diff options
| author | Oliver Upton <oliver.upton@linux.dev> | 2023-07-18 18:45:37 +0000 |
|---|---|---|
| committer | Oliver Upton <oliver.upton@linux.dev> | 2023-07-19 16:59:18 +0000 |
| commit | 84f68679032147dcdac9bb4d8eb8f4638e995dc6 (patch) | |
| tree | 2baa8c096effd45f28496a319abe1a9260abf31e /arch/arm64 | |
| parent | 9d2a55b403eea26cab7c831d8e1c00ef1e6a6850 (diff) | |
KVM: arm64: Allow pKVM on v1.0 compatible FF-A implementations
pKVM initialization fails on systems with v1.1+ FF-A implementations, as
the hyp does a strict match on the returned version from FFA_VERSION.
This is a stronger assertion than required by the specification, which
requires minor revisions be backwards compatible with earlier revisions
of the same major version.
Relax the check in hyp_ffa_init() to only test the returned major
version. Even though v1.1 broke ABI, the expectation is that firmware
incapable of using the v1.0 ABI return NOT_SUPPORTED instead of a valid
version.
Acked-by: Marc Zyngier <maz@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20230718184537.3220867-1-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Diffstat (limited to 'arch/arm64')
| -rw-r--r-- | arch/arm64/kvm/hyp/nvhe/ffa.c | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/arch/arm64/kvm/hyp/nvhe/ffa.c b/arch/arm64/kvm/hyp/nvhe/ffa.c index 58dcd92bf346..ab4f5d160c58 100644 --- a/arch/arm64/kvm/hyp/nvhe/ffa.c +++ b/arch/arm64/kvm/hyp/nvhe/ffa.c @@ -705,7 +705,20 @@ int hyp_ffa_init(void *pages) if (res.a0 == FFA_RET_NOT_SUPPORTED) return 0; - if (res.a0 != FFA_VERSION_1_0) + /* + * Firmware returns the maximum supported version of the FF-A + * implementation. Check that the returned version is + * backwards-compatible with the hyp according to the rules in DEN0077A + * v1.1 REL0 13.2.1. + * + * Of course, things are never simple when dealing with firmware. v1.1 + * broke ABI with v1.0 on several structures, which is itself + * incompatible with the aforementioned versioning scheme. The + * expectation is that v1.x implementations that do not support the v1.0 + * ABI return NOT_SUPPORTED rather than a version number, according to + * DEN0077A v1.1 REL0 18.6.4. + */ + if (FFA_MAJOR_VERSION(res.a0) != 1) return -EOPNOTSUPP; arm_smccc_1_1_smc(FFA_ID_GET, 0, 0, 0, 0, 0, 0, 0, &res); |