From eab9f71feb1851b5b700ca12ae614b6a0a441021 Mon Sep 17 00:00:00 2001 From: Avi Kivity Date: Thu, 29 May 2008 14:20:16 +0300 Subject: [PATCH] KVM: MMU: Optimize prefetch_page() Instead of reading each pte individually, read 256 bytes worth of ptes and batch process them. Signed-off-by: Avi Kivity --- arch/x86/kvm/paging_tmpl.h | 28 +++++++++++++++------------- 1 file changed, 15 insertions(+), 13 deletions(-) diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h index 934c7b6..4d91822 100644 --- a/arch/x86/kvm/paging_tmpl.h +++ b/arch/x86/kvm/paging_tmpl.h @@ -460,8 +460,9 @@ static gpa_t FNAME(gva_to_gpa)(struct kvm_vcpu *vcpu, gva_t vaddr) static void FNAME(prefetch_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp) { - int i, offset = 0, r = 0; - pt_element_t pt; + int i, j, offset, r; + pt_element_t pt[256 / sizeof(pt_element_t)]; + gpa_t pte_gpa; if (sp->role.metaphysical || (PTTYPE == 32 && sp->role.level > PT_PAGE_TABLE_LEVEL)) { @@ -469,19 +470,20 @@ static void FNAME(prefetch_page)(struct kvm_vcpu *vcpu, return; } - if (PTTYPE == 32) + pte_gpa = gfn_to_gpa(sp->gfn); + if (PTTYPE == 32) { offset = sp->role.quadrant << PT64_LEVEL_BITS; + pte_gpa += offset * sizeof(pt_element_t); + } - for (i = 0; i < PT64_ENT_PER_PAGE; ++i) { - gpa_t pte_gpa = gfn_to_gpa(sp->gfn); - pte_gpa += (i+offset) * sizeof(pt_element_t); - - r = kvm_read_guest_atomic(vcpu->kvm, pte_gpa, &pt, - sizeof(pt_element_t)); - if (r || is_present_pte(pt)) - sp->spt[i] = shadow_trap_nonpresent_pte; - else - sp->spt[i] = shadow_notrap_nonpresent_pte; + for (i = 0; i < PT64_ENT_PER_PAGE; i += ARRAY_SIZE(pt)) { + r = kvm_read_guest_atomic(vcpu->kvm, pte_gpa, pt, sizeof pt); + pte_gpa += ARRAY_SIZE(pt) * sizeof(pt_element_t); + for (j = 0; j < ARRAY_SIZE(pt); ++j) + if (r || is_present_pte(pt[j])) + sp->spt[i+j] = shadow_trap_nonpresent_pte; + else + sp->spt[i+j] = shadow_notrap_nonpresent_pte; } } -- 2.7.4