[Xen-devel] [PATCH 3/5] kexec/xen: use libxc to get location of crash notes

[David Vrabel <david.vrabel@xxxxxxxxxx>]

From: David Vrabel <david.vrabel@xxxxxxxxxx>

Use xc_kexec_get_range(KEXEC_RANGE_MA_CPU) instead of parsing
/proc/iomem (which is only populated by non-upstream ("classic") Xen
kernels).

Signed-off-by: David Vrabel <david.vrabel@xxxxxxxxxx>
---
 kexec/crashdump-xen.c |   67 +++++++++++++++++++++++++++++-------------------
 1 files changed, 40 insertions(+), 27 deletions(-)

diff --git a/kexec/crashdump-xen.c b/kexec/crashdump-xen.c
index ff4706c..4a5cd8a 100644
--- a/kexec/crashdump-xen.c
+++ b/kexec/crashdump-xen.c
@@ -163,42 +163,55 @@ unsigned long xen_architecture(struct crash_elf_info 
*elf_info)
        return machine;
 }
 
-static int xen_crash_note_callback(void *UNUSED(data), int nr,
-                                  char *UNUSED(str),
-                                  unsigned long base,
-                                  unsigned long length)
-{
-       struct crash_note_info *note = xen_phys_notes + nr;
-
-       note->base = base;
-       note->length = length;
-
-       return 0;
-}
-
+#ifdef HAVE_LIBXENCTRL
 int xen_get_nr_phys_cpus(void)
 {
-       char *match = "Crash note\n";
-       int cpus, n;
+       xc_interface *xc;
+       int max_cpus;
+       int cpu;
 
        if (xen_phys_cpus)
                return xen_phys_cpus;
 
-       if ((cpus = kexec_iomem_for_each_line(match, NULL, NULL))) {
-               n = sizeof(struct crash_note_info) * cpus;
-               xen_phys_notes = malloc(n);
-               if (!xen_phys_notes) {
-                       fprintf(stderr, "failed to allocate xen_phys_notes.\n");
-                       return -1;
-               }
-               memset(xen_phys_notes, 0, n);
-               kexec_iomem_for_each_line(match,
-                                         xen_crash_note_callback, NULL);
-               xen_phys_cpus = cpus;
+       xc = xc_interface_open(NULL, NULL, 0);
+       if (!xc) {
+               fprintf(stderr, "failed to open xen control interface.\n");
+               return -1;
+       }
+
+       max_cpus = xc_get_max_cpus(xc);
+       if (max_cpus <= 0)
+               return -1;
+
+       xen_phys_notes = calloc(max_cpus, sizeof(*xen_phys_notes));
+       if (xen_phys_notes == NULL)
+               return -1;
+
+       for (cpu = 0; cpu < max_cpus; cpu++) {
+               uint64_t size, start;
+               int ret;
+
+               ret = xc_kexec_get_range(xc, KEXEC_RANGE_MA_CPU, cpu, &size, 
&start);
+               if (ret < 0)
+                       break;
+
+               xen_phys_notes[cpu].base = start;
+               xen_phys_notes[cpu].length = size;
        }
 
-       return cpus;
+       xc_interface_close(xc);
+
+       xen_phys_cpus = cpu;
+
+       return cpu;
 }
+#else
+int xen_get_nr_phys_cpus(void)
+{
+       return -1;
+}
+#endif
+
 
 int xen_get_note(int cpu, uint64_t *addr, uint64_t *len)
 {
-- 
1.7.2.5


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