RE: Introducing paravirt_ops for x86_64

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Glauber de Oliveira Costa wrote:
> On 8/8/07, Nakajima, Jun <[email protected]> wrote:
> > Glauber de Oliveira Costa wrote:
> > > Hi folks,
> > > 
> > > After some time away from it, and a big rebase as a consequence,
here is
> > > the updated version of paravirt_ops for x86_64, heading to
inclusion.
> > > 
> > > Your criticism is of course, very welcome.
> > > 
> > > Have fun
> > 
> > Do you assume that the kernel ougtht to use 2MB pages for its
mappings
> > (e.g. initilal text/data,  direct mapping of physical memory) under
your
> > paravirt_ops?  As far as I look at the patches, I don't find one.
> 
> I don't think how it could be relevant here. lguest kernel does use
> 2MB pages, and it goes smootly. For 2MB pages, we will update the page
> tables in the very same way, and in the very places we did before.
> Just that the operations can now be overwritten.
> 
> So, unless I'm very wrong,  it only makes sense to talk about not
> supporting large pages in the guest level. But it is not a
> paravirt_ops problem.

Some MMU-related PV techiniques (including Xen, and direct paging mode
for Xen/KVM) need to write-protect page tables, avoiding to use 2MB
pages when mapping page tables. Looks like you did not, and that
exaplains why the patches are missing the relevant (many) paravirt_ops
in include/asm-x86_64/pgalloc.h, for example, compared with the i386
tree. 

Jun
---
Intel Open Source Technology Center
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux