Messages in this thread | | | Date | Wed, 29 Jun 2022 03:53:42 +0300 | From | "Kirill A. Shutemov" <> | Subject | Re: [PATCHv3 6/8] x86/mm: Provide ARCH_GET_UNTAG_MASK and ARCH_ENABLE_TAGGED_ADDR |
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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@linux.intel.com/
-- Kirill A. Shutemov
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