* [merged] virtio-mem-use-page_offline_startend-when-setting-pageoffline.patch removed from -mm tree
@ 2021-07-06 19:18 akpm
0 siblings, 0 replies; only message in thread
From: akpm @ 2021-07-06 19:18 UTC (permalink / raw)
To: adobriyan, alex.shi, david, guro, haiyangz, jasowang, jbohac,
kys, mhocko, mike.kravetz, mm-commits, mst, naoya.horiguchi,
osalvador, rppt, steven.price, sthemmin, wei.liu, willy, yaoaili
The patch titled
Subject: virtio-mem: use page_offline_(start|end) when setting PageOffline()
has been removed from the -mm tree. Its filename was
virtio-mem-use-page_offline_startend-when-setting-pageoffline.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: David Hildenbrand <david@redhat.com>
Subject: virtio-mem: use page_offline_(start|end) when setting PageOffline()
Let's properly use page_offline_(start|end) to synchronize setting
PageOffline(), so we won't have valid page access to unplugged memory
regions from /proc/kcore.
Existing balloon implementations usually allow reading inflated memory;
doing so might result in unnecessary overhead in the hypervisor, which is
currently the case with virtio-mem.
For future virtio-mem use cases, it will be different when using shmem,
huge pages, !anonymous private mappings, ... as backing storage for a VM.
virtio-mem unplugged memory must no longer be accessed and access might
result in undefined behavior. There will be a virtio spec extension to
document this change, including a new feature flag indicating the changed
behavior. We really don't want to race against PFN walkers reading random
page content.
Link: https://lkml.kernel.org/r/20210526093041.8800-6-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Aili Yao <yaoaili@kingsoft.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jiri Bohac <jbohac@suse.cz>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Steven Price <steven.price@arm.com>
Cc: Wei Liu <wei.liu@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
drivers/virtio/virtio_mem.c | 2 ++
1 file changed, 2 insertions(+)
--- a/drivers/virtio/virtio_mem.c~virtio-mem-use-page_offline_startend-when-setting-pageoffline
+++ a/drivers/virtio/virtio_mem.c
@@ -1065,6 +1065,7 @@ static int virtio_mem_memory_notifier_cb
static void virtio_mem_set_fake_offline(unsigned long pfn,
unsigned long nr_pages, bool onlined)
{
+ page_offline_begin();
for (; nr_pages--; pfn++) {
struct page *page = pfn_to_page(pfn);
@@ -1075,6 +1076,7 @@ static void virtio_mem_set_fake_offline(
ClearPageReserved(page);
}
}
+ page_offline_end();
}
/*
_
Patches currently in -mm which might be from david@redhat.com are
memory-hotplugrst-complete-admin-guide-overhaul.patch
^ permalink raw reply [flat|nested] only message in thread
only message in thread, other threads:[~2021-07-06 19:18 UTC | newest]
Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-07-06 19:18 [merged] virtio-mem-use-page_offline_startend-when-setting-pageoffline.patch removed from -mm tree akpm
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.