Re: [PATCH v2 2/3] intel_iommu: make types match

[Yi Liu <yi.l.liu@intel.com>]

On 2024/7/5 06:13, Michael S. Tsirkin wrote:
> On Thu, Jul 04, 2024 at 03:12:48PM +0000, CLEMENT MATHIEU--DRIF wrote:
>> From: Clément Mathieu--Drif <clement.mathieu--drif@eviden.com>
>>
>> The 'level' field in vtd_iotlb_key is an unsigned integer.
>> We don't need to store level as an int in vtd_lookup_iotlb.
>>
>> VTDIOTLBPageInvInfo.mask is used in binary operations with addresses.
> 
> this last sentence is a bit opaque. is there a bug ? E.g.
> can mask ever get so big it does not fit in u8?

yes, this looks to be a bug. It's initialized and used by below code.
The am is a u8. So it may make more sense to split this patch. One
is to make type match, another is to fix a bug.

info.mask = ~((1 << am) - 1);

uint64_t gfn = (info->addr >> VTD_PAGE_SHIFT_4K) & info->mask;

>> Signed-off-by: Clément Mathieu--Drif <clement.mathieu--drif@eviden.com>
>> ---
>>   hw/i386/intel_iommu.c          | 2 +-
>>   hw/i386/intel_iommu_internal.h | 2 +-
>>   2 files changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
>> index 37c21a0aec..be0cb39b5c 100644
>> --- a/hw/i386/intel_iommu.c
>> +++ b/hw/i386/intel_iommu.c
>> @@ -358,7 +358,7 @@ static VTDIOTLBEntry *vtd_lookup_iotlb(IntelIOMMUState *s, uint16_t source_id,
>>   {
>>       struct vtd_iotlb_key key;
>>       VTDIOTLBEntry *entry;
>> -    int level;
>> +    unsigned level;
>>   
>>       for (level = VTD_SL_PT_LEVEL; level < VTD_SL_PML4_LEVEL; level++) {
>>           key.gfn = vtd_get_iotlb_gfn(addr, level);
>> diff --git a/hw/i386/intel_iommu_internal.h b/hw/i386/intel_iommu_internal.h
>> index cbc4030031..5fcbe2744f 100644
>> --- a/hw/i386/intel_iommu_internal.h
>> +++ b/hw/i386/intel_iommu_internal.h
>> @@ -436,7 +436,7 @@ struct VTDIOTLBPageInvInfo {
>>       uint16_t domain_id;
>>       uint32_t pasid;
>>       uint64_t addr;
>> -    uint8_t mask;
>> +    uint64_t mask;
>>   };
>>   typedef struct VTDIOTLBPageInvInfo VTDIOTLBPageInvInfo;
>>   
>> -- 
>> 2.45.2
> 

-- 
Regards,
Yi Liu