arch/arm64/kvm/hyp/nvhe/Makefile | 1 + arch/arm64/kvm/hyp/nvhe/ffa.c | 217 ++++++++++++++++++++++++++------------- include/linux/arm_ffa.h | 1 + 3 files changed, 146 insertions(+), 73 deletions(-)
Hi,
The FF-A 1.2 specification introduces a new SEND_DIRECT2 ABI which
allows registers x4-x17 to be used for the message payload. This patch
set prevents the host from using a lower FF-A version than what has
already been negotiated with the hypervisor. This is necessary because
the hypervisor does not have the necessary compatibility paths to
translate from the hypervisor FF-A version to a previous version.
Support for FF-A 1.2 in the hypervisor is added as a precursor to the
addition of the FFA_MSG_SEND_DIRECT_REQ2 messaging interface. Notably,
this patch updates all smc calls to use SMCCC 1.2 as it makes it simpler
to support interfaces that need to accept more than 8 arguments and/or
return more than 4 values. The list of optional/unsupported interfaces
was updated to reflect additions in FF-A 1.2.
Tested by booting Android under QEMU and loading Trusty as the guest
VM and observing the SEND_DIRECT2 ABI being used successfully during
guest boot.
Changes in v11:
- 2/6: ffa_set_retval: Add more details about anticipated FF-A 1.3 update. Fix typo.
- Link to v10: https://lore.kernel.org/r/20250809-virtio-msg-ffa-v10-0-189eeecf8ae8@google.com
Changes in v10:
- 2/6: Return registers x0-x17 unconditionally in ffa_set_retval for consistency with passthrough code
- 4/6: ffa_call_supported: Drop case FFA_EL3_INTR_HANDLE
Added Acked-by: Will Deacon <will@kernel.org>
- Link to v9: https://lore.kernel.org/r/20250730-virtio-msg-ffa-v9-0-7f1b55c8d149@google.com
Changes in v9:
- 2/7 -> 2/6: Updated explanatory comment in ffa_set_retval
- 4/7 -> 4/6: Restore to v7: Mark FFA_MSG_SEND_DIRECT_REQ2 unsupported
- 5/7 -> 5/6: Added Acked-by: Will Deacon <will@kernel.org>
- 6/7 -> 6/6: Added Acked-by: Will Deacon <will@kernel.org>
- 7/7: Dropped
- Link to v8: https://lore.kernel.org/r/20250719-virtio-msg-ffa-v8-0-03e8e8dbe856@google.com
Changes in v8:
- 2/5 -> 2/7: Use func_id argument to distinguish SMC32/SMC64. Update rationale.
- 4/5 -> 4/7: Split up 4/5: Add optional FF-A 1.2 interfaces
- 4/5 -> 5/7: Split up 4/5: Mask FFA_RXTX_MAP minium buffer size in a2. Don't check MBZ bits.
- 4/5 -> 6/7: Remainder of 4/5: Bump supported version to FF-A 1.2
- 5/5 -> 7/7: Don't check src id in do_ffa_direct_msg2
- Link to v7: https://lore.kernel.org/r/20250701-virtio-msg-ffa-v7-0-995afc3d385e@google.com
Changes in v7:
- 0/6: Revised cover letter slightly
- 4/6: ffa_call_supported: Clarify optional interfaces
hyp_ffa_post_init: Sanitize MBZ bits in x2 and x3
address nit: use GENMASK
- Link to v6: https://lore.kernel.org/r/20250627-virtio-msg-ffa-v6-0-8c02fd94edac@google.com
Changes since v5:
- 3/6 -> 2/5: Merged with parent patch as they were closely related
Don't rename variables from "res" to "regs" to avoid churn
Update and clarify reasoning for condition added to ffa_set_retval
Adopt style suggested by Marc when passing regs to arm_smccc_1_2_smc
Fix inadvertent duplicate statements in ffa_{map,unmap}_hyp_buffers
- Link to v5: https://lore.kernel.org/r/20250619-virtio-msg-ffa-v5-0-412c98558807@google.com
Changes since v4:
- 1/5 -> 1/6: Added Acked-by: Will Deacon <will@kernel.org>y
Reworded patch subject and description
- 2/5: Dropped patch: zero x4-x7 in ffa_set_retval
- 2/6: New: use SMCCC 1.2 during hyp init
- 3/6: New: use SMCCC 1.2 in host FF-A handler
- 3/5 -> 4/6: No change; can revisit denylist design in later patchset
Added Acked-by: Will Deacon <will@kernel.org>
- 4/5 -> 5/6: No change
- 5/5 -> 6/6: No change
- Link to v4: https://lore.kernel.org/r/20250516-virtio-msg-ffa-v4-0-580ee70e5081@google.com
Changes since v3:
- all: Remove Signed-off-by: Per Larsen <perl@immunant.com>
- 2/5: Split out from 2/3, zero x4-x7 in set_ffa_retval
- 3/5: Split out from 2/3, Mark FFA_NOTIFICATION_* calls as
unsupported
- 2/3 -> 4/5: Drop ffa_get_hypervisor_version, access hyp_ffa_version
directly when version negotiation is complete.
- 3/3 -> 5/5: Call ffa_to_smccc_1_2_error directly in
do_do_ffa_direct_msg2
Push call to ffa_call_needs_smccc_1_2 lower down by adding
ffa_get_func_id and ffa_set_retval_smccc_1_x.
