From: Nicolin Chen <nicolinc@nvidia.com>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: <will@kernel.org>, <robin.murphy@arm.com>, <kevin.tian@intel.com>,
<suravee.suthikulpanit@amd.com>, <joro@8bytes.org>,
<linux-kernel@vger.kernel.org>, <iommu@lists.linux.dev>,
<linux-arm-kernel@lists.infradead.org>,
<linux-tegra@vger.kernel.org>, <yi.l.liu@intel.com>,
<eric.auger@redhat.com>, <vasant.hegde@amd.com>,
<jon.grimm@amd.com>, <santosh.shukla@amd.com>,
<Dhaval.Giani@amd.com>, <shameerali.kolothum.thodi@huawei.com>
Subject: Re: [PATCH RFCv1 13/14] iommufd: Add mmap infrastructure
Date: Sun, 12 May 2024 21:43:42 -0700 [thread overview]
Message-ID: <ZkGafm+qAe77bvIW@nvidia.com> (raw)
In-Reply-To: <ZkDd8A2qAYnuxGJQ@nvidia.com>
On Sun, May 12, 2024 at 12:19:12PM -0300, Jason Gunthorpe wrote:
> On Fri, Apr 12, 2024 at 08:47:10PM -0700, Nicolin Chen wrote:
> > Add for sharing the kernel page with user space. This allows to pass
> > through HW resource (VCMDQ MMIO pages for example) to user space VMM
> > and guest OS. Use vma->vm_pgoff as the carrier of a viommu_id.
> >
> > Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
> > ---
> > drivers/iommu/iommufd/main.c | 40 ++++++++++++++++++++++++++++++++++++
> > include/linux/iommufd.h | 4 ++++
> > 2 files changed, 44 insertions(+)
> >
> > diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c
> > index 96ef81530809..5b401c80cca8 100644
> > --- a/drivers/iommu/iommufd/main.c
> > +++ b/drivers/iommu/iommufd/main.c
> > @@ -16,6 +16,7 @@
> > #include <linux/mutex.h>
> > #include <linux/bug.h>
> > #include <uapi/linux/iommufd.h>
> > +#include <linux/iommu.h>
> > #include <linux/iommufd.h>
> >
> > #include "io_pagetable.h"
> > @@ -427,11 +428,50 @@ static long iommufd_fops_ioctl(struct file *filp, unsigned int cmd,
> > return ret;
> > }
> >
> > +static int iommufd_fops_mmap(struct file *filp, struct vm_area_struct *vma)
> > +{
> > + struct iommufd_ctx *ictx = filp->private_data;
> > + size_t size = vma->vm_end - vma->vm_start;
> > + u32 viommu_id = (u32)vma->vm_pgoff;
>
> Don't do mmaps this way, it doesn't scale well for future things.
>
> The pgoff/length should *always* come from the kernel as some
> 'mmap_offset' output. I usually call this the mmap cookie.
>
> In this case have the mmap cookie for the tegra doorbell return in the
> viommu's driver data struct, then userspace just passes the opaque
> cookie to mmap to get the correct tegra doorbell.
>
> The core code has some simple xarray/maple tree to allocate cookies
> and dispatch them to the correct mmap callback. Usually I'd say to
> provide a mmap callback pointer when allocating the cookie.
>
> Also look at the RDMA Code around mmap there is a bunch of VMA
> validations needed. Ie we must insist on VM_SHARED and check
> permissions, etc.
Yea, the vm_pgoff as a carrier is a bit of hack, as mentioned
in the cover-letter. Let me revisit the whole thing and study
from RDMA code also.
Thanks
Nicolin
next prev parent reply other threads:[~2024-05-13 4:44 UTC|newest]
Thread overview: 98+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-13 3:46 [PATCH RFCv1 00/14] Add Tegra241 (Grace) CMDQV Support (part 2/2) Nicolin Chen
2024-04-13 3:46 ` [PATCH RFCv1 01/14] iommufd: Move iommufd_object to public iommufd header Nicolin Chen
2024-05-12 13:21 ` Jason Gunthorpe
2024-05-12 22:40 ` Nicolin Chen
2024-05-13 22:30 ` Jason Gunthorpe
2024-04-13 3:46 ` [PATCH RFCv1 02/14] iommufd: Swap _iommufd_object_alloc and __iommufd_object_alloc Nicolin Chen
2024-05-12 13:26 ` Jason Gunthorpe
2024-05-13 2:29 ` Nicolin Chen
2024-05-13 3:44 ` Nicolin Chen
2024-05-13 22:30 ` Jason Gunthorpe
2024-04-13 3:47 ` [PATCH RFCv1 03/14] iommufd: Prepare for viommu structures and functions Nicolin Chen
