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KVM: arm64: Fix rollback in hyp_trace_buffer_share_hyp()

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When sharing the trace buffer with the hypervisor, if sharing a page
fails, the rollback path in hyp_trace_buffer_share_hyp() misses
unsharing the metadata page (meta_va) which was successfully shared
before entering the page sharing loop.

Additionally, if a failure occurs, the cleanup calls
hyp_trace_buffer_unshare_hyp() with an incorrect CPU index.  Since that
CPU's pages were already rolled back locally in the loop, this leads to
duplicate unsharing attempts.

Fix both issues affecting the rollback.

Fixes: 3aed038aac ("KVM: arm64: Add trace remote for the nVHE/pKVM hyp")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Link: https://patch.msgid.link/20260521124613.911067-3-vdonnefort@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
This commit is contained in:
Vincent Donnefort 2026-05-21 13:46:12 +01:00 committed by Marc Zyngier
parent 0f7abb6eaa
commit a23780ea9d
1 changed files with 3 additions and 2 deletions
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5
arch/arm64/kvm/hyp_trace.c
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@ -212,14 +212,15 @@ static int hyp_trace_buffer_share_hyp(struct hyp_trace_buffer *trace_buffer)
}
if (ret) {
for (p--; p >= 0; p--)
while (--p >= 0)
__unshare_page(rb_desc->page_va[p]);
__unshare_page(rb_desc->meta_va);
break;
}
}
if (ret)
hyp_trace_buffer_unshare_hyp(trace_buffer, cpu--);
hyp_trace_buffer_unshare_hyp(trace_buffer, --cpu);
return ret;
}