On 11/28/2017 03:43 PM, 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>
---
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) {
As an alternative, I believe you can also do:
if (!!spapr->patb_entry) {
because the !! will return false if patb_entry is either undefined (as in
TCG) or zero (as set in spapr_reallocate_hpt). This is the same logic used
in spapr_patb_entry_needed too.
But I am fine with what you did and it's also clearer, so
Reviewed-by: Daniel Henrique Barboza <danie...@linux.vnet.ibm.com>
PowerPCCPU *cpu = POWERPC_CPU(first_cpu);
bool radix = !!(spapr->patb_entry & PATBE1_GR);
bool gtse = !!(cpu->env.spr[SPR_LPCR] & LPCR_GTSE);
