On 2012-08-14 12:51, Avi Kivity wrote: > On 08/14/2012 01:44 PM, Jan Kiszka wrote: >> On 2012-08-14 12:20, Avi Kivity wrote: >>> 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. >> >> We can also easily automatically disable it when there is insufficient >> (<1MB) memory. Will post a patch. > > Would be nicer if it auto-disables itself, but don't know if the option > ROM has access to the memory size.
There is that global ram_size, also used by vmport. Not really nice but no precedent. Jan -- Siemens AG, Corporate Technology, CT RTC ITP SDP-DE Corporate Competence Center Embedded Linux