File 5d417b38-AMD-IOMMU-correct-IRTE-updating.patch of Package xen.17316

References: bsc#1135799

# Commit 9e0e225a3aeccd807a8db88ba4669f8ab30ecc99
# Date 2019-07-31 13:27:52 +0200
# Author Jan Beulich <jbeulich@suse.com>
# Committer Jan Beulich <jbeulich@suse.com>
AMD/IOMMU: correct IRTE updating

Flushing didn't get done along the lines of what the specification says.
Mark entries to be updated as not remapped (which will result in
interrupt requests to get target aborted, but the interrupts should be
masked anyway at that point in time), issue the flush, and only then
write the new entry.

In update_intremap_entry_from_msi_msg() also fold the duplicate initial
lock determination and acquire into just a single instance.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Brian Woods <brian.woods@amd.com>

--- a/xen/drivers/passthrough/amd/iommu_intr.c
+++ b/xen/drivers/passthrough/amd/iommu_intr.c
@@ -213,15 +213,13 @@ static void update_intremap_entry(const
             },
         };
 
-        ACCESS_ONCE(entry.ptr128->raw[0]) = 0;
+        ASSERT(!entry.ptr128->full.remap_en);
+        entry.ptr128->raw[1] = irte.raw[1];
         /*
-         * Low half, in particular RemapEn, needs to be cleared first.  See
+         * High half needs to be set before low one (containing RemapEn).  See
          * comment in free_intremap_entry() regarding the choice of barrier.
          */
         smp_wmb();
-        entry.ptr128->raw[1] = irte.raw[1];
-        /* High half needs to be set before low one (containing RemapEn). */
-        smp_wmb();
         ACCESS_ONCE(entry.ptr128->raw[0]) = irte.raw[0];
     }
     else
@@ -296,6 +294,20 @@ static int update_intremap_entry_from_io
     }
 
     entry = get_intremap_entry(iommu, req_id, offset);
+
+    /* The RemapEn fields match for all formats. */
+    while ( iommu->enabled && entry.ptr32->flds.remap_en )
+    {
+        entry.ptr32->flds.remap_en = false;
+        spin_unlock(lock);
+
+        spin_lock(&iommu->lock);
+        amd_iommu_flush_intremap(iommu, req_id);
+        spin_unlock(&iommu->lock);
+
+        spin_lock(lock);
+    }
+
     if ( fresh )
         /* nothing */;
     else if ( !lo_update )
@@ -325,13 +337,6 @@ static int update_intremap_entry_from_io
 
     spin_unlock_irqrestore(lock, flags);
 
-    if ( iommu->enabled && !fresh )
-    {
-        spin_lock_irqsave(&iommu->lock, flags);
-        amd_iommu_flush_intremap(iommu, req_id);
-        spin_unlock_irqrestore(&iommu->lock, flags);
-    }
-
     set_rte_index(rte, offset);
 
     return 0;
@@ -587,19 +592,27 @@ static int update_intremap_entry_from_ms
     req_id = get_dma_requestor_id(iommu->seg, bdf);
     alias_id = get_intremap_requestor_id(iommu->seg, bdf);
 
+    lock = get_intremap_lock(iommu->seg, req_id);
+    spin_lock_irqsave(lock, flags);
+
     if ( msg == NULL )
     {
-        lock = get_intremap_lock(iommu->seg, req_id);
-        spin_lock_irqsave(lock, flags);
         for ( i = 0; i < nr; ++i )
             free_intremap_entry(iommu, req_id, *remap_index + i);
         spin_unlock_irqrestore(lock, flags);
-        goto done;
-    }
 
-    lock = get_intremap_lock(iommu->seg, req_id);
+        if ( iommu->enabled )
+        {
+            spin_lock_irqsave(&iommu->lock, flags);
+            amd_iommu_flush_intremap(iommu, req_id);
+            if ( alias_id != req_id )
+                amd_iommu_flush_intremap(iommu, alias_id);
+            spin_unlock_irqrestore(&iommu->lock, flags);
+        }
+
+        return 0;
+    }
 
-    spin_lock_irqsave(lock, flags);
     dest_mode = (msg->address_lo >> MSI_ADDR_DESTMODE_SHIFT) & 0x1;
     delivery_mode = (msg->data >> MSI_DATA_DELIVERY_MODE_SHIFT) & 0x1;
     vector = (msg->data >> MSI_DATA_VECTOR_SHIFT) & MSI_DATA_VECTOR_MASK;
@@ -623,6 +636,22 @@ static int update_intremap_entry_from_ms
     }
 
     entry = get_intremap_entry(iommu, req_id, offset);
+
+    /* The RemapEn fields match for all formats. */
+    while ( iommu->enabled && entry.ptr32->flds.remap_en )
+    {
+        entry.ptr32->flds.remap_en = false;
+        spin_unlock(lock);
+
+        spin_lock(&iommu->lock);
+        amd_iommu_flush_intremap(iommu, req_id);
+        if ( alias_id != req_id )
+            amd_iommu_flush_intremap(iommu, alias_id);
+        spin_unlock(&iommu->lock);
+
+        spin_lock(lock);
+    }
+
     update_intremap_entry(iommu, entry, vector, delivery_mode, dest_mode, dest);
     spin_unlock_irqrestore(lock, flags);
 
@@ -642,16 +671,6 @@ static int update_intremap_entry_from_ms
                get_ivrs_mappings(iommu->seg)[alias_id].intremap_table);
     }
 
-done:
-    if ( iommu->enabled )
-    {
-        spin_lock_irqsave(&iommu->lock, flags);
-        amd_iommu_flush_intremap(iommu, req_id);
-        if ( alias_id != req_id )
-            amd_iommu_flush_intremap(iommu, alias_id);
-        spin_unlock_irqrestore(&iommu->lock, flags);
-    }
-
     return 0;
 }