jos...@linux.vnet.ibm.com writes: > On Thu, Jul 20, 2017 at 10:18:18PM -0300, jos...@linux.vnet.ibm.com wrote: >> On Thu, Jul 20, 2017 at 03:21:59PM +1000, Paul Mackerras wrote: >> > >> > Did you check the host kernel logs for any oops messages? >> >> dmesg was clean but after sometime waiting (I forgot QEMU running in >> another terminal) I got the oops below (after rebooting the host I >> couldn't reproduce it again). >> >> Another test that I did was: >> Compile with transparent huge pages disabled: KVM works fine >> Compile with transparent huge pages enabled: doesn't work >> + disabling it in /sys/kernel/mm/transparent_hugepage: doesn't work >> >> Just out of my own curiosity I made this small change: >> >> diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h >> b/arch/powerpc/include >> index c0737c8..f94a3b6 100644 >> --- a/arch/powerpc/include/asm/book3s/64/pgtable.h >> +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h >> @@ -80,7 +80,7 @@ >> >> #define _PAGE_SOFT_DIRTY _RPAGE_SW3 /* software: software dirty >> tracking >> #define _PAGE_SPECIAL _RPAGE_SW2 /* software: special page */ >> -#define _PAGE_DEVMAP _RPAGE_SW1 /* software: ZONE_DEVICE page >> */ >> +#define _PAGE_DEVMAP _RPAGE_RSV3 >> #define __HAVE_ARCH_PTE_DEVMAP >> >> and it works. I chose _RPAGE_RSV3 because it uses the same value that >> x86 uses (0x0400000000000000UL) but I don't if it could have any side >> effect >> > > Does this change make any sense to you people?
No :) I think it's just hiding the bug somehow. Presumably we have some code somewhere that is getting confused by _RPAGE_SW1 being set, or setting that bit incorrectly. cheers