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| author | Laszlo Ersek <lersek@redhat.com> | 2017-05-06 18:09:28 +0200 |
|---|---|---|
| committer | Laszlo Ersek <lersek@redhat.com> | 2017-05-18 23:38:46 +0200 |
| commit | f78c8bf2c64f57d5148bea1a56ade2218a13e4d7 (patch) | |
| tree | a973b4832e78a9d87396af934a676cdd69e1847b /OvmfPkg/README | |
| parent | c9e7907d09eaf2702ae5c6963f24ab53fc57dc33 (diff) | |
| download | edk2-f78c8bf2c64f57d5148bea1a56ade2218a13e4d7.tar.gz edk2-f78c8bf2c64f57d5148bea1a56ade2218a13e4d7.tar.bz2 edk2-f78c8bf2c64f57d5148bea1a56ade2218a13e4d7.zip | |
OvmfPkg/README: document 4MB flash layout
Cc: Jordan Justen <jordan.l.justen@intel.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=527
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Diffstat (limited to 'OvmfPkg/README')
| -rw-r--r-- | OvmfPkg/README | 39 |
1 files changed, 31 insertions, 8 deletions
diff --git a/OvmfPkg/README b/OvmfPkg/README index 304e69fbe5..33ff9432bb 100644 --- a/OvmfPkg/README +++ b/OvmfPkg/README @@ -245,15 +245,20 @@ longer.) === OVMF Flash Layout ===
-Like all current IA32/X64 system designs, OVMF's firmware
-device (rom/flash) appears in QEMU's physical address space
-just below 4GB (0x100000000).
+Like all current IA32/X64 system designs, OVMF's firmware device (rom/flash)
+appears in QEMU's physical address space just below 4GB (0x100000000).
-The layout of the firmware device in memory looks like:
+OVMF supports building a 1MB, 2MB or 4MB flash image (see the DSC files for the
+FD_SIZE_1MB, FD_SIZE_2MB, FD_SIZE_4MB build defines). The base address for the
+1MB image in QEMU physical memory is 0xfff00000. The base address for the 2MB
+image is 0xffe00000. The base address for the 4MB image is 0xffc00000.
+
+Using the 1MB or 2MB image, the layout of the firmware device in memory looks
+like:
+--------------------------------------- 4GB (0x100000000)
| VTF0 (16-bit reset code) and OVMF SEC
-| (SECFV)
+| (SECFV, 208KB/0x34000)
+--------------------------------------- varies based on flash size
|
| Compressed main firmware image
@@ -271,9 +276,27 @@ The layout of the firmware device in memory looks like: | area (56KB/0xe000)
+--------------------------------------- base address
-OVMF supports building a 1MB or a 2MB flash image. The base address for
-a 1MB image in QEMU physical memory is 0xfff00000. The base address for
-a 2MB image is 0xffe00000.
+Using the 4MB image, the layout of the firmware device in memory looks like:
+
++--------------------------------------- base + 0x400000 (4GB/0x100000000)
+| VTF0 (16-bit reset code) and OVMF SEC
+| (SECFV, 208KB/0x34000)
++--------------------------------------- base + 0x3cc000
+|
+| Compressed main firmware image
+| (FVMAIN_COMPACT, 3360KB/0x348000)
+|
++--------------------------------------- base + 0x84000
+| Fault-tolerant write (FTW)
+| Spare blocks (264KB/0x42000)
++--------------------------------------- base + 0x42000
+| FTW Work block (4KB/0x1000)
++--------------------------------------- base + 0x41000
+| Event log area (4KB/0x1000)
++--------------------------------------- base + 0x40000
+| Non-volatile variable storage
+| area (256KB/0x40000)
++--------------------------------------- base address (0xffc00000)
The code in SECFV locates FVMAIN_COMPACT, and decompresses the
main firmware (MAINFV) into RAM memory at address 0x800000. The
|