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1
2=== OVMF OVERVIEW ===
3
4The Open Virtual Machine Firmware (OVMF) project aims
5to support firmware for Virtual Machines using the edk2
6code base.  More information can be found at:
7
8http://www.tianocore.org/ovmf/
9
10=== STATUS ===
11
12Current capabilities:
13* IA32 and X64 architectures
14* QEMU (0.10.0 or later)
15  - Video, keyboard, IDE, CD-ROM, serial
16  - Runs UEFI shell
17  - Optional NIC support.  Requires QEMU (0.12.2 or later)
18* UEFI Linux boots
19* UEFI Windows 8 boots
20* UEFI Windows 7 & Windows 2008 Server boot (see important notes below!)
21
22=== FUTURE PLANS ===
23
24* Test/Stabilize UEFI Self-Certification Tests (SCT) results
25
26=== BUILDING OVMF ===
27
28Pre-requisites:
29* Build environment capable of build the edk2 MdeModulePkg.
30* A properly configured ASL compiler:
31  - Intel ASL compiler: Available from http://www.acpica.org
32  - Microsoft ASL compiler: Available from http://www.acpi.info
33* NASM: http://www.nasm.us/
34
35Update Conf/target.txt ACTIVE_PLATFORM for OVMF:
36                             PEI arch   DXE arch   UEFI interfaces
37* OvmfPkg/OvmfPkgIa32.dsc      IA32       IA32           IA32
38* OvmfPkg/OvmfPkgIa32X64.dsc   IA32       X64            X64
39* OvmfPkg/OvmfPkgX64.dsc       X64        X64            X64
40
41Update Conf/target.txt TARGET_ARCH based on the .dsc file:
42                             TARGET_ARCH
43* OvmfPkg/OvmfPkgIa32.dsc     IA32
44* OvmfPkg/OvmfPkgIa32X64.dsc  IA32 X64
45* OvmfPkg/OvmfPkgX64.dsc      X64
46
47Following the edk2 build process, you will find the OVMF binaries
48under the $WORKSPACE/Build/*/*/FV directory.  The actual path will
49depend on how your build is configured.  You can expect to find
50these binary outputs:
51* OVMF.FD
52  - Please note!  This filename has changed.  Older releases used OVMF.Fv.
53* OvmfVideo.rom
54  - This file is not built separately any longer, starting with svn r13520.
55
56More information on building OVMF can be found at:
57
58https://github.com/tianocore/tianocore.github.io/wiki/How%20to%20build%20OVMF
59
60=== RUNNING OVMF on QEMU ===
61
62* QEMU 0.12.2 or later is required.
63* Be sure to use qemu-system-x86_64, if you are using and X64 firmware.
64  (qemu-system-x86_64 works for the IA32 firmware as well, of course.)
65* Use OVMF for QEMU firmware (3 options available)
66  - Option 1: QEMU 1.6 or newer; Use QEMU -pflash parameter
67    * QEMU/OVMF will use emulated flash, and fully support UEFI variables
68    * Run qemu with: -pflash path/to/OVMF.fd
69    * Note that this option is required for running SecureBoot-enabled builds
70      (-D SECURE_BOOT_ENABLE).
71  - Option 2: Use QEMU -bios parameter
72    * Note that UEFI variables will be partially emulated, and non-volatile
73      variables may lose their contents after a reboot
74    * Run qemu with: -bios path/to/OVMF.fd
75  - Option 3: Use QEMU -L parameter
76    * Note that UEFI variables will be partially emulated, and non-volatile
77      variables may lose their contents after a reboot
78    * Either copy, rename or symlink OVMF.fd => bios.bin
79    * Use the QEMU -L parameter to specify the directory where the bios.bin
80      file is located.
81* The EFI shell is built into OVMF builds at this time, so it should
82  run automatically if a UEFI boot application is not found on the
83  removable media.
84* On Linux, newer version of QEMU may enable KVM feature, and this might
85  cause OVMF to fail to boot.  The QEMU '-no-kvm' may allow OVMF to boot.
86* Capturing OVMF debug messages on qemu:
87  - The default OVMF build writes debug messages to IO port 0x402.  The
88    following qemu command line options save them in the file called
89    debug.log: '-debugcon file:debug.log -global isa-debugcon.iobase=0x402'.
90  - It is possible to revert to the original behavior, when debug messages were
91    written to the emulated serial port (potentially intermixing OVMF debug
92    output with UEFI serial console output).  For this the
93    '-D DEBUG_ON_SERIAL_PORT' option has to be passed to the build command (see
94    the next section), and in order to capture the serial output qemu needs to
95    be started with eg. '-serial file:serial.log'.
96  - Debug messages fall into several categories.  Logged vs. suppressed
97    categories are controlled at OVMF build time by the
98    'gEfiMdePkgTokenSpaceGuid.PcdDebugPrintErrorLevel' bitmask (an UINT32
99    value) in the selected .dsc file.  Individual bits of this bitmask are
100    defined in <MdePkg/Include/Library/DebugLib.h>.  One non-default bit (with
101    some performance impact) that is frequently set for debugging is 0x00400000
102    (DEBUG_VERBOSE).
