[XEN,v8,00/22] Xen FF-A mediator

Message

Jens Wiklander April 13, 2023, 7:14 a.m. UTC

Hi,

This patch sets add an FF-A [1] mediator to the TEE mediator framework
already present in Xen.  The FF-A mediator implements the subset of the
FF-A 1.1 specification needed to communicate with OP-TEE using FF-A as
transport mechanism instead of SMC/HVC as with the TEE mediator. It allows
a similar design in OP-TEE as with the TEE mediator where OP-TEE presents
one virtual partition of itself to each guest in Xen.

The FF-A mediator is generic in the sense it has nothing OP-TEE specific
except that only the subset needed for OP-TEE is implemented so far. The
hooks needed to inform OP-TEE that a guest is created or destroyed are part
of the FF-A specification.

It should be possible to extend the FF-A mediator to implement a larger
portion of the FF-A 1.1 specification without breaking with the way OP-TEE
is communicated with here. So it should be possible to support any TEE or
Secure Partition using FF-A as transport with this mediator.

The patches are also available at https://github.com/jenswi-linaro/xen
branch "xen_ffa_v8".

With help from Bertrand I've integrated this in a test setup with OP-TEE.
Please check prerequisites at
https://optee.readthedocs.io/en/latest/building/prerequisites.html

My setup is duplicated using:
repo init -u https://github.com/jenswi-linaro/manifest.git -m qemu_v8.xml \
        -b qemu_xen_ffa
repo sync -j8
cd build
make -j8 toolchains
make -j8 all
make run-only

Test in dom0 with for instance:
xtest 1004

at the prompt.

To start up a domu and connect to it do:
cd /mnt/host/build/qemu_v8/xen
xl create guest_ffa.cfg
xl console domu

Then test as usual with "xtest 1004".

The setup uses the branch "ffa" from https://github.com/jenswi-linaro/xen.
That's currently the same as the "xen_ffa_v8" branch, but the "ffa" branch
may change later as I update for a new version of the patch set.

[1] https://developer.arm.com/documentation/den0077/latest

Thanks,
Jens

v7->v8:
* Adding "xen/arm: ffa: list current limitations" as requested
* Adding tags to "xen/arm: smccc: add support for SMCCCv1.2 extended
  input/output registers"
* Patch "xen/arm: tee: add a primitive FF-A mediator":
  - Changing license for ffa.h and ffa.c to GPL-2.0-only
  - Avoiding IS_ENABLED() in the constant FFA_NR_FUNCS
  - Accepting version 1.1 SPMC only to keep things simple
  - Removes 32bit and only supports 64bit to keep things simple
* Patch "tools: add Arm FF-A mediator"
  - Adding Reviewed-by: Bertrand Marquis <[e-mail]>
  - Adding LIBXL_HAVE_BUILDINFO_ARCH_ARM_TEE_FFA for the "ffa" value 
    in arch_arm.tee
* Patch "docs: add Arm FF-A mediator"
  - Fixing a spell error
  - Moving the patch last in the series
* Patch "xen/arm: ffa: add remaining SMC function IDs"
  - Adding Reviewed-by: Bertrand Marquis <[e-mail]>
  - Renaming the define FFA_MSG_RUN to FFA_RUN to match the specification
* Patch "xen/arm: ffa: add flags for FFA_PARTITION_INFO_GET"
  - Updating the comment describing the flags for FFA_PARTITION_INFO_GET
* Patch "xen/arm: ffa: add defines for framework direct request/response
  messages"
  - Updating the comment describing the flags for MSG_SEND_DIRECT_REQ/RESP
* Patch "xen/arm: ffa: enforce dependency on 4k pages"
  - Updating title of patch
  - Adding Reviewed-by: Bertrand Marquis <[e-mail]>
* Patch "xen/arm: ffa: add support for FFA_ID_GET"
  - In ffa_domain_init(), check that domain_id isn't greater than
    UINT16_MAX to avoid a future potential integer overflow in get_vm_id()
* Patch "xen/arm: ffa: add direct request support"
  - Move preemption (interrupted) parts to a separate patch "xen/arm: ffa:
    support preemption of SP during direct request"
  - Remove loop in handle_msg_send_direct_req() to return eventual
    errors back to the VM instead of the SP.
* Patch "xen/arm: ffa: map SPMC rx/tx buffers"
  - Adding a FFA_RXTX_PAGE_COUNT define instead of using 1 directly
* New patch "xen/arm: ffa: support preemption of SP during direct request"
* Patch "xen/arm: ffa: send guest events to Secure Partitions"
  - Replacing unsigned int with uint16_t for subscr_vm_created_count and
    subscr_vm_destroyed_count plus the needed range check to see that
    they don't overflow.
* Patch "xen/arm: ffa: support mapping guest RX/TX buffers"
  - Limit the number of pages in VM RX/TX buffers to 32 using a new
    FFA_MAX_RXTX_PAGE_COUNT define.
* Patch "xen/arm: ffa: support guest FFA_PARTITION_INFO_GET"
  - Renaming tx_is_mine to rx_is_free as requested
  - Simplified the FFA_PARTITION_INFO_GET_COUNT_FLAG check in
    handle_partition_info_get()
  - Adding a comment on ownership of the RX buffer
  - Adding the patch "xen/arm: ffa: improve lock granularity" to address
    parts of the locking concerns.
* Patch "xen/arm: move regpair_to_uint64() and uint64_to_regpair() to regs.h"
  - Adding Reviewed-by: Bertrand Marquis <[e-mail]>
* Patch "xen/arm: ffa: add defines for sharing memory"
  - Fixing reference for FFA_NORMAL_MEM_REG_ATTR and FFA_MEM_ACC_RW
  - Updating descirption for FFA_MAX_SHM_PAGE_COUNT
* Patch "xen/arm: ffa: add ABI structs for sharing memory"
  - Changing name of the "global_handle" memeber in struct
    ffa_mem_transaction_* to "handle".
* Patch "xen/arm: ffa: support sharing memory"
  - Use FFA_MEM_SHARE_64 only since we changed to only suporting ARM_64.
  - Rename struct ffa_mem_transaction_x to struct ffa_mem_transaction_int
    as requested.
  - Adding a check that shm->page_count isn't 0 before calling share_shm()
  - Masking return value from FFA_MEM_FRAG_RX to avoid an implic cast to
    the int32_t returned by ffa_mem_share().
* Patch "xen/arm: ffa: add support to reclaim shared memory"
  - Adding Reviewed-by: Bertrand Marquis <[e-mail]>
* Patch "xen/arm: ffa: support sharing large memory ranges"
  - Adding commetns for struct ffa_ctx
  - Cleaning up and removing the fragmentation state if handle_mem_frag_tx()
    detects an error.
* Adding "xen/arm: ffa: improve lock granularity" to address some of the
  locking concerns.

