[PATCH v3 10/10] KVM MMU: optimize sync/update unsync-page

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



invlpg only need update unsync page, sp->unsync and sp->unsync_children
can help us to find it

Now, a gfn may have many shadow pages, when one sp need be synced, we
write protect sp->gfn and sync this sp but we keep other shadow pages
asynchronous

So, while gfn happen page fault, let it not touch unsync page, the unsync
page only updated at invlpg/flush TLB time

Signed-off-by: Xiao Guangrong <xiaoguangrong@xxxxxxxxxxxxxx>
---
 arch/x86/kvm/mmu.c         |    3 ++-
 arch/x86/kvm/paging_tmpl.h |   11 +++++++----
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index aa6faa7..c093d69 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2719,7 +2719,8 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
 
 restart:
 	hlist_for_each_entry_safe(sp, node, n, bucket, hash_link) {
-		if (sp->gfn != gfn || sp->role.direct || sp->role.invalid)
+		if (sp->gfn != gfn || sp->role.direct || sp->role.invalid ||
+		      sp->unsync)
 			continue;
 		pte_size = sp->role.cr4_pae ? 8 : 4;
 		misaligned = (offset ^ (offset + bytes - 1)) & ~(pte_size - 1);
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 749cb1a..624b38f 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -474,10 +474,14 @@ static void FNAME(invlpg)(struct kvm_vcpu *vcpu, gva_t gva)
 		level = iterator.level;
 		sptep = iterator.sptep;
 
+		sp = page_header(__pa(sptep));
 		if (is_last_spte(*sptep, level)) {
 			int shift;
 
-			sp = page_header(__pa(sptep));
+			if (!sp->unsync)
+				break;
+
+			WARN_ON(level != PT_PAGE_TABLE_LEVEL);
 			shift = PAGE_SHIFT -
 				  (PT_LEVEL_BITS - PT64_LEVEL_BITS) * level;
 			gfn = sp->gfn;
@@ -494,7 +498,7 @@ static void FNAME(invlpg)(struct kvm_vcpu *vcpu, gva_t gva)
 			break;
 		}
 
-		if (!is_shadow_present_pte(*sptep))
+		if (!is_shadow_present_pte(*sptep) || !sp->unsync_children)
 			break;
 	}
 
@@ -515,8 +519,7 @@ static void FNAME(invlpg)(struct kvm_vcpu *vcpu, gva_t gva)
 
 	mmu_guess_page_from_pte_write(vcpu, gfn_to_gpa(gfn) + offset, gentry);
 	spin_lock(&vcpu->kvm->mmu_lock);
-	if (atomic_read(&vcpu->kvm->arch.invlpg_counter) == invlpg_counter &&
-			sp->role.level == PT_PAGE_TABLE_LEVEL) {
+	if (atomic_read(&vcpu->kvm->arch.invlpg_counter) == invlpg_counter) {
 		++vcpu->kvm->stat.mmu_pte_updated;
 		FNAME(update_pte)(vcpu, sp, sptep, &gentry);
 	}
-- 
1.6.1.2



--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[Index of Archives]     [KVM ARM]     [KVM ia64]     [KVM ppc]     [Virtualization Tools]     [Spice Development]     [Libvirt]     [Libvirt Users]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite Questions]     [Linux Kernel]     [Linux SCSI]     [XFree86]
  Powered by Linux