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

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Date:   Tue, 5 Mar 2019 17:56:57 +0100
From:   Juergen Gross <jgross@...e.com>
To:     Arnd Bergmann <arnd@...db.de>
Cc:     Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        Stefano Stabellini <sstabellini@...nel.org>,
        Oleksandr Andrushchenko <oleksandr_andrushchenko@...m.com>,
        Paul Durrant <paul.durrant@...rix.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        xen-devel <xen-devel@...ts.xenproject.org>
Subject: Re: [PATCH] [v2] xen: avoid link error on ARM

On 05/03/2019 17:49, Arnd Bergmann wrote:
> On Tue, Mar 5, 2019 at 3:57 PM Juergen Gross <jgross@...e.com> wrote:
>> On 05/03/2019 14:43, Boris Ostrovsky wrote:
>>> On 3/5/19 8:30 AM, Arnd Bergmann wrote:
> 
>>>> @@ -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.
> 
> Putting it into xlate_mmu.c was my first attempt, but I was not sure how to
> solve the dependency on CONFIG_XEN_AUTO_XLATE. So
> xen_feature(XENFEAT_auto_translated_physmap)) would be guaranteed
> to return false if CONFIG_XEN_AUTO_XLATE is disabled?

Yes.


Juergen