Hi Stefano,
On 06/16/2017 06:33 PM, Stefano Stabellini wrote:
On Fri, 16 Jun 2017, Julien Grall wrote:
Hi Stefano,
On 15/06/2017 23:28, Stefano Stabellini wrote:
On Tue, 13 Jun 2017, Julien Grall wrote:
xenheap_mfn_end is storing an MFN and not a physical address. Thankfully
xenheap_mfn_end is not used in the arm64 code. So drop it.
That's fine, but in that case I would prefer to move the definition of
xenheap_mfn_end under #ifdef CONFIG_ARM_32. In fact, there is another
assignment of xenheap_mfn_end few lines below in the arm64 version of
setup_mm: don't we need to remove that too?
The other xenheap_mfn_end contains valid mfn that point to the end and I
didn't want to #ifdef it because:
1) It complexify the code
2) All regions should be bound with start/end to simplify potential
use.
I am only suggesting to move its definition and declaration under #ifdef
CONFIG_ARM_32 in xen/include/asm-arm/mm.h and xen/arch/arm/mm.c.
After that, all users of xenheap_mfn_end are already #ifdef
CONFIG_ARM_32, except for xen/arch/arm/setup.c:setup_mm. The setup_mm
under #ifdef CONFIG_ARM_32 will be fine. The setup_mm under
#ifdef CONFIG_ARM_64, doesn't need xenheap_mfn_end and we could just
remove it from there.
Does it make sense? Am I missing something?
To be honest, I really want to limit the ifdefery in the mm code. This
is a bit complex to follow. One of my side project is to look at that.
Also, even if xenheap_mfn_end today is not used, I think the current
value is valid and could be helpful to have in hand. For instance, it
does not seem justify to have different implementation of at least
is_xen_heap_page for arm32 and arm64.
So I am not in favor of dropping xenheap_mfn_end at the moment.
Cheers,
--
Julien Grall
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