ShellPkg: Fix potentially uninitialized variable compiler warning

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jaben Carsey <Jaben.carsey@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@14598 6f19259b-4bc3-4df7-8a09-765794883524
EmbeddedPkg/EmbeddedPkg.dsc: Fixed PCD settings

Invalid PCD syntax.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Olivier Martin <olivier.martin@arm.com>


git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@14599 6f19259b-4bc3-4df7-8a09-765794883524
OvmfPkg: Build and use the UEFI shell by default

Previously OVMF included the older EFI shell binary when building.

Now we will build and use the UEFI shell (ShellPkg) instead.

v2:
 * Don't bother building UEFI shell when USE_OLD_SHELL is defined
 * Fix errors in OvmfPkgIa32X64.fdf

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

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@14600 6f19259b-4bc3-4df7-8a09-765794883524
OvmfPkg: Virtio: load used ring element strictly after loading used index

Enforce in-order execution of these steps even on not sequentially
consistent architectures, as discussed in [1]. These changes should be
unnecessary on x86 (the only architecture OVMF currently supports), but
they align the OVMF virtio code with the virtio specification and could be
necessary for future OVMF ports.

[1] http://lists.linuxfoundation.org/pipermail/virtualization/2013-June/024547.html

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

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@14601 6f19259b-4bc3-4df7-8a09-765794883524