mirror of
https://github.com/CloverHackyColor/CloverBootloader.git
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442 lines
18 KiB
Plaintext
442 lines
18 KiB
Plaintext
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=== OVMF OVERVIEW ===
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The Open Virtual Machine Firmware (OVMF) project aims
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to support firmware for Virtual Machines using the edk2
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code base. More information can be found at:
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http://www.tianocore.org/ovmf/
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=== STATUS ===
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Current capabilities:
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* IA32 and X64 architectures
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* QEMU (version 1.7.1 or later, with 1.7 or later machine types)
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- Video, keyboard, IDE, CD-ROM, serial
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- Runs UEFI shell
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- Optional NIC support.
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* UEFI Linux boots
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* UEFI Windows 8 boots
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* UEFI Windows 7 & Windows 2008 Server boot (see important notes below!)
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=== FUTURE PLANS ===
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* Test/Stabilize UEFI Self-Certification Tests (SCT) results
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=== BUILDING OVMF ===
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Pre-requisites:
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* Build environment capable of build the edk2 MdeModulePkg.
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* A properly configured ASL compiler:
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- Intel ASL compiler: Available from http://www.acpica.org
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- Microsoft ASL compiler: Available from http://www.acpi.info
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* NASM: http://www.nasm.us/
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Update Conf/target.txt ACTIVE_PLATFORM for OVMF:
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PEI arch DXE arch UEFI interfaces
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* OvmfPkg/OvmfPkgIa32.dsc IA32 IA32 IA32
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* OvmfPkg/OvmfPkgIa32X64.dsc IA32 X64 X64
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* OvmfPkg/OvmfPkgX64.dsc X64 X64 X64
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Update Conf/target.txt TARGET_ARCH based on the .dsc file:
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TARGET_ARCH
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* OvmfPkg/OvmfPkgIa32.dsc IA32
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* OvmfPkg/OvmfPkgIa32X64.dsc IA32 X64
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* OvmfPkg/OvmfPkgX64.dsc X64
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Following the edk2 build process, you will find the OVMF binaries
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under the $WORKSPACE/Build/*/*/FV directory. The actual path will
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depend on how your build is configured. You can expect to find
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these binary outputs:
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* OVMF.FD
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- Please note! This filename has changed. Older releases used OVMF.Fv.
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* OvmfVideo.rom
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- This file is not built separately any longer, starting with svn r13520.
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If you are new to building in edk2 or looking for the latest build
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instructions, visit https://github.com/tianocore/tianocore.github.io/wiki/Build-Instructions
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More OVMF-specific build information can be found at:
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https://github.com/tianocore/tianocore.github.io/wiki/How%20to%20build%20OVMF
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=== RUNNING OVMF on QEMU ===
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* Be sure to use qemu-system-x86_64, if you are using an X64 firmware.
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(qemu-system-x86_64 works for the IA32 firmware as well, of course.)
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* Use OVMF for QEMU firmware (3 options available)
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- Option 1: Use QEMU -pflash parameter
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* QEMU/OVMF will use emulated flash, and fully support UEFI variables
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* Run qemu with: -pflash path/to/OVMF.fd
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* Note that this option is required for running SecureBoot-enabled builds
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(-D SECURE_BOOT_ENABLE).
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- Option 2: Use QEMU -bios parameter
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* Note that UEFI variables will be partially emulated, and non-volatile
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variables may lose their contents after a reboot
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* Run qemu with: -bios path/to/OVMF.fd
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- Option 3: Use QEMU -L parameter
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* Note that UEFI variables will be partially emulated, and non-volatile
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variables may lose their contents after a reboot
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* Either copy, rename or symlink OVMF.fd => bios.bin
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* Use the QEMU -L parameter to specify the directory where the bios.bin
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file is located.
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* The EFI shell is built into OVMF builds at this time, so it should
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run automatically if a UEFI boot application is not found on the
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removable media.
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* On Linux, newer version of QEMU may enable KVM feature, and this might
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cause OVMF to fail to boot. The QEMU '-no-kvm' may allow OVMF to boot.
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* Capturing OVMF debug messages on qemu:
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- The default OVMF build writes debug messages to IO port 0x402. The
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following qemu command line options save them in the file called
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debug.log: '-debugcon file:debug.log -global isa-debugcon.iobase=0x402'.
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- It is possible to revert to the original behavior, when debug messages were
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written to the emulated serial port (potentially intermixing OVMF debug
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output with UEFI serial console output). For this the
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'-D DEBUG_ON_SERIAL_PORT' option has to be passed to the build command (see
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the next section), and in order to capture the serial output qemu needs to
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be started with eg. '-serial file:serial.log'.
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- Debug messages fall into several categories. Logged vs. suppressed
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categories are controlled at OVMF build time by the
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'gEfiMdePkgTokenSpaceGuid.PcdDebugPrintErrorLevel' bitmask (an UINT32
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value) in the selected .dsc file. Individual bits of this bitmask are
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defined in <MdePkg/Include/Library/DebugLib.h>. One non-default bit (with
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some performance impact) that is frequently set for debugging is 0x00400000
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(DEBUG_VERBOSE).
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- The RELEASE build target ('-b RELEASE' build option, see below) disables
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all debug messages. The default build target is DEBUG.
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=== Build Scripts ===
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On systems with the bash shell you can use OvmfPkg/build.sh to simplify
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building and running OVMF.
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So, for example, to build + run OVMF X64:
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$ OvmfPkg/build.sh -a X64
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$ OvmfPkg/build.sh -a X64 qemu
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And to run a 64-bit UEFI bootable ISO image:
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$ OvmfPkg/build.sh -a X64 qemu -cdrom /path/to/disk-image.iso
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To build a 32-bit OVMF without debug messages using GCC 5:
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$ OvmfPkg/build.sh -a IA32 -b RELEASE -t GCC
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=== Secure Boot ===
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Secure Boot is a security feature that ensures only trusted and digitally
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signed software is allowed to run during the boot process. This is achieved
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by storing Secure Boot keys in UEFI Variables, as result it can be easily
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bypassed by writing directly to the flash varstore. To avoid this situation,
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it's necessary to make the varstore with SB keys read-only and/or provide an
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isolated execution environment for flash access (such as SMM).
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* In order to support Secure Boot, OVMF must be built with the
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"-D SECURE_BOOT_ENABLE" option.
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* By default, OVMF is not shipped with any SecureBoot keys installed. The user
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need to install them with "Secure Boot Configuration" utility in the firmware
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UI, or enroll the default UEFI keys using the OvmfPkg/EnrollDefaultKeys app.
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For the EnrollDefaultKeys application, the hypervisor is expected to add a
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string entry to the "OEM Strings" (Type 11) SMBIOS table. The string should
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have the following format:
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4e32566d-8e9e-4f52-81d3-5bb9715f9727:<Base64 X509 cert for PK and first KEK>
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Such string can be generated with the following script, for example:
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sed \
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-e 's/^-----BEGIN CERTIFICATE-----$/4e32566d-8e9e-4f52-81d3-5bb9715f9727:/' \
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-e '/^-----END CERTIFICATE-----$/d' \
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PkKek1.pem \
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| tr -d '\n' \
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> PkKek1.oemstr
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- Using QEMU 5.2 or later, the SMBIOS type 11 field can be specified from a
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file:
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-smbios type=11,path=PkKek1.oemstr \
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- Using QEMU 5.1 or earlier, the string has to be passed as a value:
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-smbios type=11,value="$(< PkKek1.oemstr)"
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=== SMM support ===
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Requirements:
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* SMM support requires QEMU 2.5.
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* The minimum required QEMU machine type is "pc-q35-2.5".
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* SMM with KVM requires Linux 4.4 (host).
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OVMF is capable of utilizing SMM if the underlying QEMU or KVM hypervisor
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emulates SMM. SMM is put to use in the S3 suspend and resume infrastructure,
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and in the UEFI variable driver stack. The purpose is (virtual) hardware
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separation between the runtime guest OS and the firmware (OVMF), with the
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intent to make Secure Boot actually secure, by preventing the runtime guest OS
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from tampering with the variable store and S3 areas.
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For SMM support, OVMF must be built with the "-D SMM_REQUIRE" option. The
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resultant firmware binary will check if QEMU actually provides SMM emulation;
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if it doesn't, then OVMF will log an error and trigger an assertion failure
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during boot (even in RELEASE builds). Both the naming of the flag (SMM_REQUIRE,
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instead of SMM_ENABLE), and this behavior are consistent with the goal
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described above: this is supposed to be a security feature, and fallbacks are
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not allowed. Similarly, a pflash-backed variable store is a requirement.
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QEMU should be started with the options listed below (in addition to any other
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guest-specific flags). The command line should be gradually composed from the
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hints below. '\' is used to extend the command line to multiple lines, and '^'
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can be used on Windows.
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* QEMU binary and options specific to 32-bit guests:
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$ qemu-system-i386 -cpu coreduo,-nx \
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or
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$ qemu-system-x86_64 -cpu <MODEL>,-lm,-nx \
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* QEMU binary for running 64-bit guests (no particular options):
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$ qemu-system-x86_64 \
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* Flags common to all SMM scenarios (only the Q35 machine type is supported):
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-machine q35,smm=on,accel=(tcg|kvm) \
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-m ... \
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-smp ... \
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-global driver=cfi.pflash01,property=secure,value=on \
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-drive if=pflash,format=raw,unit=0,file=OVMF_CODE.fd,readonly=on \
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-drive if=pflash,format=raw,unit=1,file=copy_of_OVMF_VARS.fd \
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* In order to disable S3, add:
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-global ICH9-LPC.disable_s3=1 \
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=== Network Support ===
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OVMF provides a UEFI network stack by default. Its lowest level driver is the
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NIC driver, higher levels are generic. In order to make DHCP, PXE Boot, and eg.
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socket test utilities from the StdLib edk2 package work, (1) qemu has to be
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configured to emulate a NIC, (2) a matching UEFI NIC driver must be available
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when OVMF boots.
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(If a NIC is configured for the virtual machine, and -- dependent on boot order
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-- PXE booting is attempted, but no DHCP server responds to OVMF's DHCP
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DISCOVER message at startup, the boot process may take approx. 3 seconds
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longer.)
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* For each NIC emulated by qemu, a GPLv2 licensed UEFI driver is available from
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the iPXE project. The qemu source distribution contains prebuilt binaries of
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these drivers (and of course allows one to rebuild them from source as well).
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This is the recommended set of drivers.
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* Use the qemu -netdev and -device options, or the legacy -net option, to
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enable NIC support: <http://wiki.qemu.org/Documentation/Networking>.
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* The iPXE drivers are automatically available to and configured for OVMF in
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the default qemu installation.
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* Independently of the iPXE NIC drivers, the default OVMF build provides a
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basic virtio-net driver, located in OvmfPkg/VirtioNetDxe.
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* Also independently of the iPXE NIC drivers, Intel's proprietary E1000 NIC
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driver (from the BootUtil distribution) can be embedded in the OVMF image at
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build time:
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- Download BootUtil:
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- Navigate to
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https://downloadcenter.intel.com/download/19186/Ethernet-Intel-Ethernet-Connections-Boot-Utility-Preboot-Images-and-EFI-Drivers
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- Click the download link for "PREBOOT.EXE".
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- Accept the Intel Software License Agreement that appears.
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- Unzip "PREBOOT.EXE" into a separate directory (this works with the
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"unzip" utility on platforms different from Windows as well).
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- Copy the "APPS/EFI/EFIx64/E3522X2.EFI" driver binary to
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"Intel3.5/EFIX64/E3522X2.EFI" in your WORKSPACE.
