Hi Vijay,
On 03/15/2017 05:11 AM, Vijay Kilari wrote:
On Tue, Mar 14, 2017 at 9:02 PM, Julien Grall <julien.gr...@arm.com> wrote:
Hello Vijay,
On 13/03/17 11:43, vijay.kil...@gmail.com wrote:
From: Vijaya Kumar K <vijaya.ku...@cavium.com>
On ARM, virt_to_mfn uses the hardware for address
translation. So if the virtual address is not mapped translation
fault is raised.On ARM, DIRECTMAP_VIRT region is direct mapped.
This is not true. As I said before, all the memory will be direct mapped on
ARM64 but not on ARM32.
For ARM32, only xenheap will be direct mapped. So you may want to return
is_xenheap_mfn(...). Or even return false in all the case. Either is fine by
me, but it would need to be explained in the code.
Is this ok?.
/*
* On ARM64 DIRECTMAP_VIRT region is directly mapped. Hence return true;
* On ARM only xenheap memory is directly mapped. Hence return false.
*/
static inline bool_t arch_mfn_below_directmap_max_mfn(unsigned long mfn)
{
#ifdef CONFIG_ARM_64
return true;
#else
return false;
#endif
}
I would implement the helper in {arm32,arm64}/mm.h and avoid the #ifdef
in the implementation.
Cheers,
--
Julien Grall
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