On Wed, 1 Apr 2020 08:37:54 -0400 Christian Borntraeger <borntrae...@de.ibm.com> wrote:
> Older QEMU versions did fixup the ram size to match what can be reported > via sclp. We need to mimic this behaviour for machine types 4.2 and > older to not fail on inbound migration for memory sizes that do not fit. > Old machines with proper aligned memory sizes are not affected. > > Alignment table: > VM size (<=) | Alignment > -------------------------- > 1020M | 1M > 2040M | 2M > 4080M | 4M > 8160M | 8M > 16320M | 16M > 32640M | 32M > 65280M | 64M > 130560M | 128M > 261120M | 256M > 522240M | 512M > 1044480M | 1G > 2088960M | 2G > 4177920M | 4G > 8355840M | 8G > > Suggested action is to replace unaligned -m value with a suitable > aligned one or if a change to a newer machine type is possible, use a > machine version >= 5.0. > > A future versions might remove the compatibility handling. > > For machine types >= 5.0 we can simply use an increment size of 1M and > use the full range of increment number which allows for all possible > memory sizes. The old limitation of having a maximum of 1020 increments > was added for standby memory, which we no longer support. With that we > can now support even weird memory sizes like 10001234 MB. > > As we no longer fixup maxram_size as well, make other users use ram_size > instead. Keep using maxram_size when setting the maximum ram size in KVM, > as that will come in handy in the future when supporting memory hotplug > (in contrast, storage keys and storage attributes for hotplugged memory > will have to be migrated per RAM block in the future). > > Fixes: 3a12fc61af5c ("390x/s390-virtio-ccw: use memdev for RAM") > Reported-by: Lukáš Doktor <ldok...@redhat.com> > Cc: Igor Mammedov <imamm...@redhat.com> > Cc: Dr. David Alan Gilbert <dgilb...@redhat.com> > Signed-off-by: David Hildenbrand <da...@redhat.com> > Signed-off-by: Christian Borntraeger <borntrae...@de.ibm.com> Acked-by: Igor Mammedov <imamm...@redhat.com> minor nit below if you have to respin > --- > hw/s390x/s390-skeys.c | 2 +- > hw/s390x/s390-stattrib-kvm.c | 4 ++-- > hw/s390x/s390-virtio-ccw.c | 21 +++++++++++++++++++++ > hw/s390x/sclp.c | 17 +++++------------ > include/hw/boards.h | 7 +++++++ > softmmu/vl.c | 3 +++ > 6 files changed, 39 insertions(+), 15 deletions(-) > > diff --git a/hw/s390x/s390-skeys.c b/hw/s390x/s390-skeys.c > index 5da6e5292f..a9a4ae7b39 100644 > --- a/hw/s390x/s390-skeys.c > +++ b/hw/s390x/s390-skeys.c > @@ -176,7 +176,7 @@ static void qemu_s390_skeys_init(Object *obj) > QEMUS390SKeysState *skeys = QEMU_S390_SKEYS(obj); > MachineState *machine = MACHINE(qdev_get_machine()); > > - skeys->key_count = machine->maxram_size / TARGET_PAGE_SIZE; > + skeys->key_count = machine->ram_size / TARGET_PAGE_SIZE; > skeys->keydata = g_malloc0(skeys->key_count); > } > > diff --git a/hw/s390x/s390-stattrib-kvm.c b/hw/s390x/s390-stattrib-kvm.c > index c7e1f35524..f89d8d9d16 100644 > --- a/hw/s390x/s390-stattrib-kvm.c > +++ b/hw/s390x/s390-stattrib-kvm.c > @@ -85,7 +85,7 @@ static int kvm_s390_stattrib_set_stattr(S390StAttribState > *sa, > { > KVMS390StAttribState *sas = KVM_S390_STATTRIB(sa); > MachineState *machine = MACHINE(qdev_get_machine()); > - unsigned long max = machine->maxram_size / TARGET_PAGE_SIZE; > + unsigned long max = machine->ram_size / TARGET_PAGE_SIZE; > > if (start_gfn + count > max) { > error_report("Out of memory bounds when setting storage attributes"); > @@ -104,7 +104,7 @@ static void > kvm_s390_stattrib_synchronize(S390StAttribState *sa) > { > KVMS390StAttribState *sas = KVM_S390_STATTRIB(sa); > MachineState *machine = MACHINE(qdev_get_machine()); > - unsigned long max = machine->maxram_size / TARGET_PAGE_SIZE; > + unsigned long max = machine->ram_size / TARGET_PAGE_SIZE; > /* We do not need to reach the maximum buffer size allowed */ > unsigned long cx, len = KVM_S390_SKEYS_MAX / 2; > int r; > diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c > index 3cf19c99f3..61a8a0e693 100644 > --- a/hw/s390x/s390-virtio-ccw.c > +++ b/hw/s390x/s390-virtio-ccw.c > @@ -27,6 +27,7 @@ > #include "qemu/ctype.h" > #include "qemu/error-report.h" > #include "qemu/option.h" > +#include "qemu/qemu-print.h" > #include "s390-pci-bus.h" > #include "sysemu/reset.h" > #include "hw/s390x/storage-keys.h" > @@ -579,6 +580,25 @@ static void s390_nmi(NMIState *n, int cpu_index, Error > **errp) > s390_cpu_restart(S390_CPU(cs)); > } > > +static ram_addr_t s390_fixup_ram_size(ram_addr_t sz) > +{ > + /* same logic as in sclp.c */ > + int increment_size = 20; > + ram_addr_t newsz; > + > + while ((sz >> increment_size) > MAX_STORAGE_INCREMENTS) { > + increment_size++; > + } > + newsz = sz >> increment_size << increment_size; > + > + if (sz != newsz) { > + qemu_printf("Ram size %" PRIu64 "MB was fixed up to %" PRIu64 ^^^^^^^^ for unaware user it could be confusing as it could be read as 'value was increased' s/fixed up/amended/ might be better > + "MB to match machine restrictions. Consider updating " > + "the guest definition.i\n", sz / MiB, newsz / MiB); also it might be better to use size_to_str() to format numbers > + } > + return newsz; > +} > + > static void ccw_machine_class_init(ObjectClass *oc, void *data) > { > MachineClass *mc = MACHINE_CLASS(oc); > @@ -808,6 +828,7 @@ static void ccw_machine_4_2_instance_options(MachineState > *machine) > static void ccw_machine_4_2_class_options(MachineClass *mc) > { > ccw_machine_5_0_class_options(mc); > + mc->fixup_ram_size = s390_fixup_ram_size; > compat_props_add(mc->compat_props, hw_compat_4_2, hw_compat_4_2_len); > } > DEFINE_CCW_MACHINE(4_2, "4.2", false); > diff --git a/hw/s390x/sclp.c b/hw/s390x/sclp.c > index d8ae207731..ede056b3ef 100644 > --- a/hw/s390x/sclp.c > +++ b/hw/s390x/sclp.c > @@ -361,27 +361,20 @@ out: > static void sclp_memory_init(SCLPDevice *sclp) > { > MachineState *machine = MACHINE(qdev_get_machine()); > + MachineClass *machine_class = MACHINE_GET_CLASS(qdev_get_machine()); > ram_addr_t initial_mem = machine->ram_size; > int increment_size = 20; > > /* The storage increment size is a multiple of 1M and is a power of 2. > - * The number of storage increments must be MAX_STORAGE_INCREMENTS or > fewer. > + * For some machine types, the number of storage increments must be > + * MAX_STORAGE_INCREMENTS or fewer. > * The variable 'increment_size' is an exponent of 2 that can be > * used to calculate the size (in bytes) of an increment. */ > - while ((initial_mem >> increment_size) > MAX_STORAGE_INCREMENTS) { > + while (machine_class->fixup_ram_size != NULL && > + (initial_mem >> increment_size) > MAX_STORAGE_INCREMENTS) { > increment_size++; > } > sclp->increment_size = increment_size; > - > - /* The core memory area needs to be aligned with the increment size. > - * In effect, this can cause the user-specified memory size to be rounded > - * down to align with the nearest increment boundary. */ > - initial_mem = initial_mem >> increment_size << increment_size; > - > - machine->ram_size = initial_mem; > - machine->maxram_size = initial_mem; > - /* let's propagate the changed ram size into the global variable. */ > - ram_size = initial_mem; > } > > static void sclp_init(Object *obj) > diff --git a/include/hw/boards.h b/include/hw/boards.h > index 236d239c19..fd4d62b501 100644 > --- a/include/hw/boards.h > +++ b/include/hw/boards.h > @@ -152,6 +152,12 @@ typedef struct { > * It also will be used as a way to optin into "-m" option support. > * If it's not set by board, '-m' will be ignored and generic code will > * not create default RAM MemoryRegion. > + * @fixup_ram_size: > + * Amends user provided ram size (with -m option) using machine > + * specific algorithm. To be used by old machine types for compat > + * purposes only. > + * Applies only to default memory backend, i.e., explicit memory backend > + * wasn't used. > */ > struct MachineClass { > /*< private >*/ > @@ -218,6 +224,7 @@ struct MachineClass { > unsigned cpu_index); > const CPUArchIdList *(*possible_cpu_arch_ids)(MachineState *machine); > int64_t (*get_default_cpu_node_id)(const MachineState *ms, int idx); > + ram_addr_t (*fixup_ram_size)(ram_addr_t size); > }; > > /** > diff --git a/softmmu/vl.c b/softmmu/vl.c > index 1d33a28340..09f8a1b0a7 100644 > --- a/softmmu/vl.c > +++ b/softmmu/vl.c > @@ -2601,6 +2601,9 @@ static bool set_memory_options(uint64_t *ram_slots, > ram_addr_t *maxram_size, > } > > sz = QEMU_ALIGN_UP(sz, 8192); > + if (mc->fixup_ram_size) { > + sz = mc->fixup_ram_size(sz); > + } > ram_size = sz; > if (ram_size != sz) { > error_report("ram size too large");