On 22/09/2016 23:04, Radim Krčmář wrote: > Cluster x2APIC cannot work without KVM's x2apic API when the maximal > APIC ID is > 8. Make the code simpler by completely forbidding EIM > without KVM's x2apic API. > > Signed-off-by: Radim Krčmář <rkrc...@redhat.com> > --- > I think it the dependency would be nicer in the eim setter, but the > other dependency, for interrupt remapping, isn't there and I didn't > venture for reasons. > --- > hw/i386/intel_iommu.c | 7 +++++++ > target-i386/kvm-stub.c | 5 +++++ > target-i386/kvm.c | 13 +++++++++++++ > target-i386/kvm_i386.h | 1 + > 4 files changed, 26 insertions(+) > > diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c > index 269e37e71af4..0304a1bf6f1d 100644 > --- a/hw/i386/intel_iommu.c > +++ b/hw/i386/intel_iommu.c > @@ -32,6 +32,7 @@ > #include "hw/pci-host/q35.h" > #include "sysemu/kvm.h" > #include "hw/i386/apic_internal.h" > +#include "kvm_i386.h" > > /*#define DEBUG_INTEL_IOMMU*/ > #ifdef DEBUG_INTEL_IOMMU > @@ -2485,6 +2486,12 @@ static void vtd_realize(DeviceState *dev, Error **errp) > "kernel-irqchip=on, please use 'split|off'."); > exit(1); > } > + > + if (s->eim_supported && kvm_irqchip_in_kernel() && > + !kvm_enable_x2apic()) { > + error_report("EIM requires support from the KVM side (X2APIC_API)."); > + exit(1); > + } > } > > static void vtd_class_init(ObjectClass *klass, void *data) > diff --git a/target-i386/kvm-stub.c b/target-i386/kvm-stub.c > index cdf15061091d..bda4dc2f0c57 100644 > --- a/target-i386/kvm-stub.c > +++ b/target-i386/kvm-stub.c > @@ -25,6 +25,11 @@ bool kvm_has_smm(void) > return 1; > } > > +bool kvm_enable_x2apic(void) > +{ > + return false; > +} > + > /* This function is only called inside conditionals which we > * rely on the compiler to optimize out when CONFIG_KVM is not > * defined. > diff --git a/target-i386/kvm.c b/target-i386/kvm.c > index f1ad805665ad..4c0a4df5eaea 100644 > --- a/target-i386/kvm.c > +++ b/target-i386/kvm.c > @@ -128,6 +128,19 @@ bool kvm_allows_irq0_override(void) > return !kvm_irqchip_in_kernel() || kvm_has_gsi_routing(); > } > > +static bool kvm_x2apic_api_set_flags(uint64_t flags) > +{ > + KVMState *s = KVM_STATE(current_machine->accelerator); > + > + return !kvm_vm_enable_cap(s, KVM_CAP_X2APIC_API, 0, flags); > +} > + > +bool kvm_enable_x2apic(void) > +{ > + return kvm_x2apic_api_set_flags(KVM_X2APIC_API_USE_32BIT_IDS | > + KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK); > +} > + > static int kvm_get_tsc(CPUState *cs) > { > X86CPU *cpu = X86_CPU(cs); > diff --git a/target-i386/kvm_i386.h b/target-i386/kvm_i386.h > index 42b00af1b1c3..559dd8b5acd2 100644 > --- a/target-i386/kvm_i386.h > +++ b/target-i386/kvm_i386.h > @@ -41,4 +41,5 @@ int kvm_device_msix_set_vector(KVMState *s, uint32_t > dev_id, uint32_t vector, > int kvm_device_msix_assign(KVMState *s, uint32_t dev_id); > int kvm_device_msix_deassign(KVMState *s, uint32_t dev_id); > > +bool kvm_enable_x2apic(void); > #endif >
Since the whole IOMMU feature is new and somewhat experimental, I think it's okay to just make EIM the default for >=2.8 machine types if KVM is on (using DEFINE_PROP_ON_OFF_AUTO; auto means true if KVM is on and false otherwise, and pc-2.7 would set eim=off). It means requiring kernel 4.8 by default, but I don't think it's a big deal. Paolo