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[Qemu-devel] [PATCH 3/3] pc-bios/s390-ccw/net: Try to load pxelinux.cfg
From: |
Thomas Huth |
Subject: |
[Qemu-devel] [PATCH 3/3] pc-bios/s390-ccw/net: Try to load pxelinux.cfg file accoring to the UUID |
Date: |
Wed, 30 May 2018 11:16:58 +0200 |
With the STSI instruction, we can get the UUID of the current VM instance,
so we can support loading pxelinux config files via UUID in the file name,
too.
Signed-off-by: Thomas Huth <address@hidden>
---
pc-bios/s390-ccw/netmain.c | 46 +++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 45 insertions(+), 1 deletion(-)
diff --git a/pc-bios/s390-ccw/netmain.c b/pc-bios/s390-ccw/netmain.c
index e84bb2b..7ece302 100644
--- a/pc-bios/s390-ccw/netmain.c
+++ b/pc-bios/s390-ccw/netmain.c
@@ -235,6 +235,49 @@ static void net_release(filename_ip_t *fn_ip)
}
/**
+ * Retrieve the Universally Unique Identifier of the VM.
+ * @return UUID string, or NULL in case of errors
+ */
+static const char *get_uuid(void)
+{
+ register int r0 asm("0");
+ register int r1 asm("1");
+ uint8_t *mem, *buf, uuid[16];
+ int i, chk = 0;
+ static char uuid_str[37];
+
+ mem = malloc(2 * PAGE_SIZE);
+ if (!mem) {
+ puts("Out of memory ... can not get UUID.");
+ return NULL;
+ }
+ buf = (uint8_t *)(((uint64_t)mem + PAGE_SIZE - 1) & ~(PAGE_SIZE - 1));
+ memset(buf, 0, PAGE_SIZE);
+
+ /* Get SYSIB 3.2.2 */
+ r0 = (3 << 28) | 2;
+ r1 = 2;
+ asm volatile(" stsi 0(%2)\n" : : "d" (r0), "d" (r1), "a" (buf)
+ : "cc", "memory");
+
+ for (i = 0; i < 16; i++) {
+ uuid[i] = buf[8 * 4 + 12 * 4 + i];
+ chk |= uuid[i];
+ }
+ free(mem);
+ if (!chk) {
+ return NULL;
+ }
+
+ sprintf(uuid_str, "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-"
+ "%02x%02x%02x%02x%02x%02x", uuid[0], uuid[1], uuid[2], uuid[3],
+ uuid[4], uuid[5], uuid[6], uuid[7], uuid[8], uuid[9], uuid[10],
+ uuid[11], uuid[12], uuid[13], uuid[14], uuid[15]);
+
+ return uuid_str;
+}
+
+/**
* Load a kernel with initrd (i.e. with the information that we've got from
* a pxelinux.cfg config file)
*/
@@ -284,7 +327,8 @@ static int net_try_pxelinux_cfg(filename_ip_t *fn_ip)
struct pl_cfg_entry entries[MAX_PXELINUX_ENTRIES];
int num_ent, def_ent = 0;
- num_ent = pxelinux_load_parse_cfg(fn_ip, mac, NULL, DEFAULT_TFTP_RETRIES,
+ num_ent = pxelinux_load_parse_cfg(fn_ip, mac, get_uuid(),
+ DEFAULT_TFTP_RETRIES,
cfgbuf, sizeof(cfgbuf),
entries, MAX_PXELINUX_ENTRIES, &def_ent);
if (num_ent > 0) {
--
1.8.3.1