lkml.org 
[lkml]   [2012]   [Sep]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v6 12/12] KVM: indicate readonly access fault
On Wed, Sep 12, 2012 at 06:34:33PM +0300, Avi Kivity wrote:
> On 09/11/2012 05:39 PM, Marcelo Tosatti wrote:
> > On Tue, Sep 11, 2012 at 12:18:22PM +0300, Avi Kivity wrote:
> >> > The same can happen with slot deletion, for example.
> >> >
> >> > Userspace (which performed the modification which can result in faults
> >> > to non-existant/read-only/.../new-tag memslot), must handle the faults
> >> > properly or avoid the possibility for reference to memslot information
> >> > from the past.
> >> >
> >> > I think its worthwhile to add a note about this in the API
> >> > documentation: "The user of this interface is responsible for handling
> >> > references to stale memslot information, either by handling
> >> > exit notifications which reference stale memslot information or not
> >> > allowing these notifications to exist by stopping all vcpus in userspace
> >> > before performing modifications to the memslots map".
> >>
> >> Or we can drop the new interface and rely on userspace to perform the
> >> lookup under its own locking rules.
> >>
> >> It's slow, but writes to ROM or ROM/device are rare anyway.
> >
> > Lookup what information?
>
> Where to dispatch the write.
>
> In fact userspace has to do that anyway if it's a ROM/device. There's
> no way userspace can guess that unless we pass in the slot number (which
> isn't synchronized with anything).

Alright, do you prefer the details of this exit to be worked out later,
when necessary, then?

That is, not merge this particular patch of the series?



\
 
 \ /
  Last update: 2012-09-12 18:41    [W:0.112 / U:12.932 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site