OvmfPkg: QemuFlashFvbServicesRuntimeDxe: fix out-of-LBA write access

When QemuFlashWrite() is asked to write a range that includes the last
byte of the LBA, then the byte that the function uses to switch the flash
device back to read mode (ROMD mode in KVM speak) actually falls out of
the LBA.

Normally this doesn't cause visible problems. However, if the variable
store and the firmware code are backed by separate flash devices, as
implemented by

  [Qemu-devel] [PATCH v2] hw/i386/pc_sysfw: support two flash drives
  http://thread.gmane.org/gmane.comp.emulators.qemu/243678

plus

  [edk2] [edk2 PATCH] OvmfPkg: split the variable store to a separate file
  http://thread.gmane.org/gmane.comp.bios.tianocore.devel/5045/focus=5046

then the READ_ARRAY_CMD not only reaches a different LBA, it reaches a
different qemu device. This results in a guest reboot soon after.

Fix this by ensuring that we always stay within the LBA just written when
issuing READ_ARRAY_CMD.

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@14996 6f19259b-4bc3-4df7-8a09-765794883524
OvmfPkg: IndustryStandard/VirtioBlk: add extra horizontal whitespace

We're going to introduce a new macro and a new VIRTIO_BLK_CONFIG member
that need realignment of existing definitions and comments. Separate out
the whitespace changes in this patch.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
OvmfPkg: IndustryStandard/VirtioBlk: introduce topology-related definitions

Based on
<https://tools.oasis-open.org/version-control/browse/wsvn/virtio/virtio-v1.0-wd01-part1-specification.txt?rev=159>,
which is the last text format revision.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
OvmfPkg/VirtioBlkDxe/VirtioBlk.c: rewrap overlong lines

Lines should be no longer than 79 characters.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
OvmfPkg: VirtioBlkInit(): expose virtio-blk topology in BlockIo

UEFI spec                                virtio spec
=======================================  =================================
LowestAlignedLba EFI_LBA (UINT64)        alignment_offset u8
+--------------------------------------  +--------------------------------
| first LBA that is aligned to a         | offset of first aligned
| physical block boundary (SCSI          | logical block
| definition)

LogicalBlocksPerPhysicalBlock UINT32     physical_block_exp u8
+--------------------------------------  +--------------------------------
| number of logical blocks per           | # of logical blocks per
| physical block [...] does not contain  | physical block (log2)
| an exponential value

OptimalTransferLengthGranularity UINT32  opt_io_size le32
+--------------------------------------  +--------------------------------
| optimal transfer length granularity    | optimal (suggested maximum) I/O
| as a number of logical blocks [...] A  | size in blocks
| value of 0 means there is no reported
| optimal transfer length granularity

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
OvmfPkg: VirtioBlkInit(): log topology attributes

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