From 54ec2bd9e0173b75daf84675d07c56584f96564b Mon Sep 17 00:00:00 2001 From: Gautam Menghani Date: Wed, 5 Jun 2024 17:09:10 +0530 Subject: [PATCH] KVM: PPC: Book3S HV nestedv2: Fix doorbell emulation 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@vger.kernel.org # v6.7+ Signed-off-by: Gautam Menghani Reviewed-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://msgid.link/20240605113913.83715-3-gautam@linux.ibm.com --- arch/powerpc/kvm/book3s_hv.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 83bd331a4ef45..9df24fb50b0e9 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -4187,6 +4187,11 @@ static int kvmhv_vcpu_entry_nestedv2(struct kvm_vcpu *vcpu, u64 time_limit, 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();