v6->v7:
* Split some of the larger patches into smaller patches for easier review.
  For instance, the v6 patch "xen/arm: add a primitive FF-A mediator" has
  been replaced with:
  - "xen/arm: add a primitive FF-A mediator"
  - "tools: add Arm FF-A mediator"
  - "docs: add Arm FF-A mediator"
  - "xen/arm: ffa: add remaining SMC function IDs"
* Some small fixes in the error path for handle_mem_share()
* Switched to SPDX for license in new files.
* Fixed comment style issues in
  "xen/arm: smccc: add support for SMCCCv1.2 extended input/output registers"
* Made FFA support UNSUPPORTED in "xen/arm: add a primitive FF-A mediator"
* Replaced ffa_get_call_count() with FFA_NR_FUNCS
* Update the FFA_MAX_SHM_PAGE_COUNT with a formula instead of a value.
* Replaced XEN_ARM_FLAGS_FFA with XEN_DOMCTL_CONFIG_TEE_FFA to minimize impact
  on struct xen_arch_domainconfig. This works because the FF-A mediator and
  the OP-TEE mediator will not be used at the same time in by a guest.
* Replaced "ffa" boolean in the guest config with a new "ffa" value to the
  enumeration "tee_type".
* Integrated the FF-A mediator in the TEE mediator framework instead of
  being its own.
* Rebased on staging as of 2023-02-16

v5->v6:
* Updated "xen/arm: move regpair_to_uint64() and uint64_to_regpair() to regs.h"
  commit message and moved the patch right before the patch which needs it.
  Applied Michal Orzel's R-B tag.
* Renamed the guest configuration option "ffa_enabled" to "ffa" and
  updated the description.
* More tools update in "xen/arm: add a primitive FF-A mediator" with the "ffa"
  option, including golang and ocaml.
* Update ffa_domain_init() to return an error if communication with
  the SPMC can't be established.
* Factored out a ffa_domain_destroy() from ffa_relinquish_resources().
* Added ffa_get_call_count() to give an accurate number of FF-A function,
  updated in each patch as new FF-A functions are added.
* Added a flags field in struct xen_arch_domainconfig that replaces the
  ffa_enabled field.
* Made check_mandatory_feature() __init
* Replaced a few printk() calls with gprintk() where needed.
* Rebased on staging as of 2022-09-14

