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

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

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@oracle.com>
[v2: Use DIV_ROUND_UP macro as suggested by Daniel]
[v3: Use 'int' for bits instead of 'unsigned int' as spotted by Boris]
---
 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);
 
-- 
1.9.3