[PATCH 3/3] KVM: MMU: Make drop_large_spte() more generic

[Takuya Yoshikawa <yoshikawa.takuya@xxxxxxxxxxxxx>]

There are many places where we drop large spte and we are always doing
much the same as drop_large_spte().

To avoid these duplications, this patch makes drop_large_spte() more
generically usable: it now takes an argument to know if it must flush
the remote tlbs and returns true or false depending on is_large_pte()
check result.

Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@xxxxxxxxxxxxx>
---
 arch/x86/kvm/mmu.c         |   35 +++++++++++++++++------------------
 arch/x86/kvm/paging_tmpl.h |    4 ++--
 2 files changed, 19 insertions(+), 20 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 5e761ff..2db12b3 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1023,6 +1023,19 @@ static void drop_spte(struct kvm *kvm, u64 *sptep)
 		rmap_remove(kvm, sptep);
 }
 
+static bool drop_large_spte(struct kvm *kvm, u64 *sptep, bool flush_now)
+{
+	if (!is_large_pte(*sptep))
+		return false;
+
+	drop_spte(kvm, sptep);
+	--kvm->stat.lpages;
+
+	if (flush_now)
+		kvm_flush_remote_tlbs(kvm);
+	return true;
+}
+
 int kvm_mmu_rmap_write_protect(struct kvm *kvm, u64 gfn,
 			       struct kvm_memory_slot *slot)
 {
@@ -1052,8 +1065,7 @@ int kvm_mmu_rmap_write_protect(struct kvm *kvm, u64 gfn,
 			BUG_ON(!is_large_pte(*spte));
 			pgprintk("rmap_write_protect(large): spte %p %llx %lld\n", spte, *spte, gfn);
 			if (is_writable_pte(*spte)) {
-				drop_spte(kvm, spte);
-				--kvm->stat.lpages;
+				drop_large_spte(kvm, spte, false);
 				spte = NULL;
 				write_protected = 1;
 			}
@@ -1799,15 +1811,6 @@ static void link_shadow_page(u64 *sptep, struct kvm_mmu_page *sp)
 	mmu_spte_set(sptep, spte);
 }
 
-static void drop_large_spte(struct kvm_vcpu *vcpu, u64 *sptep)
-{
-	if (is_large_pte(*sptep)) {
-		drop_spte(vcpu->kvm, sptep);
-		--vcpu->kvm->stat.lpages;
-		kvm_flush_remote_tlbs(vcpu->kvm);
-	}
-}
-
 static void validate_direct_spte(struct kvm_vcpu *vcpu, u64 *sptep,
 				   unsigned direct_access)
 {
@@ -1839,9 +1842,8 @@ static bool mmu_page_zap_pte(struct kvm *kvm, struct kvm_mmu_page *sp,
 	pte = *spte;
 	if (is_shadow_present_pte(pte)) {
 		if (is_last_spte(pte, sp->role.level)) {
-			drop_spte(kvm, spte);
-			if (is_large_pte(pte))
-				--kvm->stat.lpages;
+			if (!drop_large_spte(kvm, spte, false))
+				drop_spte(kvm, spte);
 		} else {
 			child = page_header(pte & PT64_BASE_ADDR_MASK);
 			drop_parent_pte(child, spte);
@@ -3859,11 +3861,8 @@ void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot)
 			      !is_last_spte(pt[i], sp->role.level))
 				continue;
 
-			if (is_large_pte(pt[i])) {
-				drop_spte(kvm, &pt[i]);
-				--kvm->stat.lpages;
+			if (drop_large_spte(kvm, &pt[i], false))
 				continue;
-			}
 
 			/* avoid RMW */
 			if (is_writable_pte(pt[i]))
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 52e9d58..c40f074 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -498,7 +498,7 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
 		gfn_t table_gfn;
 
 		clear_sp_write_flooding_count(it.sptep);
-		drop_large_spte(vcpu, it.sptep);
+		drop_large_spte(vcpu->kvm, it.sptep, true);
 
 		sp = NULL;
 		if (!is_shadow_present_pte(*it.sptep)) {
@@ -526,7 +526,7 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
 		clear_sp_write_flooding_count(it.sptep);
 		validate_direct_spte(vcpu, it.sptep, direct_access);
 
-		drop_large_spte(vcpu, it.sptep);
+		drop_large_spte(vcpu->kvm, it.sptep, true);
 
 		if (is_shadow_present_pte(*it.sptep))
 			continue;
-- 
1.7.5.4

--
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