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SubjectRe: [PATCH 11/14] arm64: KVM: Add HYP per-cpu accessors
On Tue, May 22, 2018 at 04:06:45PM +0100, Marc Zyngier wrote:
> As we're going to require to access per-cpu variables at EL2,
> let's craft the minimum set of accessors required to implement
> reading a per-cpu variable, relying on tpidr_el2 to contain the
> per-cpu offset.
>
> Reviewed-by: Christoffer Dall <christoffer.dall@arm.com>
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

Reviewed-by: Mark Rutland <mark.rutland@arm.com>

Mark.

> ---
> arch/arm64/include/asm/kvm_asm.h | 27 +++++++++++++++++++++++++--
> 1 file changed, 25 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
> index f6648a3e4152..fefd8cf42c35 100644
> --- a/arch/arm64/include/asm/kvm_asm.h
> +++ b/arch/arm64/include/asm/kvm_asm.h
> @@ -71,14 +71,37 @@ extern u32 __kvm_get_mdcr_el2(void);
>
> extern u32 __init_stage2_translation(void);
>
> +/* Home-grown __this_cpu_{ptr,read} variants that always work at HYP */
> +#define __hyp_this_cpu_ptr(sym) \
> + ({ \
> + void *__ptr = hyp_symbol_addr(sym); \
> + __ptr += read_sysreg(tpidr_el2); \
> + (typeof(&sym))__ptr; \
> + })
> +
> +#define __hyp_this_cpu_read(sym) \
> + ({ \
> + *__hyp_this_cpu_ptr(sym); \
> + })
> +
> #else /* __ASSEMBLY__ */
>
> -.macro get_host_ctxt reg, tmp
> - adr_l \reg, kvm_host_cpu_state
> +.macro hyp_adr_this_cpu reg, sym, tmp
> + adr_l \reg, \sym
> mrs \tmp, tpidr_el2
> add \reg, \reg, \tmp
> .endm
>
> +.macro hyp_ldr_this_cpu reg, sym, tmp
> + adr_l \reg, \sym
> + mrs \tmp, tpidr_el2
> + ldr \reg, [\reg, \tmp]
> +.endm
> +
> +.macro get_host_ctxt reg, tmp
> + hyp_adr_this_cpu \reg, kvm_host_cpu_state, \tmp
> +.endm
> +
> .macro get_vcpu_ptr vcpu, ctxt
> get_host_ctxt \ctxt, \vcpu
> ldr \vcpu, [\ctxt, #HOST_CONTEXT_VCPU]
> --
> 2.14.2
>

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