Re: [Xen-devel] [PATCH v1 2/5] libxc/trace: Add xc_tbuf_set_cpu_mask_array a variant of xc_tbuf_set_cpu_mask (v3)

[George Dunlap <george.dunlap@xxxxxxxxxxxxx>]

On 06/04/2014 02:44 PM, Konrad Rzeszutek Wilk wrote:
> which uses an xc_cpumap_t instead of a uint32_t. This means
> we can use an arbitrary bitmap without being limited to the
> 32-bits the xc_tbuf_set_cpu_mask_array can only do.
>
> We also add an macro which can be used by both libxc and
> xentrace.
>
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
> [v2: Use DIV_ROUND_UP macro as suggested by Daniel]
> [v3: Use 'int' for bits instead of 'unsigned int' as spotted by Boris]

Acked-by: George Dunlap <george.dunlap@xxxxxxxxxxxxx>

> ---
>   tools/libxc/xc_bitops.h |  2 ++
>   tools/libxc/xc_tbuf.c   | 40 ++++++++++++++++++++++++++++++++++++++++
>   tools/libxc/xenctrl.h   |  1 +
>   3 files changed, 43 insertions(+)
>
> diff --git a/tools/libxc/xc_bitops.h b/tools/libxc/xc_bitops.h
> index d8e0c16..b8cf2bd 100644
> --- a/tools/libxc/xc_bitops.h
> +++ b/tools/libxc/xc_bitops.h
> @@ -12,6 +12,8 @@
>   #define BITMAP_ENTRY(_nr,_bmap) ((_bmap))[(_nr)/BITS_PER_LONG]
>   #define BITMAP_SHIFT(_nr) ((_nr) % BITS_PER_LONG)
>
> +#define DIV_ROUND_UP(n, d) (((n) + (d) - 1) / (d))
> +
>   /* calculate required space for number of longs needed to hold nr_bits */
>   static inline int bitmap_size(int nr_bits)
>   {
> diff --git a/tools/libxc/xc_tbuf.c b/tools/libxc/xc_tbuf.c
> index 4fb7bb1..efa8094 100644
> --- a/tools/libxc/xc_tbuf.c
> +++ b/tools/libxc/xc_tbuf.c
> @@ -24,6 +24,7 @@
>    */
>
>   #include "xc_private.h"
> +#include "xc_bitops.h"
>   #include <xen/trace.h>
>
>   static int tbuf_enable(xc_interface *xch, int enable)
> @@ -143,6 +144,45 @@ int xc_tbuf_set_cpu_mask(xc_interface *xch, uint32_t mask)
>    out:
>       return ret;
>   }
> +int xc_tbuf_set_cpu_mask_array(xc_interface *xch, xc_cpumap_t mask, int bits)
> +{
> +    DECLARE_SYSCTL;
> +    DECLARE_HYPERCALL_BUFFER(uint8_t, bytemap);
> +    int ret = -1;
> +    int local_bits;
> +
> +    if ( bits <= 0 )
> +        goto out;
> +
> +    local_bits = xc_get_max_cpus(xch);
> +    if ( bits > local_bits )
> +    {
> +        PERROR("Wrong amount of bits supplied: %u, using %u\n", bits, 
> local_bits);
> +        bits = local_bits;
> +    }
> +    bytemap = xc_hypercall_buffer_alloc(xch, bytemap, DIV_ROUND_UP(bits, 8));
> +    if ( bytemap == NULL )
> +    {
> +        PERROR("Could not allocate memory for xc_tbuf_set_cpu_mask_array 
> hypercall");
> +        goto out;
> +    }
> +
> +    memcpy(bytemap, mask, DIV_ROUND_UP(bits, 8));
> +
> +    sysctl.cmd = XEN_SYSCTL_tbuf_op;
> +    sysctl.interface_version = XEN_SYSCTL_INTERFACE_VERSION;
> +    sysctl.u.tbuf_op.cmd  = XEN_SYSCTL_TBUFOP_set_cpu_mask;
> +
> +    set_xen_guest_handle(sysctl.u.tbuf_op.cpu_mask.bitmap, bytemap);
> +    sysctl.u.tbuf_op.cpu_mask.nr_bits = bits;
> +
> +    ret = do_sysctl(xch, &sysctl);
> +
> +    xc_hypercall_buffer_free(xch, bytemap);
> +
> + out:
> +    return ret;
> +}
>
>   int xc_tbuf_set_evt_mask(xc_interface *xch, uint32_t mask)
>   {
> diff --git a/tools/libxc/xenctrl.h b/tools/libxc/xenctrl.h
> index 400f0df..df9eb46 100644
> --- a/tools/libxc/xenctrl.h
> +++ b/tools/libxc/xenctrl.h
> @@ -1472,6 +1472,7 @@ int xc_tbuf_set_size(xc_interface *xch, unsigned long 
> size);
>   int xc_tbuf_get_size(xc_interface *xch, unsigned long *size);
>
>   int xc_tbuf_set_cpu_mask(xc_interface *xch, uint32_t mask);
> +int xc_tbuf_set_cpu_mask_array(xc_interface *xch, xc_cpumap_t mask, int bits);
>
>   int xc_tbuf_set_evt_mask(xc_interface *xch, uint32_t mask);

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