Re: [PATCH v4 18/21] KVM: arm64: Remove __pkvm_mark_hyp

[Fuad Tabba <tabba@google.com>]

Hi Quentin,

On Mon, Aug 9, 2021 at 5:25 PM Quentin Perret <qperret@google.com> wrote:
>
> Now that we mark memory owned by the hypervisor in the host stage-2
> during __pkvm_init(), we no longer need to rely on the host to
> explicitly mark the hyp sections later on.
>
> Remove the __pkvm_mark_hyp() hypercall altogether.
>
> Signed-off-by: Quentin Perret <qperret@google.com>
> ---

Reviewed-by: Fuad Tabba <tabba@google.com>

Thanks,
/fuad

>  arch/arm64/include/asm/kvm_asm.h              |  3 +-
>  arch/arm64/kvm/arm.c                          | 46 -------------------
>  arch/arm64/kvm/hyp/include/nvhe/mem_protect.h |  1 -
>  arch/arm64/kvm/hyp/nvhe/hyp-main.c            |  9 ----
>  arch/arm64/kvm/hyp/nvhe/mem_protect.c         | 19 --------
>  5 files changed, 1 insertion(+), 77 deletions(-)
>
> diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
> index 9f0bf2109be7..432a9ea1f02e 100644
> --- a/arch/arm64/include/asm/kvm_asm.h
> +++ b/arch/arm64/include/asm/kvm_asm.h
> @@ -63,8 +63,7 @@
>  #define __KVM_HOST_SMCCC_FUNC___pkvm_create_private_mapping    17
>  #define __KVM_HOST_SMCCC_FUNC___pkvm_cpu_set_vector            18
>  #define __KVM_HOST_SMCCC_FUNC___pkvm_prot_finalize             19
> -#define __KVM_HOST_SMCCC_FUNC___pkvm_mark_hyp                  20
> -#define __KVM_HOST_SMCCC_FUNC___kvm_adjust_pc                  21
> +#define __KVM_HOST_SMCCC_FUNC___kvm_adjust_pc                  20
>
>  #ifndef __ASSEMBLY__
>
> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> index e9a2b8f27792..2f378482471b 100644
> --- a/arch/arm64/kvm/arm.c
> +++ b/arch/arm64/kvm/arm.c
> @@ -1954,57 +1954,11 @@ static void _kvm_host_prot_finalize(void *discard)
>         WARN_ON(kvm_call_hyp_nvhe(__pkvm_prot_finalize));
>  }
>
> -static inline int pkvm_mark_hyp(phys_addr_t start, phys_addr_t end)
> -{
> -       return kvm_call_hyp_nvhe(__pkvm_mark_hyp, start, end);
> -}
> -
> -#define pkvm_mark_hyp_section(__section)               \
> -       pkvm_mark_hyp(__pa_symbol(__section##_start),   \
> -                       __pa_symbol(__section##_end))
> -
>  static int finalize_hyp_mode(void)
>  {
> -       int cpu, ret;
> -
>         if (!is_protected_kvm_enabled())
>                 return 0;
>
> -       ret = pkvm_mark_hyp_section(__hyp_idmap_text);
> -       if (ret)
> -               return ret;
> -
> -       ret = pkvm_mark_hyp_section(__hyp_text);
> -       if (ret)
> -               return ret;
> -
> -       ret = pkvm_mark_hyp_section(__hyp_rodata);
> -       if (ret)
> -               return ret;
> -
> -       ret = pkvm_mark_hyp_section(__hyp_bss);
> -       if (ret)
> -               return ret;
> -
> -       ret = pkvm_mark_hyp(hyp_mem_base, hyp_mem_base + hyp_mem_size);
> -       if (ret)
> -               return ret;
> -
> -       for_each_possible_cpu(cpu) {
> -               phys_addr_t start = virt_to_phys((void *)kvm_arm_hyp_percpu_base[cpu]);
> -               phys_addr_t end = start + (PAGE_SIZE << nvhe_percpu_order());
> -
> -               ret = pkvm_mark_hyp(start, end);
> -               if (ret)
> -                       return ret;
> -
> -               start = virt_to_phys((void *)per_cpu(kvm_arm_hyp_stack_page, cpu));
> -               end = start + PAGE_SIZE;
> -               ret = pkvm_mark_hyp(start, end);
> -               if (ret)
> -                       return ret;
> -       }
> -
>         /*
>          * Flip the static key upfront as that may no longer be possible
>          * once the host stage 2 is installed.
> diff --git a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
> index 49db0ec5a606..0118527b07b0 100644
> --- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
> +++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
> @@ -49,7 +49,6 @@ extern struct host_kvm host_kvm;
>  extern const u8 pkvm_hyp_id;
>
>  int __pkvm_prot_finalize(void);
> -int __pkvm_mark_hyp(phys_addr_t start, phys_addr_t end);
>
>  bool addr_is_memory(phys_addr_t phys);
>  int host_stage2_idmap_locked(phys_addr_t addr, u64 size, enum kvm_pgtable_prot prot);
> diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
> index 1632f001f4ed..7900d5b66ba3 100644
> --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c
> +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
> @@ -163,14 +163,6 @@ static void handle___pkvm_prot_finalize(struct kvm_cpu_context *host_ctxt)
>  {
>         cpu_reg(host_ctxt, 1) = __pkvm_prot_finalize();
>  }
> -
> -static void handle___pkvm_mark_hyp(struct kvm_cpu_context *host_ctxt)
> -{
> -       DECLARE_REG(phys_addr_t, start, host_ctxt, 1);
> -       DECLARE_REG(phys_addr_t, end, host_ctxt, 2);
> -
> -       cpu_reg(host_ctxt, 1) = __pkvm_mark_hyp(start, end);
> -}
>  typedef void (*hcall_t)(struct kvm_cpu_context *);
>
>  #define HANDLE_FUNC(x) [__KVM_HOST_SMCCC_FUNC_##x] = (hcall_t)handle_##x
> @@ -196,7 +188,6 @@ static const hcall_t host_hcall[] = {
>         HANDLE_FUNC(__pkvm_create_mappings),
>         HANDLE_FUNC(__pkvm_create_private_mapping),
>         HANDLE_FUNC(__pkvm_prot_finalize),
> -       HANDLE_FUNC(__pkvm_mark_hyp),
>  };
>
>  static void handle_host_hcall(struct kvm_cpu_context *host_ctxt)
> diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
> index cb023d31666e..2991dc6996b9 100644
> --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
> +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
> @@ -339,25 +339,6 @@ static int host_stage2_idmap(u64 addr)
>         return ret;
>  }
>
> -int __pkvm_mark_hyp(phys_addr_t start, phys_addr_t end)
> -{
> -       int ret;
> -
> -       /*
> -        * host_stage2_unmap_dev_all() currently relies on MMIO mappings being
> -        * non-persistent, so don't allow changing page ownership in MMIO range.
> -        */
> -       if (!range_is_memory(start, end))
> -               return -EINVAL;
> -
> -       hyp_spin_lock(&host_kvm.lock);
> -       ret = host_stage2_try(kvm_pgtable_stage2_set_owner, &host_kvm.pgt,
> -                             start, end - start, &host_s2_pool, pkvm_hyp_id);
> -       hyp_spin_unlock(&host_kvm.lock);
> -
> -       return ret != -EAGAIN ? ret : 0;
> -}
> -
>  void handle_host_mem_abort(struct kvm_cpu_context *host_ctxt)
>  {
>         struct kvm_vcpu_fault_info fault;
> --
> 2.32.0.605.g8dce9f2422-goog
>