Support loading a live update image for xen from kexec userspace.
For a multiboot2 Elf on a xen setup, this will:
- load the Elf into KEXEC_RANGE_MA_XEN
- load purgatory and modules into KEXEC_RANGE_MA_LIVEUPDATE
- append the Elf cmdline with " liveupdate=<size>@<addr>
v2: define xen related symbols outside of HAVE_LIBXENCTRL
Signed-off-by: Varad Gautam <vrd@xxxxxxxxx>
---
kexec/arch/i386/kexec-mb2-x86.c | 74 ++++++++++++++++++++++++++++++++++++++---
kexec/kexec-xen.c | 8 +++--
kexec/kexec-xen.h | 17 +++++++++-
kexec/kexec.c | 31 ++++++++++++++++-
kexec/kexec.h | 5 ++-
5 files changed, 125 insertions(+), 10 deletions(-)
diff --git a/kexec/arch/i386/kexec-mb2-x86.c b/kexec/arch/i386/kexec-mb2-x86.c
index b839d59..1ad8aed 100644
--- a/kexec/arch/i386/kexec-mb2-x86.c
+++ b/kexec/arch/i386/kexec-mb2-x86.c
@@ -42,6 +42,8 @@
#include "../../kexec.h"
#include "../../kexec-elf.h"
#include "kexec-x86.h"
+#include "../../kexec-syscall.h"
+#include "../../kexec-xen.h"
#include <arch/options.h>
/* From GNU GRUB */
@@ -388,6 +390,15 @@ static uint64_t multiboot2_mbi_end(void *mbi_buf, uint64_t mbi_ptr)
return mbi_ptr;
}
+static inline int multiboot2_rel_valid(struct multiboot_header_tag_relocatable *rel_tag,
+ uint64_t rel_start, uint64_t rel_end)
+{
+ if (rel_start >= rel_tag->min_addr && rel_end <= rel_tag->max_addr)
+ return 1;
+
+ return 0;
+}
+
int multiboot2_x86_load(int argc, char **argv, const char *buf, off_t len,
struct kexec_info *info)
{
@@ -413,6 +424,7 @@ int multiboot2_x86_load(int argc, char **argv, const char *buf, off_t len,
{ 0, 0, 0, 0 },
};
static const char short_options[] = KEXEC_ARCH_OPT_STR "";
+ uint64_t rel_min, rel_max;
/* Probe for the MB header if it's not already found */
if (mbh == NULL && multiboot_x86_probe(buf, len) != 1)
@@ -459,19 +471,59 @@ int multiboot2_x86_load(int argc, char **argv, const char *buf, off_t len,
if (tmp_cmdline) {
free(tmp_cmdline);
}
+
+ if (xen_present() && info->kexec_flags & KEXEC_LIVE_UPDATE ) {
+ if (!mhi.rel_tag) {
+ fprintf(stderr, "Multiboot2 image must be relocatable"
+ "for KEXEC_LIVE_UPDATE.\n");
+ return -1;
+ }
+ cmdline_add_liveupdate(&command_line);
+ }
+
command_line_len = strlen(command_line) + 1;
/* Load the ELF executable */
- if (mhi.rel_tag)
+ if (mhi.rel_tag) {
+ rel_min = mhi.rel_tag->min_addr;
+ rel_max = mhi.rel_tag->max_addr;
+
+ if (info->kexec_flags & KEXEC_LIVE_UPDATE && xen_present()) {
+ /* TODO also check if elf is xen */
+ /* On a live update, load target xen over the current xen image. */
+ uint64_t xen_start, xen_end;
+
+ xen_get_kexec_range(KEXEC_RANGE_MA_XEN, &xen_start, &xen_end);
+ if (multiboot2_rel_valid(mhi.rel_tag, xen_start, xen_end)) {
+ rel_min = xen_start;
+ } else {
+ fprintf(stderr, "Cannot place Elf into "
+ "KEXEC_RANGE_MA_XEN for KEXEC_LIVE_UPDATE.\n");
+ return -1;
+ }
+ }
+
elf_exec_build_load_relocatable(info, &ehdr, buf, len, 0,
- mhi.rel_tag->min_addr, mhi.rel_tag->max_addr,
- mhi.rel_tag->align);
- else
+ rel_min, rel_max, mhi.rel_tag->align);
+ } else
