KVM: PPC: Disable MSR_FEx for Cell hosts
Cell can't handle MSR_FE0 and MSR_FE1 too well. It gets dog slow.
So let's just override the guest whenever we see one of the two and mask them
out. See commit ddf5f75a16b3e7460ffee881795aa168dffcd0cf for reference.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/powerpc/kvm/book3s.c b/arch/powerpc/kvm/book3s.c
index ed57584..41c23b6 100644
--- a/arch/powerpc/kvm/book3s.c
+++ b/arch/powerpc/kvm/book3s.c
@@ -357,6 +357,10 @@
!strcmp(cur_cpu_spec->platform, "ppc970"))
vcpu->arch.hflags |= BOOK3S_HFLAG_DCBZ32;
+ /* Cell performs badly if MSR_FEx are set. So let's hope nobody
+ really needs them in a VM on Cell and force disable them. */
+ if (!strcmp(cur_cpu_spec->platform, "ppc-cell-be"))
+ to_book3s(vcpu)->msr_mask &= ~(MSR_FE0 | MSR_FE1);
}
/* Book3s_32 CPUs always have 32 bytes cache line size, which Linux assumes. To