Re: [RFC PATCH 09/27] KVM: arm64: Allow using kvm_nvhe_sym() in hyp code

From: David Brazdil
Date: Mon Nov 23 2020 - 07:59:43 EST


On Tue, Nov 17, 2020 at 06:15:49PM +0000, 'Quentin Perret' via kernel-team wrote:
> In order to allow the usage of code shared by the host and the hyp in
> static inline library function, allow the usage of kvm_nvhe_sym() at el2
> by defaulting to the raw symbol name.
>
> Signed-off-by: Quentin Perret <qperret@xxxxxxxxxx>
> ---
> arch/arm64/include/asm/hyp_image.h | 4 ++++
> arch/arm64/include/asm/kvm_asm.h | 4 ++--
> arch/arm64/kvm/arm.c | 2 +-
> 3 files changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/arch/arm64/include/asm/hyp_image.h b/arch/arm64/include/asm/hyp_image.h
> index daa1a1da539e..8b807b646b8f 100644
> --- a/arch/arm64/include/asm/hyp_image.h
> +++ b/arch/arm64/include/asm/hyp_image.h
> @@ -7,11 +7,15 @@
> #ifndef __ARM64_HYP_IMAGE_H__
> #define __ARM64_HYP_IMAGE_H__
>
> +#ifndef __KVM_NVHE_HYPERVISOR__
> /*
> * KVM nVHE code has its own symbol namespace prefixed with __kvm_nvhe_,
> * to separate it from the kernel proper.
> */
> #define kvm_nvhe_sym(sym) __kvm_nvhe_##sym
> +#else
> +#define kvm_nvhe_sym(sym) sym
> +#endif
>
> #ifdef LINKER_SCRIPT
>
> diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
> index 1a86581e581e..e4934f5e4234 100644
> --- a/arch/arm64/include/asm/kvm_asm.h
> +++ b/arch/arm64/include/asm/kvm_asm.h
> @@ -173,11 +173,11 @@ struct kvm_s2_mmu;
> DECLARE_KVM_NVHE_SYM(__kvm_hyp_init);
> DECLARE_KVM_NVHE_SYM(__kvm_hyp_host_vector);
> DECLARE_KVM_HYP_SYM(__kvm_hyp_vector);
> -DECLARE_KVM_NVHE_SYM(__kvm_hyp_psci_cpu_entry);
> #define __kvm_hyp_init CHOOSE_NVHE_SYM(__kvm_hyp_init)
> #define __kvm_hyp_host_vector CHOOSE_NVHE_SYM(__kvm_hyp_host_vector)
> #define __kvm_hyp_vector CHOOSE_HYP_SYM(__kvm_hyp_vector)
> -#define __kvm_hyp_psci_cpu_entry CHOOSE_NVHE_SYM(__kvm_hyp_psci_cpu_entry)
> +
> +void kvm_nvhe_sym(__kvm_hyp_psci_cpu_entry)(void);
>
> extern unsigned long kvm_arm_hyp_percpu_base[NR_CPUS];
> DECLARE_KVM_NVHE_SYM(__per_cpu_start);
> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> index 882eb383bd75..391cf6753a13 100644
> --- a/arch/arm64/kvm/arm.c
> +++ b/arch/arm64/kvm/arm.c
> @@ -1369,7 +1369,7 @@ static void cpu_prepare_hyp_mode(int cpu)
>
> params->vector_hyp_va = kern_hyp_va((unsigned long)kvm_ksym_ref(__kvm_hyp_host_vector));
> params->stack_hyp_va = kern_hyp_va(per_cpu(kvm_arm_hyp_stack_page, cpu) + PAGE_SIZE);
> - params->entry_hyp_va = kern_hyp_va((unsigned long)kvm_ksym_ref(__kvm_hyp_psci_cpu_entry));
> + params->entry_hyp_va = kern_hyp_va((unsigned long)kvm_ksym_ref_nvhe(__kvm_hyp_psci_cpu_entry));

Why is this change needed?

> params->pgd_pa = kvm_mmu_get_httbr();
>
> /*
> --
> 2.29.2.299.gdc1121823c-goog
>
> --
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