[PATCH v4 09/13] OvmfPkg/MptScsiDxe: Set and restore PCI attributes

["Nikita Leshenko" <nikita.leshchenko@oracle.com>]

Enable the IO Space and Bus Mastering and restore the original values
when the device is stopped. This is a standard procedure in PCI
drivers.

Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=2390
Signed-off-by: Nikita Leshenko <nikita.leshchenko@oracle.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
---
 OvmfPkg/MptScsiDxe/MptScsi.c | 42 +++++++++++++++++++++++++++++++++++-
 1 file changed, 41 insertions(+), 1 deletion(-)

diff --git a/OvmfPkg/MptScsiDxe/MptScsi.c b/OvmfPkg/MptScsiDxe/MptScsi.c
index 275265774252..4bfd03d2acb0 100644
--- a/OvmfPkg/MptScsiDxe/MptScsi.c
+++ b/OvmfPkg/MptScsiDxe/MptScsi.c
@@ -36,6 +36,7 @@ typedef struct {
   EFI_EXT_SCSI_PASS_THRU_PROTOCOL PassThru;
   EFI_EXT_SCSI_PASS_THRU_MODE     PassThruMode;
   EFI_PCI_IO_PROTOCOL             *PciIo;
+  UINT64                          OriginalPciAttributes;
 } MPT_SCSI_DEV;
 
 #define MPT_SCSI_FROM_PASS_THRU(PassThruPtr) \
@@ -308,6 +309,30 @@ MptScsiControllerStart (
     goto FreePool;
   }
 
+  Status = Dev->PciIo->Attributes (
+                         Dev->PciIo,
+                         EfiPciIoAttributeOperationGet,
+                         0,
+                         &Dev->OriginalPciAttributes
+                         );
+  if (EFI_ERROR (Status)) {
+    goto CloseProtocol;
+  }
+
+  //
+  // Enable I/O Space & Bus-Mastering
+  //
+  Status = Dev->PciIo->Attributes (
+                         Dev->PciIo,
+                         EfiPciIoAttributeOperationEnable,
+                         (EFI_PCI_IO_ATTRIBUTE_IO |
+                          EFI_PCI_IO_ATTRIBUTE_BUS_MASTER),
+                         NULL
+                         );
+  if (EFI_ERROR (Status)) {
+    goto CloseProtocol;
+  }
+
   //
   // Host adapter channel, doesn't exist
   //
@@ -332,11 +357,19 @@ MptScsiControllerStart (
                   &Dev->PassThru
                   );
   if (EFI_ERROR (Status)) {
-    goto CloseProtocol;
+    goto RestoreAttributes;
   }
 
   return EFI_SUCCESS;
 
+RestoreAttributes:
+  Dev->PciIo->Attributes (
+                Dev->PciIo,
+                EfiPciIoAttributeOperationEnable,
+                Dev->OriginalPciAttributes,
+                NULL
+                );
+
 CloseProtocol:
   gBS->CloseProtocol (
          ControllerHandle,
@@ -388,6 +421,13 @@ MptScsiControllerStop (
     return Status;
   }
 
+  Dev->PciIo->Attributes (
+                Dev->PciIo,
+                EfiPciIoAttributeOperationEnable,
+                Dev->OriginalPciAttributes,
+                NULL
+                );
+
   gBS->CloseProtocol (
          ControllerHandle,
          &gEfiPciIoProtocolGuid,
-- 
2.20.1