Re: [Qemu-devel] [PATCH 4/5] target-arm: get_phys_addr_lpae: more xn control

[Andrew Jones <drjones@redhat.com>]

On Tue, Mar 10, 2015 at 04:55:53PM +0000, Peter Maydell wrote:
> On 10 March 2015 at 16:48, Andrew Jones <drjones@redhat.com> wrote:
> > On Tue, Mar 10, 2015 at 03:56:11PM +0000, Peter Maydell wrote:
> 
> >> For instance, you're missing a shift here on the ap bits, because
> >> get_rw_prot needs AP[2:0] and 'ap' here is AP[2:1].
> >
> > Don't need the shift because get_rw_prot supports the 2-bit format.
> 
> No it doesn't...

Yes it does :-) That's the support patch 2/5 adds.

> 
> >> Doesn't this lose us the "you need read permission to execute"
> >> check (for 32-bit)? Something in here should be doing a
> >> PAGE_READ check to see if we can have PAGE_EXEC.
> >
> > It's there. It's the '!user_rw' and the '!prot_rw'
> 
> Ah yes, and that works because you can't have a page which
> is writable but not readable (which is what I'd forgotten).
> 
> -- PMM