[PATCH V2 5/10] KVM/MMU: Flush tlb with range list in sync_page()

[lantianyu1986 at gmail.com]

From: Lan Tianyu <Tianyu.Lan at microsoft.com>

This patch is to flush tlb via flush list function. Put
page into flush list when return value of set_spte()
includes flag SET_SPTE_NEED_REMOTE_TLB_FLUSH. kvm_flush_remote_
tlbs_with_list() checks whether the flush list is empty
or not. It also checks whether range tlb flush is available
and go back to tradiion flush if not.

Signed-off-by: Lan Tianyu <Tianyu.Lan at microsoft.com>
---
Change since v1:
       Use check of list_empty in the kvm_flush_remote_tlbs_with_list()
       to determine flush or not instead of checking set_spte_ret.
 
arch/x86/kvm/paging_tmpl.h | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 6bdca39829bc..d84486e75345 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -970,7 +970,7 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
 	int i, nr_present = 0;
 	bool host_writable;
 	gpa_t first_pte_gpa;
-	int set_spte_ret = 0;
+	HLIST_HEAD(flush_list);
 
 	/* direct kvm_mmu_page can not be unsync. */
 	BUG_ON(sp->role.direct);
@@ -978,6 +978,7 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
 	first_pte_gpa = FNAME(get_level1_sp_gpa)(sp);
 
 	for (i = 0; i < PT64_ENT_PER_PAGE; i++) {
+		int set_spte_ret = 0;
 		unsigned pte_access;
 		pt_element_t gpte;
 		gpa_t pte_gpa;
@@ -1027,14 +1028,20 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
 
 		host_writable = sp->spt[i] & SPTE_HOST_WRITEABLE;
 
-		set_spte_ret |= set_spte(vcpu, &sp->spt[i],
+		set_spte_ret = set_spte(vcpu, &sp->spt[i],
 					 pte_access, PT_PAGE_TABLE_LEVEL,
 					 gfn, spte_to_pfn(sp->spt[i]),
 					 true, false, host_writable);
+
+		if (set_spte_ret & SET_SPTE_NEED_REMOTE_TLB_FLUSH) {
+			struct kvm_mmu_page *leaf_sp = page_header(sp->spt[i]
+					& PT64_BASE_ADDR_MASK);
+			hlist_add_head(&leaf_sp->flush_link, &flush_list);
+		}
+
 	}
 
-	if (set_spte_ret & SET_SPTE_NEED_REMOTE_TLB_FLUSH)
-		kvm_flush_remote_tlbs(vcpu->kvm);
+	kvm_flush_remote_tlbs_with_list(vcpu->kvm, &flush_list);
 
 	return nr_present;
 }
-- 
2.14.4