linux-kernel - [PATCH] KVM: arm64: Use correct accessor to parse stage-1 PTEs

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Message-ID: <20221025145156.855308-1-qperret@google.com>
Date:   Tue, 25 Oct 2022 14:51:56 +0000
From:   Quentin Perret <qperret@...gle.com>
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:     Quentin Perret <qperret@...gle.com>,
        linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.linux.dev,
        kvmarm@...ts.cs.columbia.edu, linux-kernel@...r.kernel.org
Subject: [PATCH] KVM: arm64: Use correct accessor to parse stage-1 PTEs

hyp_get_page_state() is used with pKVM to retrieve metadata about a page
by parsing a hypervisor stage-1 PTE. However, it incorrectly uses a
helper which parses *stage-2* mappings. Ouch.

Luckily, pkvm_getstate() only looks at the software bits, which happen
to be in the same place for stage-1 and stage-2 PTEs, and this all ends
up working correctly by accident. But clearly, we should do better.

Fix hyp_get_page_state() to use the correct helper.

Fixes: e82edcc75c4e ("KVM: arm64: Implement do_share() helper for sharing memory")
Signed-off-by: Quentin Perret <qperret@...gle.com>
---
 arch/arm64/kvm/hyp/nvhe/mem_protect.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
index 1e78acf9662e..07f9dc9848ef 100644
--- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
+++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
@@ -516,7 +516,7 @@ static enum pkvm_page_state hyp_get_page_state(kvm_pte_t pte)
 	if (!kvm_pte_valid(pte))
 		return PKVM_NOPAGE;
 
-	return pkvm_getstate(kvm_pgtable_stage2_pte_prot(pte));
+	return pkvm_getstate(kvm_pgtable_hyp_pte_prot(pte));
 }
 
 static int __hyp_check_page_state_range(u64 addr, u64 size,
-- 
2.38.0.135.g90850a2211-goog