linux-kernel - [PATCH 5.14 124/169] KVM: MMU: Reset mmu->pkru

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Message-Id: <20211025191033.518954123@linuxfoundation.org>
Date:   Mon, 25 Oct 2021 21:15:05 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Chenyi Qiang <chenyi.qiang@...el.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>
Subject: [PATCH 5.14 124/169] KVM: MMU: Reset mmu->pkru_mask to avoid stale data

From: Chenyi Qiang <chenyi.qiang@...el.com>

commit a3ca5281bb771d8103ea16f0a6a8a5df9a7fb4f3 upstream.

When updating mmu->pkru_mask, the value can only be added but it isn't
reset in advance. This will make mmu->pkru_mask keep the stale data.
Fix this issue.

Fixes: 2d344105f57c ("KVM, pkeys: introduce pkru_mask to cache conditions")
Signed-off-by: Chenyi Qiang <chenyi.qiang@...el.com>
Message-Id: <20211021071022.1140-1-chenyi.qiang@...el.com>
Reviewed-by: Sean Christopherson <seanjc@...gle.com>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 arch/x86/kvm/mmu/mmu.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4465,10 +4465,10 @@ static void update_pkru_bitmask(struct k
 	unsigned bit;
 	bool wp;
 
-	if (!is_cr4_pke(mmu)) {
-		mmu->pkru_mask = 0;
+	mmu->pkru_mask = 0;
+
+	if (!is_cr4_pke(mmu))
 		return;
-	}
 
 	wp = is_cr0_wp(mmu);