This reverts commit 7c3ded5735141ff4d049747c9f76672a8b737c49.
On PowerNV, when a nested guest tries to use a feature prohibited by
HFSCR, the nested hypervisor (L1) should get a H_FAC_UNAVAILABLE trap
and then L1 can emulate the feature. But with the change introduced by
commit 7c3ded573514 ("KVM: PPC: Book3S HV Nested: Stop forwarding all HFUs to
L1")
the L1 ends up getting a H_EMUL_ASSIST because of which, the L1 ends up
injecting a SIGILL when L2 (nested guest) tries to use doorbells.
Signed-off-by: Gautam Menghani <gau...@linux.ibm.com>
---
arch/powerpc/kvm/book3s_hv.c | 31 ++-----------------------------
1 file changed, 2 insertions(+), 29 deletions(-)
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index daaf7faf21a5..cea28ac05923 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -2052,36 +2052,9 @@ static int kvmppc_handle_nested_exit(struct kvm_vcpu
*vcpu)
fallthrough; /* go to facility unavailable handler */
#endif
- case BOOK3S_INTERRUPT_H_FAC_UNAVAIL: {
- u64 cause = vcpu->arch.hfscr >> 56;
-
- /*
- * Only pass HFU interrupts to the L1 if the facility is
- * permitted but disabled by the L1's HFSCR, otherwise
- * the interrupt does not make sense to the L1 so turn
- * it into a HEAI.
- */
- if (!(vcpu->arch.hfscr_permitted & (1UL << cause)) ||
- (vcpu->arch.nested_hfscr & (1UL << cause))) {
- ppc_inst_t pinst;
- vcpu->arch.trap = BOOK3S_INTERRUPT_H_EMUL_ASSIST;
-
- /*
- * If the fetch failed, return to guest and
- * try executing it again.
- */
- r = kvmppc_get_last_inst(vcpu, INST_GENERIC, &pinst);
- vcpu->arch.emul_inst = ppc_inst_val(pinst);
- if (r != EMULATE_DONE)
- r = RESUME_GUEST;
- else
- r = RESUME_HOST;
- } else {
- r = RESUME_HOST;
- }
-
+ case BOOK3S_INTERRUPT_H_FAC_UNAVAIL:
+ r = RESUME_HOST;
break;
- }
case BOOK3S_INTERRUPT_HV_RM_HARD:
vcpu->arch.trap = 0;
--
2.45.1
