[Xen-changelog] [xen master] xen/arm: traps: MMIO should only be emulated for fault translation

[patchbot@xxxxxxx]

commit def427387f37cec21a68f280d8964d1f0d61fb74
Author:     Julien Grall <julien.grall@xxxxxxx>
AuthorDate: Thu Aug 4 18:50:05 2016 +0100
Commit:     Stefano Stabellini <sstabellini@xxxxxxxxxx>
CommitDate: Thu Aug 4 10:55:35 2016 -0700

    xen/arm: traps: MMIO should only be emulated for fault translation
    
    The function do_trap_data_abort_guest assumes that a stage-2 data abort
    can only be taken for a translation fault or permission fault today.
    
    Whilst this is true today, it might not be in the future. Rather than
    emulating the MMIO for any fault other than the permission one, print
    a warning message when the fault is not handled by Xen.
    
    Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
    Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
---
 xen/arch/arm/traps.c | 51 ++++++++++++++++++++++++++++-----------------------
 1 file changed, 28 insertions(+), 23 deletions(-)

diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index 7206a7e..46922eb 100644
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -2467,35 +2467,40 @@ static void do_trap_data_abort_guest(struct 
cpu_user_regs *regs,
         /* Trap was triggered by mem_access, work here is done */
         if ( !rc )
             return;
+        break;
     }
-    break;
-    }
-
-    if ( dabt.s1ptw )
-        goto bad_data_abort;
+    case FSC_FLT_TRANS:
+        if ( dabt.s1ptw )
+            goto bad_data_abort;
 
-    /* XXX: Decode the instruction if ISS is not valid */
-    if ( !dabt.valid )
-        goto bad_data_abort;
+        /* XXX: Decode the instruction if ISS is not valid */
+        if ( !dabt.valid )
+            goto bad_data_abort;
 
-    /*
-     * Erratum 766422: Thumb store translation fault to Hypervisor may
-     * not have correct HSR Rt value.
-     */
-    if ( check_workaround_766422() && (regs->cpsr & PSR_THUMB) && dabt.write )
-    {
-        rc = decode_instruction(regs, &info.dabt);
-        if ( rc )
+        /*
+         * Erratum 766422: Thumb store translation fault to Hypervisor may
+         * not have correct HSR Rt value.
+         */
+        if ( check_workaround_766422() && (regs->cpsr & PSR_THUMB) &&
+             dabt.write )
         {
-            gprintk(XENLOG_DEBUG, "Unable to decode instruction\n");
-            goto bad_data_abort;
+            rc = decode_instruction(regs, &info.dabt);
+            if ( rc )
+            {
+                gprintk(XENLOG_DEBUG, "Unable to decode instruction\n");
+                goto bad_data_abort;
+            }
         }
-    }
 
-    if (handle_mmio(&info))
-    {
-        advance_pc(regs, hsr);
-        return;
+        if ( handle_mmio(&info) )
+        {
+            advance_pc(regs, hsr);
+            return;
+        }
+        break;
+    default:
+        gprintk(XENLOG_WARNING, "Unsupported DFSC: HSR=%#x DFSC=%#x\n",
+                hsr.bits, dabt.dfsc);
     }
 
 bad_data_abort:
--
generated by git-patchbot for /home/xen/git/xen.git#master

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