Re: [libvirt] [PATCH v3 09/13] CPU selection infrastructure
On Wed, Dec 16, 2009 at 12:04:06AM +0100, Jiri Denemark wrote:
diff --git a/src/cpu/cpu_x86.c b/src/cpu/cpu_x86.c
new file mode 100644
index 0000000..3bb0df3
--- /dev/null
+++ b/src/cpu/cpu_x86.c
+#if HAVE_CPUID
+static int
+cpuidSet(uint32_t base, struct cpuX86cpuid **set)
+{
+ uint32_t max;
+ uint32_t i;
+
+ asm("cpuid"
+ : "=a" (max)
+ : "a" (base));
I'm having trouble with this asm block causing a SEGV on i386
==10392== Invalid read of size 4
==10392== at 0x404FC50: ??? (in
/home/berrange/src/xen/libvirt/src/.libs/libvirt.so.0.7.4)
==10392== by 0x409199D: x86NodeData (cpu_x86.c:1129)
==10392== by 0x408F298: cpuNodeData (cpu.c:218)
==10392== by 0x8093BA9: qemudCapsInitCPU (qemu_conf.c:987)
==10392== by 0x8093D23: qemudCapsInit (qemu_conf.c:1031)
==10392== by 0x807DEBC: qemudStartup (qemu_driver.c:1067)
==10392== by 0x4096F8D: virStateInitialize (libvirt.c:830)
==10392== by 0x805FB8B: main (libvirtd.c:3149)
==10392== Address 0x756e666b is not stack'd, malloc'd or (recently) free'd
==10392==
==10392==
==10392== Process terminating with default action of signal 11 (SIGSEGV)
==10392== Access not within mapped region at address 0x756E666B
==10392== at 0x404FC50: ??? (in
/home/berrange/src/xen/libvirt/src/.libs/libvirt.so.0.7.4)
==10392== by 0x409199D: x86NodeData (cpu_x86.c:1129)
==10392== by 0x408F298: cpuNodeData (cpu.c:218)
==10392== by 0x8093BA9: qemudCapsInitCPU (qemu_conf.c:987)
==10392== by 0x8093D23: qemudCapsInit (qemu_conf.c:1031)
==10392== by 0x807DEBC: qemudStartup (qemu_driver.c:1067)
==10392== by 0x4096F8D: virStateInitialize (libvirt.c:830)
==10392== by 0x805FB8B: main (libvirtd.c:3149)
+
+ max -= base;
+
+ if (virAllocN(set, sizeof(**set), max + 1) < 0) {
+ virReportOOMError(NULL);
+ return -1;
+ }
+
+ for (i = 0; i <= max; i++) {
+ struct cpuX86cpuid *cpuid = (*set) + i;
+
+ cpuid->function = base | i;
+
+#if __x86_64__
+ asm("cpuid"
+ : "=a" (cpuid->eax),
+ "=b" (cpuid->ebx),
+ "=c" (cpuid->ecx),
+ "=d" (cpuid->edx)
+ : "a" (cpuid->function));
+#else
+ /* we need to avoid direct use of ebx for CPUID output as it is used
+ * for global offset table on i386 with -fPIC
+ */
+ asm("push %%ebx;"
+ "cpuid;"
+ "mov %%ebx, %1;"
+ "pop %%ebx;"
+ : "=a" (cpuid->eax),
+ "=r" (cpuid->ebx),
+ "=c" (cpuid->ecx),
+ "=d" (cpuid->edx)
+ : "a" (cpuid->function)
+ : "cc");
+#endif
+ }
+
+ return max + 1;
+}
+
Regards,
Daniel
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