kexec-tools/kexec-tools-xen-present.diff
Petr Tesařík c8c1a9440a Accepting request 125015 from home:olh:branches:Kernel:kdump
Without theses changes from sles11sp2 installation in
a Xen HVM guest can not work in factory because the
installer uses kexec to boot into second stage..


- Fix xen cpuid() inline asm to not clobber stack's red zone 
  See xen-unstable changeset 24344:72f4e4cb7440

- Balloon up in a Xen PVonHVM guest before kexec (bnc#694863)
- Update xen_present check for xenfs in pv_ops kernel (bnc#694863)
- Change xen_present hv check (bnc#658413)

OBS-URL: https://build.opensuse.org/request/show/125015
OBS-URL: https://build.opensuse.org/package/show/Kernel:kdump/kexec-tools?expand=0&rev=21
2012-06-19 12:31:17 +00:00

134 lines
3.5 KiB
Diff

From: Olaf Hering <ohering@novell.com>
References: bnc#658413, bnc#694863
Subject: xen_present() should be named is_xen_pv() (includes also dom0).
A hvm guest is like physical hardware and should not need special handling.
Use code from xen-detect.c instead of stat() to distinguish hvm from pv because
xenfs in a pv_ops kernel generates /proc/xen/capabilities unconditionally.
---
kexec/crashdump-xen.c | 100 +++++++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 95 insertions(+), 5 deletions(-)
Index: kexec-tools-2.0.2/kexec/crashdump-xen.c
===================================================================
--- kexec-tools-2.0.2.orig/kexec/crashdump-xen.c
+++ kexec-tools-2.0.2/kexec/crashdump-xen.c
@@ -10,6 +10,8 @@
#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"
@@ -25,14 +27,102 @@ struct crash_note_info {
unsigned long length;
};
-int xen_phys_cpus = 0;
-struct crash_note_info *xen_phys_notes;
+static int xen_phys_cpus;
+static struct crash_note_info *xen_phys_notes;
-int xen_present(void)
+/* 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)
{
- struct stat buf;
+ 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];
+}
- return stat("/proc/xen", &buf) == 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)