linux-kernel - [PATCH MANUALSEL 5.15 4/9] KVM: SEV: do not take kvm->lock when destroying

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Message-Id: <20211213141944.352249-4-sashal@kernel.org>
Date:   Mon, 13 Dec 2021 09:19:37 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Sasha Levin <sashal@...nel.org>, tglx@...utronix.de,
        mingo@...hat.com, bp@...en8.de, dave.hansen@...ux.intel.com,
        x86@...nel.org, kvm@...r.kernel.org
Subject: [PATCH MANUALSEL 5.15 4/9] KVM: SEV: do not take kvm->lock when destroying

From: Paolo Bonzini <pbonzini@...hat.com>

[ Upstream commit 10a37929efeb4c51a0069afdd537c4fa3831f6e5 ]

Taking the lock is useless since there are no other references,
and there are already accesses (e.g. to sev->enc_context_owner)
that do not take it.  So get rid of it.

Reviewed-by: Sean Christopherson <seanjc@...gle.com>
Message-Id: <20211123005036.2954379-12-pbonzini@...hat.com>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 arch/x86/kvm/svm/sev.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 134c4ea5e6ad8..ae8092f0d401e 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -1842,8 +1842,6 @@ void sev_vm_destroy(struct kvm *kvm)
 		return;
 	}
 
-	mutex_lock(&kvm->lock);
-
 	/*
 	 * Ensure that all guest tagged cache entries are flushed before
 	 * releasing the pages back to the system for use. CLFLUSH will
@@ -1863,8 +1861,6 @@ void sev_vm_destroy(struct kvm *kvm)
 		}
 	}
 
-	mutex_unlock(&kvm->lock);
-
 	sev_unbind_asid(kvm, sev->handle);
 	sev_asid_free(sev);
 }
-- 
2.33.0