On 08/14/2012 11:44 AM, Markus Armbruster wrote: > > Next error: > > $ gdb --args qemu-system-x86_64 -nodefaults --enable-kvm -vnc :0 -monitor > stdio -m 640k > [...] > Program received signal SIGSEGV, Segmentation fault. > [...] > (gdb) bt > #0 0x0000003b0de884ac in __memcmp_sse2 () from /lib64/libc.so.6 > #1 0x000000000063f1ad in patch_hypercalls (s=0x139b350) > at /work/armbru/qemu/hw/i386/../kvmvapic.c:532 > #2 0x000000000063f3fe in vapic_prepare (s=0x139b350) > at /work/armbru/qemu/hw/i386/../kvmvapic.c:597 > #3 0x000000000063f4ed in vapic_write (opaque=0x139b350, addr=0, data=32, > size= > 2) at /work/armbru/qemu/hw/i386/../kvmvapic.c:634 > #4 0x0000000000677a44 in memory_region_write_accessor (opaque=0x139d670, > addr= > > Happens when -m argument is a multiple of 4k in [648k..768k]. Only with > --enable-kvm. With and without my CMOS fix applied.
kvmvapic requires RAM to be present underneath the ROM. We could fix up kvmvapic to allocate a 4k region and insert it as an overlay, but it's sufficient IMO to require sub-1M users to disable it. It won't be of any use to the anyway as Windows XP requires more than 1MB. > > And another one: > > $ qemu-system-x86_64 -nodefaults --enable-kvm -vnc :0 -monitor stdio -m > 900k > QEMU 1.1.50 monitor - type 'help' for more information > (qemu) KVM internal error. Suberror: 1 > emulation failure > EAX=000fdb78 EBX=00000000 ECX=00000000 EDX=000fdb64 > ESI=00000000 EDI=000fdb64 EBP=00000000 ESP=00006f98 > EIP=000e3492 EFL=00000006 [-----P-] CPL=0 II=0 A20=1 SMM=0 HLT=0 > ES =0010 00000000 ffffffff 00c09300 DPL=0 DS [-WA] > CS =0008 00000000 ffffffff 00c09b00 DPL=0 CS32 [-RA] > SS =0010 00000000 ffffffff 00c09300 DPL=0 DS [-WA] > DS =0010 00000000 ffffffff 00c09300 DPL=0 DS [-WA] > FS =0010 00000000 ffffffff 00c09300 DPL=0 DS [-WA] > GS =0010 00000000 ffffffff 00c09300 DPL=0 DS [-WA] > LDT=0000 00000000 0000ffff 00008200 DPL=0 LDT > TR =0000 00000000 0000ffff 00008b00 DPL=0 TSS32-busy > GDT= 000fcd68 00000037 > IDT= 000fdb60 00000000 > CR0=00000011 CR2=00000000 CR3=00000000 CR4=00000000 > DR0=0000000000000000 DR1=0000000000000000 DR2=0000000000000000 > DR3=0000000000000000 > DR6=00000000ffff0ff0 DR7=0000000000000400 > EFER=0000000000000000 > Code=00 00 b8 26 00 00 00 eb 95 83 c8 ff 83 c4 4c 5b 5e 5f 5d c3 <57> 56 > 53 89 d6 39 c2 72 06 89 c7 f3 a4 eb 1b 8d 51 ff 01 d0 01 d6 89 cf 31 d2 eb 08 > 8a 1c > q > Not sure what's the problem. 57 is a push reg instruction which we ought to emulate fine. 900k is 0xe1000, just below eip, but we ought to execute just fine from unshadowed ROM. > Breakpoint on kvm_handle_internal_error() yields backtrace: > > #0 kvm_handle_internal_error (env=0x1389b30, run=0x7ffff7ffa000) > at /work/armbru/qemu/kvm-all.c:1424 > #1 0x0000000000674c5a in kvm_cpu_exec (env=0x1389b30) > at /work/armbru/qemu/kvm-all.c:1586 > #2 0x000000000060e0b4 in qemu_kvm_cpu_thread_fn (arg=0x1389b30) > at /work/armbru/qemu/cpus.c:757 > #3 0x0000003b0ea07d14 in start_thread () from /lib64/libpthread.so.0 > #4 0x0000003b0def197d in clone () from /lib64/libc.so.6 > > Also seen with 904k, 908k, 964k, 968k, 972k 976k, and a whole lot more. Same EIP in the dump with those? > Not reproduced with 1024k+. > > An easy way to "fix" these is to require 1MiB of RAM :) Or disabling kvm. -- error compiling committee.c: too many arguments to function
