From a2855afc7ee88475e8feb16840b23f787bfc994d Mon Sep 17 00:00:00 2001 From: Ben Gardon <bgardon@google.com> Date: Tue, 2 Feb 2021 10:57:29 -0800 Subject: [PATCH] KVM: x86/mmu: Allow parallel page faults for the TDP MMU Make the last few changes necessary to enable the TDP MMU to handle page faults in parallel while holding the mmu_lock in read mode. Reviewed-by: Peter Feiner <pfeiner@google.com> Signed-off-by: Ben Gardon <bgardon@google.com> Message-Id: <20210202185734.1680553-24-bgardon@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> --- arch/x86/kvm/mmu/mmu.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 329930d57774c..e8bfff9acd5e2 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -3718,7 +3718,12 @@ static int direct_page_fault(struct kvm_vcpu *vcpu, gpa_t gpa, u32 error_code, return r; r = RET_PF_RETRY; - write_lock(&vcpu->kvm->mmu_lock); + + if (is_tdp_mmu_root(vcpu->kvm, vcpu->arch.mmu->root_hpa)) + read_lock(&vcpu->kvm->mmu_lock); + else + write_lock(&vcpu->kvm->mmu_lock); + if (mmu_notifier_retry(vcpu->kvm, mmu_seq)) goto out_unlock; r = make_mmu_pages_available(vcpu); @@ -3733,7 +3738,10 @@ static int direct_page_fault(struct kvm_vcpu *vcpu, gpa_t gpa, u32 error_code, prefault, is_tdp); out_unlock: - write_unlock(&vcpu->kvm->mmu_lock); + if (is_tdp_mmu_root(vcpu->kvm, vcpu->arch.mmu->root_hpa)) + read_unlock(&vcpu->kvm->mmu_lock); + else + write_unlock(&vcpu->kvm->mmu_lock); kvm_release_pfn_clean(pfn); return r; } -- GitLab