6.10-stable review patch. If anyone has any objections, please let me know.
------------------
From: Gautam Menghani <gautam@xxxxxxxxxxxxx>
commit 54ec2bd9e0173b75daf84675d07c56584f96564b upstream.
Doorbell emulation is broken for KVM on PAPR guests as support for DPDES
was not added in the initial patch series. Due to this, a KVM on PAPR
guest with SMT > 1 cannot be booted with the XICS interrupt controller
as doorbells are setup in the initial probe path when using XICS
(pSeries_smp_probe()).
Command to replicate the above bug:
qemu-system-ppc64 \
-drive file=rhel.qcow2,format=qcow2 \
-m 20G \
-smp 8,cores=1,threads=8 \
-cpu host \
-nographic \
-machine pseries,ic-mode=xics -accel kvm
Add doorbell state handling support in the host KVM code to fix doorbell
emulation.
Fixes: 19d31c5f1157 ("KVM: PPC: Add support for nestedv2 guests")
Cc: stable@xxxxxxxxxxxxxxx # v6.7+
Signed-off-by: Gautam Menghani <gautam@xxxxxxxxxxxxx>
Reviewed-by: Nicholas Piggin <npiggin@xxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Link: https://msgid.link/20240605113913.83715-3-gautam@xxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/powerpc/kvm/book3s_hv.c | 5 +++++
1 file changed, 5 insertions(+)
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -4116,6 +4116,11 @@ static int kvmhv_vcpu_entry_nestedv2(str
int trap;
long rc;
+ if (vcpu->arch.doorbell_request) {
+ vcpu->arch.doorbell_request = 0;
+ kvmppc_set_dpdes(vcpu, 1);
+ }
+
io = &vcpu->arch.nestedv2_io;
msr = mfmsr();
