On 09/14/2012 05:59 PM, Xiao Guangrong wrote:

> +             return FNAME(prefetch_gpte)(vcpu, sp, spte, gptep[i], true);

Sorry, this was wrong. Update this patch.

[PATCH v2 5/5] KVM: MMU: introduce FNAME(prefetch_gpte)

The only different thing between FNAME(update_pte) and FNAME(pte_prefetch)
is that the former is allowed to prefetch gfn from dirty logged slot, so
introduce a common function to prefetch spte

Signed-off-by: Xiao Guangrong <xiaoguangr...@linux.vnet.ibm.com>
---
 arch/x86/kvm/paging_tmpl.h |   50 ++++++++++++++++---------------------------
 1 files changed, 19 insertions(+), 31 deletions(-)

diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 1a738c5..32facf7 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -356,35 +356,45 @@ no_present:
        return true;
 }

-static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
-                             u64 *spte, const void *pte)
+static void
+FNAME(prefetch_gpte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
+                    u64 *spte, pt_element_t gpte, bool no_dirty_log)
 {
-       pt_element_t gpte;
        unsigned pte_access;
+       gfn_t gfn;
        pfn_t pfn;

-       gpte = *(const pt_element_t *)pte;
        if (FNAME(prefetch_invalid_gpte)(vcpu, sp, spte, gpte))
                return;

        pgprintk("%s: gpte %llx spte %p\n", __func__, (u64)gpte, spte);
+
+       gfn = gpte_to_gfn(gpte);
        pte_access = sp->role.access & FNAME(gpte_access)(vcpu, gpte, true);
-       pfn = gfn_to_pfn_atomic(vcpu->kvm, gpte_to_gfn(gpte));
+       pfn = pte_prefetch_gfn_to_pfn(vcpu, gfn,
+                       no_dirty_log && (pte_access & ACC_WRITE_MASK));
        if (mmu_invalid_pfn(pfn))
                return;

        /*
         * we call mmu_set_spte() with host_writable = true because that
-        * vcpu->arch.update_pte.pfn was fetched from get_user_pages(write = 1).
+        * pte_prefetch_gfn_to_pfn always gets a writable pfn.
         */
        mmu_set_spte(vcpu, spte, sp->role.access, pte_access, 0, 0,
-                    NULL, PT_PAGE_TABLE_LEVEL,
-                    gpte_to_gfn(gpte), pfn, true, true);
+                    NULL, PT_PAGE_TABLE_LEVEL, gfn, pfn, true, true);

        if (!is_error_pfn(pfn))
                kvm_release_pfn_clean(pfn);
 }

+static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
+                             u64 *spte, const void *pte)
+{
+       pt_element_t gpte = *(const pt_element_t *)pte;
+
+       return FNAME(prefetch_gpte)(vcpu, sp, spte, gpte, false);
+}
+
 static bool FNAME(gpte_changed)(struct kvm_vcpu *vcpu,
                                struct guest_walker *gw, int level)
 {
@@ -428,35 +438,13 @@ static void FNAME(pte_prefetch)(struct kvm_vcpu *vcpu, 
struct guest_walker *gw,
        spte = sp->spt + i;

        for (i = 0; i < PTE_PREFETCH_NUM; i++, spte++) {
-               pt_element_t gpte;
-               unsigned pte_access;
-               gfn_t gfn;
-               pfn_t pfn;
-
                if (spte == sptep)
                        continue;

                if (is_shadow_present_pte(*spte))
                        continue;

-               gpte = gptep[i];
-
-               if (FNAME(prefetch_invalid_gpte)(vcpu, sp, spte, gpte))
-                       continue;
-
-               pte_access = sp->role.access & FNAME(gpte_access)(vcpu, gpte,
-                                                                 true);
-               gfn = gpte_to_gfn(gpte);
-               pfn = pte_prefetch_gfn_to_pfn(vcpu, gfn,
-                                     pte_access & ACC_WRITE_MASK);
-               if (mmu_invalid_pfn(pfn))
-                       break;
-
-               mmu_set_spte(vcpu, spte, sp->role.access, pte_access, 0, 0,
-                            NULL, PT_PAGE_TABLE_LEVEL, gfn,
-                            pfn, true, true);
-               if (!is_error_pfn(pfn))
-                       kvm_release_pfn_clean(pfn);
+               FNAME(prefetch_gpte)(vcpu, sp, spte, gptep[i], true);
        }
 }

-- 
1.7.7.6

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