[Xen-devel] [PATCH 1/2] x86/hvm/ioreq: MMIO range checking completely ignores direction flag

[Paul Durrant <paul.durrant@xxxxxxxxxx>]

hvm_select_ioreq_server() is used to route an ioreq to the appropriate
ioreq server. For MMIO this is done by comparing the range of the ioreq
to the ranges registered by the device models of each ioreq server.
Unfortunately the calculation of the range if the ioreq completely ignores
the direction flag and thus may calculate the wrong range for comparison.
Thus the ioreq may either be routed to the wrong server or erroneously
terminated by null_ops.

NOTE: The patch also fixes whitespace in the switch statement to make it
      style compliant.

Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
---
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 xen/arch/x86/hvm/ioreq.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/xen/arch/x86/hvm/ioreq.c b/xen/arch/x86/hvm/ioreq.c
index 7c515b3ef7..940a2c9728 100644
--- a/xen/arch/x86/hvm/ioreq.c
+++ b/xen/arch/x86/hvm/ioreq.c
@@ -1353,20 +1353,25 @@ struct hvm_ioreq_server *hvm_select_ioreq_server(struct 
domain *d,
 
         switch ( type )
         {
-            unsigned long end;
+            unsigned long start, end;
 
         case XEN_DMOP_IO_RANGE_PORT:
-            end = addr + p->size - 1;
-            if ( rangeset_contains_range(r, addr, end) )
+            start = addr;
+            end = start + p->size - 1;
+            if ( rangeset_contains_range(r, start, end) )
                 return s;
 
             break;
+
         case XEN_DMOP_IO_RANGE_MEMORY:
-            end = addr + (p->size * p->count) - 1;
-            if ( rangeset_contains_range(r, addr, end) )
+            start = hvm_mmio_first_byte(p);
+            end = hvm_mmio_last_byte(p);
+
+            if ( rangeset_contains_range(r, start, end) )
                 return s;
 
             break;
+
         case XEN_DMOP_IO_RANGE_PCI:
             if ( rangeset_contains_singleton(r, addr >> 32) )
             {
-- 
2.11.0


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