[PATCH v4 5/5] KVM: MMU: introduce FNAME(prefetch_gpte)

Xiao Guangrong
2012-10-07T12:05:17Z

The only difference 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 <xiaoguangrong@linux.vnet.ibm.com>
---
arch/x86/kvm/paging_tmpl.h | 55 +++++++++++++++++++------------------------
1 files changed, 24 insertions(+), 31 deletions(-)

diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 36a80ed..f887e4c 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -305,31 +305,43 @@ static int FNAME(walk_addr_nested)(struct guest_walker *walker,
addr, access);
}

-static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
- u64 *spte, const void *pte)
+static bool
+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 (prefetch_invalid_gpte(vcpu, sp, spte, gpte))
- return;
+ return false;

pgprintk("%s: gpte %llx spte %p\n", __func__, (u64)gpte, spte);
+
+ gfn = gpte_to_gfn(gpte);
pte_access = sp->role.access & gpte_access(vcpu, gpte);
protect_clean_gpte(&pte_access, gpte);
- 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 (is_invalid_pfn(pfn))
- return;
+ return false;

/*
- * we call mmu_set_spte() with host_writable = true because that
- * vcpu->arch.update_pte.pfn was fetched from get_user_pages(write = 1).
+ * we call mmu_set_spte() with host_writable = true because
+ * 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);
+
+ return true;
+}
+
+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;
+
+ FNAME(prefetch_gpte)(vcpu, sp, spte, gpte, false);
}

static bool FNAME(gpte_changed)(struct kvm_vcpu *vcpu,
@@ -375,33 +387,14 @@ 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 (prefetch_invalid_gpte(vcpu, sp, spte, gpte))
- continue;
-
- pte_access = sp->role.access & gpte_access(vcpu, gpte);
- protect_clean_gpte(&pte_access, gpte);
- gfn = gpte_to_gfn(gpte);
- pfn = pte_prefetch_gfn_to_pfn(vcpu, gfn,
- pte_access & ACC_WRITE_MASK);
- if (is_invalid_pfn(pfn))
+ if (!FNAME(prefetch_gpte)(vcpu, sp, spte, gptep[i], true))
break;
-
- mmu_set_spte(vcpu, spte, sp->role.access, pte_access, 0, 0,
- NULL, PT_PAGE_TABLE_LEVEL, gfn,
- pfn, true, true);
}
}

--
1.7.7.6