[PATCH 09/17] OvmfPkg/PvScsiDxe: Backup/Restore PCI attributes on Init/UnInit

["Liran Alon" <liran.alon@oracle.com>]

This commit doesn't change semantics.
It is done as a preparation for future commits which will modify
PCI attributes.

Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=2567
Reviewed-by: Nikita Leshenko <nikita.leshchenko@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
---
 OvmfPkg/PvScsiDxe/PvScsi.c | 53 +++++++++++++++++++++++++++++++++++++-
 OvmfPkg/PvScsiDxe/PvScsi.h |  1 +
 2 files changed, 53 insertions(+), 1 deletion(-)

diff --git a/OvmfPkg/PvScsiDxe/PvScsi.c b/OvmfPkg/PvScsiDxe/PvScsi.c
index b6a83d73cead..92e0f4a98965 100644
--- a/OvmfPkg/PvScsiDxe/PvScsi.c
+++ b/OvmfPkg/PvScsiDxe/PvScsi.c
@@ -281,18 +281,59 @@ PvScsiGetNextTarget (
   return EFI_NOT_FOUND;
 }
 
+STATIC
+EFI_STATUS
+PvScsiSetPCIAttributes (
+  IN OUT PVSCSI_DEV *Dev
+  )
+{
+  EFI_STATUS Status;
+
+  //
+  // Set saved original PCI attirubtes to invalid value
+  // such that cleanup logic could determine if it should restore
+  // PCI attributes or not
+  //
+  Dev->OriginalPciAttributes = (UINT64)(-1);
+
+  //
+  // Backup original PCI Attributes
+  //
+  Status = Dev->PciIo->Attributes (
+                         Dev->PciIo,
+                         EfiPciIoAttributeOperationGet,
+                         0,
+                         &Dev->OriginalPciAttributes
+                         );
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  return EFI_SUCCESS;
+}
+
 STATIC
 EFI_STATUS
 PvScsiInit (
   IN OUT PVSCSI_DEV *Dev
   )
 {
+  EFI_STATUS Status;
+
   //
   // Init configuration
   //
   Dev->MaxTarget = PcdGet8 (PcdPvScsiMaxTargetLimit);
   Dev->MaxLun = PcdGet8 (PcdPvScsiMaxLunLimit);
 
+  //
+  // Set PCI Attributes
+  //
+  Status = PvScsiSetPCIAttributes (Dev);
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
   //
   // Populate the exported interface's attributes
   //
@@ -331,7 +372,17 @@ PvScsiUninit (
   IN OUT PVSCSI_DEV *Dev
   )
 {
-  // Currently nothing to do here
+  //
+  // Restore PCI Attributes
+  //
+  if (Dev->OriginalPciAttributes != (UINT64)(-1)) {
+    Dev->PciIo->Attributes (
+                  Dev->PciIo,
+                  EfiPciIoAttributeOperationSet,
+                  Dev->OriginalPciAttributes,
+                  NULL
+                  );
+  }
 }
 
 //
diff --git a/OvmfPkg/PvScsiDxe/PvScsi.h b/OvmfPkg/PvScsiDxe/PvScsi.h
index e1e5ae18ebf2..5f611dbbc98c 100644
--- a/OvmfPkg/PvScsiDxe/PvScsi.h
+++ b/OvmfPkg/PvScsiDxe/PvScsi.h
@@ -20,6 +20,7 @@
 typedef struct {
   UINT32                          Signature;
   EFI_PCI_IO_PROTOCOL             *PciIo;
+  UINT64                          OriginalPciAttributes;
   UINT8                           MaxTarget;
   UINT8                           MaxLun;
   EFI_EXT_SCSI_PASS_THRU_PROTOCOL PassThru;
-- 
2.20.1