On Tue, Jun 28, 2022 at 04:42:40PM -0700, Andy Lutomirski wrote: > On 6/10/22 07:35, Kirill A. Shutemov wrote: > > > + /* Update CR3 to get LAM active */ > > + switch_mm(current->mm, current->mm, current); > > Can you at least justify this oddity? When changing an LDT, we use a > dedicated mechanism. Is there a significant benefit to abusing switch_mm > for this? I'm not sure I follow. LAM mode is set in CR3. switch_mm() has to handle it anyway to context switch. Why do you consider it abuse? > > Also, why can't we enable LAM on a multithreaded process? We can change an > LDT, and the code isn't even particularly complicated. I reworked this in v4[1] and it allows multithreaded processes. Have you got that version? Intel had issue with mail server, but I assumed it didn't affect my patchset since I see it in the archive. [1] https://lore.kernel.org/all/20220622162230.83474-1-kirill.shutemov@xxxxxxxxxxxxxxx/ -- Kirill A. Shutemov
