From: "Liu, Yi L" <yi.l.liu@intel.com>
To: Alex Williamson <alex.williamson@redhat.com>
Cc: "jean-philippe@linaro.org" <jean-philippe@linaro.org>,
"Tian, Kevin" <kevin.tian@intel.com>,
"Raj, Ashok" <ashok.raj@intel.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"Tian, Jun J" <jun.j.tian@intel.com>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"Sun, Yi Y" <yi.y.sun@intel.com>, "Wu, Hao" <hao.wu@intel.com>
Subject: RE: [PATCH v1 1/8] vfio: Add VFIO_IOMMU_PASID_REQUEST(alloc/free)
Date: Wed, 8 Apr 2020 00:52:46 +0000 [thread overview]
Message-ID: <A2975661238FB949B60364EF0F2C25743A225A3C@SHSMSX104.ccr.corp.intel.com> (raw)
In-Reply-To: <20200403115011.4aba8ff3@w520.home>
Hi Alex,
> From: Alex Williamson <alex.williamson@redhat.com>
> Sent: Saturday, April 4, 2020 1:50 AM
> Subject: Re: [PATCH v1 1/8] vfio: Add VFIO_IOMMU_PASID_REQUEST(alloc/free)
>
> On Fri, 3 Apr 2020 13:12:50 +0000
> "Liu, Yi L" <yi.l.liu@intel.com> wrote:
>
> > Hi Alex,
> >
> > > From: Alex Williamson <alex.williamson@redhat.com>
> > > Sent: Friday, April 3, 2020 1:50 AM
> > > Subject: Re: [PATCH v1 1/8] vfio: Add VFIO_IOMMU_PASID_REQUEST(alloc/free)
> > >
> > > On Sun, 22 Mar 2020 05:31:58 -0700
> > > "Liu, Yi L" <yi.l.liu@intel.com> wrote:
> > >
> > > > From: Liu Yi L <yi.l.liu@intel.com>
> > > >
[...]
> > > > static long vfio_iommu_type1_ioctl(void *iommu_data,
> > > > unsigned int cmd, unsigned long arg)
> > > > {
> > > > @@ -2276,6 +2333,53 @@ static long vfio_iommu_type1_ioctl(void
> > > *iommu_data,
> > > >
> > > > return copy_to_user((void __user *)arg, &unmap, minsz) ?
> > > > -EFAULT : 0;
> > > > +
> > > > + } else if (cmd == VFIO_IOMMU_PASID_REQUEST) {
> > > > + struct vfio_iommu_type1_pasid_request req;
> > > > + unsigned long offset;
> > > > +
> > > > + minsz = offsetofend(struct vfio_iommu_type1_pasid_request,
> > > > + flags);
> > > > +
> > > > + if (copy_from_user(&req, (void __user *)arg, minsz))
> > > > + return -EFAULT;
> > > > +
> > > > + if (req.argsz < minsz ||
> > > > + !vfio_iommu_type1_pasid_req_valid(req.flags))
> > > > + return -EINVAL;
> > > > +
> > > > + if (copy_from_user((void *)&req + minsz,
> > > > + (void __user *)arg + minsz,
> > > > + sizeof(req) - minsz))
> > > > + return -EFAULT;
> > >
> > > Huh? Why do we have argsz if we're going to assume this is here?
> >
> > do you mean replacing sizeof(req) with argsz? if yes, I can do that.
>
> No, I mean the user tells us how much data they've provided via argsz.
> We create minsz the the end of flags and verify argsz includes flags.
> Then we proceed to ignore argsz to see if the user has provided the
> remainder of the structure.
I think I should avoid using sizeof(req) as it may be variable
new flag is added. I think better to make a data[] field in struct
vfio_iommu_type1_pasid_request and copy data[] per flag. I'll
make this change in new version.
