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FROMLIST: KVM: arm64: Restrict FF-A host version renegotiation

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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.

Bug: 269285339
Link: https://lore.kernel.org/all/20250516-virtio-msg-ffa-v4-1-580ee70e5081@google.com
Change-Id: I18e26a1a467f89ce421f31f577b3f15c37dfcf1a
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Per Larsen <perlarsen@google.com>
This commit is contained in:
Per Larsen
2025-05-02 02:21:06 -07:00
committed by Treehugger Robot
parent e97af2a2f5
commit cf1ef61244
1 changed files with 4 additions and 1 deletions
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5
arch/arm64/kvm/hyp/nvhe/ffa.c
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@@ -1367,7 +1367,10 @@ 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;
}