linux-kernel - Re: [PATCH] [v2] xen: avoid link error on ARM

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Date:   Tue, 5 Mar 2019 15:57:44 +0100
From:   Juergen Gross <jgross@...e.com>
To:     Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        Arnd Bergmann <arnd@...db.de>
Cc:     Stefano Stabellini <sstabellini@...nel.org>,
        Oleksandr Andrushchenko <oleksandr_andrushchenko@...m.com>,
        Paul Durrant <paul.durrant@...rix.com>,
        linux-kernel@...r.kernel.org, xen-devel@...ts.xenproject.org
Subject: Re: [PATCH] [v2] xen: avoid link error on ARM

On 05/03/2019 14:43, Boris Ostrovsky wrote:
> On 3/5/19 8:30 AM, Arnd Bergmann wrote:
>>  
>> diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
>> index b24ddac1604b..290b6aca7e1d 100644
>> --- a/drivers/xen/privcmd.c
>> +++ b/drivers/xen/privcmd.c
>> @@ -723,26 +723,6 @@ static long privcmd_ioctl_restrict(struct file *file, void __user *udata)
>>  	return 0;
>>  }
>>  
>> -struct remap_pfn {
>> -	struct mm_struct *mm;
>> -	struct page **pages;
>> -	pgprot_t prot;
>> -	unsigned long i;
>> -};
>> -
>> -static int remap_pfn_fn(pte_t *ptep, pgtable_t token, unsigned long addr,
>> -			void *data)
>> -{
>> -	struct remap_pfn *r = data;
>> -	struct page *page = r->pages[r->i];
>> -	pte_t pte = pte_mkspecial(pfn_pte(page_to_pfn(page), r->prot));
>> -
>> -	set_pte_at(r->mm, addr, ptep, pte);
>> -	r->i++;
>> -
>> -	return 0;
>> -}
>> -
>>  static long privcmd_ioctl_mmap_resource(struct file *file, void __user *udata)
>>  {
>>  	struct privcmd_data *data = file->private_data;
>> @@ -809,15 +789,7 @@ static long privcmd_ioctl_mmap_resource(struct file *file, void __user *udata)
>>  		goto out;
>>  
>>  	if (xen_feature(XENFEAT_auto_translated_physmap)) {
>> -		struct remap_pfn r = {
>> -			.mm = vma->vm_mm,
>> -			.pages = vma->vm_private_data,
>> -			.prot = vma->vm_page_prot,
>> -		};
>> -
>> -		rc = apply_to_page_range(r.mm, kdata.addr,
>> -					 kdata.num << PAGE_SHIFT,
>> -					 remap_pfn_fn, &r);
>> +		rc = xen_remap_vma_range(vma, kdata.addr, kdata.num << PAGE_SHIFT);
> 
> I wonder whether drivers/xen/xlate_mmu.c might be a good place for these
> routines.

Hmm, probably. This would require a stub in the header to avoid
problems in case of CONFIG_XEN_AUTO_XLATE not defined, though
(the #ifdef is already there).

I think this is the cleanest solution.


Juergen