Re: [PATCH 11/22] KVM: MMU: Add infrastructure for two-level page walker

Avi Kivity
2010-04-28T11:09:22Z

On 04/28/2010 02:03 PM, Joerg Roedel wrote:
> On Tue, Apr 27, 2010 at 03:34:10PM +0300, Avi Kivity wrote:
>
>> On 04/27/2010 01:38 PM, Joerg Roedel wrote:
>>
>>> This patch introduces a mmu-callback to translate gpa
>>> addresses in the walk_addr code. This is later used to
>>> translate l2_gpa addresses into l1_gpa addresses.
>>>
>>> +static inline gfn_t gpa_to_gfn(gpa_t gpa)
>>> +{
>>> + return (gfn_t)gpa>> PAGE_SHIFT;
>>> +}
>>> +
>>>
>> This overflows on 32-bit, since gpa_t is u64 and gfn_t is ulong.
>>
> Thinking again about it, on 32 bit the physical address width is only 36
> bits. So there shouldn't be an overflow, no?
>

It's limited by MAXPHYADDR (at least on Intel) even on 32-bits.

--
error compiling committee.c: too many arguments to function