[PATCH V3 9/13] KVM/MMU: Replace tlb flush function with range list flush function

From: Tianyu Lan
Date: Wed Sep 26 2018 - 23:49:52 EST


This patch is to use range list flush function in the
mmu_sync_children(), kvm_mmu_commit_zap_page() and
FNAME(sync_page)().

Signed-off-by: Lan Tianyu <Tianyu.Lan@xxxxxxxxxxxxx>
---
arch/x86/kvm/mmu.c | 26 +++++++++++++++++++++++---
arch/x86/kvm/paging_tmpl.h | 5 ++++-
2 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index a1cbbc852271..5f3a69425142 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1092,6 +1092,13 @@ static void update_gfn_disallow_lpage_count(struct kvm_memory_slot *slot,
}
}

+static void kvm_mmu_queue_flush_request(struct kvm_mmu_page *sp,
+ struct list_head *flush_list)
+{
+ if (sp->sptep && is_last_spte(*sp->sptep, sp->role.level))
+ list_add(&sp->flush_link, flush_list);
+}
+
void kvm_mmu_gfn_disallow_lpage(struct kvm_memory_slot *slot, gfn_t gfn)
{
update_gfn_disallow_lpage_count(slot, gfn, 1);
@@ -2369,12 +2376,16 @@ static void mmu_sync_children(struct kvm_vcpu *vcpu,

while (mmu_unsync_walk(parent, &pages)) {
bool protected = false;
+ LIST_HEAD(flush_list);

- for_each_sp(pages, sp, parents, i)
+ for_each_sp(pages, sp, parents, i) {
protected |= rmap_write_protect(vcpu, sp->gfn);
+ kvm_mmu_queue_flush_request(sp, &flush_list);
+ }

if (protected) {
- kvm_flush_remote_tlbs(vcpu->kvm);
+ kvm_flush_remote_tlbs_with_list(vcpu->kvm,
+ &flush_list);
flush = false;
}

@@ -2710,6 +2721,7 @@ static void kvm_mmu_commit_zap_page(struct kvm *kvm,
struct list_head *invalid_list)
{
struct kvm_mmu_page *sp, *nsp;
+ LIST_HEAD(flush_list);

if (list_empty(invalid_list))
return;
@@ -2723,7 +2735,15 @@ static void kvm_mmu_commit_zap_page(struct kvm *kvm,
* In addition, kvm_flush_remote_tlbs waits for all vcpus to exit
* guest mode and/or lockless shadow page table walks.
*/
- kvm_flush_remote_tlbs(kvm);
+ if (kvm_available_flush_tlb_with_range()) {
+ list_for_each_entry(sp, invalid_list, link)
+ kvm_mmu_queue_flush_request(sp, &flush_list);
+
+ if (!list_empty(&flush_list))
+ kvm_flush_remote_tlbs_with_list(kvm, &flush_list);
+ } else {
+ kvm_flush_remote_tlbs(kvm);
+ }

list_for_each_entry_safe(sp, nsp, invalid_list, link) {
WARN_ON(!sp->role.invalid || sp->root_count);
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 5cbaf7c4a729..a5f967e81429 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -972,6 +972,7 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
bool host_writable;
gpa_t first_pte_gpa;
int set_spte_ret = 0;
+ LIST_HEAD(flush_list);

/* direct kvm_mmu_page can not be unsync. */
BUG_ON(sp->role.direct);
@@ -1032,10 +1033,12 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
pte_access, PT_PAGE_TABLE_LEVEL,
gfn, spte_to_pfn(sp->spt[i]),
true, false, host_writable);
+ if (set_spte_ret && kvm_available_flush_tlb_with_range())
+ kvm_mmu_queue_flush_request(sp, &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