Commit Graph

6 Commits

Author SHA1 Message Date
Marc Hartmayer f148df4cc3 genprotimg: fix table in README.md
Fix the table used in README.md.

Reviewed-by: Jan Höppner <hoeppner@linux.ibm.com>
Signed-off-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
2020-05-06 17:36:39 +02:00
Marc Hartmayer 4d61a21811 genprotimg: fix dependency tracking for .lds generation
Variable names are case sensitive in Makefiles, therefore fix the typo
in the variable reference.

Fixes: 2d600570df ("genprotimg: boot: use C pre-processor for linker script generation")
Reviewed-by: Jan Höppner <hoeppner@linux.ibm.com>
Signed-off-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
2020-05-06 17:36:39 +02:00
Marc Hartmayer 65b9fc442c genprotimg: introduce new tool for the creation of PV images
Protected VMs (PVM) are KVM VMs, where KVM can't access the VM's state
like guest memory and guest registers anymore. Instead the PVMs are
mostly managed by a new entity called Ultravisor (UV), which provides
an API, so KVM and the PV can request management actions.

PVMs are encrypted at rest and protected from hypervisor access while
running. They switch from a normal operation into protected mode, so
we can still use the standard boot process to load an encrypted image
and then move it into protected mode.

This commit adds the tool 'genprotimg'. It takes a kernel, key files,
optionally an initrd, optionally a file with the kernel command line,
and it generates a single, loadable image file. The image consists of
a concatenation of a plain text boot loader, the encrypted components
for kernel, initrd, and cmdline, and the integrity-protected PV
header, containing metadata necessary for running the guest in PV
mode.

It's possible to use this image file as a kernel for zipl or for a
direct kernel boot using QEMU.

Reviewed-by: Bjoern Walk <bwalk@linux.ibm.com>
Acked-by: Patrick Steuer <patrick.steuer@de.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Jan Höppner <hoeppner@linux.ibm.com>
Signed-off-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
2020-03-16 13:41:35 +01:00
Marc Hartmayer d2f8f972cf genprotimg: add relocator for stage3b
Add support for the placement of the stage3b loader at other addresses
than 0xa000. For this add a position independent relocator that first
copies the original stage3b code to the memory location 0xa000 and
then starts it.

Reviewed-by: Philipp Rudo <prudo@linux.ibm.com>
Signed-off-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
2020-03-16 13:39:10 +01:00
Marc Hartmayer 2d600570df genprotimg: boot: use C pre-processor for linker script generation
Use C pre-processor for linker script generation. This allows the
usage of constants in our "linker scripts" `*.lds.S` (actually, these
are assembler files, so we can make us of the C pre-processor and its
capabilities).

Suggested-by: Philipp Rudo <prudo@linux.ibm.com>
Reviewed-by: Philipp Rudo <prudo@linux.ibm.com>
Signed-off-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
2020-03-16 13:39:10 +01:00
Marc Hartmayer 3356d6f4fa genprotimg: boot: initial bootloader support
Add a boot loader for protected virtualization (PV) that can be
combined with a kernel/initrd/parmfile to form a single bootable file.
This file must be constructed in a way that it can be used (1) for a
QEMU direct kernel boot and (2) it can be zipl'ed by the normal,
unmodified zipl program.

This new boot loader consists of two parts:

1. stage3a boot loader (cleartext), this loader is responsible for
   the transition into the protected mode by doing diag308 subcode 8
   and 10 calls.

2. stage3b boot loader (encrypted), this loader is very similar to the
   normal zipl stage3 boot loader. It will be loaded by the Ultravisor
   after the successful transition into protected mode. Like the zipl
   stage3 boot loader it moves the kernel and patches in the values
   for initrd and parmline.

The requirements for (1) and (2) result in the following constraints:

1. It must be possible to place stage3a and stage3b at a location >=
   0x10000 because the zipl stage3 loader zeroes out everything at
   addresses lower than 0x10000 of the image.

2. As the stage3 loader of zipl assumes that the passed kernel image
   looks like a normal kernel image, the zipl stage3 loader modifies the
   content at the memory area 0x10400 - 0x10800, therefore we leave this
   area unused in our stage3a loader.

3. The default entry address used by the zipl stage3 loader is 0x10000
   so we add a simple branch to 0x11000 at 0x10000 so the zipl stage3
   loader can modify the area 0x10400 - 0x10800 without affecting the
   stage3a loader.

The stage3b loader is linked at address 0x9000, therefore it will not
work at another address. The relocation support for the stage3b
loader, so that it can be placed at addresses != 0x9000, is added in
the next patch. This loader with relocation support has the name
'stage3b_reloc'.

The memory layout of the single bootable file looks like:

+-----------------------+-----------+------------------------+
|Start                  |End        |Use                     |
+=======================+===========+========================+
|0                      |0x7        |Short PSW, starting     |
|                       |           |instruction at 0x11000  |
+-----------------------+-----------+------------------------+
|0x10000                |0x10012    |Branch to 0x11000       |
+-----------------------+-----------+------------------------+
|0x10013                |0x10fff    |Left intentionally      |
|                       |           |unused                  |
+-----------------------+-----------+------------------------+
|0x11000                |0x12fff    |Stage3a                 |
+-----------------------+-----------+------------------------+
|0x13000                |0x13fff    |IPIB used as argument   |
|                       |           |for the diag308 call    |
+-----------------------+-----------+------------------------+
|0x14000                |0x1[45]fff |UV header used for the  |
|                       |           |diag308 call (size can  |
|                       |           |be either 1 or 2 pages) |
+-----------------------+-----------+------------------------+
|NEXT_PAGE_ALIGNED_ADDR |           |Encrypted Kernel        |
+-----------------------+-----------+------------------------+
|NEXT_PAGE_ALIGNED_ADDR |           |Encrypted Cmdline       |
+-----------------------+-----------+------------------------+
|NEXT_PAGE_ALIGNED_ADDR |           |Encrypted Initrd        |
+-----------------------+-----------+------------------------+
|NEXT_PAGE_ALIGNED_ADDR |           |Encrypted Stage3b_reloc |
+-----------------------+-----------+------------------------+

Reviewed-by: Philipp Rudo <prudo@linux.ibm.com>
Signed-off-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
2020-03-16 13:39:10 +01:00