elf_exec_build_load(info, &ehdr, buf, len, 0);
+ if (info->kexec_flags & KEXEC_LIVE_UPDATE && xen_present()) {
+ uint64_t lu_start, lu_end;
+
+ xen_get_kexec_range(7 /* KEXEC_RANGE_MA_LIVEUPDATE */, &lu_start, &lu_end);
+ /* Fit everything else into lu_start-lu_end. First page after lu_start is
+ * reserved for LU breadcrumb. */
+ rel_min = lu_start + 4096;
+ rel_max = lu_end;
+ } else {
+ rel_min = 0;
+ rel_max = ULONG_MAX;
+ }
+
/* Load the setup code */
elf_rel_build_load(info, &info->rhdr, purgatory, purgatory_size,
- 0, ULONG_MAX, 1, 0);
+ rel_min, rel_max, 1, 0);
/* Construct information tags. */
mbi_bytes = multiboot2_get_mbi_size(info->memory_ranges, command_line_len, modules, mod_command_line_space);
@@ -480,6 +532,18 @@ int multiboot2_x86_load(int argc, char **argv, const char *buf, off_t len,
mbi_ptr = multiboot2_make_mbi(info, command_line, command_line_len, info->rhdr.rel_addr, mbi_buf, mbi_bytes);
free(command_line);
+ if (info->kexec_flags & KEXEC_LIVE_UPDATE && xen_present()) {
+ if (multiboot2_rel_valid(mhi.rel_tag, rel_min, rel_max)) {
+ /* Shrink the reloc range to fit into LU region for xen. */
+ mhi.rel_tag->min_addr = rel_min;
+ mhi.rel_tag->max_addr = rel_max;
+ } else {
+ fprintf(stderr, "Multiboot2 image cannot be relocated into "
+ "KEXEC_RANGE_MA_LIVEUPDATE for KEXEC_LIVE_UPDATE.\n");
+ return -1;
+ }
+ }
+
/* Load modules */
if (modules) {
char *mod_filename, *mod_command_line, *mod_clp, *buf;
diff --git a/kexec/kexec-xen.c b/kexec/kexec-xen.c
index afcfc5b..83629ba 100644
--- a/kexec/kexec-xen.c
+++ b/kexec/kexec-xen.c
@@ -177,8 +177,12 @@ int xen_kexec_load(struct kexec_info *info)
seg++;
}
- type = (info->kexec_flags & KEXEC_ON_CRASH) ? KEXEC_TYPE_CRASH
- : KEXEC_TYPE_DEFAULT;
+ if (info->kexec_flags & KEXEC_ON_CRASH)
+ type = KEXEC_TYPE_CRASH;
+ else if (info->kexec_flags & KEXEC_LIVE_UPDATE )
+ type = KEXEC_TYPE_LIVE_UPDATE;
+ else
+ type = KEXEC_TYPE_DEFAULT;
arch = (info->kexec_flags & KEXEC_ARCH_MASK) >> 16;
#if defined(__i386__) || defined(__x86_64__)
diff --git a/kexec/kexec-xen.h b/kexec/kexec-xen.h
index 94d22cd..70fb576 100644
--- a/kexec/kexec-xen.h
+++ b/kexec/kexec-xen.h
@@ -64,9 +64,24 @@ extern int __xc_interface_close(xc_interface *xch);
#endif /* CONFIG_LIBXENCTRL_DL */
-
#endif /* HAVE_LIBXENCTRL */
+#ifndef KEXEC_RANGE_MA_XEN
+#define KEXEC_RANGE_MA_XEN 1
+#endif
+
+#ifndef KEXEC_RANGE_MA_LIVEUPDATE
+#define KEXEC_RANGE_MA_LIVEUPDATE 7
+#endif
+
+#ifndef KEXEC_TYPE_LIVE_UPDATE
+#define KEXEC_TYPE_LIVE_UPDATE 2
+#endif
+
+#ifndef KEXEC_LIVE_UPDATE
+#define KEXEC_LIVE_UPDATE 0x00000004
+#endif
+
int xen_get_kexec_range(int range, uint64_t *start, uint64_t *end);
#endif /* KEXEC_XEN_H */
diff --git a/kexec/kexec.c b/kexec/kexec.c
index 6601f1f..da61d6d 100644
--- a/kexec/kexec.c
+++ b/kexec/kexec.c
@@ -47,6 +47,7 @@
#include "kexec.h"
#include "kexec-syscall.h"
#include "kexec-elf.h"
+#include "kexec-xen.h"
#include "kexec-sha256.h"
#include "kexec-zlib.h"
#include "kexec-lzma.h"
@@ -1022,6 +1023,8 @@ void usage(void)
