[patch 027/166] virtio-balloon: pull page poisoning config out of free page hinting

Andrew Morton
2020-04-07T03:05:04Z

From: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Subject: virtio-balloon: pull page poisoning config out of free page hinting

Currently the page poisoning setting wasn't being enabled unless free page
hinting was enabled. However we will need the page poisoning tracking
logic as well for free page reporting. As such pull it out and make it a
separate bit of config in the probe function.

In addition we need to add support for the more recent init_on_free
feature which expects a behavior similar to page poisoning in that we
expect the page to be pre-zeroed.

Link: http://lkml.kernel.org/r/20200211224646.29318.695.stgit@localhost.localdomain
Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Nitesh Narayan Lal <nitesh@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pankaj Gupta <pagupta@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Wang <wei.w.wang@intel.com>
Cc: Yang Zhang <yang.zhang.wz@gmail.com>
Cc: wei qi <weiqi4@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

drivers/virtio/virtio_balloon.c | 23 +++++++++++++++++------
1 file changed, 17 insertions(+), 6 deletions(-)

--- a/drivers/virtio/virtio_balloon.c~virtio-balloon-pull-page-poisoning-config-out-of-free-page-hinting
+++ a/drivers/virtio/virtio_balloon.c
@@ -864,7 +864,6 @@ static int virtio_balloon_register_shrin
static int virtballoon_probe(struct virtio_device *vdev)
{
struct virtio_balloon *vb;
- __u32 poison_val;
int err;

if (!vdev->config->get) {
@@ -930,11 +929,20 @@ static int virtballoon_probe(struct virt
VIRTIO_BALLOON_CMD_ID_STOP);
spin_lock_init(&vb->free_page_list_lock);
INIT_LIST_HEAD(&vb->free_page_list);
- if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_PAGE_POISON)) {
+ }
+ if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_PAGE_POISON)) {
+ /* Start with poison val of 0 representing general init */
+ __u32 poison_val = 0;
+
+ /*
+ * Let the hypervisor know that we are expecting a
+ * specific value to be written back in balloon pages.
+ */
+ if (!want_init_on_free())
memset(&poison_val, PAGE_POISON, sizeof(poison_val));
- virtio_cwrite(vb->vdev, struct virtio_balloon_config,
- poison_val, &poison_val);
- }
+
+ virtio_cwrite(vb->vdev, struct virtio_balloon_config,
+ poison_val, &poison_val);
}
/*
* We continue to use VIRTIO_BALLOON_F_DEFLATE_ON_OOM to decide if a
@@ -1045,7 +1053,10 @@ static int virtballoon_restore(struct vi

static int virtballoon_validate(struct virtio_device *vdev)
{
- if (!page_poisoning_enabled())
+ /* Tell the host whether we care about poisoned pages. */
+ if (!want_init_on_free() &&
+ (IS_ENABLED(CONFIG_PAGE_POISONING_NO_SANITY) ||
+ !page_poisoning_enabled()))
__virtio_clear_bit(vdev, VIRTIO_BALLOON_F_PAGE_POISON);

__virtio_clear_bit(vdev, VIRTIO_F_IOMMU_PLATFORM);
_