Re: [Xen-devel] [PATCH 6/7] x86/pagewalk: Consistently use guest_walk_*() helpers for translation

[Tim Deegan <tim@xxxxxxx>]

At 14:03 +0000 on 27 Feb (1488204197), Andrew Cooper wrote:
> hap_p2m_ga_to_gfn() and sh_page_fault() currently use guest_l1e_get_gfn() to
> obtain the translation of a pagewalk.  This is conceptually wrong (the
> semantics of gw.l1e is an internal detail), and will actually be wrong when
> PSE36 superpage support is fixed.  Switch them to using guest_walk_to_gfn().
> 
> Take the opportunity to const-correct the walk_t parameter of the
> guest_walk_to_*() helpers, and implement guest_walk_to_gpa() in terms of
> guest_walk_to_gfn() to avoid duplicating the actual translation calculation.
> 
> While editing guest_walk_to_gpa(), fix a latent bug by causing it to return
> INVALID_PADDR rather than 0 for a failed translation, as 0 is also a valid
> successful result.  The sole caller, sh_page_fault(), has already confirmed
> that the translation is valid, so this doesn't cause a behavioural change.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>

Reviewed-by: Tim Deegan <tim@xxxxxxx>

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel