+OVMF provides a UEFI network stack by default. Its lowest level driver is the\r
+NIC driver, higher levels are generic. In order to make DHCP, PXE Boot, and eg.\r
+socket test utilities from the StdLib edk2 package work, (1) qemu has to be\r
+configured to emulate a NIC, (2) a matching UEFI NIC driver must be available\r
+when OVMF boots.\r
+\r
+(If a NIC is configured for the virtual machine, and -- dependent on boot order\r
+-- PXE booting is attempted, but no DHCP server responds to OVMF's DHCP\r
+DISCOVER message at startup, the boot process may take approx. 3 seconds\r
+longer.)\r
+\r
+* For each NIC emulated by qemu, a GPLv2 licensed UEFI driver is available from\r
+ the iPXE project. The qemu source distribution contains prebuilt binaries of\r
+ these drivers (and of course allows one to rebuild them from source as well).\r
+ This is the recommended set of drivers.\r
+\r
+* Use the qemu -netdev and -device options, or the legacy -net option, to\r
+ enable NIC support: <http://wiki.qemu.org/Documentation/Networking>.\r
+\r
+* The iPXE drivers are automatically available to and configured for OVMF in\r
+ the default qemu installation.\r
+\r
+* Independently of the iPXE NIC drivers, the default OVMF build provides a\r
+ basic virtio-net driver, located in OvmfPkg/VirtioNetDxe.\r
+\r
+* Also independently of the iPXE NIC drivers, Intel's proprietary E1000 NIC\r
+ driver (from the BootUtil distribution) can be embedded in the OVMF image at\r
+ build time:\r
+\r
+ - Download BootUtil:\r
+ - Navigate to\r
+ https://downloadcenter.intel.com/download/19186/Ethernet-Intel-Ethernet-Connections-Boot-Utility-Preboot-Images-and-EFI-Drivers\r
+ - Click the download link for "PREBOOT.EXE".\r
+ - Accept the Intel Software License Agreement that appears.\r
+ - Unzip "PREBOOT.EXE" into a separate directory (this works with the\r
+ "unzip" utility on platforms different from Windows as well).\r
+ - Copy the "APPS/EFI/EFIx64/E3522X2.EFI" driver binary to\r
+ "Intel3.5/EFIX64/E3522X2.EFI" in your WORKSPACE.\r
+ - Intel have stopped distributing an IA32 driver binary (which used to\r
+ match the filename pattern "E35??E2.EFI"), thus this method will only\r
+ work for the IA32X64 and X64 builds of OVMF.\r
+\r
+ - Include the driver in OVMF during the build:\r
+ - Add "-D E1000_ENABLE" to your build command (only when building\r
+ "OvmfPkg/OvmfPkgIa32X64.dsc" or "OvmfPkg/OvmfPkgX64.dsc").\r
+ - For example: "build -D E1000_ENABLE".\r
+\r
+* When a matching iPXE driver is configured for a NIC as described above, it\r
+ takes priority over other drivers that could possibly drive the card too:\r
+\r
+ | e1000 ne2k_pci pcnet rtl8139 virtio-net-pci\r
+ ---------------------+------------------------------------------------\r
+ iPXE | x x x x x\r
+ VirtioNetDxe | x\r
+ Intel BootUtil (X64) | x\r
+\r
+=== HTTPS Boot ===\r
+\r
+HTTPS Boot is an alternative solution to PXE. It replaces the tftp server\r
+with a HTTPS server so the firmware can download the images through a trusted\r
+and encrypted connection.\r
+\r
+* To enable HTTPS Boot, you have to build OVMF with -D NETWORK_HTTP_BOOT_ENABLE\r
+ and -D NETWORK_TLS_ENABLE. The former brings in the HTTP stack from\r
+ NetworkPkg while the latter enables TLS support in both NetworkPkg and\r
+ CryptoPkg.\r
+\r
+ If you want to exclude the unsecured HTTP connection completely, OVMF has to\r
+ be built with -D NETWORK_ALLOW_HTTP_CONNECTIONS=FALSE so that only the HTTPS\r
+ connections will be accepted.\r
+\r
+* By default, there is no trusted certificate. The user has to import the\r
+ certificates either manually with "Tls Auth Configuration" utility in the\r
+ firmware UI or through the fw_cfg entry, etc/edk2/https/cacerts.\r
+\r
+ -fw_cfg name=etc/edk2/https/cacerts,file=<certdb>\r
+\r
+ The blob for etc/edk2/https/cacerts has to be in the format of Signature\r
+ Database(*1). You can use p11-kit(*2) or efisiglit(*3) to create the\r
+ certificate list.\r
+\r
+ If you want to create the certificate list based on the CA certificates\r
+ in your local host, p11-kit will be a good choice. Here is the command to\r
+ create the list:\r
+\r
+ p11-kit extract --format=edk2-cacerts --filter=ca-anchors \\r
+ --overwrite --purpose=server-auth <certdb>\r
+\r
+ If you only want to import one certificate, efisiglist is the tool for you:\r
+\r
+ efisiglist -a <cert file> -o <certdb>\r
+\r
+ Please note that the certificate has to be in the DER format.\r
+\r
+ You can also append a certificate to the existing list with the following\r
+ command:\r
+\r
+ efisiglist -i <old certdb> -a <cert file> -o <new certdb>\r
+\r
+ NOTE: You may need the patch to make efisiglist generate the correct header.\r
+ (https://github.com/rhboot/pesign/pull/40)\r
+\r
