Re: [PATCH v11 for-xen-4.5 01/20] common/symbols: Export hypervisor symbols to privileged guest

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Mon, Sep 22, 2014 at 07:57:42PM -0400, Boris Ostrovsky wrote:
> Export Xen's symbols as {<address><type><name>} triplet via new XENPF_get_symbol
> hypercall
> 
> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> Reviewed-by: Dietmar Hahn <dietmar.hahn@ts.fujitsu.com>
> Tested-by: Dietmar Hahn <dietmar.hahn@ts.fujitsu.com>

Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> ---
>  xen/arch/x86/platform_hypercall.c | 33 ++++++++++++++++++++++++
>  xen/common/symbols.c              | 54 +++++++++++++++++++++++++++++++++++++++
>  xen/include/public/platform.h     | 19 ++++++++++++++
>  xen/include/xen/symbols.h         |  3 +++
>  xen/include/xlat.lst              |  1 +
>  5 files changed, 110 insertions(+)
> 
> diff --git a/xen/arch/x86/platform_hypercall.c b/xen/arch/x86/platform_hypercall.c
> index 2162811..68bc6d9 100644
> --- a/xen/arch/x86/platform_hypercall.c
> +++ b/xen/arch/x86/platform_hypercall.c
> @@ -23,6 +23,7 @@
>  #include <xen/cpu.h>
>  #include <xen/pmstat.h>
>  #include <xen/irq.h>
> +#include <xen/symbols.h>
>  #include <asm/current.h>
>  #include <public/platform.h>
>  #include <acpi/cpufreq/processor_perf.h>
> @@ -601,6 +602,38 @@ ret_t do_platform_op(XEN_GUEST_HANDLE_PARAM(xen_platform_op_t) u_xenpf_op)
>      }
>      break;
>  
> +    case XENPF_get_symbol:
> +    {
> +        static char name[KSYM_NAME_LEN + 1]; /* protected by xenpf_lock */
> +        XEN_GUEST_HANDLE(char) nameh;
> +        uint32_t namelen, copylen;
> +
> +        guest_from_compat_handle(nameh, op->u.symdata.name);
> +
> +        ret = xensyms_read(&op->u.symdata.symnum, &op->u.symdata.type,
> +                           &op->u.symdata.address, name);
> +
> +        namelen = strlen(name) + 1;
> +
> +        if ( namelen > op->u.symdata.namelen )
> +        {
> +            /* Caller's buffer is too small for the whole string */
> +            if ( op->u.symdata.namelen )
> +                name[op->u.symdata.namelen] = '\0';
> +            copylen = op->u.symdata.namelen;
> +        }
> +        else
> +            copylen = namelen;
> +
> +        op->u.symdata.namelen = namelen;
> +
> +        if ( !ret && copy_to_guest(nameh, name, copylen) )
> +            ret = -EFAULT;
> +        if ( !ret && __copy_field_to_guest(u_xenpf_op, op, u.symdata) )
> +            ret = -EFAULT;
> +    }
> +    break;
> +
>      default:
>          ret = -ENOSYS;
>          break;
> diff --git a/xen/common/symbols.c b/xen/common/symbols.c
> index bc2fde6..2c0942d 100644
> --- a/xen/common/symbols.c
> +++ b/xen/common/symbols.c
> @@ -17,6 +17,8 @@
>  #include <xen/lib.h>
>  #include <xen/string.h>
>  #include <xen/spinlock.h>
> +#include <public/platform.h>
> +#include <xen/guest_access.h>
>  
>  #ifdef SYMBOLS_ORIGIN
>  extern const unsigned int symbols_offsets[1];
> @@ -148,3 +150,55 @@ const char *symbols_lookup(unsigned long addr,
>      *offset = addr - symbols_address(low);
>      return namebuf;
>  }
> +
> +/*
> + * Get symbol type information. This is encoded as a single char at the
> + * beginning of the symbol name.
> + */
> +static char symbols_get_symbol_type(unsigned int off)
> +{
> +    /*
> +     * Get just the first code, look it up in the token table,
> +     * and return the first char from this token.
