From: Cornelia Huck <cohuck@redhat.com>
To: Jason Wang <jasowang@redhat.com>,
pasic@linux.ibm.com, hca@linux.ibm.com, gor@linux.ibm.com,
borntraeger@de.ibm.com, agordeev@linux.ibm.com, mst@redhat.com,
jasowang@redhat.com, linux-s390@vger.kernel.org,
virtualization@lists.linux-foundation.org, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org
Cc: ben@decadent.org.uk, david@redhat.com
Subject: Re: [PATCH V3] virtio: disable notification hardening by default
Date: Wed, 22 Jun 2022 10:32:26 +0200 [thread overview]
Message-ID: <87h74d85et.fsf@redhat.com> (raw)
In-Reply-To: <20220622012940.21441-1-jasowang@redhat.com>
On Wed, Jun 22 2022, Jason Wang <jasowang@redhat.com> wrote:
> We try to harden virtio device notifications in 8b4ec69d7e09 ("virtio:
> harden vring IRQ"). It works with the assumption that the driver or
> core can properly call virtio_device_ready() at the right
> place. Unfortunately, this seems to be not true and uncover various
> bugs of the existing drivers, mainly the issue of using
> virtio_device_ready() incorrectly.
>
> So let's having a Kconfig option and disable it by default. It gives
s/having/have/
> us a breath to fix the drivers and then we can consider to enable it
> by default.
>
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
> Changes since V2:
> - Tweak the Kconfig help
> - Add comment for the read_lock() pairing in virtio_ccw
> ---
> drivers/s390/virtio/virtio_ccw.c | 9 ++++++++-
> drivers/virtio/Kconfig | 13 +++++++++++++
> drivers/virtio/virtio.c | 2 ++
> drivers/virtio/virtio_ring.c | 12 ++++++++++++
> include/linux/virtio_config.h | 2 ++
> 5 files changed, 37 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c
> index 97e51c34e6cf..1f6a358f65f0 100644
> --- a/drivers/s390/virtio/virtio_ccw.c
> +++ b/drivers/s390/virtio/virtio_ccw.c
> @@ -1136,8 +1136,13 @@ static void virtio_ccw_int_handler(struct ccw_device *cdev,
> vcdev->err = -EIO;
> }
> virtio_ccw_check_activity(vcdev, activity);
> - /* Interrupts are disabled here */
> +#ifdef CONFIG_VIRTIO_HARDEN_NOTIFICATION
> + /*
> + * Paried with virtio_ccw_synchronize_cbs() and interrupts are
s/Paried/Paired/
> + * disabled here.
> + */
> read_lock(&vcdev->irq_lock);
> +#endif
> for_each_set_bit(i, indicators(vcdev),
> sizeof(*indicators(vcdev)) * BITS_PER_BYTE) {
> /* The bit clear must happen before the vring kick. */
> @@ -1146,7 +1151,9 @@ static void virtio_ccw_int_handler(struct ccw_device *cdev,
> vq = virtio_ccw_vq_by_ind(vcdev, i);
> vring_interrupt(0, vq);
> }
> +#ifdef CONFIG_VIRTIO_HARDEN_NOTIFICATION
> read_unlock(&vcdev->irq_lock);
> +#endif
> if (test_bit(0, indicators2(vcdev))) {
> virtio_config_changed(&vcdev->vdev);
> clear_bit(0, indicators2(vcdev));
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
next prev parent reply other threads:[~2022-06-22 8:32 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-22 1:29 [PATCH V3] virtio: disable notification hardening by default Jason Wang
2022-06-22 7:02 ` Michael S. Tsirkin
2022-06-22 7:09 ` Jason Wang
2022-06-24 6:31 ` Michael S. Tsirkin
2022-06-27 2:50 ` Jason Wang
2022-06-27 7:33 ` Michael S. Tsirkin
2022-06-27 8:11 ` Jason Wang
2022-06-27 9:52 ` Michael S. Tsirkin
2022-06-28 3:49 ` Jason Wang
2022-06-28 4:59 ` Michael S. Tsirkin
2022-06-28 6:17 ` Jason Wang
2022-06-28 6:24 ` Michael S. Tsirkin
2022-06-28 6:32 ` Jason Wang
2022-06-28 6:44 ` Michael S. Tsirkin
2022-06-29 4:07 ` Jason Wang
2022-06-29 6:31 ` Michael S. Tsirkin
2022-06-29 7:02 ` Jason Wang
2022-06-29 7:15 ` Michael S. Tsirkin
2022-06-29 8:34 ` Jason Wang
2022-06-29 8:52 ` Michael S. Tsirkin
2022-06-30 2:01 ` Jason Wang
2022-06-30 8:38 ` Michael S. Tsirkin
2022-07-04 4:23 ` Jason Wang
2022-07-04 6:22 ` Michael S. Tsirkin
2022-07-04 6:40 ` Jason Wang
2022-07-04 7:00 ` Michael S. Tsirkin
2022-06-22 8:32 ` Cornelia Huck [this message]
2022-06-24 8:41 ` Xuan Zhuo
2022-06-24 9:05 ` Michael S. Tsirkin
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