Thread (11 messages) 11 messages, 2 authors, 2021-10-26

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

From: Paolo Bonzini <pbonzini@redhat.com>
Date: 2021-10-26 16:18:09
Also in: kvm, lkml

On 25/10/21 22:38, Sasha Levin wrote:
quoted hunk ↗ jump to hunk
From: Chenyi Qiang <redacted>

[ 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 <redacted>
Message-Id: [off-list ref]
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
  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);
  
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
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