OVMF: Add support for saving the NV variables to disk following each SetVariable...
authorjljusten <jljusten@6f19259b-4bc3-4df7-8a09-765794883524>
Sat, 26 Sep 2009 07:15:55 +0000 (07:15 +0000)
committerjljusten <jljusten@6f19259b-4bc3-4df7-8a09-765794883524>
Sat, 26 Sep 2009 07:15:55 +0000 (07:15 +0000)
commit9607962def9f847c243b9fecb590c0cf94eec4fc
tree14e8488f9882ce5a59dc0bfbd89a90237b26c431
parent27f58ea1b22a59f6eb1950a6af2a47e3dc9b70c1
OVMF: Add support for saving the NV variables to disk following each SetVariable call.

Note:
* This only works before ExitBootServices
* For OVMF, variables are only preserved on the disk if there
  is a hard disk connected which has a writeable FAT file system.

The Ovmf/Library/EmuVariableFvbLib library will look for the
gUefiOvmfPkgTokenSpaceGuid.PcdEmuVariableEvent PCD to be set to
a non-zero value.  If set, it is treated as an event handle, and
each write to the EmuVariableFvb will cause the event to be
signaled.

In this change, the OVMF platform BDS library sets up this event,
and sets the PCD so that after each write to the EMU Variable FVB,
the non-volatile variables will be saved out to the file system.

The end result is that NV variables that are written prior to the
ExitBootServices call should be preserved by storing them on the
disk.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@9318 6f19259b-4bc3-4df7-8a09-765794883524
OvmfPkg/Include/Library/NvVarsFileLib.h
OvmfPkg/Library/NvVarsFileLib/NvVarsFileLib.c
OvmfPkg/Library/PlatformBdsLib/BdsPlatform.c
OvmfPkg/Library/PlatformBdsLib/PlatformBdsLib.inf