On Tue, 2017-11-28 at 18:43 +0100, Laurent Vivier wrote: > Migration of pseries is broken with TCG because > QEMU tries to restore KVM MMU state unconditionally. > > The result is a SIGSEGV in kvm_vm_ioctl(): > > #0 kvm_vm_ioctl (s=0x0, type=-2146390353) > at qemu/accel/kvm/kvm-all.c:2032 > #1 0x00000001003e3e2c in kvmppc_configure_v3_mmu (cpu=<optimized > out>, > radix=<optimized out>, gtse=<optimized out>, > proc_tbl=<optimized out>) > at qemu/target/ppc/kvm.c:396 > #2 0x00000001002f8b88 in spapr_post_load (opaque=0x1019103c0, > version_id=<optimized out>) at qemu/hw/ppc/spapr.c:1578 > #3 0x000000010059e4cc in vmstate_load_state (f=0x106230000, > vmsd=0x1009479e0 <vmstate_spapr>, opaque=0x1019103c0, > version_id=<optimized out>) at qemu/migration/vmstate.c:165 > #4 0x00000001005987e0 in vmstate_load (f=<optimized out>, > se=<optimized out>) > at qemu/migration/savevm.c:748 > > This patch fixes the problem by not calling the KVM function with the > TCG mode. > > Fixes: d39c90f5f3 ("spapr: Fix migration of Radix guests") > Signed-off-by: Laurent Vivier <lviv...@redhat.com>
Ah, guess I never hit this because I never tested tcg migration with a qemu compiled on a kvm enabled system. Nice catch :) Reviewed-by: Suraj Jitindar Singh <sjitindarsi...@gmail.com> > --- > v2: fix the comment to keep GDB backtrace lines starting with '#' > > hw/ppc/spapr.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c > index 9efddeaee5..a471de6cab 100644 > --- a/hw/ppc/spapr.c > +++ b/hw/ppc/spapr.c > @@ -1570,7 +1570,7 @@ static int spapr_post_load(void *opaque, int > version_id) > err = spapr_rtc_import_offset(&spapr->rtc, spapr- > >rtc_offset); > } > > - if (spapr->patb_entry) { > + if (kvm_enabled() && spapr->patb_entry) { > PowerPCCPU *cpu = POWERPC_CPU(first_cpu); > bool radix = !!(spapr->patb_entry & PATBE1_GR); > bool gtse = !!(cpu->env.spr[SPR_LPCR] & LPCR_GTSE);