19 May
2021
19 May
'21
11:33 a.m.
On Wed, May 12, 2021 at 11:32:35AM +0200, Joerg Roedel wrote:
On Wed, May 12, 2021 at 10:58:20AM +0200, Juergen Gross wrote:
No, those were used before, but commit 9da3f2b7405440 broke Xen's use case. That is why I did commit 1457d8cf7664f.
[...]
Having the distinction between user and kernel memory accesses explicitly in the code seems to be the most robust solution.
On the other hand, as I found out today, 9da3f2b7405440 had a short life-time and got reverted upstream. So using __get_user()/__put_user() should be fine in this code path. It just deserves a comment explaining its use here and why pagefault_enable()/disable() is not needed. Even the get_kernel* helpers use __get_user_size() internally.
Regards,
Joerg