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- Intel have stopped distributing an IA32 driver binary (which used to
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match the filename pattern "E35??E2.EFI"), thus this method will only
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work for the IA32X64 and X64 builds of OVMF.
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- Include the driver in OVMF during the build:
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- Add "-D E1000_ENABLE" to your build command (only when building
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"OvmfPkg/OvmfPkgIa32X64.dsc" or "OvmfPkg/OvmfPkgX64.dsc").
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- For example: "build -D E1000_ENABLE".
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* When a matching iPXE driver is configured for a NIC as described above, it
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takes priority over other drivers that could possibly drive the card too:
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| e1000 ne2k_pci pcnet rtl8139 virtio-net-pci
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---------------------+------------------------------------------------
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iPXE | x x x x x
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VirtioNetDxe | x
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Intel BootUtil (X64) | x
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=== HTTPS Boot ===
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HTTPS Boot is an alternative solution to PXE. It replaces the tftp server
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with a HTTPS server so the firmware can download the images through a trusted
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and encrypted connection.
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* To enable HTTPS Boot, you have to build OVMF with -D NETWORK_HTTP_BOOT_ENABLE
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and -D NETWORK_TLS_ENABLE. The former brings in the HTTP stack from
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NetworkPkg while the latter enables TLS support in both NetworkPkg and
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CryptoPkg.
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If you want to exclude the unsecured HTTP connection completely, OVMF has to
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be built with -D NETWORK_ALLOW_HTTP_CONNECTIONS=FALSE so that only the HTTPS
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connections will be accepted.
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* By default, there is no trusted certificate. The user has to import the
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certificates either manually with "Tls Auth Configuration" utility in the
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firmware UI or through the fw_cfg entry, etc/edk2/https/cacerts.
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-fw_cfg name=etc/edk2/https/cacerts,file=<certdb>
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The blob for etc/edk2/https/cacerts has to be in the format of Signature
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Database(*1). You can use p11-kit(*2) or efisiglit(*3) to create the
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certificate list.
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If you want to create the certificate list based on the CA certificates
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in your local host, p11-kit will be a good choice. Here is the command to
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create the list:
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p11-kit extract --format=edk2-cacerts --filter=ca-anchors \
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--overwrite --purpose=server-auth <certdb>
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If you only want to import one certificate, efisiglist is the tool for you:
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efisiglist -a <cert file> -o <certdb>
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Please note that the certificate has to be in the DER format.
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You can also append a certificate to the existing list with the following
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command:
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efisiglist -i <old certdb> -a <cert file> -o <new certdb>
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NOTE: You may need the patch to make efisiglist generate the correct header.
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(https://github.com/rhboot/pesign/pull/40)
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* Besides the trusted certificates, it's also possible to configure the trusted
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cipher suites for HTTPS through another fw_cfg entry: etc/edk2/https/ciphers.
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OVMF expects a binary UINT16 array which comprises the cipher suites HEX
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IDs(*4). If the cipher suite list is given, OVMF will choose the cipher
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suite from the intersection of the given list and the built-in cipher
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suites. Otherwise, OVMF just chooses whatever proper cipher suites from the
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built-in ones.
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- Using QEMU 5.2 or later, QEMU can expose the ordered list of permitted TLS
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cipher suites from the host side to OVMF:
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-object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \
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-fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0
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(Refer to the QEMU manual and to
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<https://gnutls.org/manual/html_node/Priority-Strings.html> for more
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information on the "priority" property.)
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- Using QEMU 5.1 or earlier, the array has to be passed from a file:
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-fw_cfg name=etc/edk2/https/ciphers,file=<cipher suites>
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whose contents can be generated with the following script, for example:
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export LC_ALL=C
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openssl ciphers -V \
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| sed -r -n \
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-e 's/^ *0x([0-9A-F]{2}),0x([0-9A-F]{2}) - .*$/\\\\x\1 \\\\x\2/p' \
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| xargs -r -- printf -- '%b' > ciphers.bin
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This script creates ciphers.bin that contains all the cipher suite IDs
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supported by openssl according to the local host configuration.
