[PATCH v4 3/7] ARM: KVM: move to a KVM provided HYP idmap

[Christoffer Dall]

On Fri, Apr 12, 2013 at 11:12 AM, Marc Zyngier <marc.zyngier at arm.com> 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.
>
> Acked-by: Will Deacon <will.deacon at arm.com>
> Signed-off-by: Marc Zyngier <marc.zyngier at arm.com>
> ---
>  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            | 32 +-------------------------------
>  4 files changed, 24 insertions(+), 34 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 96d61da..bfc5927 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..83cb3ac 100644
> --- a/arch/arm/mm/idmap.c
> +++ b/arch/arm/mm/idmap.c
> @@ -8,7 +8,6 @@
>  #include <asm/pgtable.h>
>  #include <asm/sections.h>
>  #include <asm/system_info.h>
> -#include <asm/virt.h>
>
>  pgd_t *idmap_pgd;
>
> @@ -83,37 +82,10 @@ 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 +95,10 @@ 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
>

Russell,

I would appreciate your ack on this one so we can merge this through
the KVM tree, or alternatively let us know if this needs to go your
tree, so we can plan accordingly for the next merge window.

Thanks a bunch,
-Christoffer