Messages in this thread | | | Date | Tue, 10 Oct 2023 08:33:57 -0300 | From | Jason Gunthorpe <> | Subject | Re: [PATCH v11 1/1] vfio/nvgpu: Add vfio pci variant module for grace hopper |
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On Tue, Oct 10, 2023 at 08:42:13AM +0000, Tian, Kevin wrote: > > From: ankita@nvidia.com <ankita@nvidia.com> > > Sent: Sunday, October 8, 2023 4:23 AM > > > > PCI BAR are aligned to the power-of-2, but the actual memory on the > > device may not. A read or write access to the physical address from the > > last device PFN up to the next power-of-2 aligned physical address > > results in reading ~0 and dropped writes. > > > > my question to v10 was not answered. posted again: > -- > Though the variant driver emulates the access to the offset beyond > the available memory size, how does the userspace driver or the guest > learn to know the actual size and avoid using the invalid hole to hold > valid data?
The device FW knows and tells the VM.
Jason
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