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Shutemov" Cc: x86@kernel.org, Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , Andy Lutomirski , Peter Zijlstra , Rick Edgecombe , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="us-ascii" On Tue, Mar 12, 2024 at 02:35:46PM +0200, Kirill A. Shutemov wrote: > On Tue, Mar 12, 2024 at 03:59:50AM +0000, Yosry Ahmed wrote: > > diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c > > index 76e91fc68c5f3..748d2b3bdb985 100644 > > --- a/arch/x86/kernel/process_64.c > > +++ b/arch/x86/kernel/process_64.c > > @@ -753,10 +753,12 @@ static long prctl_map_vdso(const struct vdso_image *image, unsigned long addr) > > static void enable_lam_func(void *__mm) > > { > > struct mm_struct *mm = __mm; > > + unsigned long lam = mm_lam_cr3_mask(mm); > > + u64 untag_mask = mm_untag_mask(mm); > > > > Maybe push these mm dereferences inside the if block below? > I am not sure if compiler can re-order operations past this_cpu_read(). I am not sure either, so I will push them inside. Better safe than sorry. Will send a v2 shortly, thanks for the reviews! > > > if (this_cpu_read(cpu_tlbstate.loaded_mm) == mm) { > > - write_cr3(__read_cr3() | mm->context.lam_cr3_mask); > > - set_tlbstate_lam_mode(mm); > > + write_cr3(__read_cr3() | lam); > > + cpu_tlbstate_update_lam(lam, untag_mask); > > } > > } > > > > -- > Kiryl Shutsemau / Kirill A. Shutemov