Re: [PATCH v4 1/2] xenoprof: fix up ability to disable it

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 17/02/16 18:02, Doug Goldstein wrote:
> Allow Xenoprof to be fully disabled when toggling the option off.
>
> Signed-off-by: Doug Goldstein <cardoe@cardoe.com>
> ---
> CC: Keir Fraser <keir@xen.org>
> CC: Jan Beulich <jbeulich@suse.com>
> CC: Andrew Cooper <andrew.cooper3@citrix.com>
>
> change since v3:
> - drop (void)var; from static inlines
> - fix typo that broke build (must have forgotten to do XEN_CONFIG_EXPERT=y make
> change since v2:
> - move all functions in xenoprof.h inside CONFIG_XENOPROF as suggested by
>   Andrew Cooper
> change since v1:
> - switch to #define empty 'functions' as suggested by Andrew Cooper
> ---
>  xen/arch/x86/Makefile              |  2 +-
>  xen/arch/x86/Rules.mk              |  2 ++
>  xen/arch/x86/x86_64/compat/entry.S |  4 ++++
>  xen/arch/x86/x86_64/entry.S        |  4 ++++
>  xen/include/asm-x86/config.h       |  1 -
>  xen/include/asm-x86/xenoprof.h     | 19 +++++++++++++++++++
>  xen/include/xen/xenoprof.h         | 25 +++++++++++++++++++------
>  7 files changed, 49 insertions(+), 8 deletions(-)
>
> diff --git a/xen/arch/x86/Makefile b/xen/arch/x86/Makefile
> index 8e6e901..434d985 100644
> --- a/xen/arch/x86/Makefile
> +++ b/xen/arch/x86/Makefile
> @@ -3,7 +3,7 @@ subdir-y += cpu
>  subdir-y += genapic
>  subdir-y += hvm
>  subdir-y += mm
> -subdir-y += oprofile
> +subdir-$(xenoprof) += oprofile
>  subdir-y += x86_64
>  
>  obj-bin-y += alternative.init.o
> diff --git a/xen/arch/x86/Rules.mk b/xen/arch/x86/Rules.mk
> index a1cdae0..94e4efd 100644
> --- a/xen/arch/x86/Rules.mk
> +++ b/xen/arch/x86/Rules.mk
> @@ -10,6 +10,8 @@ CFLAGS += -I$(BASEDIR)/include/asm-x86/mach-generic
>  CFLAGS += -I$(BASEDIR)/include/asm-x86/mach-default
>  CFLAGS += '-D__OBJECT_LABEL__=$(subst /,$$,$(subst -,_,$(subst $(BASEDIR)/,,$(CURDIR))/$@))'
>  
> +CFLAGS-$(xenoprof) += -DCONFIG_XENOPROF
> +
>  # Prevent floating-point variables from creeping into Xen.
>  CFLAGS += -msoft-float
>  
> diff --git a/xen/arch/x86/x86_64/compat/entry.S b/xen/arch/x86/x86_64/compat/entry.S
> index 3088aa7..6424ed0 100644
> --- a/xen/arch/x86/x86_64/compat/entry.S
> +++ b/xen/arch/x86/x86_64/compat/entry.S
> @@ -394,6 +394,10 @@ compat_crash_page_fault:
>  #define compat_kexec_op do_ni_hypercall
>  #endif
>  
> +#ifndef CONFIG_XENOPROF
> +#define compat_xenoprof_op do_ni_hypercall
> +#endif
> +
>  ENTRY(compat_hypercall_table)
>          .quad compat_set_trap_table     /*  0 */
>          .quad do_mmu_update
> diff --git a/xen/arch/x86/x86_64/entry.S b/xen/arch/x86/x86_64/entry.S
> index 94a54aa..0a73878 100644
> --- a/xen/arch/x86/x86_64/entry.S
> +++ b/xen/arch/x86/x86_64/entry.S
> @@ -727,6 +727,10 @@ ENTRY(exception_table)
>  #define do_kexec_op do_ni_hypercall
>  #endif
>  
> +#ifndef CONFIG_XENOPROF
> +#define do_xenoprof_op do_ni_hypercall
> +#endif
> +
>  ENTRY(hypercall_table)
>          .quad do_set_trap_table     /*  0 */
>          .quad do_mmu_update
> diff --git a/xen/include/asm-x86/config.h b/xen/include/asm-x86/config.h
> index d97877d..a45d3ee 100644
> --- a/xen/include/asm-x86/config.h
> +++ b/xen/include/asm-x86/config.h
> @@ -47,7 +47,6 @@
>  #define CONFIG_VGA 1
>  #define CONFIG_VIDEO 1
>  
> -#define CONFIG_XENOPROF 1
>  #define CONFIG_WATCHDOG 1
>  
>  #define CONFIG_MULTIBOOT 1
> diff --git a/xen/include/asm-x86/xenoprof.h b/xen/include/asm-x86/xenoprof.h
> index b006ddc..7044084 100644
> --- a/xen/include/asm-x86/xenoprof.h
> +++ b/xen/include/asm-x86/xenoprof.h
> @@ -67,9 +67,28 @@ void xenoprof_backtrace(struct vcpu *, const struct cpu_user_regs *,
>                   "xenoprof/x86 with autotranslated mode enabled"    \
>                   "isn't supported yet\n");                          \
>      } while (0)
> +
> +#ifdef CONFIG_XENOPROF

Sorry for not commenting before you resubmitted.

I would suggest having this #ifdef immediately under this files
inclusion guard.  That way you hide all symbols and declarations in the
!CONFIG_XENOPROF case.  Given that this patch compiles, I don't expect
you will encounter any issues from moving it.

>  int passive_domain_do_rdmsr(unsigned int msr, uint64_t *msr_content);
>  int passive_domain_do_wrmsr(unsigned int msr, uint64_t msr_content);
>  void passive_domain_destroy(struct vcpu *v);
> +#else

As a matter of style, please put newlines around here to space it out a
bit, and /* CONFIG_XENOPROF */ after the else, as the original #if is a
long way away.

> +static inline int passive_domain_do_rdmsr(unsigned int msr,
> +                                          uint64_t *msr_content)
> +{
> +    return 0;
> +}
> +
> +static inline int passive_domain_do_wrmsr(unsigned int msr,
> +                                          uint64_t msr_content)
> +{
> +    return 0;
> +}
> +
> +static inline void passive_domain_destroy(struct vcpu *v)

For brevity, "static inline void passive_domain_destroy(struct vcpu *v)
{}" is perfectly fine here.

> +{
> +}
> +#endif
>  
>  #endif /* __ASM_X86_XENOPROF_H__ */
>  
> diff --git a/xen/include/xen/xenoprof.h b/xen/include/xen/xenoprof.h
> index 9b9ef56..8148c01 100644
> --- a/xen/include/xen/xenoprof.h
> +++ b/xen/include/xen/xenoprof.h
> @@ -64,19 +64,32 @@ struct xenoprof {
>  #endif
>  
>  struct domain;
> -int is_active(struct domain *d);
> -int is_passive(struct domain *d);
> -void free_xenoprof_pages(struct domain *d);
> -
> -int xenoprof_add_trace(struct vcpu *, uint64_t pc, int mode);
> -
>  #define PMU_OWNER_NONE          0
>  #define PMU_OWNER_XENOPROF      1
>  #define PMU_OWNER_HVM           2
> +
> +#ifdef CONFIG_XENOPROF

Same comment concerning the position of this #ifdef.  I can't see any
symbols which will cause an issue.

With these issues addressed, Reviewed-by: Andrew Cooper
<andrew.cooper3@citrix.com>