" context of current kernel during kexec.\n"
" --load-jump-back-helper Load a helper image to jump back\n"
" to original kernel.\n"
+ " --load-live-update Load the new kernel to overwrite the\n"
+ " running kernel.\n"
" --entry=<addr> Specify jump back address.\n"
" (0 means it's not jump back or\n"
" preserve context)\n"
@@ -1171,6 +1174,25 @@ char *concat_cmdline(const char *base, const char *append)
return cmdline;
}
+void cmdline_add_liveupdate(char **base)
+{
+ uint64_t lu_start, lu_end, lu_sizeM;
+ char *str;
+ char buf[64];
+ size_t len;
+
+ if ( !xen_present() )
+ return;
+
+ xen_get_kexec_range(KEXEC_RANGE_MA_LIVEUPDATE, &lu_start, &lu_end);
+ lu_sizeM = (lu_end - lu_start) / (1024 * 1024) + 1;
+ sprintf(buf, " liveupdate=%luM@0x%lx", lu_sizeM, lu_start);
+ len = strlen(*base) + strlen(buf) + 1;
+ str = xmalloc(len);
+ sprintf(str, "%s%s", *base, buf);
+ *base = str;
+}
+
/* New file based kexec system call related code */
static int do_kexec_file_load(int fileind, int argc, char **argv,
unsigned long flags) {
@@ -1402,11 +1424,13 @@ int main(int argc, char *argv[])
}
break;
case OPT_LOAD_PRESERVE_CONTEXT:
+ case OPT_LOAD_LIVE_UPDATE:
do_load = 1;
do_exec = 0;
do_shutdown = 0;
do_sync = 1;
- kexec_flags = KEXEC_PRESERVE_CONTEXT;
+ kexec_flags = (opt == OPT_LOAD_PRESERVE_CONTEXT) ?
+ KEXEC_PRESERVE_CONTEXT : KEXEC_LIVE_UPDATE;
break;
case OPT_TYPE:
type = optarg;
@@ -1504,6 +1528,11 @@ int main(int argc, char *argv[])
"\"--mem-max\" parameter\n");
}
+ if (do_load && (kexec_flags & KEXEC_LIVE_UPDATE) &&
+ !xen_present()) {
+ die("--load-live-update can only be used with xen\n");
+ }
+
fileind = optind;
/* Reset getopt for the next pass; called in other source modules */
opterr = 1;
diff --git a/kexec/kexec.h b/kexec/kexec.h
index 28fd129..8021f39 100644
--- a/kexec/kexec.h
+++ b/kexec/kexec.h
@@ -233,7 +233,8 @@ extern int file_types;
#define OPT_LOAD_JUMP_BACK_HELPER 260
#define OPT_ENTRY 261
#define OPT_PRINT_CKR_SIZE 262
-#define OPT_MAX 263
+#define OPT_LOAD_LIVE_UPDATE 263
+#define OPT_MAX 264
#define KEXEC_OPTIONS \
{ "help", 0, 0, OPT_HELP }, \
{ "version", 0, 0, OPT_VERSION }, \
@@ -246,6 +247,7 @@ extern int file_types;
{ "exec", 0, 0, OPT_EXEC }, \
{ "load-preserve-context", 0, 0, OPT_LOAD_PRESERVE_CONTEXT}, \
{ "load-jump-back-helper", 0, 0, OPT_LOAD_JUMP_BACK_HELPER }, \
+ { "load-live-update", 0, 0, OPT_LOAD_LIVE_UPDATE }, \
{ "entry", 1, 0, OPT_ENTRY }, \
{ "type", 1, 0, OPT_TYPE }, \
{ "load-panic", 0, 0, OPT_PANIC }, \
@@ -319,6 +321,7 @@ const char * proc_iomem(void);
#define MAX_LINE 160
char *concat_cmdline(const char *base, const char *append);
+void cmdline_add_liveupdate(char **base);
int xen_present(void);
int xen_kexec_load(struct kexec_info *info);
--
2.7.4
Amazon Development Center Germany GmbH
Krausenstr. 38
10117 Berlin
Geschaeftsfuehrung: Christian Schlaeger, Jonathan Weiss
Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B
Sitz: Berlin
Ust-ID: DE 289 237 879
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