2024-05-12 13:42 ` Jason Gunthorpe
2024-05-13 2:35 ` Nicolin Chen
2024-04-13 3:47 ` [PATCH RFCv1 04/14] iommufd: Add struct iommufd_viommu and iommufd_viommu_ops Nicolin Chen
2024-05-12 14:03 ` Jason Gunthorpe
2024-05-13 3:34 ` Nicolin Chen
2024-05-14 15:55 ` Jason Gunthorpe
2024-05-22 8:58 ` Tian, Kevin
2024-05-22 9:57 ` Baolu Lu
2024-05-22 13:39 ` Jason Gunthorpe
2024-05-23 1:43 ` Tian, Kevin
2024-05-23 4:01 ` Nicolin Chen
2024-05-23 5:40 ` Tian, Kevin
2024-05-23 12:58 ` Jason Gunthorpe
2024-05-24 2:16 ` Tian, Kevin
2024-05-24 13:03 ` Jason Gunthorpe
2024-05-24 2:36 ` Tian, Kevin
2024-04-13 3:47 ` [PATCH RFCv1 05/14] iommufd: Add IOMMUFD_OBJ_VIOMMU and IOMMUFD_CMD_VIOMMU_ALLOC Nicolin Chen
2024-05-12 14:27 ` Jason Gunthorpe
2024-05-13 4:33 ` Nicolin Chen
2024-05-14 15:38 ` Jason Gunthorpe
2024-05-15 1:20 ` Nicolin Chen
2024-05-21 18:05 ` Jason Gunthorpe
2024-05-22 0:13 ` Nicolin Chen
2024-05-22 16:46 ` Jason Gunthorpe
2024-04-13 3:47 ` [PATCH RFCv1 06/14] iommufd/selftest: Add IOMMU_VIOMMU_ALLOC test coverage Nicolin Chen
2024-04-13 3:47 ` [PATCH RFCv1 07/14] iommufd: Add viommu set/unset_dev_id ops Nicolin Chen
2024-05-12 14:46 ` Jason Gunthorpe
2024-05-13 4:39 ` Nicolin Chen
2024-05-14 15:53 ` Jason Gunthorpe
2024-05-15 1:59 ` Nicolin Chen
2024-05-21 18:24 ` Jason Gunthorpe
2024-05-21 22:27 ` Nicolin Chen
2024-05-22 13:59 ` Jason Gunthorpe
2024-05-23 6:19 ` Tian, Kevin
2024-05-23 15:01 ` Jason Gunthorpe
2024-05-24 2:21 ` Tian, Kevin
2024-05-24 3:26 ` Nicolin Chen
2024-05-24 5:24 ` Tian, Kevin
2024-05-24 5:57 ` Nicolin Chen
2024-05-24 7:21 ` Tian, Kevin
2024-05-24 13:12 ` Jason Gunthorpe
2024-05-24 13:05 ` Jason Gunthorpe
2024-05-23 5:44 ` Tian, Kevin
2024-05-23 6:09 ` Nicolin Chen
2024-05-23 6:22 ` Tian, Kevin
2024-05-23 13:33 ` Jason Gunthorpe
2024-05-12 14:51 ` Jason Gunthorpe
2024-04-13 3:47 ` [PATCH RFCv1 08/14] iommufd: Add IOMMU_VIOMMU_SET_DEV_ID ioctl Nicolin Chen
2024-05-12 14:58 ` Jason Gunthorpe
2024-05-13 5:24 ` Nicolin Chen
2024-05-17 5:14 ` Nicolin Chen
2024-05-21 18:30 ` Jason Gunthorpe
2024-05-22 2:15 ` Nicolin Chen
2024-05-23 6:42 ` Tian, Kevin
2024-05-24 5:40 ` Nicolin Chen
2024-05-24 7:13 ` Tian, Kevin
2024-05-24 13:19 ` Jason Gunthorpe
2024-05-27 1:08 ` Tian, Kevin
2024-05-28 20:22 ` Nicolin Chen
2024-05-28 20:33 ` Nicolin Chen
2024-05-29 2:58 ` Tian, Kevin
2024-05-29 3:20 ` Nicolin Chen
2024-05-28 20:30 ` Nicolin Chen
2024-05-24 13:20 ` Jason Gunthorpe
2024-04-13 3:47 ` [PATCH RFCv1 09/14] iommufd/selftest: Add IOMMU_VIOMMU_SET_DEV_ID test coverage Nicolin Chen
2024-04-13 3:47 ` [PATCH RFCv1 10/14] iommufd/selftest: Add IOMMU_TEST_OP_MV_CHECK_DEV_ID Nicolin Chen
2024-04-13 3:47 ` [PATCH RFCv1 11/14] iommufd: Add struct iommufd_vqueue and its related viommu ops Nicolin Chen
2024-04-13 3:47 ` [PATCH RFCv1 12/14] iommufd: Add IOMMUFD_OBJ_VQUEUE and IOMMUFD_CMD_VQUEUE_ALLOC Nicolin Chen
2024-05-12 15:02 ` Jason Gunthorpe
2024-05-13 4:41 ` Nicolin Chen
2024-05-13 22:36 ` Jason Gunthorpe
2024-05-23 6:57 ` Tian, Kevin
2024-05-24 4:42 ` Nicolin Chen
2024-05-24 5:26 ` Tian, Kevin
2024-05-24 6:03 ` Nicolin Chen
2024-05-23 7:05 ` Tian, Kevin
2024-04-13 3:47 ` [PATCH RFCv1 13/14] iommufd: Add mmap infrastructure Nicolin Chen
2024-05-12 15:19 ` Jason Gunthorpe
2024-05-13 4:43 ` Nicolin Chen [this message]
2024-04-13 3:47 ` [PATCH RFCv1 14/14] iommu/tegra241-cmdqv: Add user-space use support Nicolin Chen
2024-05-22 8:40 ` [PATCH RFCv1 00/14] Add Tegra241 (Grace) CMDQV Support (part 2/2) Tian, Kevin
2024-05-22 16:48 ` Jason Gunthorpe
2024-05-22 19:47 ` Nicolin Chen
2024-05-22 23:28 ` Jason Gunthorpe
2024-05-22 23:43 ` Tian, Kevin
2024-05-23 3:09 ` Nicolin Chen
2024-05-23 12:48 ` Jason Gunthorpe
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