linux-kernel - [PATCH v11 5/6] virtio-balloon: Pull page poisoning config out of free page hinting

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20191001152947.27008.56645.stgit@localhost.localdomain>
Date:   Tue, 01 Oct 2019 08:29:48 -0700
From:   Alexander Duyck <alexander.duyck@...il.com>
To:     virtio-dev@...ts.oasis-open.org, kvm@...r.kernel.org,
        mst@...hat.com, david@...hat.com, dave.hansen@...el.com,
        linux-kernel@...r.kernel.org, willy@...radead.org,
        mhocko@...nel.org, linux-mm@...ck.org, akpm@...ux-foundation.org,
        mgorman@...hsingularity.net, vbabka@...e.cz, osalvador@...e.de
Cc:     yang.zhang.wz@...il.com, pagupta@...hat.com,
        konrad.wilk@...cle.com, nitesh@...hat.com, riel@...riel.com,
        lcapitulino@...hat.com, wei.w.wang@...el.com, aarcange@...hat.com,
        pbonzini@...hat.com, dan.j.williams@...el.com,
        alexander.h.duyck@...ux.intel.com
Subject: [PATCH v11 5/6] virtio-balloon: Pull page poisoning config out of
 free page hinting

From: Alexander Duyck <alexander.h.duyck@...ux.intel.com>

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 unused 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.

Reviewed-by: David Hildenbrand <david@...hat.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@...ux.intel.com>
---
 drivers/virtio/virtio_balloon.c |   23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)

diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 226fbb995fb0..92099298bc16 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -842,7 +842,6 @@ static int virtio_balloon_register_shrinker(struct virtio_balloon *vb)
 static int virtballoon_probe(struct virtio_device *vdev)
 {
 	struct virtio_balloon *vb;
-	__u32 poison_val;
 	int err;
 
 	if (!vdev->config->get) {
@@ -909,11 +908,20 @@ static int virtballoon_probe(struct virtio_device *vdev)
 						  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 unused 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
@@ -1014,7 +1022,10 @@ static int virtballoon_restore(struct virtio_device *vdev)
 
 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);