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From: "Xia, Chenbo" <chenbo.xia@intel.com>
To: Maxime Coquelin <maxime.coquelin@redhat.com>,
	"dev@dpdk.org" <dev@dpdk.org>,
	"amorenoz@redhat.com" <amorenoz@redhat.com>
Cc: "stable@dpdk.org" <stable@dpdk.org>
Subject: Re: [dpdk-stable] [PATCH 1/7] vhost: fix virtqueues metadata allocation
Date: Thu, 22 Oct 2020 11:00:16 +0000	[thread overview]
Message-ID: <MN2PR11MB4063D4583C9DBF43557280089C1D0@MN2PR11MB4063.namprd11.prod.outlook.com> (raw)
In-Reply-To: <cdfd2baf-88dc-a7b8-1df9-96bca4404871@redhat.com>

> -----Original Message-----
> From: Maxime Coquelin <maxime.coquelin@redhat.com>
> Sent: Wednesday, October 21, 2020 8:07 PM
> To: Xia, Chenbo <chenbo.xia@intel.com>; dev@dpdk.org; amorenoz@redhat.com
> Cc: stable@dpdk.org
> Subject: Re: [PATCH 1/7] vhost: fix virtqueues metadata allocation
> 
> Hi Chenbon
> 
> On 10/21/20 1:10 PM, Xia, Chenbo wrote:
> > Hi Maxime,
> >
> >> -----Original Message-----
> >> From: Maxime Coquelin <maxime.coquelin@redhat.com>
> >> Sent: Tuesday, October 20, 2020 1:34 AM
> >> To: dev@dpdk.org; Xia, Chenbo <chenbo.xia@intel.com>;
> amorenoz@redhat.com
> >> Cc: Maxime Coquelin <maxime.coquelin@redhat.com>; stable@dpdk.org
> >> Subject: [PATCH 1/7] vhost: fix virtqueues metadata allocation
> >>
> >> The Vhost-user backend implementation assumes there will be
> >> no holes in the device's array of virtqueues metadata
> >> pointers.
> >>
> >> It can happen though, and would cause segmentation faults,
> >> memory leaks or undefined behaviour.
> >
> > Could I ask when will this happen?
> >
> > When QEMU does not configure all virtqueues? I'm not very sure.
> > Could you point that out for me?
> 
> It has been reported by our QE when doing reconnect with multiqueue with
> vIOMMU enabled:
> https://bugzilla.redhat.com/show_bug.cgi?id=1880299
> 
> Regards,
> Maxime
> 
> > Thanks!
> > Chenbo
> >
> >>
> >> This patch keep the assumption that there is no holes in this
> >> array, and allocate all uninitialized virtqueues metadata up
> >> to requested index.
> >>
> >> Fixes: 160cbc815b41 ("vhost: remove a hack on queue allocation")
> >> Cc: stable@dpdk.org
> >>
> >> Suggested-by: Adrian Moreno <amorenoz@redhat.com>
> >> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> >> ---
> >>  lib/librte_vhost/vhost.c | 33 ++++++++++++++++++++-------------
> >>  1 file changed, 20 insertions(+), 13 deletions(-)
> >>
> >> diff --git a/lib/librte_vhost/vhost.c b/lib/librte_vhost/vhost.c
> >> index 6068c38ec6..0c9ba3b3af 100644
> >> --- a/lib/librte_vhost/vhost.c
> >> +++ b/lib/librte_vhost/vhost.c
> >> @@ -579,22 +579,29 @@ int
> >>  alloc_vring_queue(struct virtio_net *dev, uint32_t vring_idx)
> >>  {
> >>  	struct vhost_virtqueue *vq;
> >> +	uint32_t i;
> >>
> >> -	vq = rte_malloc(NULL, sizeof(struct vhost_virtqueue), 0);
> >> -	if (vq == NULL) {
> >> -		VHOST_LOG_CONFIG(ERR,
> >> -			"Failed to allocate memory for vring:%u.\n", vring_idx);
> >> -		return -1;
> >> -	}
> >> +	/* Also allocate holes, if any, up to requested vring index. */
> >> +	for (i = 0; i <= vring_idx; i++) {
> >> +		if (dev->virtqueue[i])
> >> +			continue;
> >>
> >> -	dev->virtqueue[vring_idx] = vq;
> >> -	init_vring_queue(dev, vring_idx);
> >> -	rte_spinlock_init(&vq->access_lock);
> >> -	vq->avail_wrap_counter = 1;
> >> -	vq->used_wrap_counter = 1;
> >> -	vq->signalled_used_valid = false;
> >> +		vq = rte_malloc(NULL, sizeof(struct vhost_virtqueue), 0);
> >> +		if (vq == NULL) {
> >> +			VHOST_LOG_CONFIG(ERR,
> >> +				"Failed to allocate memory for vring:%u.\n", i);
> >> +			return -1;
> >> +		}
> >> +
> >> +		dev->virtqueue[i] = vq;
> >> +		init_vring_queue(dev, vring_idx);
> >> +		rte_spinlock_init(&vq->access_lock);
> >> +		vq->avail_wrap_counter = 1;
> >> +		vq->used_wrap_counter = 1;
> >> +		vq->signalled_used_valid = false;
> >> +	}
> >>
> >> -	dev->nr_vring += 1;
> >> +	dev->nr_vring = RTE_MAX(dev->nr_vring, vring_idx + 1);
> >>
> >>  	return 0;
> >>  }
> >> --
> >> 2.26.2
> >

Reviewed-by: Chenbo Xia <chenbo.xia@intel.com>

  reply	other threads:[~2020-10-22 11:00 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20201019173415.582407-1-maxime.coquelin@redhat.com>
2020-10-19 17:34 ` Maxime Coquelin
2020-10-21 11:10   ` Xia, Chenbo
2020-10-21 12:06     ` Maxime Coquelin
2020-10-22 11:00       ` Xia, Chenbo [this message]
2020-10-19 17:34 ` [dpdk-stable] [PATCH 2/7] vhost: validate index in available entries API Maxime Coquelin
2020-10-21 11:28   ` Xia, Chenbo
2020-10-19 17:34 ` [dpdk-stable] [PATCH 3/7] vhost: validate index in guest notification API Maxime Coquelin
2020-10-21 11:30   ` Xia, Chenbo
2020-10-19 17:34 ` [dpdk-stable] [PATCH 4/7] vhost: validate index in live-migration API Maxime Coquelin
2020-10-21 11:30   ` Xia, Chenbo
2020-10-19 17:34 ` [dpdk-stable] [PATCH 5/7] vhost: validate index in inflight API Maxime Coquelin
2020-10-21 11:30   ` Xia, Chenbo
2020-10-19 17:34 ` [dpdk-stable] [PATCH 6/7] vhost: validate index in async API Maxime Coquelin
2020-10-21 11:31   ` Xia, Chenbo

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