Re: [PATCH] KVM: arm64: Drop sort_memblock_regions()

[Gavin Shan]

On 3/13/25 12:53 PM, Anshuman Khandual wrote:
> On 3/11/25 10:07, Gavin Shan wrote:
> > Drop sort_memblock_regions() and avoid sorting the copied memory
> > regions to be ascending order on their base addresses, because the
> > source memory regions should have been sorted correctly when they
> > are added by memblock_add() or its variants.
> >
> > This is generally reverting commit a14307f5310c ("KVM: arm64: Sort
> > the hypervisor memblocks"). No functional changes intended.
>
> Just wondering what prompted this change ?

I found the unnecessary sorting by code inspection. Hope there is nothing I
missed and it's why Quentin Perret has been copied, to confirm it. Commit
a14307f5310c was introduced by the initial series [1/2] to support pKVM.

[1] https://lore.kernel.org/kvmarm/20201117181607.1761516-1-qperret@xxxxxxxxxx/
[2] https://lore.kernel.org/all/20210319100146.1149909-1-qperret@xxxxxxxxxx/

Thanks,
Gavin

> > Signed-off-by: Gavin Shan <gshan@xxxxxxxxxx>
> > ---
> >   arch/arm64/kvm/pkvm.c | 19 -------------------
> >   1 file changed, 19 deletions(-)
> >
> > diff --git a/arch/arm64/kvm/pkvm.c b/arch/arm64/kvm/pkvm.c
> > index 930b677eb9b0..d9c9174f89a1 100644
> > --- a/arch/arm64/kvm/pkvm.c
> > +++ b/arch/arm64/kvm/pkvm.c
> > @@ -10,7 +10,6 @@
> >   #include <asm/kvm_mmu.h>
> >   #include <linux/memblock.h>
> >   #include <linux/mutex.h>
> > -#include <linux/sort.h>
> >   
> >   #include <asm/kvm_pkvm.h>
> >   
> > @@ -24,23 +23,6 @@ static unsigned int *hyp_memblock_nr_ptr = &kvm_nvhe_sym(hyp_memblock_nr);
> >   phys_addr_t hyp_mem_base;
> >   phys_addr_t hyp_mem_size;
> >   
> > -static int cmp_hyp_memblock(const void *p1, const void *p2)
> > -{
> > -	const struct memblock_region *r1 = p1;
> > -	const struct memblock_region *r2 = p2;
> > -
> > -	return r1->base < r2->base ? -1 : (r1->base > r2->base);
> > -}
> > -
> > -static void __init sort_memblock_regions(void)
> > -{
> > -	sort(hyp_memory,
> > -	     *hyp_memblock_nr_ptr,
> > -	     sizeof(struct memblock_region),
> > -	     cmp_hyp_memblock,
> > -	     NULL);
> > -}
> > -
> >   static int __init register_memblock_regions(void)
> >   {
> >   	struct memblock_region *reg;
> > @@ -52,7 +34,6 @@ static int __init register_memblock_regions(void)
> >   		hyp_memory[*hyp_memblock_nr_ptr] = *reg;
> >   		(*hyp_memblock_nr_ptr)++;
> >   	}
> > -	sort_memblock_regions();
> >   
> >   	return 0;
> >   }