Re: [PATCH v8 3/9] KVM: arm64: Move hyp_symbol_addr to fix dependency

From: Dave Martin
Date: Fri Apr 05 2019 - 07:02:26 EST


On Tue, Apr 02, 2019 at 07:57:11AM +0530, Amit Daniel Kachhap wrote:
> Currently hyp_symbol_addr is placed in kvm_mmu.h which is mostly
> used by __hyp_this_cpu_ptr in kvm_asm.h but it cannot include
> kvm_mmu.h directly as kvm_mmu.h uses kvm_ksym_ref which is
> defined inside kvm_asm.h. Hence, hyp_symbol_addr is moved inside
> kvm_asm.h to fix this dependency on each other.
>
> Also, hyp_symbol_addr corresponding counterpart, kvm_ksym_ref,
> is already in kvm_asm.h, making it more sensible to move
> kvm_symbol_addr to the same file.
>
> Suggested by: James Morse <james.morse@xxxxxxx>
> Signed-off-by: Amit Daniel Kachhap <amit.kachhap@xxxxxxx>
> Reviewed-by: Julien Thierry <julien.thierry@xxxxxxx>
> Cc: Marc Zyngier <marc.zyngier@xxxxxxx>
> Cc: Christoffer Dall <christoffer.dall@xxxxxxx>
> Cc: kvmarm@xxxxxxxxxxxxxxxxxxxxx
> ---
>
> Changes since v7:
> * Slight change in commit message [Julien Thierry].
>
> arch/arm64/include/asm/kvm_asm.h | 20 ++++++++++++++++++++
> arch/arm64/include/asm/kvm_mmu.h | 20 --------------------
> 2 files changed, 20 insertions(+), 20 deletions(-)
>
> diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
> index f5b79e9..57a07e8 100644
> --- a/arch/arm64/include/asm/kvm_asm.h
> +++ b/arch/arm64/include/asm/kvm_asm.h
> @@ -80,6 +80,26 @@ extern void __vgic_v3_init_lrs(void);
>
> extern u32 __kvm_get_mdcr_el2(void);
>
> +/*
> + * Obtain the PC-relative address of a kernel symbol
> + * s: symbol
> + *
> + * The goal of this macro is to return a symbol's address based on a
> + * PC-relative computation, as opposed to a loading the VA from a
> + * constant pool or something similar. This works well for HYP, as an
> + * absolute VA is guaranteed to be wrong. Only use this if trying to
> + * obtain the address of a symbol (i.e. not something you obtained by
> + * following a pointer).
> + */
> +#define hyp_symbol_addr(s) \
> + ({ \
> + typeof(s) *addr; \
> + asm("adrp %0, %1\n" \
> + "add %0, %0, :lo12:%1\n" \
> + : "=r" (addr) : "S" (&s)); \
> + addr; \
> + })
> +

Do we need to include <asm/kvm_asm.h> in vgic-v2-cpuif-proxy.c now?

Otherwise,

Reviewed-by: Dave Martin <Dave.Martin@xxxxxxx>