From: Julien Grall <julien.grall@arm.com>
To: Peng Fan <van.freenix@gmail.com>
Cc: sstabellini@kernel.org, xen-devel@lists.xen.org
Subject: Re: [PATCH] xen/arm: mm: optimize setup_pagetables
Date: Wed, 11 May 2016 11:03:06 +0100 [thread overview]
Message-ID: <5733035A.2090403@arm.com> (raw)
In-Reply-To: <20160511095719.GA21540@linux-7smt.suse>
On 11/05/2016 10:57, Peng Fan wrote:
> Hi Julien,
Hi Peng,
> On Wed, May 11, 2016 at 10:31:49AM +0100, Julien Grall wrote:
>>
>> [...]
>>
>>> diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
>>> index 94ea054..bebd82f 100644
>>> --- a/xen/arch/arm/mm.c
>>> +++ b/xen/arch/arm/mm.c
>>> @@ -443,12 +443,6 @@ void __init setup_pagetables(unsigned long boot_phys_offset, paddr_t xen_paddr)
>>> lpae_t pte, *p;
>>> int i;
>>>
>>> - /* Map the destination in the boot misc area. */
>>> - dest_va = BOOT_RELOC_VIRT_START;
>>> - pte = mfn_to_xen_entry(xen_paddr >> PAGE_SHIFT, WRITEALLOC);
>>> - write_pte(xen_second + second_table_offset(dest_va), pte);
>>> - flush_xen_data_tlb_range_va_local(dest_va, SECOND_SIZE);
>>> -
>>> /* Calculate virt-to-phys offset for the new location */
>>> phys_offset = xen_paddr - (unsigned long) _start;
>>>
>>> @@ -498,6 +492,11 @@ void __init setup_pagetables(unsigned long boot_phys_offset, paddr_t xen_paddr)
>>> /* Map the destination in the boot misc area. */
>>> dest_va = BOOT_RELOC_VIRT_START;
>>> pte = mfn_to_xen_entry(xen_paddr >> PAGE_SHIFT, WRITEALLOC);
>>> + xen_second[second_table_offset(dest_va)] = pte;
>>> +
>>> + /* Map the destination in the boot misc area. */
>>> + dest_va = BOOT_RELOC_VIRT_START;
>>> + pte = mfn_to_xen_entry(xen_paddr >> PAGE_SHIFT, WRITEALLOC);
>>
>> Why do you need to recompute "pte" and "dest_va"? They will be the same for
>> "boot_second" and "xen_second".
>
> I just change "write_pte(xen_second + second_table_offset(dest_va), pte);" to
> "xen_second[second_table_offset(dest_va)] = pte;".
>
> The pte and dest_va are not changed.
So you could do some like:
/* Comment */
dest_va = BOOT...
pte = ...
/* Comment */
xen_second[...] = pte
/* Comment */
write_pte(boot_second...);
Regards,
--
Julien Grall
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next prev parent reply other threads:[~2016-05-11 10:03 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-11 7:59 [PATCH] xen/arm: mm: optimize setup_pagetables Peng Fan
2016-05-11 9:31 ` Julien Grall
2016-05-11 9:57 ` Peng Fan
2016-05-11 10:03 ` Julien Grall [this message]
2016-05-11 10:08 ` Peng Fan
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