+* Besides the trusted certificates, it's also possible to configure the trusted\r
+ cipher suites for HTTPS through another fw_cfg entry: etc/edk2/https/ciphers.\r
+\r
+ OVMF expects a binary UINT16 array which comprises the cipher suites HEX\r
+ IDs(*4). If the cipher suite list is given, OVMF will choose the cipher\r
+ suite from the intersection of the given list and the built-in cipher\r
+ suites. Otherwise, OVMF just chooses whatever proper cipher suites from the\r
+ built-in ones.\r
+\r
+ - Using QEMU 5.2 or later, QEMU can expose the ordered list of permitted TLS\r
+ cipher suites from the host side to OVMF:\r
+\r
+ -object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \\r
+ -fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0\r
+\r
+ (Refer to the QEMU manual and to\r
+ <https://gnutls.org/manual/html_node/Priority-Strings.html> for more\r
+ information on the "priority" property.)\r
+\r
+ - Using QEMU 5.1 or earlier, the array has to be passed from a file:\r
+\r
+ -fw_cfg name=etc/edk2/https/ciphers,file=<cipher suites>\r
+\r
+ whose contents can be generated with the following script, for example:\r
+\r
+ export LC_ALL=C\r
+ openssl ciphers -V \\r
+ | sed -r -n \\r
+ -e 's/^ *0x([0-9A-F]{2}),0x([0-9A-F]{2}) - .*$/\\\\x\1 \\\\x\2/p' \\r
+ | xargs -r -- printf -- '%b' > ciphers.bin\r
+\r
+ This script creates ciphers.bin that contains all the cipher suite IDs\r
+ supported by openssl according to the local host configuration.\r
+\r
+ You may want to enable only a limited set of cipher suites. Then, you\r
+ should check the validity of your list first:\r
+\r
+ openssl ciphers -V <cipher list>\r
+\r
+ If all the cipher suites in your list map to the proper HEX IDs, go ahead\r
+ to modify the script and execute it:\r
+\r
+ export LC_ALL=C\r
+ openssl ciphers -V <cipher list> \\r
+ | sed -r -n \\r
+ -e 's/^ *0x([0-9A-F]{2}),0x([0-9A-F]{2}) - .*$/\\\\x\1 \\\\x\2/p' \\r
+ | xargs -r -- printf -- '%b' > ciphers.bin\r
+\r
+(*1) See "31.4.1 Signature Database" in UEFI specification 2.7 errata A.\r
+(*2) p11-kit: https://github.com/p11-glue/p11-kit/\r
+(*3) efisiglist: https://github.com/rhboot/pesign/blob/master/src/efisiglist.c\r
+(*4) https://wiki.mozilla.org/Security/Server_Side_TLS#Cipher_names_correspondence_table\r
+\r
+=== OVMF Flash Layout ===\r
+\r
+Like all current IA32/X64 system designs, OVMF's firmware device (rom/flash)\r
+appears in QEMU's physical address space just below 4GB (0x100000000).\r
+\r
+OVMF supports building a 1MB, 2MB or 4MB flash image (see the DSC files for the\r
+FD_SIZE_1MB, FD_SIZE_2MB, FD_SIZE_4MB build defines). The base address for the\r
+1MB image in QEMU physical memory is 0xfff00000. The base address for the 2MB\r
+image is 0xffe00000. The base address for the 4MB image is 0xffc00000.\r
+\r
+Using the 1MB or 2MB image, the layout of the firmware device in memory looks\r
+like:\r
+\r
++--------------------------------------- 4GB (0x100000000)\r
+| VTF0 (16-bit reset code) and OVMF SEC\r
+| (SECFV, 208KB/0x34000)\r
++--------------------------------------- varies based on flash size\r
+|\r
+| Compressed main firmware image\r
+| (FVMAIN_COMPACT)\r
+|\r
++--------------------------------------- base + 0x20000\r
+| Fault-tolerant write (FTW)\r
+| Spare blocks (64KB/0x10000)\r
++--------------------------------------- base + 0x10000\r
+| FTW Work block (4KB/0x1000)\r
++--------------------------------------- base + 0x0f000\r
+| Event log area (4KB/0x1000)\r
++--------------------------------------- base + 0x0e000\r
+| Non-volatile variable storage\r
+| area (56KB/0xe000)\r
++--------------------------------------- base address\r
+\r
+Using the 4MB image, the layout of the firmware device in memory looks like:\r
+\r
++--------------------------------------- base + 0x400000 (4GB/0x100000000)\r
+| VTF0 (16-bit reset code) and OVMF SEC\r
+| (SECFV, 208KB/0x34000)\r
++--------------------------------------- base + 0x3cc000\r
+|\r
+| Compressed main firmware image\r
+| (FVMAIN_COMPACT, 3360KB/0x348000)\r
+|\r
++--------------------------------------- base + 0x84000\r
+| Fault-tolerant write (FTW)\r
+| Spare blocks (264KB/0x42000)\r
++--------------------------------------- base + 0x42000\r
+| FTW Work block (4KB/0x1000)\r
++--------------------------------------- base + 0x41000\r
+| Event log area (4KB/0x1000)\r
++--------------------------------------- base + 0x40000\r
+| Non-volatile variable storage\r
+| area (256KB/0x40000)\r
++--------------------------------------- base address (0xffc00000)\r
+\r
+The code in SECFV locates FVMAIN_COMPACT, and decompresses the\r
+main firmware (MAINFV) into RAM memory at address 0x800000. The\r
+remaining OVMF firmware then uses this decompressed firmware\r
+volume image.\r
+\r
+=== UEFI Windows 7 & Windows 2008 Server ===\r