V4->v5:
* Added "xen/arm: move regpair_to_uint64() and uint64_to_regpair() to regs.h"
* Added documentation for the "ffa_enabled" guest config flag
* Changed to GPL license for xen/arch/arm/ffa.c
* Added __read_mostly and const where applicable
* Added more describing comments in the code
* Moved list of shared memory object ("ffa_mem_list") into the guest context
  as they are guest specific
* Simplified a few of the simple wrapper functions for SMC to SPMC
* Added a BUILD_BUG_ON(PAGE_SIZE != FFA_PAGE_SIZE) since the mediator
  currently depends on the page size to be same as FFA_PAGE_SIZE (4k).
* Added max number of shared memory object per guest and max number of
  size of each shared memory object
* Added helper macros to calculate offsets of different FF-A data structures
  in the communication buffer instead of relying on pointer arithmetic
* Addressed style issues and other comments
* Broke the commit "xen/arm: add FF-A mediator" into multiple parts, trying
  to add a few features at a time as requested
* Added a missing call to rxtx_unmap() in ffa_relinquish_resources()
* Assignment of "ffa_enabled" is kept as is until I have something definitive
  on the type etc.
* Tested with CONFIG_DEBUG=y

v3->v4:
* Missed v3 and sent a v4 instead by mistake.

v2->v3:
* Generates offsets into struct arm_smccc_1_2_regs with asm-offsets.c in
  order to avoid hard coded offsets in the assembly function
  arm_smccc_1_2_smc()
* Adds an entry in SUPPORT.md on the FF-A status
* Adds a configuration variable "ffa_enabled" to tell if FF-A should be
  enabled for a particular domu guest
* Moves the ffa_frag_list for fragmented memory share requests into
  struct ffa_ctx instead to keep it per guest in order to avoid mixups
  and simplify locking
* Adds a spinlock to struct ffa_ctx for per guest locking
* Addressing style issues and suggestions
* Uses FFA_FEATURES to check that all the needed features are available
  before initializing the mediator
* Rebased on staging as of 2022-06-20

v1->v2:
* Rebased on staging to resolve some merge conflicts as requested



Jens Wiklander (22):
  xen/arm: smccc: add support for SMCCCv1.2 extended input/output
    registers
  xen/arm: tee: add a primitive FF-A mediator
  tools: add Arm FF-A mediator
  xen/arm: ffa: add remaining SMC function IDs
  xen/arm: ffa: add flags for FFA_PARTITION_INFO_GET
  xen/arm: ffa: add defines for framework direct request/response
    messages
  xen/arm: ffa: enforce dependency on 4k pages
  xen/arm: ffa: add support for FFA_ID_GET
  xen/arm: ffa: add direct request support
  xen/arm: ffa: map SPMC rx/tx buffers
  xen/arm: ffa: send guest events to Secure Partitions
  xen/arm: ffa: support mapping guest RX/TX buffers
  xen/arm: ffa: support guest FFA_PARTITION_INFO_GET
  xen/arm: move regpair_to_uint64() and uint64_to_regpair() to regs.h
  xen/arm: ffa: add defines for sharing memory
  xen/arm: ffa: add ABI structs for sharing memory
  xen/arm: ffa: support sharing memory
  xen/arm: ffa: add support to reclaim shared memory
  xen/arm: ffa: support sharing large memory ranges
  xen/arm: ffa: improve lock granularity
  xen/arm: ffa: list current limitations
  docs: add Arm FF-A mediator

 SUPPORT.md                         |    8 +
 docs/man/xl.cfg.5.pod.in           |   15 +
 tools/include/libxl.h              |    5 +
 tools/libs/light/libxl_arm.c       |    3 +
 tools/libs/light/libxl_types.idl   |    3 +-
 xen/arch/arm/arm64/asm-offsets.c   |    9 +
 xen/arch/arm/arm64/smc.S           |   42 +
 xen/arch/arm/include/asm/psci.h    |    4 +
 xen/arch/arm/include/asm/regs.h    |   12 +
 xen/arch/arm/include/asm/smccc.h   |   40 +
 xen/arch/arm/include/asm/tee/ffa.h |   35 +
 xen/arch/arm/tee/Kconfig           |   11 +
 xen/arch/arm/tee/Makefile          |    1 +
 xen/arch/arm/tee/ffa.c             | 1950 ++++++++++++++++++++++++++++
 xen/arch/arm/tee/optee.c           |   11 -
 xen/arch/arm/vsmc.c                |   19 +-
 xen/include/public/arch-arm.h      |    1 +
 17 files changed, 2153 insertions(+), 16 deletions(-)
 create mode 100644 xen/arch/arm/include/asm/tee/ffa.h
 create mode 100644 xen/arch/arm/tee/ffa.c