| Message ID | 20221129191946.1735662-4-oliver.upton@linux.dev (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: arm64: Parallel access faults | expand |
On Tue, Nov 29, 2022 at 07:19:45PM +0000, Oliver Upton wrote: > 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. > > Signed-off-by: Oliver Upton <oliver.upton@linux.dev> > --- > arch/arm64/kvm/hyp/pgtable.c | 2 +- > arch/arm64/kvm/mmu.c | 4 ++-- > 2 files changed, 3 insertions(+), 3 deletions(-) > > diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c > index 9626f615d9b8..1a3dd9774707 100644 > --- a/arch/arm64/kvm/hyp/pgtable.c > +++ b/arch/arm64/kvm/hyp/pgtable.c > @@ -1097,7 +1097,7 @@ kvm_pte_t kvm_pgtable_stage2_mkyoung(struct kvm_pgtable *pgt, u64 addr) > int ret; > > ret = stage2_update_leaf_attrs(pgt, addr, 1, KVM_PTE_LEAF_ATTR_LO_S2_AF, 0, > - &pte, NULL, 0); > + &pte, NULL, KVM_PGTABLE_WALK_SHARED); > if (!ret) > dsb(ishst); > > diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c > index 886ad5ee767a..347985a56414 100644 > --- a/arch/arm64/kvm/mmu.c > +++ b/arch/arm64/kvm/mmu.c > @@ -1404,10 +1404,10 @@ 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)); > -- > 2.38.1.584.g0f3c55d4c2-goog > > _______________________________________________ > kvmarm mailing list > kvmarm@lists.cs.columbia.edu > https://lists.cs.columbia.edu/mailman/listinfo/kvmarm Reviewed-by: Ricardo Koller <ricarkol@google.com>
diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c index 9626f615d9b8..1a3dd9774707 100644 --- a/arch/arm64/kvm/hyp/pgtable.c +++ b/arch/arm64/kvm/hyp/pgtable.c @@ -1097,7 +1097,7 @@ kvm_pte_t kvm_pgtable_stage2_mkyoung(struct kvm_pgtable *pgt, u64 addr) int ret; ret = stage2_update_leaf_attrs(pgt, addr, 1, KVM_PTE_LEAF_ATTR_LO_S2_AF, 0, - &pte, NULL, 0); + &pte, NULL, KVM_PGTABLE_WALK_SHARED); if (!ret) dsb(ishst); diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index 886ad5ee767a..347985a56414 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -1404,10 +1404,10 @@ 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));
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. Signed-off-by: Oliver Upton <oliver.upton@linux.dev> --- arch/arm64/kvm/hyp/pgtable.c | 2 +- arch/arm64/kvm/mmu.c | 4 ++-- 2 files changed, 3 insertions(+), 3 deletions(-)