Re: [Qemu-devel] [PATCH v3 4/4] sclp-s390: Add memory hotplug SCLPs

[Matthew Rosato]

On 05/12/2014 03:35 AM, Christian Borntraeger wrote:
> On 07/05/14 20:05, Matthew Rosato wrote:
>> Add memory information to read SCP info and add handlers for
>> Read Storage Element Information, Attach Storage Element,
>> Assign Storage and Unassign Storage.
>>
>> Signed-off-by: Matthew Rosato <address@hidden>
>> ---
>>  hw/s390x/sclp.c    |  245 
>> ++++++++++++++++++++++++++++++++++++++++++++++++++--
>>  target-s390x/cpu.h |   15 ++++
>>  target-s390x/kvm.c |    5 ++
>>  3 files changed, 258 insertions(+), 7 deletions(-)
>>
>> diff --git a/hw/s390x/sclp.c b/hw/s390x/sclp.c
>> index 338dbdf..b9425ca 100644
>> --- a/hw/s390x/sclp.c
>> +++ b/hw/s390x/sclp.c
>> @@ -16,7 +16,8 @@
>>  #include "sysemu/kvm.h"
>>  #include "exec/memory.h"
>>  #include "sysemu/sysemu.h"
>> -
>> +#include "exec/address-spaces.h"
>> +#include "qemu/config-file.h"
>>  #include "hw/s390x/sclp.h"
>>  #include "hw/s390x/event-facility.h"
>>
>> @@ -33,10 +34,18 @@ static inline SCLPEventFacility *get_event_facility(void)
>>  static void read_SCP_info(SCCB *sccb)
>>  {
>>      ReadInfo *read_info = (ReadInfo *) sccb;
>> +    sclpMemoryHotplugDev *mhd = get_sclp_memory_hotplug_dev();
> 
> 
> This only works for the ccw machine. The legacy machine does not yet have 
> this device and qemu complains about the system bus not being hotplug capable.
> Cant you just initialize the device in the ccw machine and check here only 
> for the existence?

Agh, forgot about the legacy machine.  Sure, I can split out creation
from the get_sclp_memory_hotplug_dev() code, and then rework the code here.

But then I got to thinking -- should I not be setting
SCLP_FC_ASSIGN_ATTACH_READ_STOR below when we are running in the legacy
machine?  Because without the sclp_memory_hotplug_dev, we really aren't
supporting these new functions (assign_storage, unassign_storage,
assign_storage_element, read_storage_element*_info).
Then, I can probably add some assert(mhd) for the remaining
get_sclp_memory_hotplug_dev() calls, since we shouldn't get getting
there for the legacy machine.

What do you think?  Alternatively, I'd have to add code to fudge returns
for each of these new fuctions.

