On Tue, Oct 18, 2022 at 02:00:38PM -0700, Dave Hansen wrote:
> > diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h
> > index b0e9ea23758b..6b9ac2c60cec 100644
> > --- a/arch/x86/include/asm/mmu_context.h
> > +++ b/arch/x86/include/asm/mmu_context.h
> > @@ -113,6 +113,8 @@ static inline void mm_reset_untag_mask(struct mm_struct *mm)
> > mm->context.untag_mask = -1UL;
> > }
> >
> > +#define arch_pgtable_dma_compat(mm) \
> > + (!mm_lam_cr3_mask(mm) || (mm->context.flags & MM_CONTEXT_FORCE_TAGGED_SVM))
> > #else
>
> This needs to be a 'static inline' unless there's a compelling and
> documented reason that it can't be.
Seems work fine.
> > static inline unsigned long mm_lam_cr3_mask(struct mm_struct *mm)
> > diff --git a/arch/x86/include/uapi/asm/prctl.h b/arch/x86/include/uapi/asm/prctl.h
> > index a31e27b95b19..7bd22defb558 100644
> > --- a/arch/x86/include/uapi/asm/prctl.h
> > +++ b/arch/x86/include/uapi/asm/prctl.h
> > @@ -23,5 +23,6 @@
> > #define ARCH_GET_UNTAG_MASK 0x4001
> > #define ARCH_ENABLE_TAGGED_ADDR 0x4002
> > #define ARCH_GET_MAX_TAG_BITS 0x4003
> > +#define ARCH_FORCE_TAGGED_SVM 0x4004
> >
> > #endif /* _ASM_X86_PRCTL_H */
> > diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
> > index 9952e9f517ec..8faa8774bb93 100644
> > --- a/arch/x86/kernel/process_64.c
> > +++ b/arch/x86/kernel/process_64.c
> > @@ -783,6 +783,13 @@ static int prctl_enable_tagged_addr(struct mm_struct *mm, unsigned long nr_bits)
> > goto out;
> > }
> >
> > +#ifdef CONFIG_IOMMU_SVA
> > + if (pasid_valid(mm->pasid) &&
> > + !(mm->context.flags & MM_CONTEXT_FORCE_TAGGED_SVM)) {
> > + ret = -EBUSY;
> > + goto out;
> > + }
> > +#endif
>
> Is this #ifdef really necessary? CONFIG_IOMMU_SVA selects IOASID,
> without which pasid_valid() is just stubbed out to 0.
mm->pasid is only defined for CONFIG_IOMMU_SVA=y.
Do you want me to add mm_has_valid_pasid()?
--
Kiryl Shutsemau / Kirill A. Shutemov
