Re: [PATCH 2/2] KVM: Device assignemnt with VT-d

[Avi Kivity <avi@qumranet.com>]

Yang, Sheng wrote:
> On Thursday 07 August 2008 22:14:47 Ben-Ami Yassour wrote:
>   
>> Based on a patch by: Kay, Allen M <allen.m.kay@intel.com>
>>
>> This patch enables pci device assignment based on VT-d support.
>> When a device is assigned to the guest, the guest memory is pinned
>> and the mapping is updated in the VT-d IOMMU.
>>
>>     
>
> I am afraid there still some compatible problem...
>
>   
>> Signed-off-by: Kay, Allen M <allen.m.kay@intel.com>
>> Signed-off-by: Weidong Han <weidong.han@intel.com>
>> Signed-off-by: Ben-Ami Yassour <benami@il.ibm.com>
>> ---
>>  arch/x86/kvm/Makefile      |    3 +
>>  arch/x86/kvm/vtd.c         |  203
>>     
> [snip]
>   
>> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
>> index a97157c..5cfc21a 100644
>> --- a/arch/x86/kvm/x86.c
>> +++ b/arch/x86/kvm/x86.c
>> @@ -35,6 +35,7 @@
>>  #include <linux/module.h>
>>  #include <linux/mman.h>
>>  #include <linux/highmem.h>
>> +#include <linux/intel-iommu.h>
>>     
>
> This broken external kernel modules before 2.6.27... If we wrapped it 
> with CONFIG_DMAR, it would also broken the commit before the patch 
> checked in and after DMAR enabled in kernel... Need a version number 
> judgement?
>
>   

kernel patches should not consider external module issues.  That keeps 
the code clean (at the expense of making the external module's 
maintainer's life mode difficult, but that's their problem).

>> diff --git a/include/asm-x86/kvm_host.h
>> b/include/asm-x86/kvm_host.h index ef019b5..b141949 100644
>> --- a/include/asm-x86/kvm_host.h
>> +++ b/include/asm-x86/kvm_host.h
>> @@ -354,6 +354,7 @@ struct kvm_arch{
>>  	 */
>>  	struct list_head active_mmu_pages;
>>  	struct list_head assigned_dev_head;
>> +	struct dmar_domain *intel_iommu_domain;
>>     
>
> Need wrapped by CONFIG_DMAR?
>
>   

I guess we can keep this, one pointer is not that expensive.  But we 
should make sure all the iommu functions are available when iommu is 
unconfigured.

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