103  - The RELEASE build target ('-b RELEASE' build option, see below) disables
104    all debug messages.  The default build target is DEBUG.
105
106=== Build Scripts ===
107
108On systems with the bash shell you can use OvmfPkg/build.sh to simplify
109building and running OVMF.
110
111So, for example, to build + run OVMF X64:
112$ OvmfPkg/build.sh -a X64
113$ OvmfPkg/build.sh -a X64 qemu
114
115And to run a 64-bit UEFI bootable ISO image:
116$ OvmfPkg/build.sh -a X64 qemu -cdrom /path/to/disk-image.iso
117
118To build a 32-bit OVMF without debug messages using GCC 4.5:
119$ OvmfPkg/build.sh -a IA32 -b RELEASE -t GCC45
120
121=== SMM support ===
122
123Requirements:
124* SMM support requires QEMU 2.5.
125* The minimum required QEMU machine type is "pc-q35-2.5".
126* SMM with KVM requires Linux 4.4 (host).
127
128OVMF is capable of utilizing SMM if the underlying QEMU or KVM hypervisor
129emulates SMM. SMM is put to use in the S3 suspend and resume infrastructure,
130and in the UEFI variable driver stack. The purpose is (virtual) hardware
131separation between the runtime guest OS and the firmware (OVMF), with the
132intent to make Secure Boot actually secure, by preventing the runtime guest OS
133from tampering with the variable store and S3 areas.
134
135For SMM support, OVMF must be built with the "-D SMM_REQUIRE" option. The
136resultant firmware binary will check if QEMU actually provides SMM emulation;
137if it doesn't, then OVMF will log an error and trigger an assertion failure
138during boot (even in RELEASE builds). Both the naming of the flag (SMM_REQUIRE,
139instead of SMM_ENABLE), and this behavior are consistent with the goal
140described above: this is supposed to be a security feature, and fallbacks are
141not allowed. Similarly, a pflash-backed variable store is a requirement.
142
143QEMU should be started with the options listed below (in addition to any other
144guest-specific flags). The command line should be gradually composed from the
145hints below. '\' is used to extend the command line to multiple lines, and '^'
146can be used on Windows.
147
148* QEMU binary and options specific to 32-bit guests:
149
150  $ qemu-system-i386 -cpu coreduo,-nx \
151
152  or
153
154  $ qemu-system-x86_64 -cpu <MODEL>,-lm,-nx \
155
156* QEMU binary for running 64-bit guests (no particular options):
157
158  $ qemu-system-x86_64 \
159
160* Flags common to all SMM scenarios (only the Q35 machine type is supported):
161
162  -machine q35,smm=on,accel=(tcg|kvm) \
163  -m ... \
164  -smp ... \
165  -global driver=cfi.pflash01,property=secure,value=on \
166  -drive if=pflash,format=raw,unit=0,file=OVMF_CODE.fd,readonly=on \
167  -drive if=pflash,format=raw,unit=1,file=copy_of_OVMF_VARS.fd \
168
169* In order to disable S3, add:
170
171  -global ICH9-LPC.disable_s3=1 \
172
173=== Network Support ===
174
175OVMF provides a UEFI network stack by default. Its lowest level driver is the
176NIC driver, higher levels are generic. In order to make DHCP, PXE Boot, and eg.
177socket test utilities from the StdLib edk2 package work, (1) qemu has to be
178configured to emulate a NIC, (2) a matching UEFI NIC driver must be available
179when OVMF boots.
180
181(If a NIC is configured for the virtual machine, and -- dependent on boot order
182-- PXE booting is attempted, but no DHCP server responds to OVMF's DHCP
183DISCOVER message at startup, the boot process may take approx. 3 seconds
184longer.)
185
186* For each NIC emulated by qemu, a GPLv2 licensed UEFI driver is available from
187  the iPXE project. The qemu source distribution, starting with version 1.5,
188  contains prebuilt binaries of these drivers (and of course allows one to
189  rebuild them from source as well). This is the recommended set of drivers.
190
191* Use the qemu -netdev and -device options, or the legacy -net option, to
192  enable NIC support: <http://wiki.qemu.org/Documentation/Networking>.
193
194* For a qemu >= 1.5 binary running *without* any "-M machine" option where
195  "machine" would identify a < qemu-1.5 configuration (for example: "-M
196  pc-i440fx-1.4" or "-M pc-0.13"), the iPXE drivers are automatically available
197  to and configured for OVMF in the default qemu installation.
