From: "Michael S. Tsirkin" <mst@redhat.com> To: Greg Kurz <groug@kaod.org> Cc: Jason Wang <jasowang@redhat.com>, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, Laurent Vivier <laurent@vivier.eu>, David Gibson <david@gibson.dropbear.id.au> Subject: Re: [PATCH] vhost: Don't call vq_access_ok() when using IOTLB Date: Mon, 28 Sep 2020 15:29:25 -0400 [thread overview] Message-ID: <20200928152859-mutt-send-email-mst@kernel.org> (raw) In-Reply-To: <160129650442.480158.12085353517983890660.stgit@bahia.lan> On Mon, Sep 28, 2020 at 02:35:04PM +0200, Greg Kurz wrote: > When the IOTLB device is enabled, the vring addresses we get from > userspace are GIOVAs. It is thus wrong to pass them to vq_access_ok() > which only takes HVAs. The IOTLB map is likely empty at this stage, > so there isn't much that can be done with these GIOVAs. Access validation > will be performed at IOTLB prefetch time anyway. > > BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1883084 > Fixes: 6b1e6cc7855b ("vhost: new device IOTLB API") > Cc: jasowang@redhat.com > CC: stable@vger.kernel.org # 4.14+ > Signed-off-by: Greg Kurz <groug@kaod.org> Hmm I was sure the addresses are HVAs in any case ... Jason? > --- > drivers/vhost/vhost.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > index b45519ca66a7..6296e33df31d 100644 > --- a/drivers/vhost/vhost.c > +++ b/drivers/vhost/vhost.c > @@ -1509,7 +1509,10 @@ static long vhost_vring_set_addr(struct vhost_dev *d, > * If it is not, we don't as size might not have been setup. > * We will verify when backend is configured. */ > if (vq->private_data) { > - if (!vq_access_ok(vq, vq->num, > + /* If an IOTLB device is present, the vring addresses are > + * GIOVAs. Access will be validated during IOTLB prefetch. */ > + if (!vq->iotlb && > + !vq_access_ok(vq, vq->num, > (void __user *)(unsigned long)a.desc_user_addr, > (void __user *)(unsigned long)a.avail_user_addr, > (void __user *)(unsigned long)a.used_user_addr)) >
WARNING: multiple messages have this Message-ID (diff)
From: "Michael S. Tsirkin" <mst@redhat.com> To: Greg Kurz <groug@kaod.org> Cc: kvm@vger.kernel.org, netdev@vger.kernel.org, Laurent Vivier <laurent@vivier.eu>, virtualization@lists.linux-foundation.org, David Gibson <david@gibson.dropbear.id.au> Subject: Re: [PATCH] vhost: Don't call vq_access_ok() when using IOTLB Date: Mon, 28 Sep 2020 15:29:25 -0400 [thread overview] Message-ID: <20200928152859-mutt-send-email-mst@kernel.org> (raw) In-Reply-To: <160129650442.480158.12085353517983890660.stgit@bahia.lan> On Mon, Sep 28, 2020 at 02:35:04PM +0200, Greg Kurz wrote: > When the IOTLB device is enabled, the vring addresses we get from > userspace are GIOVAs. It is thus wrong to pass them to vq_access_ok() > which only takes HVAs. The IOTLB map is likely empty at this stage, > so there isn't much that can be done with these GIOVAs. Access validation > will be performed at IOTLB prefetch time anyway. > > BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1883084 > Fixes: 6b1e6cc7855b ("vhost: new device IOTLB API") > Cc: jasowang@redhat.com > CC: stable@vger.kernel.org # 4.14+ > Signed-off-by: Greg Kurz <groug@kaod.org> Hmm I was sure the addresses are HVAs in any case ... Jason? > --- > drivers/vhost/vhost.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > index b45519ca66a7..6296e33df31d 100644 > --- a/drivers/vhost/vhost.c > +++ b/drivers/vhost/vhost.c > @@ -1509,7 +1509,10 @@ static long vhost_vring_set_addr(struct vhost_dev *d, > * If it is not, we don't as size might not have been setup. > * We will verify when backend is configured. */ > if (vq->private_data) { > - if (!vq_access_ok(vq, vq->num, > + /* If an IOTLB device is present, the vring addresses are > + * GIOVAs. Access will be validated during IOTLB prefetch. */ > + if (!vq->iotlb && > + !vq_access_ok(vq, vq->num, > (void __user *)(unsigned long)a.desc_user_addr, > (void __user *)(unsigned long)a.avail_user_addr, > (void __user *)(unsigned long)a.used_user_addr)) > _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
next prev parent reply other threads:[~2020-09-28 19:29 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-09-28 12:35 [PATCH] vhost: Don't call vq_access_ok() when using IOTLB Greg Kurz 2020-09-28 19:29 ` Michael S. Tsirkin [this message] 2020-09-28 19:29 ` Michael S. Tsirkin 2020-09-29 7:45 ` Michael S. Tsirkin 2020-09-29 7:45 ` Michael S. Tsirkin 2020-09-29 8:44 ` Greg Kurz
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