On Fri, May 16, 2025 at 12:14:00PM +0000, Per Larsen via B4 Relay wrote:
quoted hunk ↗ jump to hunk
From: Per Larsen <redacted>
Prevent the host from re-negotiating a lesser minor version with the
hypervisor. Once the hypervisor negotiates a version, that should
remain locked in. Fix the current behaviour by returning NOT_SUPPORTED
to avoid the FF-A interoperability rules with lesser minor versions that
allow the host version to downgrade.
Signed-off-by: Per Larsen <redacted>
---
arch/arm64/kvm/hyp/nvhe/ffa.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/kvm/hyp/nvhe/ffa.c b/arch/arm64/kvm/hyp/nvhe/ffa.c
index 3369dd0c4009f84ad3cf9481c747bdc57a162370..2c199d40811efb5bfae199c4a67d8ae3d9307357 100644
--- a/arch/arm64/kvm/hyp/nvhe/ffa.c
+++ b/arch/arm64/kvm/hyp/nvhe/ffa.c
@@ -712,7 +712,10 @@ static void do_ffa_version(struct arm_smccc_res *res,
hyp_spin_lock(&version_lock);
if (has_version_negotiated) {
- res->a0 = hyp_ffa_version;
+ if (FFA_MINOR_VERSION(ffa_req_version) < FFA_MINOR_VERSION(hyp_ffa_version))
+ res->a0 = FFA_RET_NOT_SUPPORTED;
+ else
+ res->a0 = hyp_ffa_version;
goto unlock;
}
I already Acked this one:
https://lore.kernel.org/all/20250513142113.GA9443@willie-the-truck/ (local)
So please add the tag to the patch if/when you post a new version of the
series without any changes to this patch.
For the bots:
Acked-by: Will Deacon <will@kernel.org>
Will