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Subject: Re: [Resend RFC PATCH V2 11/12] HV/Netvsc: Add Isolation VM support
 for netvsc driver
To:     Christoph Hellwig <hch@lst.de>
Cc:     kys@microsoft.com, haiyangz@microsoft.com, sthemmin@microsoft.com,
        wei.liu@kernel.org, tglx@linutronix.de, mingo@redhat.com,
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        akpm@linux-foundation.org, gregkh@linuxfoundation.org,
        konrad.wilk@oracle.com, m.szyprowski@samsung.com,
        robin.murphy@arm.com, joro@8bytes.org, will@kernel.org,
        davem@davemloft.net, kuba@kernel.org, jejb@linux.ibm.com,
        martin.petersen@oracle.com, Tianyu Lan <Tianyu.Lan@microsoft.com>,
        iommu@lists.linux-foundation.org, linux-arch@vger.kernel.org,
        linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, linux-scsi@vger.kernel.org,
        netdev@vger.kernel.org, vkuznets@redhat.com,
        thomas.lendacky@amd.com, brijesh.singh@amd.com,
        sunilmut@microsoft.com
References: <20210414144945.3460554-1-ltykernel@gmail.com>
 <20210414144945.3460554-12-ltykernel@gmail.com>
 <20210414155016.GE32045@lst.de>
From:   Tianyu Lan <ltykernel@gmail.com>
Message-ID: <de145e13-2444-aa01-906e-e3abe5a64dc4@gmail.com>
Date:   Thu, 15 Apr 2021 16:39:45 +0800
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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.