain_context_unmap(struct domain *domain, u8 
devfn,
     struct iommu *iommu;
     int ret = 0;
     u8 seg = pdev->seg, bus = pdev->bus, tmp_bus, tmp_devfn, secbus;
-    int found = 0;
 
     drhd = acpi_find_matched_drhd_unit(pdev);
     if ( !drhd )
@@ -1740,45 +1801,8 @@ static int domain_context_unmap(struct domain *domain, 
u8 devfn,
         goto out;
     }
 
-    /*
-     * if no other devices under the same iommu owned by this domain,
-     * clear iommu in iommu_bitmap and clear domain_id in domid_bitmp
-     */
-    for_each_pdev ( domain, pdev )
-    {
-        if ( pdev->seg == seg && pdev->bus == bus && pdev->devfn == devfn )
-            continue;
-
-        drhd = acpi_find_matched_drhd_unit(pdev);
-        if ( drhd && drhd->iommu == iommu )
-        {
-            found = 1;
-            break;
-        }
-    }
-
-    if ( found == 0 )
-    {
-        int iommu_domid;
-
-        clear_bit(iommu->index, &dom_iommu(domain)->arch.iommu_bitmap);
-
-        iommu_domid = domain_iommu_domid(domain, iommu);
-        if ( iommu_domid == -1 )
-        {
-            ret = -EINVAL;
-            goto out;
-        }
-
-        /*
-         * Update domid_map[] /before/ domid_bitmap[] to avoid a race with
-         * context_set_domain_id(), setting the slot to DOMID_INVALID for
-         * ->domid_map[] reads to produce a suitable value while the bit is
-         * still set.
-         */
-        iommu->domid_map[iommu_domid] = DOMID_INVALID;
-        clear_bit(iommu_domid, iommu->domid_bitmap);
-    }
+    if ( !ret )
+        check_cleanup_domid_map(domain, pdev, iommu);
 
 out:
     return ret;
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.12