KVM: Drop FOLL_GET in GUP when doing async page fault
Page pinning is not mandatory in kvm async page fault processing since
after async page fault event is delivered to a guest it accesses page once
again and does its own GUP. Drop the FOLL_GET flag in GUP in async_pf
code, and do some simplifying in check/clear processing.
Suggested-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Gu zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: chai wen <chaiw.fnst@cn.fujitsu.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
(cherry picked from commit f2e106692d5189303997ad7b96de8d8123aa5613)
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c
index b197950..8631d9c 100644
--- a/virt/kvm/async_pf.c
+++ b/virt/kvm/async_pf.c
@@ -56,7 +56,6 @@
static void async_pf_execute(struct work_struct *work)
{
- struct page *page = NULL;
struct kvm_async_pf *apf =
container_of(work, struct kvm_async_pf, work);
struct mm_struct *mm = apf->mm;
@@ -68,13 +67,12 @@
use_mm(mm);
down_read(&mm->mmap_sem);
- get_user_pages(current, mm, addr, 1, 1, 0, &page, NULL);
+ get_user_pages(current, mm, addr, 1, 1, 0, NULL, NULL);
up_read(&mm->mmap_sem);
unuse_mm(mm);
spin_lock(&vcpu->async_pf.lock);
list_add_tail(&apf->link, &vcpu->async_pf.done);
- apf->page = page;
spin_unlock(&vcpu->async_pf.lock);
/*
@@ -82,7 +80,7 @@
* this point
*/
- trace_kvm_async_pf_completed(addr, page, gva);
+ trace_kvm_async_pf_completed(addr, gva);
if (waitqueue_active(&vcpu->wq))
wake_up_interruptible(&vcpu->wq);
@@ -112,8 +110,6 @@
list_entry(vcpu->async_pf.done.next,
typeof(*work), link);
list_del(&work->link);
- if (!is_error_page(work->page))
- kvm_release_page_clean(work->page);
kmem_cache_free(async_pf_cache, work);
}
spin_unlock(&vcpu->async_pf.lock);
@@ -133,14 +129,11 @@
list_del(&work->link);
spin_unlock(&vcpu->async_pf.lock);
- if (work->page)
- kvm_arch_async_page_ready(vcpu, work);
+ kvm_arch_async_page_ready(vcpu, work);
kvm_arch_async_page_present(vcpu, work);
list_del(&work->queue);
vcpu->async_pf.queued--;
- if (!is_error_page(work->page))
- kvm_release_page_clean(work->page);
kmem_cache_free(async_pf_cache, work);
}
}
@@ -163,7 +156,7 @@
if (!work)
return 0;
- work->page = NULL;
+ work->wakeup_all = false;
work->vcpu = vcpu;
work->gva = gva;
work->addr = gfn_to_hva(vcpu->kvm, gfn);
@@ -203,7 +196,7 @@
if (!work)
return -ENOMEM;
- work->page = KVM_ERR_PTR_BAD_PAGE;
+ work->wakeup_all = true;
INIT_LIST_HEAD(&work->queue); /* for list_del to work */
spin_lock(&vcpu->async_pf.lock);