> +     */
> +    return symbols_token_table[symbols_token_index[symbols_names[off + 1]]];
> +}
> +
> +int xensyms_read(uint32_t *symnum, char *type,
> +                 uint64_t *address, char *name)
> +{
> +    /*
> +     * Symbols are most likely accessed sequentially so we remember position
> +     * from previous read. This can help us avoid the extra call to
> +     * get_symbol_offset().
> +     */
> +    static uint64_t next_symbol, next_offset;
> +    static DEFINE_SPINLOCK(symbols_mutex);
> +
> +    if ( *symnum > symbols_num_syms )
> +        return -ERANGE;
> +    if ( *symnum == symbols_num_syms )
> +    {
> +        /* No more symbols */
> +        name[0] = '\0';
> +        return 0;
> +    }
> +
> +    spin_lock(&symbols_mutex);
> +
> +    if ( *symnum == 0 )
> +        next_offset = next_symbol = 0;
> +    if ( next_symbol != *symnum )
> +        /* Non-sequential access */
> +        next_offset = get_symbol_offset(*symnum);
> +
> +    *type = symbols_get_symbol_type(next_offset);
> +    next_offset = symbols_expand_symbol(next_offset, name);
> +    *address = symbols_offsets[*symnum] + SYMBOLS_ORIGIN;
> +
> +    next_symbol = ++*symnum;
> +
> +    spin_unlock(&symbols_mutex);
> +
> +    return 0;
> +}
> diff --git a/xen/include/public/platform.h b/xen/include/public/platform.h
> index 053b9fa..4f21b17 100644
> --- a/xen/include/public/platform.h
> +++ b/xen/include/public/platform.h
> @@ -527,6 +527,24 @@ struct xenpf_core_parking {
>  typedef struct xenpf_core_parking xenpf_core_parking_t;
>  DEFINE_XEN_GUEST_HANDLE(xenpf_core_parking_t);
>  
> +#define XENPF_get_symbol   61
> +struct xenpf_symdata {
> +    /* IN/OUT variables */
> +    uint32_t namelen; /* IN:  size of name buffer                       */
> +                      /* OUT: strlen(name) of hypervisor symbol (may be */
> +                      /*      larger than what's been copied to guest)  */
> +    uint32_t symnum;  /* IN:  Symbol to read                            */
> +                      /* OUT: Next available symbol. If same as IN then */
> +                      /*      we reached the end                        */
> +
> +    /* OUT variables */
> +    char type;
> +    XEN_GUEST_HANDLE(char) name;
> +    uint64_t address;
> +};
> +typedef struct xenpf_symdata xenpf_symdata_t;
> +DEFINE_XEN_GUEST_HANDLE(xenpf_symdata_t);
> +
>  /*
>   * ` enum neg_errnoval
>   * ` HYPERVISOR_platform_op(const struct xen_platform_op*);
> @@ -553,6 +571,7 @@ struct xen_platform_op {
>          struct xenpf_cpu_hotadd        cpu_add;
>          struct xenpf_mem_hotadd        mem_add;
>          struct xenpf_core_parking      core_parking;
> +        struct xenpf_symdata           symdata;
>          uint8_t                        pad[128];
>      } u;
>  };
> diff --git a/xen/include/xen/symbols.h b/xen/include/xen/symbols.h
> index 87cd77d..1fa0537 100644
> --- a/xen/include/xen/symbols.h
> +++ b/xen/include/xen/symbols.h
> @@ -11,4 +11,7 @@ const char *symbols_lookup(unsigned long addr,
>                             unsigned long *offset,
>                             char *namebuf);
>  
> +int xensyms_read(uint32_t *symnum, char *type,
> +                 uint64_t *address, char *name);
> +
>  #endif /*_XEN_SYMBOLS_H*/
> diff --git a/xen/include/xlat.lst b/xen/include/xlat.lst
> index 9a35dd7..c8fafef 100644
> --- a/xen/include/xlat.lst
> +++ b/xen/include/xlat.lst
> @@ -86,6 +86,7 @@
>  ?	processor_px			platform.h
>  !	psd_package			platform.h
>  ?	xenpf_enter_acpi_sleep		platform.h
> +!	xenpf_symdata			platform.h
>  ?	xenpf_pcpuinfo			platform.h
>  ?	xenpf_pcpu_version		platform.h
>  !	sched_poll			sched.h
> -- 
> 1.8.1.4
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel