Re: [PATCH v5 11/15] x86/altp2m: define and implement alternate p2m HVMOP types.

From: "Sahita, Ravi" <ravi.sahita@intel.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: Tim Deegan <tim@xen.org>, "Sahita, Ravi" <ravi.sahita@intel.com>,
	Wei Liu <wei.liu2@citrix.com>,
	George Dunlap <george.dunlap@eu.citrix.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	Ian Jackson <ian.jackson@eu.citrix.com>,
	"White, Edmund H" <edmund.h.white@intel.com>,
	"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>,
	"tlengyel@novetta.com" <tlengyel@novetta.com>,
	Daniel De Graaf <dgdegra@tycho.nsa.gov>
Subject: Re: [PATCH v5 11/15] x86/altp2m: define and implement alternate p2m HVMOP types.
Date: Thu, 16 Jul 2015 09:02:08 +0000	[thread overview]
Message-ID: <DBC12B0F5509554280826E40BCDEE8BE54FD773C@ORSMSX104.amr.corp.intel.com> (raw)
In-Reply-To: <55A53AA00200007800090CE9@mail.emea.novell.com>

>From: Jan Beulich [mailto:JBeulich@suse.com]
>Sent: Tuesday, July 14, 2015 7:37 AM
>
>>>> On 14.07.15 at 02:14, <edmund.h.white@intel.com> wrote:
>> Signed-off-by: Ed White <edmund.h.white@intel.com>
>> --- a/xen/arch/x86/hvm/hvm.c
>> +++ b/xen/arch/x86/hvm/hvm.c
>> @@ -6443,6 +6443,148 @@ long do_hvm_op(unsigned long op,
>XEN_GUEST_HANDLE_PARAM(void) arg)
>>          break;
>>      }
>>
>> +    case HVMOP_altp2m:
>> +    {
>> +        struct xen_hvm_altp2m_op a;
>> +        struct domain *d = NULL;
>> +
>> +        if ( copy_from_guest(&a, arg, 1) )
>> +            return -EFAULT;
>> +
>> +        if ( a.pad[0] || a.pad[1] )
>> +            return -EINVAL;
>
>Why can't the field be uint16_t, making this a single check?
>

Could be of course;  we had asked for an example and we found domctl, which pads with uint8_t[] and followed the same approach. Change required?

Ravi

>Jan