linux-kernel - Re: [Xen-devel] [PATCH 6/8] xen/pvh: Initialize grant table for PVH guests

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Date:   Fri, 14 Oct 2016 15:43:19 -0400
From:   Boris Ostrovsky <boris.ostrovsky@...cle.com>
To:     Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Cc:     david.vrabel@...rix.com, JGross@...e.com,
        xen-devel@...ts.xenproject.org, linux-kernel@...r.kernel.org,
        roger.pau@...rix.com
Subject: Re: [Xen-devel] [PATCH 6/8] xen/pvh: Initialize grant table for PVH
 guests

On 10/14/2016 03:19 PM, Konrad Rzeszutek Wilk wrote:
> On Fri, Oct 14, 2016 at 02:05:16PM -0400, Boris Ostrovsky wrote:
>
> Perhaps add in here:
>
> PVH is like PV in that there are no PCI devices - which HVM
> code would piggyback on to find the Xen PCI platform device and
> use its MMIO space to stash the grants in.
>
> For PVH we balloon out memory and stash the grants in there.
>
> (Which begs the next question - where and when do we balloon out the
> normal memory back in?)

Are you saying that we should get back memory that we gave to grant tables?

-boris


>
>> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@...cle.com>
>> ---
>>  drivers/xen/grant-table.c | 8 ++++----
>>  1 file changed, 4 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
>> index bb36b1e..d6786b8 100644
>> --- a/drivers/xen/grant-table.c
>> +++ b/drivers/xen/grant-table.c
>> @@ -1146,13 +1146,13 @@ int gnttab_init(void)
>>  
>>  static int __gnttab_init(void)
>>  {
>> +	if (!xen_domain())
>> +		return -ENODEV;
>> +
>>  	/* Delay grant-table initialization in the PV on HVM case */
>> -	if (xen_hvm_domain())
>> +	if (xen_hvm_domain() && !xen_pvh_domain())
>>  		return 0;
>>  
>> -	if (!xen_pv_domain())
>> -		return -ENODEV;
>> -
>>  	return gnttab_init();
>>  }
>>  /* Starts after core_initcall so that xen_pvh_gnttab_setup can be called
>> -- 
>> 1.8.3.1
>>
>>
>> _______________________________________________
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>> Xen-devel@...ts.xen.org
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