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Violators will be prosecuted for from ; Tue, 26 Sep 2017 14:36:28 +0100 From: Christian Borntraeger Date: Tue, 26 Sep 2017 15:36:24 +0200 In-Reply-To: <20170926133624.155394-1-borntraeger@de.ibm.com> References: <20170926133624.155394-1-borntraeger@de.ibm.com> Message-Id: <20170926133624.155394-3-borntraeger@de.ibm.com> Subject: [Qemu-devel] [PATCH v2 2/2] s390x/ais: disable ais for compat machines List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Cornelia Huck Cc: Richard Henderson , Alexander Graf , Yi Min Zhao , Halil Pasic , qemu-devel , David Hildenbrand , "Jason J . Herne" , Christian Borntraeger , "Dr. David Alan Gilbert" With newer kernels that do support the ais feature (4.13) a qemu 2.11 will not only enable the ais feature for the 2.11 machine, but also for a <=2.10 compat machine. As this feature is not available in QEMU <=2.9 (and QEMU 2.10.1), this guest will fail to migrate back to an older qemu like 2.9 with: _snip_ error while loading state for instance 0x0 of device 's390-flic' _snip_ making the whole compat machine dis-functional. As a permanent fix, we need to fence the ais feature for machines <= 2.10 Due to ais being enabled on 2.10.0 (fixed in 2.10.1) this will prevent migration of ais-enabled guests from 2.10.0 with _snip_ qemu-system-s390x: Failed to load s390-flic/ais:tmp qemu-system-s390x: error while loading state for instance 0x0 of device 's390-flic' qemu-system-s390x: load of migration failed: Function not implemented _snip_ Signed-off-by: Christian Borntraeger Cc: Yi Min Zhao Cc: Dr. David Alan Gilbert --- hw/intc/s390_flic_kvm.c | 4 +++- hw/s390x/s390-virtio-ccw.c | 10 ++++++++++ include/hw/s390x/s390-virtio-ccw.h | 3 +++ 3 files changed, 16 insertions(+), 1 deletion(-) diff --git a/hw/intc/s390_flic_kvm.c b/hw/intc/s390_flic_kvm.c index 5c9d215..2e40968 100644 --- a/hw/intc/s390_flic_kvm.c +++ b/hw/intc/s390_flic_kvm.c @@ -22,6 +22,7 @@ #include "hw/s390x/s390_flic.h" #include "hw/s390x/adapter.h" #include "hw/s390x/css.h" +#include "hw/s390x/s390-virtio-ccw.h" #include "trace.h" #define FLIC_SAVE_INITIAL_SIZE getpagesize() @@ -559,7 +560,8 @@ static void kvm_s390_flic_realize(DeviceState *dev, Error **errp) KVM_HAS_DEVICE_ATTR, test_attr); /* try enable the AIS facility */ test_attr.group = KVM_DEV_FLIC_AISM_ALL; - if (!ioctl(flic_state->fd, KVM_HAS_DEVICE_ATTR, test_attr)) { + if (ais_allowed() && + !ioctl(flic_state->fd, KVM_HAS_DEVICE_ATTR, test_attr)) { kvm_vm_enable_cap(kvm_state, KVM_CAP_S390_AIS, 0); } diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c index 98c82c2..41b770a 100644 --- a/hw/s390x/s390-virtio-ccw.c +++ b/hw/s390x/s390-virtio-ccw.c @@ -435,6 +435,7 @@ static void ccw_machine_class_init(ObjectClass *oc, void *data) s390mc->cpu_model_allowed = true; s390mc->css_migration_enabled = true; s390mc->gs_allowed = true; + s390mc->ais_allowed = true; mc->init = ccw_init; mc->reset = s390_machine_reset; mc->hot_add_cpu = s390_hot_add_cpu; @@ -519,6 +520,11 @@ bool gs_allowed(void) return get_machine_class()->gs_allowed; } +bool ais_allowed(void) +{ + return get_machine_class()->ais_allowed; +} + static char *machine_get_loadparm(Object *obj, Error **errp) { S390CcwMachineState *ms = S390_CCW_MACHINE(obj); @@ -742,6 +748,10 @@ static void ccw_machine_2_10_instance_options(MachineState *machine) static void ccw_machine_2_10_class_options(MachineClass *mc) { + S390CcwMachineClass *s390mc = S390_MACHINE_CLASS(mc); + + s390mc->ais_allowed = false; + ccw_machine_2_11_class_options(mc); SET_MACHINE_COMPAT(mc, CCW_COMPAT_2_10); } diff --git a/include/hw/s390x/s390-virtio-ccw.h b/include/hw/s390x/s390-virtio-ccw.h index a9a90c2..d25a98f 100644 --- a/include/hw/s390x/s390-virtio-ccw.h +++ b/include/hw/s390x/s390-virtio-ccw.h @@ -41,6 +41,7 @@ typedef struct S390CcwMachineClass { bool cpu_model_allowed; bool css_migration_enabled; bool gs_allowed; + bool ais_allowed; } S390CcwMachineClass; /* runtime-instrumentation allowed by the machine */ @@ -49,6 +50,8 @@ bool ri_allowed(void); bool cpu_model_allowed(void); /* guarded-storage allowed by the machine */ bool gs_allowed(void); +/* ais allowed by the machine */ +bool ais_allowed(void); /** * Returns true if (vmstate based) migration of the channel subsystem -- 2.9.4