198
199* For a qemu binary in [0.13, 1.5), or a qemu >= 1.5 binary with an "-M
200  machine" option where "machine" selects a < qemu-1.5 configuration:
201
202  - download a >= 1.5.0-rc1 source tarball from <http://wiki.qemu.org/Download>,
203
204  - extract the following iPXE driver files from the tarball and install them
205    in a location that is accessible to qemu processes (this may depend on your
206    SELinux configuration, for example):
207
208    qemu-VERSION/pc-bios/efi-e1000.rom
209    qemu-VERSION/pc-bios/efi-ne2k_pci.rom
210    qemu-VERSION/pc-bios/efi-pcnet.rom
211    qemu-VERSION/pc-bios/efi-rtl8139.rom
212    qemu-VERSION/pc-bios/efi-virtio.rom
213
214  - extend the NIC's -device option on the qemu command line with a matching
215    "romfile=" optarg:
216
217    -device e1000,...,romfile=/full/path/to/efi-e1000.rom
218    -device ne2k_pci,...,romfile=/full/path/to/efi-ne2k_pci.rom
219    -device pcnet,...,romfile=/full/path/to/efi-pcnet.rom
220    -device rtl8139,...,romfile=/full/path/to/efi-rtl8139.rom
221    -device virtio-net-pci,...,romfile=/full/path/to/efi-virtio.rom
222
223* Independently of the iPXE NIC drivers, the default OVMF build provides a
224  basic virtio-net driver, located in OvmfPkg/VirtioNetDxe.
225
226* Also independently of the iPXE NIC drivers, Intel's proprietary E1000 NIC
227  driver (PROEFI) can be embedded in the OVMF image at build time:
228
229  - Download UEFI drivers for the e1000 NIC
230    - http://downloadcenter.intel.com/Detail_Desc.aspx?agr=Y&DwnldID=17515&lang=eng
231    - Install the drivers into a directory called Intel3.5 in your WORKSPACE.
232
233  - Include the driver in OVMF during the build:
234    - Add "-D E1000_ENABLE" to your build command,
235    - For example: "build -D E1000_ENABLE".
236
237* When a matching iPXE driver is configured for a NIC as described above, it
238  takes priority over other drivers that could possibly drive the card too:
239
240                 | e1000  ne2k_pci  pcnet  rtl8139  virtio-net-pci
241    -------------+------------------------------------------------
242    iPXE         |   x       x        x       x           x
243    VirtioNetDxe |                                        x
244    Intel PROEFI |   x
245
246=== OVMF Flash Layout ===
247
248Like all current IA32/X64 system designs, OVMF's firmware
249device (rom/flash) appears in QEMU's physical address space
250just below 4GB (0x100000000).
251
252The layout of the firmware device in memory looks like:
253
254+--------------------------------------- 4GB (0x100000000)
255| VTF0 (16-bit reset code) and OVMF SEC
256| (SECFV)
257+--------------------------------------- varies based on flash size
258|
259| Compressed main firmware image
260| (FVMAIN_COMPACT)
261|
262+--------------------------------------- base + 0x20000
263| Fault-tolerant write (FTW)
264| Spare blocks (64KB/0x10000)
265+--------------------------------------- base + 0x10000
266| FTW Work block (4KB/0x1000)
267+--------------------------------------- base + 0x0f000
268| Event log area (4KB/0x1000)
269+--------------------------------------- base + 0x0e000
270| Non-volatile variable storage
271| area (56KB/0xe000)
272+--------------------------------------- base address
273
274OVMF supports building a 1MB or a 2MB flash image. The base address for
275a 1MB image in QEMU physical memory is 0xfff00000. The base address for
276a 2MB image is 0xffe00000.
277
278The code in SECFV locates FVMAIN_COMPACT, and decompresses the
279main firmware (MAINFV) into RAM memory at address 0x800000. The
280remaining OVMF firmware then uses this decompressed firmware
281volume image.
282
283=== UNIXGCC Debug ===
284
285If you build with the UNIXGCC toolchain, then debugging will be disabled
286due to larger image sizes being produced by the UNIXGCC toolchain. The
287first choice recommendation is to use GCC44 or newer instead.
288
289If you must use UNIXGCC, then you can override the build options for
290particular libraries and modules in the .dsc to re-enable debugging
291selectively. For example:
292  [Components]
293  OvmfPkg/Library/PlatformBootManagerLib/PlatformBootManagerLib.inf {
294    <BuildOptions>
295      GCC:*_*_*_CC_FLAGS             = -UMDEPKG_NDEBUG
296  }
297  MdeModulePkg/Universal/BdsDxe/BdsDxe.inf {
298    <BuildOptions>
299      GCC:*_*_*_CC_FLAGS             = -UMDEPKG_NDEBUG
300  }
301
302=== UEFI Windows 7 & Windows 2008 Server ===
303
304* One of the '-vga std' and '-vga qxl' QEMU options should be used.
305* Only one video mode, 1024x768x32, is supported at OS runtime.
306* The '-vga qxl' QEMU option is recommended. After booting the installed
307  guest OS, select the video card in Device Manager, and upgrade its driver
308  to the QXL XDDM one. Download location:
309  <http://www.spice-space.org/download.html>, Guest | Windows binaries.
310  This enables further resolutions at OS runtime, and provides S3
311  (suspend/resume) capability.
312