Re: IOCTL_PRIVCMD_MMAPBATCH on Xen 4.13.0

[Manuel Bouyer <bouyer@xxxxxxxxxxxxxxx>]

On Fri, May 15, 2020 at 10:00:07PM +0100, Andrew Cooper wrote:
> What is qemu doing at the time?  Is it by any chance trying to map the
> IOREQ server frame?

Here's what gdb says about it:
Core was generated by `qemu-dm'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0  0x000000000046997d in cpu_x86_init (
    cpu_model=cpu_model@entry=0x4d622d "qemu32")
    at 
/home/bouyer/pkgbuild/current/sysutils/xentools413/work/xen-4.13.0/tools/qemu-xen-traditional/i386-dm/helper2.c:156
156                 rc = xenevtchn_bind_interdomain(
--Type <RET> for more, q to quit, c to continue without paging--
[Current thread is 1 (process 1480)]
(gdb) where
#0  0x000000000046997d in cpu_x86_init (
    cpu_model=cpu_model@entry=0x4d622d "qemu32")
    at 
/home/bouyer/pkgbuild/current/sysutils/xentools413/work/xen-4.13.0/tools/qemu-xen-traditional/i386-dm/helper2.c:156
#1  0x000000000043628d in pc_init1 (ram_size=<optimized out>, 
    vga_ram_size=4194304, boot_device=0x7f7fff460397 "cda", pci_enabled=1, 
    cpu_model=0x4d622d "qemu32", initrd_filename=<optimized out>, 
    kernel_cmdline=<optimized out>, kernel_filename=<optimized out>)
    at 
/home/bouyer/pkgbuild/current/sysutils/xentools413/work/xen-4.13.0/tools/qemu-xen-traditional/hw/pc.c:829
#2  0x00000000004636e7 in xen_init_fv (ram_size=0, vga_ram_size=4194304, 
    boot_device=0x7f7fff460397 "cda", kernel_filename=0x0, 
    kernel_cmdline=0x4abff6 "", initrd_filename=0x0, cpu_model=0x0, 
    direct_pci=0x0)
    at 
/home/bouyer/pkgbuild/current/sysutils/xentools413/work/xen-4.13.0/tools/qemu-xen-traditional/hw/xen_machine_fv.c:405
#3  0x00000000004a975b in main (argc=23, argv=0x7f7fff45fc78, 
    envp=<optimized out>)
    at 
/home/bouyer/pkgbuild/current/sysutils/xentools413/work/xen-4.13.0/tools/qemu-xen-traditional/vl.c:6014

Does it help ?

-- 
Manuel Bouyer <bouyer@xxxxxxxxxxxxxxx>
     NetBSD: 26 ans d'experience feront toujours la difference
--