[PATCH v2 5/6] KVM: arm/arm64: Stop using {pmd,pud,pgd}_populate

[christoffer.dall@arm.com (Christoffer Dall)]

On Wed, May 30, 2018 at 01:47:05PM +0100, Marc Zyngier wrote:
> The {pmd,pud,pgd}_populate accessors usage in the kernel have always
> been a bit weird in KVM. We don't have a struct mm to pass (and
> neither does the kernel most of the time, but still...), and
> the 32bit code has all kind of cache maintenance that doesn't make
> sense on ARMv7+ when MP extensions are mandatory (which is the
> case when the VEs are present).
> 
> Let's bite the bullet and provide our own implementations. The
> only bit of architectural code left has to do with building the table
> entry itself (arm64 having up to 52bit PA, arm lacking PUD level).
> 
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

Acked-by: Christoffer Dall <christoffer.dall@arm.com>

> ---
>  arch/arm/include/asm/kvm_mmu.h   | 4 ++++
>  arch/arm64/include/asm/kvm_mmu.h | 7 +++++++
>  virt/kvm/arm/mmu.c               | 8 +++++---
>  3 files changed, 16 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h
> index 468ff945efa0..a94ef9833bd3 100644
> --- a/arch/arm/include/asm/kvm_mmu.h
> +++ b/arch/arm/include/asm/kvm_mmu.h
> @@ -75,6 +75,10 @@ phys_addr_t kvm_get_idmap_vector(void);
>  int kvm_mmu_init(void);
>  void kvm_clear_hyp_idmap(void);
>  
> +#define kvm_mk_pmd(ptep)	__pmd(__pa(ptep) | PMD_TYPE_TABLE)
> +#define kvm_mk_pud(pmdp)	__pud(__pa(pmdp) | PMD_TYPE_TABLE)
> +#define kvm_mk_pgd(pudp)	({ BUILD_BUG(); 0; })
> +
>  static inline pte_t kvm_s2pte_mkwrite(pte_t pte)
>  {
>  	pte_val(pte) |= L_PTE_S2_RDWR;
> diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
> index 26c89b63f604..22c9f7cfdf93 100644
> --- a/arch/arm64/include/asm/kvm_mmu.h
> +++ b/arch/arm64/include/asm/kvm_mmu.h
> @@ -170,6 +170,13 @@ phys_addr_t kvm_get_idmap_vector(void);
>  int kvm_mmu_init(void);
>  void kvm_clear_hyp_idmap(void);
>  
> +#define kvm_mk_pmd(ptep)					\
> +	__pmd(__phys_to_pmd_val(__pa(ptep) | PMD_TYPE_TABLE))
> +#define kvm_mk_pud(pmdp)					\
> +	__pud(__phys_to_pud_val(__pa(pmdp) | PMD_TYPE_TABLE))
> +#define kvm_mk_pgd(pudp)					\
> +	__pgd(__phys_to_pgd_val(__pa(pudp) | PUD_TYPE_TABLE))
> +
>  static inline pte_t kvm_s2pte_mkwrite(pte_t pte)
>  {
>  	pte_val(pte) |= PTE_S2_RDWR;
> diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c
> index c9ed239c0840..ad1980d2118a 100644
> --- a/virt/kvm/arm/mmu.c
> +++ b/virt/kvm/arm/mmu.c
> @@ -191,17 +191,19 @@ static inline void kvm_set_pmd(pmd_t *pmdp, pmd_t new_pmd)
>  
>  static inline void kvm_pmd_populate(pmd_t *pmdp, pte_t *ptep)
>  {
> -	pmd_populate_kernel(NULL, pmdp, ptep);
> +	kvm_set_pmd(pmdp, kvm_mk_pmd(ptep));
>  }
>  
>  static inline void kvm_pud_populate(pud_t *pudp, pmd_t *pmdp)
>  {
> -	pud_populate(NULL, pudp, pmdp);
> +	WRITE_ONCE(*pudp, kvm_mk_pud(pmdp));
> +	dsb(ishst);
>  }
>  
>  static inline void kvm_pgd_populate(pgd_t *pgdp, pud_t *pudp)
>  {
> -	pgd_populate(NULL, pgdp, pudp);
> +	WRITE_ONCE(*pgdp, kvm_mk_pgd(pudp));
> +	dsb(ishst);
>  }
>  
>  /*
> -- 
> 2.17.1
>