Subject: [PATCH 3/7] ARM: KVM: move to a KVM provided HYP idmap

From: [email-masked] (Christoffer Dall)
Date: Wed, 3 Apr 2013 16:14:24 -0700

On Tue, Apr 02, 2013 at 02:25:11PM +0100, Marc Zyngier wrote:
> After the HYP page table rework, it is pretty easy to let the KVM
> code provide its own idmap, rather than expecting the kernel to
> provide it. It takes actually less code to do so.
> 
> Signed-off-by: Marc Zyngier <[email-masked]>
> ---
>  arch/arm/include/asm/idmap.h   |  1 -
>  arch/arm/include/asm/kvm_mmu.h |  1 -
>  arch/arm/kvm/mmu.c             | 24 +++++++++++++++++++++++-
>  arch/arm/mm/idmap.c            | 31 +------------------------------
>  4 files changed, 24 insertions(+), 33 deletions(-)
> 
> diff --git a/arch/arm/include/asm/idmap.h b/arch/arm/include/asm/idmap.h
> index 1a66f907..bf863ed 100644
> --- a/arch/arm/include/asm/idmap.h
> +++ b/arch/arm/include/asm/idmap.h
> @@ -8,7 +8,6 @@
>  #define __idmap __section(.idmap.text) noinline notrace
>  
>  extern pgd_t *idmap_pgd;
> -extern pgd_t *hyp_pgd;
>  
>  void setup_mm_for_reboot(void);
>  
> diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h
> index 970f3b5..3c71a1d 100644
> --- a/arch/arm/include/asm/kvm_mmu.h
> +++ b/arch/arm/include/asm/kvm_mmu.h
> @@ -21,7 +21,6 @@
>  
>  #include <asm/cacheflush.h>
>  #include <asm/pgalloc.h>
> -#include <asm/idmap.h>
>  
>  /*
>   * We directly use the kernel VA for the HYP, as we can directly share
> diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
> index eb4f8fa..7d23480 100644
> --- a/arch/arm/kvm/mmu.c
> +++ b/arch/arm/kvm/mmu.c
> @@ -32,6 +32,7 @@
>  
>  extern char  __hyp_idmap_text_start[], __hyp_idmap_text_end[];
>  
> +static pgd_t *hyp_pgd;
>  static DEFINE_MUTEX(kvm_hyp_pgd_mutex);
>  
>  static void kvm_tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t ipa)
> @@ -715,12 +716,33 @@ phys_addr_t kvm_mmu_get_httbr(void)
>  
>  int kvm_mmu_init(void)
>  {
> +	unsigned long hyp_idmap_start = virt_to_phys(__hyp_idmap_text_start);
> +	unsigned long hyp_idmap_end = virt_to_phys(__hyp_idmap_text_end);
> +	int err;
> +
> +	hyp_pgd = kzalloc(PTRS_PER_PGD * sizeof(pgd_t), GFP_KERNEL);
>  	if (!hyp_pgd) {
>  		kvm_err("Hyp mode PGD not allocated\n");
> -		return -ENOMEM;
> +		err = -ENOMEM;
> +		goto out;
> +	}
> +
> +	/* Create the idmap in the boot page tables */
> +	err = 	__create_hyp_mappings(boot_hyp_pgd,
> +				      hyp_idmap_start, hyp_idmap_end,
> +				      __phys_to_pfn(hyp_idmap_start),
> +				      PAGE_HYP);
> +
> +	if (err) {
> +		kvm_err("Failed to idmap %lx-%lx\n",
> +			hyp_idmap_start, hyp_idmap_end);
> +		goto out;
>  	}
>  
>  	return 0;
> +out:
> +	kfree(hyp_pgd);
> +	return err;
>  }
>  
>  /**
> diff --git a/arch/arm/mm/idmap.c b/arch/arm/mm/idmap.c
> index 5ee505c..9c467d0 100644
> --- a/arch/arm/mm/idmap.c
> +++ b/arch/arm/mm/idmap.c
> @@ -83,37 +83,10 @@ static void identity_mapping_add(pgd_t *pgd, const char *text_start,
>  	} while (pgd++, addr = next, addr != end);
>  }
>  
> -#if defined(CONFIG_ARM_VIRT_EXT) && defined(CONFIG_ARM_LPAE)
> -pgd_t *hyp_pgd;
> -
> -extern char  __hyp_idmap_text_start[], __hyp_idmap_text_end[];
> -
> -static int __init init_static_idmap_hyp(void)
> -{
> -	hyp_pgd = kzalloc(PTRS_PER_PGD * sizeof(pgd_t), GFP_KERNEL);
> -	if (!hyp_pgd)
> -		return -ENOMEM;
> -
> -	pr_info("Setting up static HYP identity map for 0x%p - 0x%p\n",
> -		__hyp_idmap_text_start, __hyp_idmap_text_end);
> -	identity_mapping_add(hyp_pgd, __hyp_idmap_text_start,
> -			     __hyp_idmap_text_end, PMD_SECT_AP1);
> -
> -	return 0;
> -}
> -#else
> -static int __init init_static_idmap_hyp(void)
> -{
> -	return 0;
> -}
> -#endif
> -
>  extern char  __idmap_text_start[], __idmap_text_end[];
>  
>  static int __init init_static_idmap(void)
>  {
> -	int ret;
> -
>  	idmap_pgd = pgd_alloc(&init_mm);
>  	if (!idmap_pgd)
>  		return -ENOMEM;
> @@ -123,12 +96,10 @@ static int __init init_static_idmap(void)
>  	identity_mapping_add(idmap_pgd, __idmap_text_start,
>  			     __idmap_text_end, 0);
>  
> -	ret = init_static_idmap_hyp();
> -
>  	/* Flush L1 for the hardware to see this page table content */
>  	flush_cache_louis();
>  
> -	return ret;
> +	return 0;
>  }
>  early_initcall(init_static_idmap);
>  
> -- 
> 1.8.1.4
> 
> 

Looks good to me, Russell, if you ack this one, I can send this through
the KVM tree, otherwise let me know if you want it through your tree.

-Christoffer