Drop ffa_to_smccc_1_2_regs and ffa_to_smccc_1_2_regs_prop
as they are no longer used.
- Link to v3: https://lore.kernel.org/r/20250513-virtio-msg-ffa-v3-0-d66c76ff1b2c@google.com
Changes since v2:
- 2/3: Removed files added by mistake.
Add and use ffa_get_hypervisor_version to access hyp_ffa_version
- 3/3: Use ffa_get_hypervisor_version to access hyp_ffa_version safely
- Link to v2: https://lore.kernel.org/r/20250508-virtio-msg-ffa-v2-0-ed84f8053965@google.com
Changes since v1:
- 1/3: Simplify commit message; drop long comment in do_ffa_version
- 2/3: Correct use of Co-developed-by: footer
s/arm_smccc_1_2_smc_fallback/arm_smccc_1_x_smc/
Always access hyp_ffa_version w/lock held
Remove superfluous comments in ffa_call_supported
Add and use FFA_FEAT_RXTX_MIN_SZ_MASK instead of constant
Add FFA_PARTITION_INFO_GET_REGS to calls that require SMCCC 1.2
- 3/3: Always access hyp_ffa_version w/lock held
Correct formatting
Thanks,
Per Larsen
--
2.49.0
---
Per Larsen (6):
KVM: arm64: Correct return value on host version downgrade attempt
KVM: arm64: Use SMCCC 1.2 for FF-A initialization and in host handler
KVM: arm64: Mark FFA_NOTIFICATION_* calls as unsupported
KVM: arm64: Mark optional FF-A 1.2 interfaces as unsupported
KVM: arm64: Mask response to FFA_FEATURE call
KVM: arm64: Bump the supported version of FF-A to 1.2
arch/arm64/kvm/hyp/nvhe/Makefile | 1 +
arch/arm64/kvm/hyp/nvhe/ffa.c | 217 ++++++++++++++++++++++++++-------------
include/linux/arm_ffa.h | 1 +
3 files changed, 146 insertions(+), 73 deletions(-)
---
base-commit: b19a97d57c15643494ac8bfaaa35e3ee472d41da
change-id: 20250506-virtio-msg-ffa-22af72c92150
Best regards,
--
Per Larsen <perlarsen@google.com>
On Wed, Aug 20, 2025 at 01:10:04AM +0000, Per Larsen via B4 Relay wrote: > Hi, > > The FF-A 1.2 specification introduces a new SEND_DIRECT2 ABI which > allows registers x4-x17 to be used for the message payload. This patch > set prevents the host from using a lower FF-A version than what has > already been negotiated with the hypervisor. This is necessary because > the hypervisor does not have the necessary compatibility paths to > translate from the hypervisor FF-A version to a previous version. > > Support for FF-A 1.2 in the hypervisor is added as a precursor to the > addition of the FFA_MSG_SEND_DIRECT_REQ2 messaging interface. Notably, > this patch updates all smc calls to use SMCCC 1.2 as it makes it simpler > to support interfaces that need to accept more than 8 arguments and/or > return more than 4 values. The list of optional/unsupported interfaces > was updated to reflect additions in FF-A 1.2. > > Tested by booting Android under QEMU and loading Trusty as the guest > VM and observing the SEND_DIRECT2 ABI being used successfully during > guest boot. > > Changes in v11: > - 2/6: ffa_set_retval: Add more details about anticipated FF-A 1.3 update. Fix typo. > - Link to v10: https://lore.kernel.org/r/20250809-virtio-msg-ffa-v10-0-189eeecf8ae8@google.com Thanks, this all looks good to me now. Assuming Marc's happy, this should go via the kvmarm tree. Will
On Wed, 20 Aug 2025 01:10:04 +0000, Per Larsen wrote:
> The FF-A 1.2 specification introduces a new SEND_DIRECT2 ABI which
> allows registers x4-x17 to be used for the message payload. This patch
> set prevents the host from using a lower FF-A version than what has
> already been negotiated with the hypervisor. This is necessary because
> the hypervisor does not have the necessary compatibility paths to
> translate from the hypervisor FF-A version to a previous version.
>
> [...]
Applied to next, thanks!
[1/6] KVM: arm64: Correct return value on host version downgrade attempt
commit: f414269392443f666bd8bef0cb3f0b53d5147be3
[2/6] KVM: arm64: Use SMCCC 1.2 for FF-A initialization and in host handler
commit: 6f4c348b1d5c08f1105e645700962cc4353a8ac9
[3/6] KVM: arm64: Mark FFA_NOTIFICATION_* calls as unsupported
commit: 79195f342417ff773048515964707aba3bfe0e41
[4/6] KVM: arm64: Mark optional FF-A 1.2 interfaces as unsupported
commit: 8d24683e3e0f93b4bfdb558df50923514042817b
[5/6] KVM: arm64: Mask response to FFA_FEATURE call
commit: 3f5952917498e7bb9d227812d4349668f62c413b
[6/6] KVM: arm64: Bump the supported version of FF-A to 1.2
commit: 162190f2ccdc5964efa2a26e9fc3e56cf80fc29b
Cheers,
M.
--
Without deviation from the norm, progress is not possible.
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