From mboxrd@z Thu Jan  1 00:00:00 1970
From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Subject: Re: [PATCH v2 1/4] pci: Do not ignore device's PXM
	information
Date: Wed, 07 Jan 2015 09:42:30 -0500
Message-ID: <54AD45D6.6040601@oracle.com>
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To: Jan Beulich <JBeulich@suse.com>
Cc: wei.liu2@citrix.com, ian.campbell@citrix.com, stefano.stabellini@eu.citrix.com, andrew.cooper3@citrix.com, dario.faggioli@citrix.com, ian.jackson@eu.citrix.com, xen-devel@lists.xen.org, ufimtseva@gmail.com, keir@xen.org
List-Id: xen-devel@lists.xenproject.org

On 01/07/2015 04:06 AM, Jan Beulich wrote:
>>>> On 06.01.15 at 03:18, <boris.ostrovsky@oracle.com> wrote:
>> @@ -618,7 +620,22 @@ ret_t do_physdev_op(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
>>           }
>>           else
>>               pdev_info.is_virtfn = 0;
>> -        ret = pci_add_device(add.seg, add.bus, add.devfn, &pdev_info);
>> +
>> +        if ( add.flags & XEN_PCI_DEV_PXM )
>> +        {
>> +            uint32_t pxm;
>> +            int optarr_off = offsetof(struct physdev_pci_device_add, optarr) /
> unsigned int or size_t.
>
>> --- a/xen/include/xen/pci.h
>> +++ b/xen/include/xen/pci.h
>> @@ -56,6 +56,8 @@ struct pci_dev {
>>   
>>       u8 phantom_stride;
>>   
>> +    int node; /* NUMA node */
> I thought I asked about this on v1 already: Does this really need to be
> an int, when commonly node numbers are stored in u8/unsigned char?
> Shrinking the field size would prevent the structure size from growing...


I kept this field as an int to be able to store NUMA_NO_NODE which I 
thought to be (int)-1.

But now I see that NUMA_NO_NODE is, in fact, 0xff but is promoted to 
(int)-1 by pxm_to_node(). Given that there is a number of tests for 
NUMA_NO_NODE and not for (int)-1, should we then make pxm_to_node() 
return u8 as well?


> Of course an additional question would be whether the node wouldn't
> better go into struct arch_pci_dev - that depends on whether we
> expect ARM to be using NUMA...
>

Since we have CPU topology in common code I thought this would be 
arch-independent as well.

-boris