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KVM: arm64: Handle access faults behind the read lock

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As the underlying software walkers are able to traverse and update
stage-2 in parallel there is no need to serialize access faults.

Only take the read lock when handling an access fault.

Link: https://lore.kernel.org/r/20221202185156.696189-6-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
This commit is contained in:
Oliver Upton 2022-12-02 18:51:55 +00:00
parent 7d29a2407d
commit fc61f554e6
2 changed files with 4 additions and 3 deletions
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3
arch/arm64/kvm/hyp/pgtable.c
View File

@ -1120,7 +1120,8 @@ kvm_pte_t kvm_pgtable_stage2_mkyoung(struct kvm_pgtable *pgt, u64 addr)
ret = stage2_update_leaf_attrs(pgt, addr, 1, KVM_PTE_LEAF_ATTR_LO_S2_AF, 0,
&pte, NULL,
KVM_PGTABLE_WALK_HANDLE_FAULT);
KVM_PGTABLE_WALK_HANDLE_FAULT |
KVM_PGTABLE_WALK_SHARED);
if (!ret)
dsb(ishst);

4
arch/arm64/kvm/mmu.c
View File

@ -1406,10 +1406,10 @@ static void handle_access_fault(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa)
trace_kvm_access_fault(fault_ipa);
write_lock(&vcpu->kvm->mmu_lock);
read_lock(&vcpu->kvm->mmu_lock);
mmu = vcpu->arch.hw_mmu;
pte = kvm_pgtable_stage2_mkyoung(mmu->pgt, fault_ipa);
write_unlock(&vcpu->kvm->mmu_lock);
read_unlock(&vcpu->kvm->mmu_lock);
if (kvm_pte_valid(pte))
kvm_set_pfn_accessed(kvm_pte_to_pfn(pte));