From: Tianyu Lan <redacted> Sent: Saturday, October 2, 2021 7:40 AM

On 10/2/2021 9:26 PM, Michael Kelley wrote:

quoted

quoted

@@ -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.

I would also be OK with just adding a comment to that effect, just so someone
looking at the code in the future understands that there's not a problem.
Your call.

Michael