From: Jason Gunthorpe <jgg@nvidia.com>
To: Ankit Agrawal <ankita@nvidia.com>
Cc: "alex.williamson@redhat.com" <alex.williamson@redhat.com>,
Yishai Hadas <yishaih@nvidia.com>,
"shameerali.kolothum.thodi@huawei.com"
<shameerali.kolothum.thodi@huawei.com>,
"kevin.tian@intel.com" <kevin.tian@intel.com>,
Aniket Agashe <aniketa@nvidia.com>, Neo Jia <cjia@nvidia.com>,
Kirti Wankhede <kwankhede@nvidia.com>,
"Tarun Gupta (SW-GPU)" <targupta@nvidia.com>,
Vikram Sethi <vsethi@nvidia.com>,
Andy Currid <acurrid@nvidia.com>,
Alistair Popple <apopple@nvidia.com>,
John Hubbard <jhubbard@nvidia.com>,
Dan Williams <danw@nvidia.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v7 1/1] vfio/nvgpu: Add vfio pci variant module for grace hopper
Date: Wed, 23 Aug 2023 11:25:11 -0300 [thread overview]
Message-ID: <ZOYWx+ny0bCJYtbD@nvidia.com> (raw)
In-Reply-To: <BY5PR12MB37635FB280AECC6A4CF59431B01CA@BY5PR12MB3763.namprd12.prod.outlook.com>
On Wed, Aug 23, 2023 at 02:18:52PM +0000, Ankit Agrawal wrote:
> >> +
> >> + /*
> >> + * Handle read on the BAR2 region. Map to the target device memory
> >> + * physical address and copy to the request read buffer.
> >> + */
> >> + if (copy_to_user(buf, (u8 *)addr + offset, read_count))
> >> + return -EFAULT;
> >
> > Just to verify, does this memory allow access of arbitrary alignment
> > and size?
>
> Please correct me if I'm wrong, but based on following gdb dump data on
> the corresponding MemoryRegion->ops, unaligned access isn't supported, and
> a read of size upto 8 may be done.
Regardless, you used MEMREMAP_WB which is equivalent to normal system
memory. It supports all accesses, including atomics, and doesn't
require __iomem accessors.
Jason
next prev parent reply other threads:[~2023-08-23 14:25 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-22 20:23 [PATCH v7 1/1] vfio/nvgpu: Add vfio pci variant module for grace hopper ankita
2023-08-22 22:29 ` Alex Williamson
2023-08-23 13:56 ` Jason Gunthorpe
2023-08-23 14:18 ` Ankit Agrawal
2023-08-23 14:25 ` Jason Gunthorpe [this message]
2023-08-23 14:26 ` Alex Williamson
2023-08-23 14:50 ` Ankit Agrawal
2023-08-23 15:14 ` Alex Williamson
2023-08-23 15:16 ` Jason Gunthorpe
2023-08-23 15:24 ` Alex Williamson
2023-08-30 13:50 ` Christoph Hellwig
2023-08-30 15:39 ` Jason Gunthorpe
2023-08-31 12:26 ` Christoph Hellwig
2023-08-31 13:51 ` Ankit Agrawal
2023-08-31 14:04 ` Christoph Hellwig
2023-08-31 18:21 ` Alex Williamson
2023-09-01 0:44 ` Jason Gunthorpe
2023-09-01 5:48 ` Christoph Hellwig
2023-09-01 5:47 ` Christoph Hellwig
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