The current way is queued a complete async pf with:
asyc_pf.page = bad_page
async_pf.arch.gfn = 0
It has two problems while kvm_check_async_pf_completion handle this
async_pf:
- since !async_pf.page, it can retry a pseudo #PF
- it can delete gfn 0 from vcpu->arch.apf.gfns[]
Actually, we can simply record this wakeup request and let
kvm_check_async_pf_completion simply break the wait
Signed-off-by: Xiao Guangrong <xiaoguangrong@xxxxxxxxxxxxxx>
---
include/linux/kvm_host.h | 1 +
virt/kvm/async_pf.c | 21 ++++++---------------
2 files changed, 7 insertions(+), 15 deletions(-)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 0c1b7c5..d91add9 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -131,6 +131,7 @@ struct kvm_vcpu {
struct list_head queue;
struct list_head done;
spinlock_t lock;
+ bool wakeup;
} async_pf;
#endif
diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c
index 5307a32..0d1f6c4 100644
--- a/virt/kvm/async_pf.c
+++ b/virt/kvm/async_pf.c
@@ -124,6 +124,11 @@ bool kvm_check_async_pf_completion(struct kvm_vcpu *vcpu)
{
struct kvm_async_pf *work;
+ if (vcpu->async_pf.wakeup) {
+ vcpu->async_pf.wakeup = false;
+ return true;
+ }
+
if (list_empty_careful(&vcpu->async_pf.done) ||
!kvm_arch_can_inject_async_page_present(vcpu))
return false;
@@ -197,20 +202,6 @@ retry_sync:
int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu)
{
- struct kvm_async_pf *work;
-
- if (!list_empty(&vcpu->async_pf.done))
- return 0;
-
- work = kmem_cache_zalloc(async_pf_cache, GFP_ATOMIC);
- if (!work)
- return -ENOMEM;
-
- work->page = bad_page;
- get_page(bad_page);
- INIT_LIST_HEAD(&work->queue); /* for list_del to work */
-
- list_add_tail(&work->link, &vcpu->async_pf.done);
- vcpu->async_pf.queued++;
+ vcpu->async_pf.wakeup = true;
return 0;
}
--
1.7.0.4
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