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SubjectRe: [PATCH v3 2/3] arch/arm64: fpsimd: Introduce fpsimd_save_and_flush_cpu_state() and use it
On Tue, Apr 23, 2019 at 02:57:18PM +0100, Julien Grall wrote:
> tent-Length: 4295
> Lines: 128
>
> The only external user of fpsimd_save() and fpsimd_flush_cpu_state() is
> the KVM FPSIMD code.
>
> A following patch will introduce a mechanism to acquire owernship of the
> FPSIMD/SVE context for performing context management operations. Rather
> than having to export the new helpers to get/put the context, we can just
> introduce a new function to combine fpsimd_save() and
> fpsimd_flush_cpu_state().
>
> This has also the advantage to remove any external call of fpsimd_save()
> and fpsimd_flush_cpu_state(), so they can be turned static.
>
> Lastly, the new function can also be used in the PM notifier.
>
> Signed-off-by: Julien Grall <julien.grall@arm.com>
>
> ---
> kernel_neon_begin() does not use fpsimd_save_and_flush_cpu_state()
> because the next patch will modify the function to also grab the
> FPSIMD/SVE context.
>
> Changes in v3:
> - Rework the commit message
> - Move the prototype of fpsimd_save_and_flush_cpu_state()
> further down in the header
> - Remove comment in kvm_arch_vcpu_put_fp()
>
> Changes in v2:
> - Patch added
> ---
> arch/arm64/include/asm/fpsimd.h | 5 ++---
> arch/arm64/kernel/fpsimd.c | 17 +++++++++++++----
> arch/arm64/kvm/fpsimd.c | 4 +---
> 3 files changed, 16 insertions(+), 10 deletions(-)
>
> diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h
> index b73d12fcc7f9..c311d36ecffe 100644
> --- a/arch/arm64/include/asm/fpsimd.h
> +++ b/arch/arm64/include/asm/fpsimd.h
> @@ -48,8 +48,6 @@ struct task_struct;
> extern void fpsimd_save_state(struct user_fpsimd_state *state);
> extern void fpsimd_load_state(struct user_fpsimd_state *state);
>
> -extern void fpsimd_save(void);
> -
> extern void fpsimd_thread_switch(struct task_struct *next);
> extern void fpsimd_flush_thread(void);
>
> @@ -63,7 +61,8 @@ extern void fpsimd_bind_state_to_cpu(struct user_fpsimd_state *state,
> void *sve_state, unsigned int sve_vl);
>
> extern void fpsimd_flush_task_state(struct task_struct *target);
> -extern void fpsimd_flush_cpu_state(void);
> +
> +extern void fpsimd_save_and_flush_cpu_state(void);

Nit: You could drop this blank line: these are all "state maintenance"
operations, roughly speaking.

But don't bother unless you respin for some other reason.

[...]

With or without that,

Reviewed-by: Dave Martin <Dave.Martin@arm.com>

Cheers
---Dave

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