> > > > +
> > > > + switch (req.flags & VFIO_PASID_REQUEST_MASK) {
> > > > + case VFIO_IOMMU_PASID_ALLOC:
> > > > + {
> > > > + int ret = 0, result;
> > > > +
> > > > + result = vfio_iommu_type1_pasid_alloc(iommu,
> > > > + req.alloc_pasid.min,
> > > > + req.alloc_pasid.max);
> > > > + if (result > 0) {
> > > > + offset = offsetof(
> > > > + struct vfio_iommu_type1_pasid_request,
> > > > + alloc_pasid.result);
> > > > + ret = copy_to_user(
> > > > + (void __user *) (arg + offset),
> > > > + &result, sizeof(result));
> > >
> > > Again assuming argsz supports this.
> >
> > same as above.
> >
> > >
> > > > + } else {
> > > > + pr_debug("%s: PASID alloc failed\n", __func__);
> > >
> > > rate limit?
> >
> > not quite get. could you give more hints?
>
> A user can spam the host logs simply by allocating their quota of
> PASIDs and then trying to allocate more, or by specifying min/max such
> that they cannot allocate the requested PASID. If this logging is
> necessary for debugging, it should be ratelimited to avoid a DoS on the
> host.
got it. thanks for the coaching. will use pr_debug_ratelimited().
Regards,
Yi Liu
_______________________________________________
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iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2020-04-08 0:52 UTC|newest]
Thread overview: 110+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-22 12:31 [PATCH v1 0/8] vfio: expose virtual Shared Virtual Addressing to VMs Liu, Yi L
2020-03-22 12:31 ` [PATCH v1 1/8] vfio: Add VFIO_IOMMU_PASID_REQUEST(alloc/free) Liu, Yi L
2020-03-22 16:21 ` kbuild test robot
2020-03-30 8:32 ` Tian, Kevin
2020-03-30 14:36 ` Liu, Yi L
2020-03-31 5:40 ` Tian, Kevin
2020-03-31 13:22 ` Liu, Yi L
2020-04-01 5:43 ` Tian, Kevin
2020-04-01 5:48 ` Liu, Yi L
2020-03-31 7:53 ` Christoph Hellwig
2020-03-31 8:17 ` Liu, Yi L
2020-03-31 8:32 ` Liu, Yi L
2020-03-31 8:36 ` Liu, Yi L
2020-03-31 9:15 ` Christoph Hellwig
2020-04-02 13:52 ` Jean-Philippe Brucker
2020-04-03 11:56 ` Liu, Yi L
2020-04-03 12:39 ` Jean-Philippe Brucker
2020-04-03 12:44 ` Liu, Yi L
2020-04-02 17:50 ` Alex Williamson
2020-04-03 5:58 ` Tian, Kevin
2020-04-03 15:14 ` Alex Williamson
2020-04-07 4:42 ` Tian, Kevin
2020-04-07 15:14 ` Alex Williamson
2020-04-03 13:12 ` Liu, Yi L
2020-04-03 17:50 ` Alex Williamson
2020-04-07 4:52 ` Tian, Kevin
2020-04-08 0:52 ` Liu, Yi L [this message]
2020-03-22 12:31 ` [PATCH v1 2/8] vfio/type1: Add vfio_iommu_type1 parameter for quota tuning Liu, Yi L
2020-03-22 17:20 ` kbuild test robot
2020-03-30 8:40 ` Tian, Kevin
2020-03-30 8:52 ` Liu, Yi L
2020-03-30 9:19 ` Tian, Kevin
2020-03-30 9:26 ` Liu, Yi L
2020-03-30 11:44 ` Tian, Kevin
2020-04-02 17:58 ` Alex Williamson
2020-04-03 8:15 ` Liu, Yi L
