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OvmfPkg: QemuVideoDxe: serialize Start() against callbacks 

If Start() succeeds, the callback is only executed when the setup is
complete (on the stack of RestoreTPL()), rather than on the stack of
InstallMultipleProtocolInterfaces(), when the driver setup may yet be
theoretically incomplete.

If Start() fails, the protocol interface will have been uninstalled
(rolled back) by the time the callback runs (again, on the stack of
RestoreTPL()). Since protocol notification callbacks begin with locating
the protocol interface in question, such attempts to locate will fail
immediately and save some work in the callback.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@15371 6f19259b-4bc3-4df7-8a09-765794883524
This commit is contained in:
Laszlo Ersek 2014-03-22 07:13:44 +00:00 committed by jljusten
parent bc4c536628
commit 9c08bbe59c
1 changed files with 9 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
OvmfPkg/QemuVideoDxe/Driver.c
View File

@ -170,6 +170,7 @@ QemuVideoControllerDriverStart (
IN EFI_DEVICE_PATH_PROTOCOL *RemainingDevicePath
)
{
EFI_TPL OldTpl;
EFI_STATUS Status;
QEMU_VIDEO_PRIVATE_DATA *Private;
EFI_DEVICE_PATH_PROTOCOL *ParentDevicePath;
@ -178,12 +179,15 @@ QemuVideoControllerDriverStart (
QEMU_VIDEO_CARD *Card;
EFI_PCI_IO_PROTOCOL *ChildPciIo;
OldTpl = gBS->RaiseTPL (TPL_CALLBACK);
//
// Allocate Private context data for GOP inteface.
//
Private = AllocateZeroPool (sizeof (QEMU_VIDEO_PRIVATE_DATA));
if (Private == NULL) {
return EFI_OUT_OF_RESOURCES;
Status = EFI_OUT_OF_RESOURCES;
goto RestoreTpl;
}
//
@ -394,6 +398,7 @@ QemuVideoControllerDriverStart (
goto UninstallGop;
}
gBS->RestoreTPL (OldTpl);
return EFI_SUCCESS;
UninstallGop:
@ -424,6 +429,9 @@ ClosePciIo:
FreePrivate:
FreePool (Private);
RestoreTpl:
gBS->RestoreTPL (OldTpl);
return Status;
}