linux-kernel - [PATCH v2 3/6] KVM: arm64: Return EAGAIN for invalid PTE in attr walker

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Date:   Fri,  2 Dec 2022 18:51:53 +0000
From:   Oliver Upton <oliver.upton@...ux.dev>
To:     Marc Zyngier <maz@...nel.org>, James Morse <james.morse@....com>,
        Alexandru Elisei <alexandru.elisei@....com>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Oliver Upton <oliver.upton@...ux.dev>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>
Cc:     linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.cs.columbia.edu,
        kvm@...r.kernel.org, kvmarm@...ts.linux.dev,
        Ricardo Koller <ricarkol@...gle.com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH v2 3/6] KVM: arm64: Return EAGAIN for invalid PTE in attr walker

Return EAGAIN for invalid PTEs in the attr walker, signaling to the
caller that any serialization and/or invalidation can be elided.

Signed-off-by: Oliver Upton <oliver.upton@...ux.dev>
---
 arch/arm64/kvm/hyp/pgtable.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
index 98818214a479..204e59e05674 100644
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c
@@ -1048,7 +1048,7 @@ static int stage2_attr_walker(const struct kvm_pgtable_visit_ctx *ctx,
 	struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops;
 
 	if (!kvm_pte_valid(ctx->old))
-		return 0;
+		return -EAGAIN;
 
 	data->level = ctx->level;
 	data->pte = pte;
-- 
2.39.0.rc0.267.gcb52ba06e7-goog