| Message ID | 20171127073017.25463-1-clg@kaod.org |
|---|---|
| State | Rejected |
| Headers | show |
| Series | KVM: PPC: Book3S HV: check for XIVE device before executing the XICS hcalls | expand |
On Mon, Nov 27, 2017 at 08:30:17AM +0100, Cédric Le Goater wrote: > When QEMU is started with the option kernel_irqchip=òff, the kvm XICS > hcalls are being used even though a kvm XICS device has not been > created on the host, resulting quickly in a failure and a broken > guest. > > The test checking if there is a XIVE device in the VM before executing > the XICS hcalls is missing from the recent XICS-over-XIVE glue. > > Signed-off-by: Cédric Le Goater <clg@kaod.org> I think this is fixing the same bug that commit 00bb6ae50062 ("KVM: PPC: Book3S HV: Don't call real-mode XICS hypercall handlers if not enabled", 2017-10-26) addresses. Do you think this patch is needed in addition to 00bb6ae50062? Paul. -- To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 12/04/2017 02:04 AM, Paul Mackerras wrote: > On Mon, Nov 27, 2017 at 08:30:17AM +0100, Cédric Le Goater wrote: >> When QEMU is started with the option kernel_irqchip=òff, the kvm XICS >> hcalls are being used even though a kvm XICS device has not been >> created on the host, resulting quickly in a failure and a broken >> guest. >> >> The test checking if there is a XIVE device in the VM before executing >> the XICS hcalls is missing from the recent XICS-over-XIVE glue. >> >> Signed-off-by: Cédric Le Goater <clg@kaod.org> > > I think this is fixing the same bug that commit 00bb6ae50062 ("KVM: > PPC: Book3S HV: Don't call real-mode XICS hypercall handlers if not > enabled", 2017-10-26) addresses. > > Do you think this patch is needed in addition to 00bb6ae50062? No. I think 00bb6ae50062 is fine. It is a bit redundant for P8 systems because the XICS device availability in the VM is already tested in the xics_rm_h_* hcalls with : struct kvmppc_xics *xics = vcpu->kvm->arch.xics; if (!xics || !xics->real_mode) return H_TOO_HARD; But, as the XICS-over-XIVE glue also assigns the VCPU 'arch.irq_type' field to KVMPPC_IRQ_XICS, we can use the macro kvmppc_xics_enabled() for both backend in the top level hcalls. Letting each backend decide whether H_TOO_HARD should be returned might be more precise. I think we will clarify that when XIVE exploitation mode support is added to KVM. Thanks, C. -- To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/powerpc/kvm/book3s_xive_template.c b/arch/powerpc/kvm/book3s_xive_template.c index c7a5deadd1cc..7aa4e02df97c 100644 --- a/arch/powerpc/kvm/book3s_xive_template.c +++ b/arch/powerpc/kvm/book3s_xive_template.c @@ -276,11 +276,15 @@ static u32 GLUE(X_PFX,scan_interrupts)(struct kvmppc_xive_vcpu *xc, X_STATIC unsigned long GLUE(X_PFX,h_xirr)(struct kvm_vcpu *vcpu) { struct kvmppc_xive_vcpu *xc = vcpu->arch.xive_vcpu; + struct kvmppc_xive *xive = vcpu->kvm->arch.xive; u8 old_cppr; u32 hirq; pr_devel("H_XIRR\n"); + if (!xive) + return H_TOO_HARD; + xc->GLUE(X_STAT_PFX,h_xirr)++; /* First collect pending bits from HW */ @@ -335,11 +339,15 @@ X_STATIC unsigned long GLUE(X_PFX,h_xirr)(struct kvm_vcpu *vcpu) X_STATIC unsigned long GLUE(X_PFX,h_ipoll)(struct kvm_vcpu *vcpu, unsigned long server) { struct kvmppc_xive_vcpu *xc = vcpu->arch.xive_vcpu; + struct kvmppc_xive *xive = vcpu->kvm->arch.xive; u8 pending = xc->pending; u32 hirq; pr_devel("H_IPOLL(server=%ld)\n", server); + if (!xive) + return H_TOO_HARD; + xc->GLUE(X_STAT_PFX,h_ipoll)++; /* Grab the target VCPU if not the current one */ @@ -388,8 +396,12 @@ static void GLUE(X_PFX,push_pending_to_hw)(struct kvmppc_xive_vcpu *xc) X_STATIC int GLUE(X_PFX,h_cppr)(struct kvm_vcpu *vcpu, unsigned long cppr) { struct kvmppc_xive_vcpu *xc = vcpu->arch.xive_vcpu; + struct kvmppc_xive *xive = vcpu->kvm->arch.xive; u8 old_cppr; + if (!xive) + return H_TOO_HARD; + pr_devel("H_CPPR(cppr=%ld)\n", cppr); xc->GLUE(X_STAT_PFX,h_cppr)++; @@ -435,6 +447,9 @@ X_STATIC int GLUE(X_PFX,h_eoi)(struct kvm_vcpu *vcpu, unsigned long xirr) u16 src; int rc = 0; + if (!xive) + return H_TOO_HARD; + pr_devel("H_EOI(xirr=%08lx)\n", xirr); xc->GLUE(X_STAT_PFX,h_eoi)++; @@ -532,9 +547,13 @@ X_STATIC int GLUE(X_PFX,h_ipi)(struct kvm_vcpu *vcpu, unsigned long server, unsigned long mfrr) { struct kvmppc_xive_vcpu *xc = vcpu->arch.xive_vcpu; + struct kvmppc_xive *xive = vcpu->kvm->arch.xive; pr_devel("H_IPI(server=%08lx,mfrr=%ld)\n", server, mfrr); + if (!xive) + return H_TOO_HARD; + xc->GLUE(X_STAT_PFX,h_ipi)++; /* Find target */
When QEMU is started with the option kernel_irqchip=òff, the kvm XICS hcalls are being used even though a kvm XICS device has not been created on the host, resulting quickly in a failure and a broken guest. The test checking if there is a XIVE device in the VM before executing the XICS hcalls is missing from the recent XICS-over-XIVE glue. Signed-off-by: Cédric Le Goater <clg@kaod.org> --- arch/powerpc/kvm/book3s_xive_template.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+)