[PATCH MANUALSEL 5.14 5/5] KVM: MMU: Reset mmu->pkru_mask to avoid stale data

[Sasha Levin]

From: Chenyi Qiang <chenyi.qiang@xxxxxxxxx>

[ Upstream commit a3ca5281bb771d8103ea16f0a6a8a5df9a7fb4f3 ]

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@xxxxxxxxx>
Message-Id: <20211021071022.1140-1-chenyi.qiang@xxxxxxxxx>
Reviewed-by: Sean Christopherson <seanjc@xxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 arch/x86/kvm/mmu/mmu.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index c268fb59f779..6719a8041f59 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4465,10 +4465,10 @@ static void update_pkru_bitmask(struct kvm_mmu *mmu)
 	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);
 
-- 
2.33.0