| Message ID | 20240605113913.83715-3-gautam@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Fix doorbell emulation for v2 API on PPC | expand |
On Wed Jun 5, 2024 at 9:39 PM AEST, Gautam Menghani wrote: > 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. Reviewed-by: Nicholas Piggin <npiggin@gmail.com> > > Fixes: 19d31c5f1157 ("KVM: PPC: Add support for nestedv2 guests") > Cc: stable@vger.kernel.org # v6.7 > Signed-off-by: Gautam Menghani <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 35cb014a0c51..21c69647d27c 100644 > --- a/arch/powerpc/kvm/book3s_hv.c > +++ b/arch/powerpc/kvm/book3s_hv.c > @@ -4116,6 +4116,11 @@ 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();
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 35cb014a0c51..21c69647d27c 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -4116,6 +4116,11 @@ 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();
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 <gautam@linux.ibm.com> --- arch/powerpc/kvm/book3s_hv.c | 5 +++++ 1 file changed, 5 insertions(+)