From 189be38db3dde12699a8b9dc22d33e8c95efe110 Mon Sep 17 00:00:00 2001 From: Xiao Guangrong Date: Sun, 22 Aug 2010 19:13:33 +0800 Subject: [PATCH] KVM: MMU: combine guest pte read between fetch and pte prefetch Combine guest pte read between guest pte check in the fetch path and pte prefetch Signed-off-by: Xiao Guangrong Signed-off-by: Marcelo Tosatti --- arch/x86/kvm/paging_tmpl.h | 40 +++++++++++++++++++++------------------- 1 file changed, 21 insertions(+), 19 deletions(-) diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h index 872ff26..a4e8389 100644 --- a/arch/x86/kvm/paging_tmpl.h +++ b/arch/x86/kvm/paging_tmpl.h @@ -67,6 +67,7 @@ struct guest_walker { int level; gfn_t table_gfn[PT_MAX_FULL_LEVELS]; pt_element_t ptes[PT_MAX_FULL_LEVELS]; + pt_element_t prefetch_ptes[PTE_PREFETCH_NUM]; gpa_t pte_gpa[PT_MAX_FULL_LEVELS]; unsigned pt_access; unsigned pte_access; @@ -302,21 +303,33 @@ static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, static bool FNAME(gpte_changed)(struct kvm_vcpu *vcpu, struct guest_walker *gw, int level) { - int r; pt_element_t curr_pte; - - r = kvm_read_guest_atomic(vcpu->kvm, gw->pte_gpa[level - 1], + gpa_t base_gpa, pte_gpa = gw->pte_gpa[level - 1]; + u64 mask; + int r, index; + + if (level == PT_PAGE_TABLE_LEVEL) { + mask = PTE_PREFETCH_NUM * sizeof(pt_element_t) - 1; + base_gpa = pte_gpa & ~mask; + index = (pte_gpa - base_gpa) / sizeof(pt_element_t); + + r = kvm_read_guest_atomic(vcpu->kvm, base_gpa, + gw->prefetch_ptes, sizeof(gw->prefetch_ptes)); + curr_pte = gw->prefetch_ptes[index]; + } else + r = kvm_read_guest_atomic(vcpu->kvm, pte_gpa, &curr_pte, sizeof(curr_pte)); + return r || curr_pte != gw->ptes[level - 1]; } -static void FNAME(pte_prefetch)(struct kvm_vcpu *vcpu, u64 *sptep) +static void FNAME(pte_prefetch)(struct kvm_vcpu *vcpu, struct guest_walker *gw, + u64 *sptep) { struct kvm_mmu_page *sp; - pt_element_t gptep[PTE_PREFETCH_NUM]; - gpa_t first_pte_gpa; - int offset = 0, i; + pt_element_t *gptep = gw->prefetch_ptes; u64 *spte; + int i; sp = page_header(__pa(sptep)); @@ -327,17 +340,6 @@ static void FNAME(pte_prefetch)(struct kvm_vcpu *vcpu, u64 *sptep) return __direct_pte_prefetch(vcpu, sp, sptep); i = (sptep - sp->spt) & ~(PTE_PREFETCH_NUM - 1); - - if (PTTYPE == 32) - offset = sp->role.quadrant << PT64_LEVEL_BITS; - - first_pte_gpa = gfn_to_gpa(sp->gfn) + - (offset + i) * sizeof(pt_element_t); - - if (kvm_read_guest_atomic(vcpu->kvm, first_pte_gpa, gptep, - sizeof(gptep)) < 0) - return; - spte = sp->spt + i; for (i = 0; i < PTE_PREFETCH_NUM; i++, spte++) { @@ -462,7 +464,7 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr, mmu_set_spte(vcpu, it.sptep, access, gw->pte_access & access, user_fault, write_fault, dirty, ptwrite, it.level, gw->gfn, pfn, false, true); - FNAME(pte_prefetch)(vcpu, it.sptep); + FNAME(pte_prefetch)(vcpu, gw, it.sptep); return it.sptep; -- 2.7.4