2020-03-22 12:32 ` [PATCH v1 3/8] vfio/type1: Report PASID alloc/free support to userspace Liu, Yi L
2020-03-30 9:43 ` Tian, Kevin
2020-04-01 7:46 ` Liu, Yi L
2020-04-01 9:41 ` Auger Eric
2020-04-01 13:13 ` Liu, Yi L
2020-04-02 18:01 ` Alex Williamson
2020-04-03 8:17 ` Liu, Yi L
2020-04-03 17:28 ` Alex Williamson
2020-04-04 11:36 ` Liu, Yi L
2020-03-22 12:32 ` [PATCH v1 4/8] vfio: Check nesting iommu uAPI version Liu, Yi L
2020-03-22 18:30 ` kbuild test robot
2020-03-22 12:32 ` [PATCH v1 5/8] vfio/type1: Report 1st-level/stage-1 format to userspace Liu, Yi L
2020-03-22 16:44 ` kbuild test robot
2020-03-30 11:48 ` Tian, Kevin
2020-04-01 7:38 ` Liu, Yi L
2020-04-01 7:56 ` Tian, Kevin
2020-04-01 8:06 ` Liu, Yi L
2020-04-01 8:08 ` Tian, Kevin
2020-04-01 8:09 ` Liu, Yi L
2020-04-01 8:51 ` Auger Eric
2020-04-01 12:51 ` Liu, Yi L
2020-04-01 13:01 ` Auger Eric
2020-04-03 8:23 ` Jean-Philippe Brucker
2020-04-07 9:43 ` Liu, Yi L
2020-04-08 1:02 ` Liu, Yi L
2020-04-08 10:27 ` Auger Eric
2020-04-09 8:14 ` Jean-Philippe Brucker
2020-04-09 9:01 ` Auger Eric
2020-04-09 12:47 ` Liu, Yi L
2020-04-10 3:28 ` Auger Eric
2020-04-10 3:48 ` Liu, Yi L
2020-04-10 12:30 ` Liu, Yi L
2020-04-02 19:20 ` Alex Williamson
2020-04-03 11:59 ` Liu, Yi L
2020-03-22 12:32 ` [PATCH v1 6/8] vfio/type1: Bind guest page tables to host Liu, Yi L
2020-03-22 18:10 ` kbuild test robot
2020-03-30 12:46 ` Tian, Kevin
2020-04-01 9:13 ` Liu, Yi L
2020-04-02 2:12 ` Tian, Kevin
2020-04-02 8:05 ` Liu, Yi L
2020-04-03 8:34 ` Jean-Philippe Brucker
2020-04-07 10:33 ` Liu, Yi L
2020-04-09 8:28 ` Jean-Philippe Brucker
2020-04-09 9:15 ` Liu, Yi L
2020-04-09 9:38 ` Jean-Philippe Brucker
2020-04-02 19:57 ` Alex Williamson
2020-04-03 13:30 ` Liu, Yi L
2020-04-03 18:11 ` Alex Williamson
2020-04-04 10:28 ` Liu, Yi L
2020-04-11 5:52 ` Liu, Yi L
2020-03-22 12:32 ` [PATCH v1 7/8] vfio/type1: Add VFIO_IOMMU_CACHE_INVALIDATE Liu, Yi L
2020-03-30 12:58 ` Tian, Kevin
2020-04-01 7:49 ` Liu, Yi L
2020-03-31 7:56 ` Christoph Hellwig
2020-03-31 10:48 ` Liu, Yi L
2020-04-02 20:24 ` Alex Williamson
2020-04-03 6:39 ` Tian, Kevin
2020-04-03 15:31 ` Jacob Pan
2020-04-03 15:34 ` Alex Williamson
2020-04-08 2:28 ` Liu, Yi L
2020-04-16 10:40 ` Liu, Yi L
2020-04-16 12:09 ` Tian, Kevin
2020-04-16 12:42 ` Auger Eric
2020-04-16 13:28 ` Tian, Kevin
2020-04-16 15:12 ` Auger Eric
2020-04-16 14:40 ` Alex Williamson
2020-04-16 14:48 ` Alex Williamson
2020-04-17 6:03 ` Liu, Yi L
2020-03-22 12:32 ` [PATCH v1 8/8] vfio/type1: Add vSVA support for IOMMU-backed mdevs Liu, Yi L
2020-03-30 13:18 ` Tian, Kevin
2020-04-01 7:51 ` Liu, Yi L
2020-04-02 20:33 ` Alex Williamson
2020-04-03 13:39 ` Liu, Yi L
2020-03-26 12:56 ` [PATCH v1 0/8] vfio: expose virtual Shared Virtual Addressing to VMs Liu, Yi L
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