Re: [PATCH V2] KVM: ARM: Remove pgtable page standard functions from stage-2 page tables

* Re: [PATCH V2] KVM: ARM: Remove pgtable page standard functions from stage-2 page tables
       [not found] ` <1552397145-10665-1-git-send-email-anshuman.khandual@arm.com>
@ 2019-04-01 16:16   ` Will Deacon
  2019-04-01 18:34     ` Yu Zhao
  2019-04-08  9:09     ` Marc Zyngier
  0 siblings, 2 replies; 9+ messages in thread
From: Will Deacon @ 2019-04-01 16:16 UTC (permalink / raw)
  To: Anshuman Khandual
  Cc: mark.rutland, yuzhao, suzuki.poulose, marc.zyngier,
	catalin.marinas, julien.thierry, christoffer.dall, linux-mm,
	james.morse, kvmarm, linux-arm-kernel

[+KVM/ARM folks, since I can't take this without an Ack in place from them]

My understanding is that this patch is intended to replace patch 3/4 in
this series:

http://lists.infradead.org/pipermail/linux-arm-kernel/2019-March/638083.html

On Tue, Mar 12, 2019 at 06:55:45PM +0530, Anshuman Khandual wrote:
> ARM64 standard pgtable functions are going to use pgtable_page_[ctor|dtor]
> or pgtable_pmd_page_[ctor|dtor] constructs. At present KVM guest stage-2
> PUD|PMD|PTE level page tabe pages are allocated with __get_free_page()
> via mmu_memory_cache_alloc() but released with standard pud|pmd_free() or
> pte_free_kernel(). These will fail once they start calling into pgtable_
> [pmd]_page_dtor() for pages which never originally went through respective
> constructor functions. Hence convert all stage-2 page table page release
> functions to call buddy directly while freeing pages.
> 
> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
> Acked-by: Yu Zhao <yuzhao@google.com>
> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
> ---
> Changes in V2:
> 
> - Updated stage2_pud_free() with NOP as per Suzuki
> - s/__free_page/free_page/ in clear_stage2_pmd_entry() for uniformity
> 
>  arch/arm/include/asm/stage2_pgtable.h   | 4 ++--
>  arch/arm64/include/asm/stage2_pgtable.h | 4 ++--
>  virt/kvm/arm/mmu.c                      | 2 +-
>  3 files changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/arm/include/asm/stage2_pgtable.h b/arch/arm/include/asm/stage2_pgtable.h
> index de2089501b8b..fed02c3b4600 100644
> --- a/arch/arm/include/asm/stage2_pgtable.h
> +++ b/arch/arm/include/asm/stage2_pgtable.h
> @@ -32,14 +32,14 @@
>  #define stage2_pgd_present(kvm, pgd)		pgd_present(pgd)
>  #define stage2_pgd_populate(kvm, pgd, pud)	pgd_populate(NULL, pgd, pud)
>  #define stage2_pud_offset(kvm, pgd, address)	pud_offset(pgd, address)
> -#define stage2_pud_free(kvm, pud)		pud_free(NULL, pud)
> +#define stage2_pud_free(kvm, pud)		do { } while (0)
>  
>  #define stage2_pud_none(kvm, pud)		pud_none(pud)
>  #define stage2_pud_clear(kvm, pud)		pud_clear(pud)
>  #define stage2_pud_present(kvm, pud)		pud_present(pud)
>  #define stage2_pud_populate(kvm, pud, pmd)	pud_populate(NULL, pud, pmd)
>  #define stage2_pmd_offset(kvm, pud, address)	pmd_offset(pud, address)
> -#define stage2_pmd_free(kvm, pmd)		pmd_free(NULL, pmd)
> +#define stage2_pmd_free(kvm, pmd)		free_page((unsigned long)pmd)
>  
>  #define stage2_pud_huge(kvm, pud)		pud_huge(pud)
>  
> diff --git a/arch/arm64/include/asm/stage2_pgtable.h b/arch/arm64/include/asm/stage2_pgtable.h
> index 5412fa40825e..915809e4ac32 100644
> --- a/arch/arm64/include/asm/stage2_pgtable.h
> +++ b/arch/arm64/include/asm/stage2_pgtable.h
> @@ -119,7 +119,7 @@ static inline pud_t *stage2_pud_offset(struct kvm *kvm,
>  static inline void stage2_pud_free(struct kvm *kvm, pud_t *pud)
>  {
>  	if (kvm_stage2_has_pud(kvm))
> -		pud_free(NULL, pud);
> +		free_page((unsigned long)pud);
>  }
>  
>  static inline bool stage2_pud_table_empty(struct kvm *kvm, pud_t *pudp)
> @@ -192,7 +192,7 @@ static inline pmd_t *stage2_pmd_offset(struct kvm *kvm,
>  static inline void stage2_pmd_free(struct kvm *kvm, pmd_t *pmd)
>  {
>  	if (kvm_stage2_has_pmd(kvm))
> -		pmd_free(NULL, pmd);
> +		free_page((unsigned long)pmd);
>  }
>  
>  static inline bool stage2_pud_huge(struct kvm *kvm, pud_t pud)
> diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c
> index e9d28a7ca673..cbfbdadca8a5 100644
> --- a/virt/kvm/arm/mmu.c
> +++ b/virt/kvm/arm/mmu.c
> @@ -191,7 +191,7 @@ static void clear_stage2_pmd_entry(struct kvm *kvm, pmd_t *pmd, phys_addr_t addr
>  	VM_BUG_ON(pmd_thp_or_huge(*pmd));
>  	pmd_clear(pmd);
>  	kvm_tlb_flush_vmid_ipa(kvm, addr);
> -	pte_free_kernel(NULL, pte_table);
> +	free_page((unsigned long)pte_table);
>  	put_page(virt_to_page(pmd));
>  }
>  
> -- 
> 2.20.1
> 

^ permalink raw reply	[flat|nested] 9+ messages in thread