From: Chun-Tse Shao <ctshao@google.com>
To: linux-kernel@vger.kernel.org, yuzhao@google.com, oliver.upton@linux.dev
Cc: Chun-Tse Shao <ctshao@google.com>, Marc Zyngier <maz@kernel.org>,
James Morse <james.morse@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Zenghui Yu <yuzenghui@huawei.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>, Ben Gardon <bgardon@google.com>,
Gavin Shan <gshan@redhat.com>,
linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev
Subject: [PATCH v1 3/3] KVM: arm64: Using rcu_read_lock() for kvm_pgtable_stage2_mkyoung()
Date: Thu, 8 Jun 2023 15:05:41 -0700 [thread overview]
Message-ID: <20230608220558.39094-4-ctshao@google.com> (raw)
In-Reply-To: <20230608220558.39094-1-ctshao@google.com>
Access bit is RCU safe and can be set without taking kvm->mmu_lock().
Replacing existing kvm->mmu_lock() with rcu_read_lock() for better
performance.
Original disussion can be found in:
https://lore.kernel.org/kvmarm/CAOUHufZrfnfcbrqSzmHkejR5MA2gmGKZ3LMRhbLHV+1427z=Tw@mail.gmail.com/
Suggested-by: Yu Zhao <yuzhao@google.com>
Signed-off-by: Chun-Tse Shao <ctshao@google.com>
---
arch/arm64/kvm/mmu.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 3b9d4d24c361..0f7ea66fb894 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -1437,10 +1437,10 @@ static void handle_access_fault(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa)
trace_kvm_access_fault(fault_ipa);
- read_lock(&vcpu->kvm->mmu_lock);
+ rcu_read_lock();
mmu = vcpu->arch.hw_mmu;
pte = kvm_pgtable_stage2_mkyoung(mmu->pgt, fault_ipa);
- read_unlock(&vcpu->kvm->mmu_lock);
+ rcu_read_unlock();
if (kvm_pte_valid(pte))
kvm_set_pfn_accessed(kvm_pte_to_pfn(pte));
--
2.41.0.162.gfafddb0af9-goog
next prev parent reply other threads:[~2023-06-08 22:06 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-08 22:05 [PATCH v1 1/3] KVM: arm64: Consistently use free_removed_table() for stage-2 Chun-Tse Shao
2023-06-08 22:05 ` [PATCH v1 2/3] KVM: arm64: Only initiate walk if page_count() > 1 in free_removed_table() Chun-Tse Shao
2023-06-08 22:05 ` Chun-Tse Shao [this message]
2023-06-09 7:44 ` [PATCH v1 3/3] KVM: arm64: Using rcu_read_lock() for kvm_pgtable_stage2_mkyoung() Marc Zyngier
2023-06-09 22:58 ` Chun-Tse Shao
2023-06-09 14:51 ` Oliver Upton
2023-06-08 22:13 ` [PATCH v1 1/3] KVM: arm64: Consistently use free_removed_table() for stage-2 Yu Zhao
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