lkml.org 
[lkml]   [2023]   [May]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 2/4] x86: always initialize xen-swiotlb when xen-pcifront is enabling
On Fri, May 19, 2023 at 12:10:26PM +0200, Marek Marczykowski-Górecki wrote:
> While I would say PCI passthrough is not very common for PV guests, can
> the decision about xen-swiotlb be delayed until you can enumerate
> xenstore to check if there are any PCI devices connected (and not
> allocate xen-swiotlb by default if there are none)? This would
> still not cover the hotplug case (in which case, you'd need to force it
> with a cmdline), but at least you wouldn't loose much memory just
> because one of your VMs may use PCI passthrough (so, you have it enabled
> in your kernel).

How early can we query xenstore? We'd need to do this before setting
up DMA for any device.

The alternative would be to finally merge swiotlb-xen into swiotlb, in
which case we might be able to do this later. Let me see what I can
do there.

\
 
 \ /
  Last update: 2023-05-19 14:43    [W:0.083 / U:0.324 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site