On Wed, Mar 13, 2019 at 01:32:00PM +1100, David Gibson wrote: > On Tue, Mar 12, 2019 at 11:01:15AM -0400, Cleber Rosa wrote: > > On Sun, Mar 10, 2019 at 07:27:00PM +1100, David Gibson wrote: > > > From: Cédric Le Goater <c...@kaod.org> > > > > > > We now have enough support to boot a PowerNV machine with a POWER9 > > > processor. Allow HV mode on POWER9. > > > > > > Signed-off-by: Cédric Le Goater <c...@kaod.org> > > > Message-Id: <20190307223548.20516-16-...@kaod.org> > > > Signed-off-by: David Gibson <da...@gibson.dropbear.id.au> > > > --- > > > target/ppc/translate_init.inc.c | 3 ++- > > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > > > diff --git a/target/ppc/translate_init.inc.c > > > b/target/ppc/translate_init.inc.c > > > index af70a3b78c..0bd555eb19 100644 > > > --- a/target/ppc/translate_init.inc.c > > > +++ b/target/ppc/translate_init.inc.c > > > @@ -8895,7 +8895,7 @@ POWERPC_FAMILY(POWER9)(ObjectClass *oc, void *data) > > > PPC_CACHE | PPC_CACHE_ICBI | PPC_CACHE_DCBZ | > > > PPC_MEM_SYNC | PPC_MEM_EIEIO | > > > PPC_MEM_TLBSYNC | > > > - PPC_64B | PPC_64BX | PPC_ALTIVEC | > > > + PPC_64B | PPC_64H | PPC_64BX | PPC_ALTIVEC | > > > PPC_SEGMENT_64B | PPC_SLBI | > > > PPC_POPCNTB | PPC_POPCNTWD | > > > PPC_CILDST; > > > @@ -8907,6 +8907,7 @@ POWERPC_FAMILY(POWER9)(ObjectClass *oc, void *data) > > > PPC2_ISA205 | PPC2_ISA207S | PPC2_FP_CVT_S64 | > > > PPC2_TM | PPC2_ISA300 | PPC2_PRCNTL; > > > pcc->msr_mask = (1ull << MSR_SF) | > > > + (1ull << MSR_SHV) | > > > (1ull << MSR_TM) | > > > (1ull << MSR_VR) | > > > (1ull << MSR_VSX) | > > > > This change prevents a Fedora 29 kernel[1] from booting... is this > > intended or a known limitation of the Fedora 29 kernel? > > > > FIY, by using a "power8" CPU the Fedora 29 kernel boots successfully. > > For a reproducer, please refer to [2]. > > Ouch. I don't know how, but this has introduced a nasty regression. > I've reproduced it myself, here's what I've observed so far. Nothing > very surprising, but helps narrow it down a bit. > > * It works with KVM > * It works with -cpu power8 > * It also fails with the current RHEL8 kernel > * It also fails on a ppc64le host (using TCG) > * Also fails with a fresh build upstream kernel > > It's very strange because a) the flags it sets are already enabled for > power8, which seems to work and b) literally the only thing that > PPC_64H seems to control is presence of the hrfid instruction, which > the guest kernel shouldn't be even attempting to use. > > It seems to be hitting an explicit panic() in the guest code (no > message because it's before we have a working console). > > Continuing to investigate...
Ok, pretty sure I found it. This patch exposed, via a roundabout
route a rather older bug. A hypercall wasn't properly setting the
LPCR[GTSE] bit which meant now that hypervisor support was turned on,
the guest kernel got an early exception because it tried to execute a
tlbie instruction which is hypervisor privileged without LPCR[GTSE].
I've posted a fix and added it to ppc-for-4.0.
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
signature.asc
Description: PGP signature
