Combine guest pte read between guest pte check in the fetch path and pte prefetch
Signed-off-by: Xiao Guangrong <[email protected]> --- arch/x86/kvm/paging_tmpl.h | 69 ++++++++++++++++++++++++++----------------- 1 files changed, 42 insertions(+), 27 deletions(-) diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h index e04c1a4..a1e6d91 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; @@ -291,12 +292,12 @@ static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, gpte_to_gfn(gpte), pfn, true, true); } -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, index, i, j, max; + pt_element_t *gptep; + int index, i, j, max; sp = page_header(__pa(sptep)); index = sptep - sp->spt; @@ -311,15 +312,7 @@ static void FNAME(pte_prefetch)(struct kvm_vcpu *vcpu, u64 *sptep) i = index & ~(PTE_PREFETCH_NUM - 1); max = index | (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; + gptep = gw->prefetch_ptes; if (pte_prefetch_topup_memory_cache(vcpu)) return; @@ -366,6 +359,35 @@ static void FNAME(pte_prefetch)(struct kvm_vcpu *vcpu, u64 *sptep) } } +static bool FNAME(check_gpte_level)(struct kvm_vcpu *vcpu, + struct guest_walker *gw, int level) +{ + pt_element_t curr_pte; + int index, ret; + u64 mask; + gpa_t base_gpa, pte_gpa = gw->pte_gpa[level - 1]; + + if (level < gw->level) + return true; + + 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); + + ret = kvm_read_guest_atomic(vcpu->kvm, base_gpa, + gw->prefetch_ptes, sizeof(gw->prefetch_ptes)); + curr_pte = gw->prefetch_ptes[index]; + } else + ret = kvm_read_guest_atomic(vcpu->kvm, pte_gpa, &curr_pte, + sizeof(curr_pte)); + + if (ret || curr_pte != gw->ptes[level - 1]) + return false; + + return true; +} + /* * Fetch a shadow pte for a specific level in the paging hierarchy. */ @@ -379,11 +401,9 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr, u64 spte, *sptep = NULL; int direct; gfn_t table_gfn; - int r; int level; bool dirty = is_dirty_gpte(gw->ptes[gw->level - 1]); unsigned direct_access; - pt_element_t curr_pte; struct kvm_shadow_walk_iterator iterator; if (!is_present_gpte(gw->ptes[gw->level - 1])) @@ -449,17 +469,12 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr, sp = kvm_mmu_get_page(vcpu, table_gfn, addr, level-1, direct, access, sptep); check_set_spte: - if (level >= gw->level) { - r = kvm_read_guest_atomic(vcpu->kvm, - gw->pte_gpa[level - 1], - &curr_pte, sizeof(curr_pte)); - if (r || curr_pte != gw->ptes[level - 1]) { - if (nonpresent) - kvm_mmu_put_page(sp, sptep); - kvm_release_pfn_clean(pfn); - sptep = NULL; - break; - } + if (!FNAME(check_gpte_level)(vcpu, gw, level)) { + if (nonpresent) + kvm_mmu_put_page(sp, sptep); + kvm_release_pfn_clean(pfn); + sptep = NULL; + break; } if (nonpresent) { @@ -476,7 +491,7 @@ check_set_spte: user_fault, write_fault, dirty, ptwrite, level, gw->gfn, pfn, false, true); - FNAME(pte_prefetch)(vcpu, sptep); + FNAME(pte_prefetch)(vcpu, gw, sptep); break; } } -- 1.6.1.2 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
