From 9688088378d41d7918ee50fc89b6f884212aaa22 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Thu, 2 Jul 2020 19:35:35 -0700 Subject: [PATCH] KVM: x86/mmu: Zero allocate shadow pages (outside of mmu_lock) Set __GFP_ZERO for the shadow page memory cache and drop the explicit clear_page() from kvm_mmu_get_page(). This moves the cost of zeroing a page to the allocation time of the physical page, i.e. when topping up the memory caches, and thus avoids having to zero out an entire page while holding mmu_lock. Cc: Peter Feiner Cc: Peter Shier Cc: Junaid Shahid Cc: Jim Mattson Suggested-by: Ben Gardon Reviewed-by: Ben Gardon Signed-off-by: Sean Christopherson Message-Id: <20200703023545.8771-12-sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/mmu/mmu.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 6e57044ae848..a9fb427107b2 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -2535,7 +2535,6 @@ trace_get_page: if (level > PG_LEVEL_4K && need_sync) flush |= kvm_sync_pages(vcpu, gfn, &invalid_list); } - clear_page(sp->spt); trace_kvm_mmu_get_page(sp, true); kvm_mmu_flush_or_zap(vcpu, &invalid_list, false, flush); @@ -5708,6 +5707,8 @@ int kvm_mmu_create(struct kvm_vcpu *vcpu) vcpu->arch.mmu_page_header_cache.kmem_cache = mmu_page_header_cache; vcpu->arch.mmu_page_header_cache.gfp_zero = __GFP_ZERO; + vcpu->arch.mmu_shadow_page_cache.gfp_zero = __GFP_ZERO; + vcpu->arch.mmu = &vcpu->arch.root_mmu; vcpu->arch.walk_mmu = &vcpu->arch.root_mmu; -- 2.11.0