From 4293ddb788c1a98bdfa6479bcfd63ad5ce0a5ce6 Mon Sep 17 00:00:00 2001 From: Mingwei Zhang Date: Mon, 2 Aug 2021 21:46:05 -0700 Subject: [PATCH] KVM: x86/mmu: Remove redundant spte present check in mmu_set_spte Drop an unnecessary is_shadow_present_pte() check when updating the rmaps after installing a non-MMIO SPTE. set_spte() is used only to create shadow-present SPTEs, e.g. MMIO SPTEs are handled early on, mmu_set_spte() runs with mmu_lock held for write, i.e. the SPTE can't be zapped between writing the SPTE and updating the rmaps. Opportunistically combine the "new SPTE" logic for large pages and rmaps. No functional change intended. Suggested-by: Ben Gardon Reviewed-by: David Matlack Reviewed-by: Ben Gardon Reviewed-by: Sean Christopherson Signed-off-by: Mingwei Zhang Message-Id: <20210803044607.599629-2-mizhang@google.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/mmu/mmu.c | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 8568ae42e867..2f6458bca65d 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -2776,17 +2776,13 @@ static int mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep, pgprintk("%s: setting spte %llx\n", __func__, *sptep); trace_kvm_mmu_set_spte(level, gfn, sptep); - if (!was_rmapped && is_large_pte(*sptep)) - ++vcpu->kvm->stat.lpages; - if (is_shadow_present_pte(*sptep)) { - if (!was_rmapped) { - rmap_count = rmap_add(vcpu, sptep, gfn); - if (rmap_count > vcpu->kvm->stat.max_mmu_rmap_size) - vcpu->kvm->stat.max_mmu_rmap_size = rmap_count; - if (rmap_count > RMAP_RECYCLE_THRESHOLD) - rmap_recycle(vcpu, sptep, gfn); - } + if (!was_rmapped) { + if (is_large_pte(*sptep)) + ++vcpu->kvm->stat.lpages; + rmap_count = rmap_add(vcpu, sptep, gfn); + if (rmap_count > RMAP_RECYCLE_THRESHOLD) + rmap_recycle(vcpu, sptep, gfn); } return ret;