lkml.org 
[lkml]   [2019]   [Mar]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 0/9] RFC: NVME VFIO mediated device
On Wed, 20 Mar 2019 18:42:02 +0200
Maxim Levitsky <mlevitsk@redhat.com> wrote:

> On Wed, 2019-03-20 at 08:28 -0700, Bart Van Assche wrote:
> > On Tue, 2019-03-19 at 16:41 +0200, Maxim Levitsky wrote:
> > > * All guest memory is mapped into the physical nvme device
> > > but not 1:1 as vfio-pci would do this.
> > > This allows very efficient DMA.
> > > To support this, patch 2 adds ability for a mdev device to listen on
> > > guest's memory map events.
> > > Any such memory is immediately pinned and then DMA mapped.
> > > (Support for fabric drivers where this is not possible exits too,
> > > in which case the fabric driver will do its own DMA mapping)
> >
> > Does this mean that all guest memory is pinned all the time? If so, are you
> > sure that's acceptable?
> I think so. The VFIO pci passthrough also pins all the guest memory.
> SPDK also does this (pins and dma maps) all the guest memory.
>
> I agree that this is not an ideal solution but this is a fastest and simplest
> solution possible.

FWIW, the pinned memory request up through the vfio iommu driver count
against the user's locked memory limits, if that's the concern. Thanks,

Alex

\
 
 \ /
  Last update: 2019-03-20 18:03    [W:0.045 / U:10.096 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site