Re: [PATCH 2/4] docs/html/: Annotations for two hypercalls

Ian Campbell
Tue, 29 Nov 2011 15:20:22 -0000

On Tue, 2011-11-29 at 15:01 +0000, Ian Jackson wrote:
> Add annotations for a couple of the hypercalls:
>  HYPERVISOR_set_trap_table
>  HYPERVISOR_mmu_update
>
> We do this by
>  * annotating the list of #defines for hypercall numbers
>  * annotating the list of error values
>  * providing a function prototype for the systematically-named functions
> The header generator does the rest.
>
> This exercise revealed a couple of infelicities:
>  * In the actual source code, do_mmu_update is defined to return an int
>    and do_set_trap_table a long.  However both functions return either
>    -Efoo (on error) or 0 for success.

Should that be fixed or would that do more harm than good?

>  * The error numbers are defined only in the private header file
>    xen/include/xen/errno.h and then only with names which will
>    typically clash with other projects.  It would be nice to include a
>    public version of this header which defines XEN_E*.  But for now
>    we run xen-headers on errno.h too.
>
> Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>

Acked-by: Ian Campbell <ian.campbell@citrix.com>

> ---
>  docs/Makefile                     |    2 +-
>  xen/include/public/arch-x86/xen.h |    6 ++++++
>  xen/include/public/xen.h          |   11 +++++++++--
>  xen/include/xen/errno.h           |    5 +++++
>  4 files changed, 21 insertions(+), 3 deletions(-)
>
> diff --git a/docs/Makefile b/docs/Makefile
> index ad315cf..a2bbf2d 100644
> --- a/docs/Makefile
> +++ b/docs/Makefile
> @@ -134,7 +134,7 @@ html/hypercall/stamp:
>  	./xen-headers -O $(@D) \
>  		-T ''arch-x86_64 - Xen public headers'' \
>  		-X arch-ia64 -X arch-x86_32 -X xen-x86_32 \
> -		../xen include/public
> +		../xen include/public include/xen/errno.h
>  	touch $@
>
>  txt/%.txt: %.txt
> diff --git a/xen/include/public/arch-x86/xen.h
b/xen/include/public/arch-x86/xen.h
> index 79ec633..d663cef 100644
> --- a/xen/include/public/arch-x86/xen.h
> +++ b/xen/include/public/arch-x86/xen.h
> @@ -82,7 +82,13 @@ typedef unsigned long xen_pfn_t;
>  typedef unsigned long xen_ulong_t;
>
>  /*
> + * ` enum neg_errnoval
> + * ` HYPERVISOR_set_trap_table(const struct trap_info traps[]);
> + * `
> + */
> +/*
>   * Send an array of these to HYPERVISOR_set_trap_table().
> + * Terminate the array with a sentinel entry, with traps[].address==0.
>   * The privilege level specifies which modes may enter a trap via a
software
>   * interrupt. On x86/64, since rings 1 and 2 are unavailable, we allocate
>   * privilege levels as follows:
> diff --git a/xen/include/public/xen.h b/xen/include/public/xen.h
> index fde9fa5..f2c9e6f 100644
> --- a/xen/include/public/xen.h
> +++ b/xen/include/public/xen.h
> @@ -55,6 +55,8 @@ DEFINE_XEN_GUEST_HANDLE(xen_pfn_t);
>   * HYPERCALLS
>   */
>
> +/* ` enum hypercall_num { // __HYPERVISOR_* => HYPERVISOR_*() */
> +
>  #define __HYPERVISOR_set_trap_table        0
>  #define __HYPERVISOR_mmu_update            1
>  #define __HYPERVISOR_set_gdt               2
> @@ -105,6 +107,8 @@ DEFINE_XEN_GUEST_HANDLE(xen_pfn_t);
>  #define __HYPERVISOR_arch_6               54
>  #define __HYPERVISOR_arch_7               55
>
> +/* ` } */
> +
>  /*
>   * HYPERCALL COMPATIBILITY.
>   */
> @@ -163,8 +167,11 @@ DEFINE_XEN_GUEST_HANDLE(xen_pfn_t);
>  #define NR_VIRQS       24
>
>  /*
> - * HYPERVISOR_mmu_update(reqs, count, pdone, foreigndom)
> - *
> + * ` enum neg_errnoval
> + * ` HYPERVISOR_mmu_update(const struct mmu_update reqs[],
> + * `                       unsigned count, unsigned *done_out,
> + * `                       unsigned foreigndom)
> + * `
>   * @reqs is an array of mmu_update_t structures ((ptr, val) pairs).
>   * @count is the length of the above array.
>   * @pdone is an output parameter indicating number of completed operations
> diff --git a/xen/include/xen/errno.h b/xen/include/xen/errno.h
> index 7cf599f..39147be 100644
> --- a/xen/include/xen/errno.h
> +++ b/xen/include/xen/errno.h
> @@ -1,6 +1,9 @@
>  #ifndef _I386_ERRNO_H
>  #define _I386_ERRNO_H
>
> +/* ` enum neg_errnoval {  [ -Efoo for each Efoo in the list below ]  } */
> +/* ` enum errnoval { */
> +
>  #define	EPERM		 1	/* Operation not permitted */
>  #define	ENOENT		 2	/* No such file or directory */
>  #define	ESRCH		 3	/* No such process */
> @@ -129,4 +132,6 @@
>  #define	ENOMEDIUM	123	/* No medium found */
>  #define	EMEDIUMTYPE	124	/* Wrong medium type */
>
> +/* ` } */
> +
>  #endif