From: Paul Durrant <pdurrant@amazon.com>
To: <linux-kernel@vger.kernel.org>, <xen-devel@lists.xenproject.org>
Cc: "Paul Durrant" <pdurrant@amazon.com>,
"Konrad Rzeszutek Wilk" <konrad.wilk@oracle.com>,
"Roger Pau Monné" <roger.pau@citrix.com>,
"Jens Axboe" <axboe@kernel.dk>,
"Boris Ostrovsky" <boris.ostrovsky@oracle.com>,
"Juergen Gross" <jgross@suse.com>,
"Stefano Stabellini" <sstabellini@kernel.org>
Subject: [PATCH 4/4] xen-blkback: support dynamic unbind/bind
Date: Thu, 5 Dec 2019 14:01:23 +0000 [thread overview]
Message-ID: <20191205140123.3817-5-pdurrant@amazon.com> (raw)
In-Reply-To: <20191205140123.3817-1-pdurrant@amazon.com>
By simply re-attaching to shared rings during connect_ring() rather than
assuming they are freshly allocated (i.e assuming the counters are zero)
it is possible for vbd instances to be unbound and re-bound from and to
(respectively) a running guest.
This has been tested by running:
while true; do dd if=/dev/urandom of=test.img bs=1M count=1024; done
in a PV guest whilst running:
while true;
do echo vbd-$DOMID-$VBD >unbind;
echo unbound;
sleep 5;
echo vbd-$DOMID-$VBD >bind;
echo bound;
sleep 3;
done
in dom0 from /sys/bus/xen-backend/drivers/vbd to continuously unbind and
re-bind its system disk image.
This is a highly useful feature for a backend module as it allows it to be
unloaded and re-loaded (i.e. updated) without requiring domUs to be halted.
This was also tested by running:
while true;
do echo vbd-$DOMID-$VBD >unbind;
echo unbound;
sleep 5;
rmmod xen-blkback;
echo unloaded;
sleep 1;
modprobe xen-blkback;
echo bound;
cd $(pwd);
sleep 3;
done
in dom0 whilst running the same loop as above in the (single) PV guest.
Some (less stressful) testing has also been done using a Windows HVM guest
with the latest 9.0 PV drivers installed.
Signed-off-by: Paul Durrant <pdurrant@amazon.com>
---
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: "Roger Pau Monné" <roger.pau@citrix.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
---
drivers/block/xen-blkback/xenbus.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index e8c5c54e1d26..0b82740c4a9d 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -196,24 +196,24 @@ static int xen_blkif_map(struct xen_blkif_ring *ring, grant_ref_t *gref,
{
struct blkif_sring *sring;
sring = (struct blkif_sring *)ring->blk_ring;
- BACK_RING_INIT(&ring->blk_rings.native, sring,
- XEN_PAGE_SIZE * nr_grefs);
+ BACK_RING_ATTACH(&ring->blk_rings.native, sring,
+ XEN_PAGE_SIZE * nr_grefs);
break;
}
case BLKIF_PROTOCOL_X86_32:
{
struct blkif_x86_32_sring *sring_x86_32;
sring_x86_32 = (struct blkif_x86_32_sring *)ring->blk_ring;
- BACK_RING_INIT(&ring->blk_rings.x86_32, sring_x86_32,
- XEN_PAGE_SIZE * nr_grefs);
+ BACK_RING_ATTACH(&ring->blk_rings.x86_32, sring_x86_32,
+ XEN_PAGE_SIZE * nr_grefs);
break;
}
case BLKIF_PROTOCOL_X86_64:
{
struct blkif_x86_64_sring *sring_x86_64;
sring_x86_64 = (struct blkif_x86_64_sring *)ring->blk_ring;
- BACK_RING_INIT(&ring->blk_rings.x86_64, sring_x86_64,
- XEN_PAGE_SIZE * nr_grefs);
+ BACK_RING_ATTACH(&ring->blk_rings.x86_64, sring_x86_64,
+ XEN_PAGE_SIZE * nr_grefs);
break;
}
default:
--
2.20.1
next prev parent reply other threads:[~2019-12-05 14:02 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-05 14:01 [PATCH 0/4] xen-blkback: support live update Paul Durrant
2019-12-05 14:01 ` [PATCH 1/4] xenbus: move xenbus_dev_shutdown() into frontend code Paul Durrant
2019-12-09 11:33 ` Jürgen Groß
2019-12-09 11:55 ` Durrant, Paul
2019-12-09 11:57 ` Jürgen Groß
2019-12-05 14:01 ` [PATCH 2/4] xenbus: limit when state is forced to closed Paul Durrant
2019-12-09 11:39 ` [Xen-devel] " Roger Pau Monné
2019-12-09 11:55 ` Jürgen Groß
2019-12-09 12:03 ` Durrant, Paul
2019-12-09 12:08 ` Jürgen Groß
2019-12-09 12:19 ` Durrant, Paul
2019-12-09 13:38 ` Jürgen Groß
2019-12-09 14:06 ` Durrant, Paul
2019-12-09 14:09 ` Jürgen Groß
2019-12-09 14:23 ` Durrant, Paul
2019-12-09 14:41 ` Jürgen Groß
2019-12-09 14:43 ` Durrant, Paul
2019-12-09 12:01 ` Durrant, Paul
2019-12-09 12:25 ` Roger Pau Monné
2019-12-09 12:40 ` Durrant, Paul
2019-12-09 14:28 ` Roger Pau Monné
2019-12-09 14:41 ` Durrant, Paul
2019-12-09 15:13 ` Roger Pau Monné
2019-12-09 16:26 ` Durrant, Paul
2019-12-09 17:17 ` Roger Pau Monné
2019-12-09 17:23 ` Durrant, Paul
2019-12-05 14:01 ` [PATCH 3/4] xen/interface: don't discard pending work in FRONT/BACK_RING_ATTACH Paul Durrant
2019-12-09 11:41 ` [Xen-devel] " Roger Pau Monné
2019-12-09 11:52 ` Jürgen Groß
2019-12-09 12:50 ` Durrant, Paul
2019-12-09 13:55 ` Jürgen Groß
2019-12-09 16:38 ` Durrant, Paul
2019-12-10 11:42 ` Jürgen Groß
2019-12-05 14:01 ` Paul Durrant [this message]
2019-12-09 12:17 ` [PATCH 4/4] xen-blkback: support dynamic unbind/bind Roger Pau Monné
2019-12-09 12:24 ` Durrant, Paul
2019-12-09 13:57 ` Jürgen Groß
2019-12-09 14:01 ` Durrant, Paul
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