On Feb 25, 2008, at 11:45 AM, Avi Kivity wrote:
Alexander Graf wrote:On Feb 25, 2008, at 10:34 AM, Avi Kivity wrote:Yang, Sheng wrote:On Monday 25 February 2008 16:41:25 Zhao, Yunfeng wrote:Hi, all, This is today's KVM test result against kvm.git 81e4400b4df4e597a81c19c1161aa03c73613710 and kvm-userspace.git 08385e49dcff3585f597870af67301d7659a1ecb. One new issue has been found in today's testing: 1. fc5/fc6/rhel5u1 no-acpi up guests can't boot on pae host https://sourceforge.net/tracker/index.php?func=detail&aid=1901208&group_ id=180599&atid=893831A quick bisect shows that the problem caused by "kvm: qemu: fix host_cpuid() on x86_64".Yeah, I just found this out the hard way (by trying to debug this -- silly me). The effects were that the "GenuineIntel" in cpuid identification was corrupted.Could you please execute this source on a computer that fails with theargument "0" (please compile with the same switches as qemu) and give me the results + disassembly?0000101c <host_cpuid>: 101c: 55 push %ebp 101d: 89 e5 mov %esp,%ebp 101f: 57 push %edi 1020: 56 push %esi 1021: 53 push %ebx 1022: 83 ec 3c sub $0x3c,%esp 1025: 89 55 d4 mov %edx,-0x2c(%ebp) 1028: 89 de mov %ebx,%esi 102a: 0f a2 cpuid 102c: 89 db mov %ebx,%ebx 102e: 89 f3 mov %esi,%ebx 1030: 89 d7 mov %edx,%edi 1032: 89 55 e4 mov %edx,-0x1c(%ebp) 1035: 8b 55 d4 mov -0x2c(%ebp),%edx 1038: 85 d2 test %edx,%edx 103a: 89 4d c4 mov %ecx,-0x3c(%ebp) 103d: 89 5d d0 mov %ebx,-0x30(%ebp) 1040: 89 45 d8 mov %eax,-0x28(%ebp) 1043: 89 5d dc mov %ebx,-0x24(%ebp) 1046: 89 4d e0 mov %ecx,-0x20(%ebp) 1049: 74 05 je 1050 <host_cpuid+0x34> 104b: 8b 55 d4 mov -0x2c(%ebp),%edx 104e: 89 02 mov %eax,(%edx) 1050: 8b 75 08 mov 0x8(%ebp),%esi 1053: 85 f6 test %esi,%esi 1055: 74 08 je 105f <host_cpuid+0x43> 1057: 8b 5d d0 mov -0x30(%ebp),%ebx 105a: 8b 4d 08 mov 0x8(%ebp),%ecx 105d: 89 19 mov %ebx,(%ecx) 105f: 8b 5d 0c mov 0xc(%ebp),%ebx 1062: 85 db test %ebx,%ebx 1064: 74 08 je 106e <host_cpuid+0x52> 1066: 8b 55 c4 mov -0x3c(%ebp),%edx 1069: 8b 45 0c mov 0xc(%ebp),%eax 106c: 89 10 mov %edx,(%eax) 106e: 8b 4d 10 mov 0x10(%ebp),%ecx 1071: 85 c9 test %ecx,%ecx 1073: 74 05 je 107a <host_cpuid+0x5e> 1075: 8b 4d 10 mov 0x10(%ebp),%ecx 1078: 89 39 mov %edi,(%ecx) 107a: 83 c4 3c add $0x3c,%esp 107d: 5b pop %ebx 107e: 5e pop %esi 107f: 5f pop %edi 1080: c9 leave 1081: c3 retLooks like %ebx was chosen for %1. I also don't see where %eax is loaded.
The ebx store was done because of PIC code, which does not allow ebx to get clobbered. If we are not in PIC code, =r contains ebx as GPR though, so the assumption that ebx needs to be restored was wrong then. This new version only enables the store/restore code if i386 and PIC code are used. There is no need to distinguish between x86_64 and i386 for the other cases.
So does this version work?
test.c
Description: Binary data
------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/
_______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
