Re: [PATCH v2] intel_iommu,dmar: reserve mmio of IOMMU registers

[Don Dutile <ddutile-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

On 04/05/2012 04:58 PM, Chris Wright wrote:
> * Donald Dutile (ddutile-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org) wrote:
>> --- a/drivers/iommu/dmar.c
>> +++ b/drivers/iommu/dmar.c
>> @@ -581,7 +581,7 @@ int __init detect_intel_iommu(void)
>>   int alloc_iommu(struct dmar_drhd_unit *drhd)
>>   {
>>   	struct intel_iommu *iommu;
>> -	int map_size;
>> +	resource_size_t map_size;
>>   	u32 ver;
>>   	static int iommu_allocated = 0;
>>   	int agaw = 0;
>> @@ -599,10 +599,17 @@ int alloc_iommu(struct dmar_drhd_unit *drhd)
>>   	iommu->seq_id = iommu_allocated++;
>>   	sprintf (iommu->name, "dmar%d", iommu->seq_id);
>>
>> -	iommu->reg = ioremap(drhd->reg_base_addr, VTD_PAGE_SIZE);
>
> I think it'd be nice to create a helper function that does the request
> and map.  This should include the map, read cap/ecap, calculate size and
> possbily remap.  Would probably simplify the error cleanup too.
>
>> +	iommu->reg_phys = drhd->reg_base_addr;
>> +	iommu->reg_size = VTD_PAGE_SIZE;
>> +	if (!request_mem_region(iommu->reg_phys, iommu->reg_size, iommu->name)) {
>> +		printk(KERN_ERR "IOMMU: can't reserve memory\n");
>> +		goto error;
>> +	}
>> +
>> +	iommu->reg = ioremap(iommu->reg_phys, iommu->reg_size);
>>   	if (!iommu->reg) {
>>   		printk(KERN_ERR "IOMMU: can't map the region\n");
>> -		goto error;
>> +		goto err_release;
>>   	}
>>   	iommu->cap = dmar_readq(iommu->reg + DMAR_CAP_REG);
>>   	iommu->ecap = dmar_readq(iommu->reg + DMAR_ECAP_REG);
>> @@ -635,19 +642,26 @@ int alloc_iommu(struct dmar_drhd_unit *drhd)
>>   	map_size = max_t(int, ecap_max_iotlb_offset(iommu->ecap),
>>   		cap_max_fault_reg_offset(iommu->cap));
>>   	map_size = VTD_PAGE_ALIGN(map_size);
>> -	if (map_size>  VTD_PAGE_SIZE) {
>> +	if (map_size>  iommu->reg_size) {
>>   		iounmap(iommu->reg);
>> -		iommu->reg = ioremap(drhd->reg_base_addr, map_size);
>> +		release_mem_region(iommu->reg_phys, iommu->reg_size);
>> +		iommu->reg_size = map_size;
>> +		if (!request_mem_region(iommu->reg_phys, iommu->reg_size,
>> +					iommu->name)) {
>> +			printk(KERN_ERR "IOMMU: can't reserve memory\n");
>> +			goto error;
>> +		}
>> +		iommu->reg = ioremap(iommu->reg_phys, iommu->reg_size);
>>   		if (!iommu->reg) {
>>   			printk(KERN_ERR "IOMMU: can't map the region\n");
>> -			goto error;
>> +			goto err_release;
>>   		}
>>   	}
>>
>>   	ver = readl(iommu->reg + DMAR_VER_REG);
>>   	pr_info("IOMMU %d: reg_base_addr %llx ver %d:%d cap %llx ecap %llx\n",
>>   		iommu->seq_id,
>> -		(unsigned long long)drhd->reg_base_addr,
>> +		(unsigned long long)iommu->reg_phys,
>>   		DMAR_VER_MAJOR(ver), DMAR_VER_MINOR(ver),
>>   		(unsigned long long)iommu->cap,
>>   		(unsigned long long)iommu->ecap);
>> @@ -659,6 +673,8 @@ int alloc_iommu(struct dmar_drhd_unit *drhd)
>>
>>    err_unmap:
>>   	iounmap(iommu->reg);
>> + err_release:
>> +	release_mem_region(iommu->reg_phys, iommu->reg_size);
>>    error:
>>   	kfree(iommu);
>>   	return -1;
>> @@ -671,8 +687,11 @@ void free_iommu(struct intel_iommu *iommu)
>>
>>   	free_dmar_iommu(iommu);
>>
>> -	if (iommu->reg)
>> +	if (iommu->reg) {
>>   		iounmap(iommu->reg);
>> +		release_mem_region(iommu->reg_phys, iommu->reg_size);
>> +	}
>> +
>>   	kfree(iommu);
>>   }
>>
>> diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
>> index e6ca56d..c6d132b 100644
>> --- a/include/linux/intel-iommu.h
>> +++ b/include/linux/intel-iommu.h
>> @@ -308,6 +308,8 @@ enum {
>>
>>   struct intel_iommu {
>>   	void __iomem	*reg; /* Pointer to hardware regs, virtual addr */
>> +	resource_size_t reg_phys;
>> +	resource_size_t reg_size;
>
> I'd make these u64

ok, will work up v3 tomorrow..

thanks for feedback!