Subject: Re: [Resend RFC PATCH V2 11/12] HV/Netvsc: Add Isolation VM support for netvsc driver

From: Tianyu Lan <[email-masked]>
Date: Thu, 15 Apr 2021 16:39:45 +0800

On 4/14/2021 11:50 PM, Christoph Hellwig wrote:
>> +struct dma_range {
>> +	dma_addr_t dma;
>> +	u32 mapping_size;
>> +};
> 
> That's a rather generic name that is bound to create a conflict sooner
> or later.

Good point. Will update.

> 
>>   #include "hyperv_net.h"
>>   #include "netvsc_trace.h"
>> +#include "../../hv/hyperv_vmbus.h"
> 
> Please move public interfaces out of the private header rather than doing
> this.

OK. Will update.

> 
>> +	if (hv_isolation_type_snp()) {
>> +		area = get_vm_area(buf_size, VM_IOREMAP);
> 
> Err, no.  get_vm_area is private a for a reason.
> 
>> +		if (!area)
>> +			goto cleanup;
>> +
>> +		vaddr = (unsigned long)area->addr;
>> +		for (i = 0; i < buf_size / HV_HYP_PAGE_SIZE; i++) {
>> +			extra_phys = (virt_to_hvpfn(net_device->recv_buf + i * HV_HYP_PAGE_SIZE)
>> +				<< HV_HYP_PAGE_SHIFT) + ms_hyperv.shared_gpa_boundary;
>> +			ret |= ioremap_page_range(vaddr + i * HV_HYP_PAGE_SIZE,
>> +					   vaddr + (i + 1) * HV_HYP_PAGE_SIZE,
>> +					   extra_phys, PAGE_KERNEL_IO);
>> +		}
>> +
>> +		if (ret)
>> +			goto cleanup;
> 
> And this is not something a driver should ever do.  I think you are badly
> reimplementing functionality that should be in the dma coherent allocator
> here.
>
OK. I will try hiding these in the Hyper-V dma ops callback. Thanks.