From: Christian Borntraeger <borntraeger@de.ibm.com>
To: Wei Wang <wei.w.wang@intel.com>,
virtio-dev@lists.oasis-open.org, linux-kernel@vger.kernel.org,
virtualization@lists.linux-foundation.org, kvm@vger.kernel.org,
linux-mm@kvack.org, mst@redhat.com, mhocko@kernel.org,
akpm@linux-foundation.org, dgilbert@redhat.com
Cc: torvalds@linux-foundation.org, pbonzini@redhat.com,
liliang.opensource@gmail.com, yang.zhang.wz@gmail.com,
quan.xu0@gmail.com, nilal@redhat.com, riel@redhat.com,
peterx@redhat.com, quintela@redhat.com,
Halil Pasic <pasic@linux.ibm.com>,
Cornelia Huck <cohuck@redhat.com>
Subject: Re: [PATCH v37 0/3] Virtio-balloon: support free page reporting
Date: Thu, 27 Dec 2018 13:17:20 +0100 [thread overview]
Message-ID: <e79b5c3d-aa89-6b99-00b1-c92c85fe214c@de.ibm.com> (raw)
In-Reply-To: <de167161-b586-6aee-d6a5-a90d47bbe1d4@de.ibm.com>
On 27.12.2018 12:59, Christian Borntraeger wrote:
> On 27.12.2018 12:31, Christian Borntraeger wrote:
>> This patch triggers random crashes in the guest kernel on s390 early during boot.
>> No migration and no setting of the balloon is involved.
>>
>
> Adding Conny and Halil,
>
> As the QEMU provides no PAGE_HINT feature yet, this quick hack makes the
> guest boot fine again:
>
>
> diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
> index 728ecd1eea305..aa2e1864c5736 100644
> --- a/drivers/virtio/virtio_balloon.c
> +++ b/drivers/virtio/virtio_balloon.c
> @@ -492,7 +492,7 @@ static int init_vqs(struct virtio_balloon *vb)
> callbacks[VIRTIO_BALLOON_VQ_FREE_PAGE] = NULL;
> }
>
> - err = vb->vdev->config->find_vqs(vb->vdev, VIRTIO_BALLOON_VQ_MAX,
> + err = vb->vdev->config->find_vqs(vb->vdev, 3, //VIRTIO_BALLOON_VQ_MAX,
> vqs, callbacks, names, NULL, NULL);
> if (err)
> return err;
>
>
> To me it looks like that virtio_ccw_find_vqs will abort if any of the virtqueues
> that it is been asked for does not exist (including the earlier ones).
>
This "hack" makes the random crashes go away, but the balloon interface itself
does not work. (setting the value to anything will hang the guest).
As patch 1 also modifies the main path, there seem to be additional issues, maybe
endianess
Looking at things like
+ vb->cmd_id_received = VIRTIO_BALLOON_CMD_ID_STOP;
+ vb->cmd_id_active = cpu_to_virtio32(vb->vdev,
+ VIRTIO_BALLOON_CMD_ID_STOP);
+ vb->cmd_id_stop = cpu_to_virtio32(vb->vdev,
+ VIRTIO_BALLOON_CMD_ID_STOP);
Why is cmd_id_received not using cpu_to_virtio32?
next prev parent reply other threads:[~2018-12-27 12:17 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-27 1:32 [PATCH v37 0/3] Virtio-balloon: support free page reporting Wei Wang
2018-08-27 1:32 ` [PATCH v37 1/3] virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT Wei Wang
2018-12-27 12:03 ` Christian Borntraeger
2018-12-28 3:12 ` Wei Wang
2018-12-28 8:03 ` Christian Borntraeger
2018-08-27 1:32 ` [PATCH v37 2/3] mm/page_poison: expose page_poisoning_enabled to kernel modules Wei Wang
2018-08-27 1:32 ` [PATCH v37 3/3] virtio-balloon: VIRTIO_BALLOON_F_PAGE_POISON Wei Wang
2018-10-25 0:58 ` [PATCH v37 0/3] Virtio-balloon: support free page reporting Michael S. Tsirkin
2018-10-25 10:18 ` Wei Wang
2018-12-27 11:31 ` Christian Borntraeger
2018-12-27 11:59 ` Christian Borntraeger
2018-12-27 12:17 ` Christian Borntraeger [this message]
2018-12-28 6:41 ` Wei Wang
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