Re: [Qemu-devel] [RFC PATCH] pc: align gpa<->hpa on 1GB boundary by splitting RAM on several regions

[Marcelo Tosatti]

On Wed, Oct 30, 2013 at 04:51:29PM -0200, Marcelo Tosatti wrote:
> On Wed, Oct 30, 2013 at 05:49:49PM +0100, Igor Mammedov wrote:
> > On Tue, 29 Oct 2013 19:38:44 -0200
> > Marcelo Tosatti <address@hidden> wrote:
> > 
> > > On Tue, Oct 29, 2013 at 07:18:49PM +0100, Igor Mammedov wrote:
> > > > Otherwise 1GB TLBs cannot be cached for the range.
> > > 
> > > This fails to back non-1GB-aligned gpas, but 2MB aligned, with 2MB large
> > > pages.
> > With current command line only one hugetlbfs mount point is possible, so it
> > will back with whatever alignment specified hugetlbfs mount point has.
> > Anything that doesn't fit into page aligned region goes to tail using
> > non hugepage baked phys_mem_set_alloc()=qemu_anon_ram_alloc() allocator.
> 
> The patch you propose allocates the non-1GB aligned tail of RAM with 4k
> pages. As mentioned, this is not acceptable (2MB pages should be used
> whenever 1GB alignment is not possible).

Tail and 3-4GB region.