Re: [PATCH v7 06/12] arm64: tlb: Refactor the core flush algorithm of __flush_tlb_range

From: Marc Zyngier
Date: Wed Aug 02 2023 - 11:58:39 EST


On Mon, 31 Jul 2023 18:36:47 +0100,
Raghavendra Rao Ananta <rananta@xxxxxxxxxx> wrote:
>
> On Thu, Jul 27, 2023 at 3:58 AM Marc Zyngier <maz@xxxxxxxxxx> wrote:
> >
> > On Sat, 22 Jul 2023 03:22:45 +0100,
> > Raghavendra Rao Ananta <rananta@xxxxxxxxxx> wrote:
> > >
> > > Currently, the core TLB flush functionality of __flush_tlb_range()
> > > hardcodes vae1is (and variants) for the flush operation. In the
> > > upcoming patches, the KVM code reuses this core algorithm with
> > > ipas2e1is for range based TLB invalidations based on the IPA.
> > > Hence, extract the core flush functionality of __flush_tlb_range()
> > > into its own macro that accepts an 'op' argument to pass any
> > > TLBI operation, such that other callers (KVM) can benefit.
> > >
> > > No functional changes intended.
> > >
> > > Signed-off-by: Raghavendra Rao Ananta <rananta@xxxxxxxxxx>
> > > Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>
> > > Reviewed-by: Gavin Shan <gshan@xxxxxxxxxx>
> > > Reviewed-by: Shaoqin Huang <shahuang@xxxxxxxxxx>
> > > ---
> > > arch/arm64/include/asm/tlbflush.h | 109 +++++++++++++++---------------
> > > 1 file changed, 56 insertions(+), 53 deletions(-)
> > >
> > > diff --git a/arch/arm64/include/asm/tlbflush.h b/arch/arm64/include/asm/tlbflush.h
> > > index 412a3b9a3c25..f7fafba25add 100644
> > > --- a/arch/arm64/include/asm/tlbflush.h
> > > +++ b/arch/arm64/include/asm/tlbflush.h
> > > @@ -278,14 +278,62 @@ static inline void flush_tlb_page(struct vm_area_struct *vma,
> > > */
> > > #define MAX_TLBI_OPS PTRS_PER_PTE
> > >
> > > +/* When the CPU does not support TLB range operations, flush the TLB
> > > + * entries one by one at the granularity of 'stride'. If the TLB
> > > + * range ops are supported, then:
> >
> > Comment format (the original was correct).
> >
> Isn't the format the same as original? Or are you referring to the
> fact that it needs to be placed inside the macro definition?

No, I'm referring to the multiline comment that starts with:

/* When the CPU does not support TLB range operations...

instead of the required:

/*
* When the CPU does not support TLB range operations

which was correct before the coment was moved.

Thanks,

M.

--
Without deviation from the norm, progress is not possible.