[RFC v2 00/24] Add Realm support to QEMU-VMM

This patchset provides minimal functionality to start a Realm VM
from an Arm RME capable host using the following command line:

qemu-system-aarch64 \
 -M confidential-guest-support=rme0 -object rme-guest,id=rme0 \
 -cpu host -M virt -enable-kvm -M gic-version=3,its=on -nodefaults ..

It is a refactoring of Jean-Philippe Brucker's initial work dating from a while
back.  It is compatible with Steven Price's v14 revision [1] of his work adding
CCA support to KVM.

* We are currently working on rebasing the work to v15.

It was tested on the QEMU SBSA machine.  For convenience, a repository is hosted
here [2], along with the TF-A [3], RMM [4] and Linux kernel [5] for the SBSA
machine (compatible with Steven's v14 patchset).

Instructions to compile and run the entire stack can be found here [6].

Device Assignment is not included.

Thanks,
Mathieu

[1]. https://lore.kernel.org/kvm/[email protected]/T/#m06dd14216aaf76acab65b0a76fb84653141ea64f
[2]. https://gitlab.com/Linaro/cca-public/qemu/-/tree/upstream-v2?ref_type=heads
[3]. https://gitlab.com/Linaro/cca-public/tf-a/trusted-firmware-a/-/tree/cca/v13?ref_type=heads
[4]. https://gitlab.com/Linaro/cca-public/rmm/-/tree/cca/v14?ref_type=heads
[5]. https://gitlab.com/Linaro/cca-public/linux/-/tree/upstream-v2?ref_type=heads 
[6]. https://gitlab.com/Linaro/cca-public/build-instructions

RFC v1:
https://lists.gnu.org/archive/html/qemu-devel/2026-07/msg02307.html

Changes for V2:
- Fixed linux headers to include correct bit shift for Realm VM (Gavin).
- Removed obsolete rme-guest options (Markus).
- Set ConfidentialGuestSupportClass::kvm_init() to kvm_arm_rme_init() (Gavin).
- Got rid of kvm_arm_rme_vm_type() (Gavin).
- Used kvm_vm_check_extension() instead of kvm_check_extension() to avoid
  error message when starting a Realm (Gavin).
- Removed obsolete kvm_arm_rme_init_guest_ram() (Gavin).
- Collected A-B and R-B.

Jean-Philippe Brucker (23):
  linux-headers: Add RME related definitions
  target/arm/kvm: Return immediately on error in kvm_arch_init()
  target/arm: Add confidential guest support
  target/arm/kvm: Split kvm_arch_get/put_registers
  target/arm/kvm-rme: Initialize vCPU
  target/arm/kvm: Create scratch Realm VM when requested
  target/arm/kvm: Use kvm_vm_check_extension() where necessary
  hw/core/loader: Add a ROM loader notifier
  target/arm/kvm-rme: Keep track of images loaded in Realm memory
  target/arm/kvm-rme: Populate Realm with runtime images
  target/arm/cpu: Set number of breakpoints and watchpoints in KVM
  target/arm/cpu: Set number of PMU counters in KVM
  target/arm/cpu: Don't read Realm registers
  hw/arm/virt: Set proper conduit method for Realms
  hw/arm/virt: Embed Realm VM type with IPA address space
  hw/arm/virt: Reserve one bit of guest physical address for RME
  hw/arm/virt: Disable DTB randomness for confidential VMs
  hw/arm/virt: Move virt_flash_create() to machvirt_init()
  hw/arm/virt: Use RAM instead of flash for confidential guest firmware
  target/arm/kvm-rme: Add DMA remapping for the shared memory region
  docs/interop/firmware.json: Add arm-rme firmware feature
  hw/arm/boot: Load DTB as is for confidential VMs
  hw/arm/boot: Skip bootloader for confidential guests

Mathieu Poirier (1):
  target/arm/kvm-rme: Add mechanic to initialize realms

 docs/interop/firmware.json                 |   5 +-
 docs/system/arm/virt.rst                   |   9 +-
 docs/system/confidential-guest-support.rst |   1 +
 hw/arm/boot.c                              |  70 ++++-
 hw/arm/virt.c                              | 142 ++++++++--
 hw/core/loader.c                           |  15 +
 include/hw/arm/boot.h                      |   9 +
 include/hw/arm/virt.h                      |   2 +-
 include/hw/core/loader.h                   |  17 ++
 linux-headers/asm-arm64/kvm.h              |   9 +
 linux-headers/linux/kvm.h                  |  10 +-
 qapi/qom.json                              |   1 +
 target/arm/arm-qmp-cmds.c                  |   1 +
 target/arm/cpu.c                           |   5 +
 target/arm/cpu.h                           |  10 +
 target/arm/cpu64.c                         | 122 ++++++++
 target/arm/kvm-rme.c                       | 313 +++++++++++++++++++++
 target/arm/kvm-stub.c                      |   9 +
 target/arm/kvm.c                           | 202 ++++++++++++-
 target/arm/kvm_arm.h                       |  20 ++
 target/arm/meson.build                     |   5 +-
 21 files changed, 927 insertions(+), 50 deletions(-)
 create mode 100644 target/arm/kvm-rme.c

-- 
2.43.0