1 files changed, 256 insertions, 0 deletions
diff --git a/kexec/crashdump-xen.c b/kexec/crashdump-xen.c
new file mode 100644
index 0000000..3f59a0d
--- /dev/null
+++ b/kexec/crashdump-xen.c
@@ -0,0 +1,256 @@
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <stdarg.h>
+#include <string.h>
+#include <stdlib.h>
+#include <elf.h>
+#include <errno.h>
+#include <limits.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <setjmp.h>
+#include <signal.h>
+#include "kexec.h"
+#include "crashdump.h"
+#include "kexec-syscall.h"
+#include "config.h"
+#include "kexec-xen.h"
+
+struct crash_note_info {
+	unsigned long base;
+	unsigned long length;
+};
+
+static int xen_phys_cpus;
+static struct crash_note_info *xen_phys_notes;
+
+/* based on code from xen-detect.c */
+static int is_dom0;
+#if defined(__i386__) || defined(__x86_64__)
+static jmp_buf xen_sigill_jmp;
+void xen_sigill_handler(int sig)
+{
+	longjmp(xen_sigill_jmp, 1);
+}
+
+static void xen_cpuid(uint32_t idx, uint32_t *regs, int pv_context)
+{
+#ifdef __i386__
+    /* Use the stack to avoid reg constraint failures with some gcc flags */
+    asm volatile (
+        "push %%eax; push %%ebx; push %%ecx; push %%edx\n\t"
+        "test %1,%1 ; jz 1f ; ud2a ; .ascii \"xen\" ; 1: cpuid\n\t"
+        "mov %%eax,(%2); mov %%ebx,4(%2)\n\t"
+        "mov %%ecx,8(%2); mov %%edx,12(%2)\n\t"
+        "pop %%edx; pop %%ecx; pop %%ebx; pop %%eax\n\t"
+        : : "a" (idx), "c" (pv_context), "S" (regs) : "memory" );
+#else
+    asm volatile (
+        "test %5,%5 ; jz 1f ; ud2a ; .ascii \"xen\" ; 1: cpuid\n\t"
+        : "=a" (regs[0]), "=b" (regs[1]), "=c" (regs[2]), "=d" (regs[3])
+        : "0" (idx), "1" (pv_context), "2" (0) );
+#endif
+}
+
+static int check_for_xen(int pv_context)
+{
+	uint32_t regs[4];
+	char signature[13];
+	uint32_t base;
+
+	for (base = 0x40000000; base < 0x40010000; base += 0x100)
+	{
+		xen_cpuid(base, regs, pv_context);
+
+		*(uint32_t *)(signature + 0) = regs[1];
+		*(uint32_t *)(signature + 4) = regs[2];
+		*(uint32_t *)(signature + 8) = regs[3];
+		signature[12] = '\0';
+
+		if (strcmp("XenVMMXenVMM", signature) == 0 && regs[0] >= (base + 2))
+			goto found;
+	}
+
+	return 0;
+
+found:
+	xen_cpuid(base + 1, regs, pv_context);
+	return regs[0];
+}
+
+static int xen_detect_pv_guest(void)
+{
+	struct sigaction act, oldact;
+	int is_pv = -1;
+
+	if (setjmp(xen_sigill_jmp))
+		return is_pv;
+
+	memset(&act, 0, sizeof(act));
+	act.sa_handler = xen_sigill_handler;
+	sigemptyset (&act.sa_mask);
+	if (sigaction(SIGILL, &act, &oldact))
+		return is_pv;
+	if (check_for_xen(1))
+		is_pv = 1;
+	sigaction(SIGILL, &oldact, NULL);
+	return is_pv;
+}
+#else
+static int xen_detect_pv_guest(void)
+{
+	return 1;
+}
+#endif
+
+/*
+ * Return 1 if its a PV guest.
+ * This includes dom0, which is the only PV guest where kexec/kdump works.
+ * HVM guests have to be handled as native hardware.
+ */
+int xen_present(void)
+{
+	if (!is_dom0) {
+		if (access("/proc/xen", F_OK) == 0)
+			is_dom0 = xen_detect_pv_guest();
+		else
+			is_dom0 = -1;
+	}
+	return is_dom0 > 0;
+}
+
+unsigned long xen_architecture(struct crash_elf_info *elf_info)
+{
+	unsigned long machine = elf_info->machine;
+#ifdef HAVE_LIBXENCTRL
+	int rc;
+	xen_capabilities_info_t capabilities;
+	xc_interface *xc;
+
+	if (!xen_present())
+		goto out;
+
+	memset(capabilities, '0', XEN_CAPABILITIES_INFO_LEN);
+
+	xc = xc_interface_open(NULL, NULL, 0);
+	if ( !xc ) {
+		fprintf(stderr, "failed to open xen control interface.\n");
+		goto out;
+	}
+
+	rc = xc_version(xc, XENVER_capabilities, &capabilities[0]);
+	if ( rc == -1 ) {
+		fprintf(stderr, "failed to make Xen version hypercall.\n");
+		goto out_close;
+	}
+
+	if (strstr(capabilities, "xen-3.0-x86_64"))
+		machine = EM_X86_64;
+        else if (strstr(capabilities, "xen-3.0-x86_32"))
+		machine = EM_386;
+
+ out_close:
+	xc_interface_close(xc);
+
+ out:
+#endif
+	return machine;
+}
+
+#ifdef HAVE_LIBXENCTRL
+int get_xen_vmcoreinfo(uint64_t *addr, uint64_t *len)
+{
+	uint64_t end;
+	int ret = 0;
+
+	ret = xen_get_kexec_range(KEXEC_RANGE_MA_VMCOREINFO, addr, &end);
+	if (ret < 0)
+	        return -1;
+
+	*len = end - *addr + 1;
+
+	return 0;
+}
+
+int xen_get_nr_phys_cpus(void)
+{
+	xc_interface *xc;
+	int max_cpus;
+	int cpu = -1;
+
+	if (xen_phys_cpus)
+		return xen_phys_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)
+		goto out;
+
+	xen_phys_notes = calloc(max_cpus, sizeof(*xen_phys_notes));
+	if (xen_phys_notes == NULL)
+		goto out;
+
+	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;
+	}
+
+	xen_phys_cpus = cpu;
+
+out:
+	xc_interface_close(xc);
+	return cpu;
+}
+#else
+int get_xen_vmcoreinfo(uint64_t *addr, uint64_t *len)
+{
+	return -1;
+}
+
+int xen_get_nr_phys_cpus(void)
+{
+	return -1;
+}
+#endif
+
+
+int xen_get_note(int cpu, uint64_t *addr, uint64_t *len)
+{
+	struct crash_note_info *note;
+
+	if (xen_phys_cpus <= 0)
+		return -1;
+
+	note = xen_phys_notes + cpu;
+
+	*addr = note->base;
+	*len = note->length;
+
+	return 0;
+}
+
+#ifdef HAVE_LIBXENCTRL
+int xen_get_crashkernel_region(uint64_t *start, uint64_t *end)
+{
+	return xen_get_kexec_range(KEXEC_RANGE_MA_CRASH, start, end);
+}
+#else
+int xen_get_crashkernel_region(uint64_t *start, uint64_t *end)
+{
+	return -1;
+}
+#endif