From: Jason Gunthorpe <jgg@nvidia.com>
To: Nicolin Chen <nicolinc@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 12:19:12 -0300 [thread overview]
Message-ID: <ZkDd8A2qAYnuxGJQ@nvidia.com> (raw)
In-Reply-To: <6fef9ff9944381d51dd18f83ec03785a26754dcf.1712978213.git.nicolinc@nvidia.com>
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.
Jason
next prev parent reply other threads:[~2024-05-12 15:19 UTC|newest]
Thread overview: 75+ 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
2024-04-13 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
2024-05-23 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
2024-04-13 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
2024-05-23 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 [this message]
2024-05-13 4:43 ` Nicolin Chen
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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