[PATCH v3 16/17] OvmfPkg/PvScsiDxe: Reset device on ExitBootServices()

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

This causes the device to forget about the request/completion rings.
We allocated said rings in EfiBootServicesData type memory, and code
executing after ExitBootServices() is permitted to overwrite it.

Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=2567
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
---
 OvmfPkg/PvScsiDxe/PvScsi.c | 43 +++++++++++++++++++++++++++++++++++++-
 OvmfPkg/PvScsiDxe/PvScsi.h |  1 +
 2 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/OvmfPkg/PvScsiDxe/PvScsi.c b/OvmfPkg/PvScsiDxe/PvScsi.c
index da3535c75220..d7f0d3c8790c 100644
--- a/OvmfPkg/PvScsiDxe/PvScsi.c
+++ b/OvmfPkg/PvScsiDxe/PvScsi.c
@@ -1221,6 +1221,31 @@ PvScsiUninit (
   PvScsiRestorePciAttributes (Dev);
 }
 
+/**
+  Event notification called by ExitBootServices()
+**/
+STATIC
+VOID
+EFIAPI
+PvScsiExitBoot (
+  IN  EFI_EVENT Event,
+  IN  VOID      *Context
+  )
+{
+  PVSCSI_DEV *Dev;
+
+  Dev = Context;
+  DEBUG ((DEBUG_VERBOSE, "%a: Context=0x%p\n", __FUNCTION__, Context));
+
+  //
+  // Reset the device to stop device usage of the rings.
+  //
+  // We allocated said rings in EfiBootServicesData type memory, and code
+  // executing after ExitBootServices() is permitted to overwrite it.
+  //
+  PvScsiResetAdapter (Dev);
+}
+
 //
 // Driver Binding
 //
@@ -1314,6 +1339,17 @@ PvScsiDriverBindingStart (
     goto ClosePciIo;
   }
 
+  Status = gBS->CreateEvent (
+                  EVT_SIGNAL_EXIT_BOOT_SERVICES,
+                  TPL_CALLBACK,
+                  &PvScsiExitBoot,
+                  Dev,
+                  &Dev->ExitBoot
+                  );
+  if (EFI_ERROR (Status)) {
+    goto UninitDev;
+  }
+
   //
   // Setup complete, attempt to export the driver instance's PassThru interface
   //
@@ -1325,11 +1361,14 @@ PvScsiDriverBindingStart (
                   &Dev->PassThru
                   );
   if (EFI_ERROR (Status)) {
-    goto UninitDev;
+    goto CloseExitBoot;
   }
 
   return EFI_SUCCESS;
 
+CloseExitBoot:
+  gBS->CloseEvent (Dev->ExitBoot);
+
 UninitDev:
   PvScsiUninit (Dev);
 
@@ -1384,6 +1423,8 @@ PvScsiDriverBindingStop (
     return Status;
   }
 
+  gBS->CloseEvent (Dev->ExitBoot);
+
   PvScsiUninit (Dev);
 
   gBS->CloseProtocol (
diff --git a/OvmfPkg/PvScsiDxe/PvScsi.h b/OvmfPkg/PvScsiDxe/PvScsi.h
index 02feac734743..544359ebc05c 100644
--- a/OvmfPkg/PvScsiDxe/PvScsi.h
+++ b/OvmfPkg/PvScsiDxe/PvScsi.h
@@ -51,6 +51,7 @@ typedef struct {
 typedef struct {
   UINT32                          Signature;
   EFI_PCI_IO_PROTOCOL             *PciIo;
+  EFI_EVENT                       ExitBoot;
   UINT64                          OriginalPciAttributes;
   PVSCSI_RING_DESC                RingDesc;
   PVSCSI_DMA_BUFFER               *DmaBuf;
-- 
2.20.1