Re: [PATCH V6 7/8] Drivers: hv: vmbus: Add SNP support for VMbus channel initiate message

[Tianyu Lan <ltykernel@gmail.com>]

Hi Michael:
      Thanks for your review.


On 10/2/2021 9:26 PM, Michael Kelley wrote:
>> @@ -303,10 +365,26 @@ void vmbus_disconnect(void)
>>   		vmbus_connection.int_page = NULL;
>>   	}
>>
>> -	hv_free_hyperv_page((unsigned long)vmbus_connection.monitor_pages[0]);
>> -	hv_free_hyperv_page((unsigned long)vmbus_connection.monitor_pages[1]);
>> -	vmbus_connection.monitor_pages[0] = NULL;
>> -	vmbus_connection.monitor_pages[1] = NULL;
>> +	if (hv_is_isolation_supported()) {
>> +		memunmap(vmbus_connection.monitor_pages[0]);
>> +		memunmap(vmbus_connection.monitor_pages[1]);
> The matching memremap() calls are made in vmbus_connect() only in the
> SNP case.  In the non-SNP case, monitor_pages and monitor_pages_original
> are the same, so you would be doing an unmap, and then doing the
> set_memory_encrypted() and hv_free_hyperv_page() using an address
> that is no longer mapped, which seems wrong.   Looking at memunmap(),
> it might be a no-op in this case, but even if it is, making them conditional
> on the SNP case might be a safer thing to do, and it would make the code
> more symmetrical.
>

Yes, memumap() does nothing is the non-SNP CVM and so I didn't check CVM
type here. I will add the check in the next version.

Thanks.