[xen stable-4.16] VT-d: fix add/remove ordering when RMRRs are in use

[patchbot@xxxxxxx]

commit cf0dc7379b9e2aa5f4b3983d81c6e2ed9811c34f
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Tue Apr 5 14:44:53 2022 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Apr 5 14:44:53 2022 +0200

    VT-d: fix add/remove ordering when RMRRs are in use
    
    In the event that the RMRR mappings are essential for device operation,
    they should be established before updating the device's context entry,
    while they should be torn down only after the device's context entry was
    successfully cleared.
    
    Also switch to %pd in related log messages.
    
    Fixes: fa88cfadf918 ("vt-d: Map RMRR in intel_iommu_add_device() if the 
device has RMRR")
    Fixes: 8b99f4400b69 ("VT-d: fix RMRR related error handling")
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
    Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>
    master commit: 3221f270cf2eba0a22fd4f92319d664eacb92889
    master date: 2022-04-05 14:16:10 +0200
---
 xen/drivers/passthrough/vtd/iommu.c | 27 ++++++++++++++-------------
 1 file changed, 14 insertions(+), 13 deletions(-)

diff --git a/xen/drivers/passthrough/vtd/iommu.c 
b/xen/drivers/passthrough/vtd/iommu.c
index 5e3740feb6..19696a8818 100644
--- a/xen/drivers/passthrough/vtd/iommu.c
+++ b/xen/drivers/passthrough/vtd/iommu.c
@@ -1997,14 +1997,6 @@ static int intel_iommu_add_device(u8 devfn, struct 
pci_dev *pdev)
     if ( !pdev->domain )
         return -EINVAL;
 
-    ret = domain_context_mapping(pdev->domain, devfn, pdev);
-    if ( ret )
-    {
-        dprintk(XENLOG_ERR VTDPREFIX, "d%d: context mapping failed\n",
-                pdev->domain->domain_id);
-        return ret;
-    }
-
     for_each_rmrr_device ( rmrr, bdf, i )
     {
         if ( rmrr->segment == pdev->seg &&
@@ -2021,12 +2013,17 @@ static int intel_iommu_add_device(u8 devfn, struct 
pci_dev *pdev)
                                          rmrr->base_address, rmrr->end_address,
                                          0);
             if ( ret )
-                dprintk(XENLOG_ERR VTDPREFIX, "d%d: RMRR mapping failed\n",
-                        pdev->domain->domain_id);
+                dprintk(XENLOG_ERR VTDPREFIX, "%pd: RMRR mapping failed\n",
+                        pdev->domain);
         }
     }
 
-    return 0;
+    ret = domain_context_mapping(pdev->domain, devfn, pdev);
+    if ( ret )
+        dprintk(XENLOG_ERR VTDPREFIX, "%pd: context mapping failed\n",
+                pdev->domain);
+
+    return ret;
 }
 
 static int intel_iommu_enable_device(struct pci_dev *pdev)
@@ -2048,11 +2045,15 @@ static int intel_iommu_remove_device(u8 devfn, struct 
pci_dev *pdev)
 {
     struct acpi_rmrr_unit *rmrr;
     u16 bdf;
-    int i;
+    int ret, i;
 
     if ( !pdev->domain )
         return -EINVAL;
 
+    ret = domain_context_unmap(pdev->domain, devfn, pdev);
+    if ( ret )
+        return ret;
+
     for_each_rmrr_device ( rmrr, bdf, i )
     {
         if ( rmrr->segment != pdev->seg ||
@@ -2068,7 +2069,7 @@ static int intel_iommu_remove_device(u8 devfn, struct 
pci_dev *pdev)
                                rmrr->end_address, 0);
     }
 
-    return domain_context_unmap(pdev->domain, devfn, pdev);
+    return 0;
 }
 
 static int __hwdom_init setup_hwdom_device(u8 devfn, struct pci_dev *pdev)
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.16