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You may want to enable only a limited set of cipher suites. Then, you
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should check the validity of your list first:
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openssl ciphers -V <cipher list>
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If all the cipher suites in your list map to the proper HEX IDs, go ahead
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to modify the script and execute it:
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export LC_ALL=C
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openssl ciphers -V <cipher list> \
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| sed -r -n \
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-e 's/^ *0x([0-9A-F]{2}),0x([0-9A-F]{2}) - .*$/\\\\x\1 \\\\x\2/p' \
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| xargs -r -- printf -- '%b' > ciphers.bin
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(*1) See "31.4.1 Signature Database" in UEFI specification 2.7 errata A.
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(*2) p11-kit: https://github.com/p11-glue/p11-kit/
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(*3) efisiglist: https://github.com/rhboot/pesign/blob/master/src/efisiglist.c
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(*4) https://wiki.mozilla.org/Security/Server_Side_TLS#Cipher_names_correspondence_table
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=== OVMF Flash Layout ===
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Like all current IA32/X64 system designs, OVMF's firmware device (rom/flash)
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appears in QEMU's physical address space just below 4GB (0x100000000).
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OVMF supports building a 1MB, 2MB or 4MB flash image (see the DSC files for the
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FD_SIZE_1MB, FD_SIZE_2MB, FD_SIZE_4MB build defines). The base address for the
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1MB image in QEMU physical memory is 0xfff00000. The base address for the 2MB
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image is 0xffe00000. The base address for the 4MB image is 0xffc00000.
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Using the 1MB or 2MB image, the layout of the firmware device in memory looks
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like:
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+--------------------------------------- 4GB (0x100000000)
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| VTF0 (16-bit reset code) and OVMF SEC
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| (SECFV, 208KB/0x34000)
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+--------------------------------------- varies based on flash size
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| Compressed main firmware image
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| (FVMAIN_COMPACT)
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+--------------------------------------- base + 0x20000
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| Fault-tolerant write (FTW)
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| Spare blocks (64KB/0x10000)
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+--------------------------------------- base + 0x10000
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| FTW Work block (4KB/0x1000)
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+--------------------------------------- base + 0x0f000
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| Event log area (4KB/0x1000)
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+--------------------------------------- base + 0x0e000
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| Non-volatile variable storage
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| area (56KB/0xe000)
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+--------------------------------------- base address
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Using the 4MB image, the layout of the firmware device in memory looks like:
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+--------------------------------------- base + 0x400000 (4GB/0x100000000)
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| VTF0 (16-bit reset code) and OVMF SEC
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| (SECFV, 208KB/0x34000)
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+--------------------------------------- base + 0x3cc000
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| Compressed main firmware image
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| (FVMAIN_COMPACT, 3360KB/0x348000)
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+--------------------------------------- base + 0x84000
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| Fault-tolerant write (FTW)
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| Spare blocks (264KB/0x42000)
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+--------------------------------------- base + 0x42000
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| FTW Work block (4KB/0x1000)
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+--------------------------------------- base + 0x41000
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| Event log area (4KB/0x1000)
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+--------------------------------------- base + 0x40000
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| Non-volatile variable storage
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| area (256KB/0x40000)
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+--------------------------------------- base address (0xffc00000)
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The code in SECFV locates FVMAIN_COMPACT, and decompresses the
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main firmware (MAINFV) into RAM memory at address 0x800000. The
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remaining OVMF firmware then uses this decompressed firmware
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volume image.
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=== UEFI Windows 7 & Windows 2008 Server ===
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* One of the '-vga std' and '-vga qxl' QEMU options should be used.
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* Only one video mode, 1024x768x32, is supported at OS runtime.
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* The '-vga qxl' QEMU option is recommended. After booting the installed
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guest OS, select the video card in Device Manager, and upgrade its driver
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to the QXL XDDM one. Download location:
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<http://www.spice-space.org/download.html>, Guest | Windows binaries.
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This enables further resolutions at OS runtime, and provides S3
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(suspend/resume) capability.
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