> 
>>      CPUState *cpu;
>> -    int shift = 0;
>>      int cpu_count = 0;
>>      int i = 0;
>> +    int rnsize, rnmax;
>> +    QemuOpts *opts = qemu_opts_find(qemu_find_opts("memory"), NULL);
>> +    int slots = qemu_opt_get_number(opts, "slots", 0);
>> +    int max_avail_slots = s390_get_memslot_count(kvm_state);
>> +
>> +    if (slots > max_avail_slots) {
>> +        slots = max_avail_slots;
>> +    }
>>
>>      CPU_FOREACH(cpu) {
>>          cpu_count++;
>> @@ -52,16 +61,222 @@ static void read_SCP_info(SCCB *sccb)
>>          read_info->entries[i].type = 0;
>>      }
>>
>> -    read_info->facilities = cpu_to_be64(SCLP_HAS_CPU_INFO);
>> +    /*
>> +     * 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.
>> +     */
>> +    while ((ram_size >> mhd->increment_size) > MAX_STORAGE_INCREMENTS) {
>> +        mhd->increment_size++;
>> +    }
>> +    while ((mhd->standby_mem_size >> mhd->increment_size) >
>> +           MAX_STORAGE_INCREMENTS) {
>> +        mhd->increment_size++;
>> +    }
>> +
>> +    mhd->standby_subregion_size = MEM_SECTION_SIZE;
>> +    /* Deduct the memory slot already used for core */
>> +    if (slots > 0) {
>> +        while ((mhd->standby_subregion_size * (slots - 1)
>> +                < mhd->standby_mem_size)) {
>> +            mhd->standby_subregion_size = mhd->standby_subregion_size << 1;
>> +        }
>> +    }
>> +    /*
>> +     * Initialize mapping of guest standby memory sections indicating which
>> +     * are and are not online. Assume all standby memory begins offline.
>> +     */
>> +    if (mhd->standby_state_map == 0) {
>> +        if (mhd->standby_mem_size % mhd->standby_subregion_size) {
>> +            mhd->standby_state_map = g_malloc0((mhd->standby_mem_size /
>> +                                           mhd->standby_subregion_size + 1) 
>> *
>> +                                          (mhd->standby_subregion_size /
>> +                                           MEM_SECTION_SIZE));
>> +        } else {
>> +            mhd->standby_state_map = g_malloc0(mhd->standby_mem_size /
>> +                                               MEM_SECTION_SIZE);
>> +        }
>> +    }
>> +
>> +    mhd->padded_ram_size = ram_size + mhd->pad_size;
>> +    mhd->rzm = 1 << mhd->increment_size;
>> +    rnsize = 1 << (mhd->increment_size - 20);
>> +    if (rnsize <= 128) {
>> +        read_info->rnsize = rnsize;
>> +    } else {
>> +        read_info->rnsize = 0;
>> +        read_info->rnsize2 = cpu_to_be32(rnsize);
>> +    }
>>
>> -    while ((ram_size >> (20 + shift)) > 65535) {
>> -        shift++;
>> +    rnmax = ((ram_size + mhd->standby_mem_size + mhd->pad_size)
>> +             >> mhd->increment_size);
>> +    if (rnmax < 0x10000) {
>> +        read_info->rnmax = cpu_to_be16(rnmax);
>> +    } else {
>> +        read_info->rnmax = cpu_to_be16(0);
>> +        read_info->rnmax2 = cpu_to_be64(rnmax);
>>      }
>> -    read_info->rnmax = cpu_to_be16(ram_size >> (20 + shift));
>> -    read_info->rnsize = 1 << shift;
>> +
>> +    read_info->facilities = cpu_to_be64(SCLP_HAS_CPU_INFO |
>> +                                        SCLP_FC_ASSIGN_ATTACH_READ_STOR);
>> +
>>      sccb->h.response_code = cpu_to_be16(SCLP_RC_NORMAL_READ_COMPLETION);
>>  }
>>
>> +static void read_storage_element0_info(SCCB *sccb)
>> +{
>> +    int i, assigned;
>> +    int subincrement_id = SCLP_STARTING_SUBINCREMENT_ID;
>> +    ReadStorageElementInfo *storage_info = (ReadStorageElementInfo *) sccb;
>> +    sclpMemoryHotplugDev *mhd = get_sclp_memory_hotplug_dev();
>> +
>> +    if ((ram_size >> mhd->increment_size) >= 0x10000) {
>> +        sccb->h.response_code = 
>> cpu_to_be16(SCLP_RC_SCCB_BOUNDARY_VIOLATION);
>> +        return;
>> +    }
>> +
>> +    /* Return information regarding core memory */
>> +    storage_info->max_id = cpu_to_be16(mhd->standby_mem_size ? 1 : 0);
>> +    assigned = ram_size >> mhd->increment_size;
>> +    storage_info->assigned = cpu_to_be16(assigned);
>> +
>> +    for (i = 0; i < assigned; i++) {
>> +        storage_info->entries[i] = cpu_to_be32(subincrement_id);
>> +        subincrement_id += SCLP_INCREMENT_UNIT;
>> +    }
>> +    sccb->h.response_code = cpu_to_be16(SCLP_RC_NORMAL_READ_COMPLETION);
>> +}
>> +
>> +static void read_storage_element1_info(SCCB *sccb)
>> +{
>> +    ReadStorageElementInfo *storage_info = (ReadStorageElementInfo *) sccb;
>> +    sclpMemoryHotplugDev *mhd = get_sclp_memory_hotplug_dev();
> 
> Same here.
> 
>> +
>> +    if ((mhd->standby_mem_size >> mhd->increment_size) >= 0x10000) {
>> +        sccb->h.response_code = 
>> cpu_to_be16(SCLP_RC_SCCB_BOUNDARY_VIOLATION);
>> +        return;
>> +    }
>> +
>> +    /* Return information regarding standby memory */
>> +    storage_info->max_id = cpu_to_be16(mhd->standby_mem_size ? 1 : 0);
>> +    storage_info->assigned = cpu_to_be16(mhd->standby_mem_size >>
>> +                                         mhd->increment_size);
>> +    storage_info->standby = cpu_to_be16(mhd->standby_mem_size >>
>> +                                        mhd->increment_size);
>> +    sccb->h.response_code = cpu_to_be16(SCLP_RC_STANDBY_READ_COMPLETION);
>> +}
>> +
>> +static void attach_storage_element(SCCB *sccb, uint16_t element)
>> +{
>> +    int i, assigned, subincrement_id;
>> +    AttachStorageElement *attach_info = (AttachStorageElement *) sccb;
>> +    sclpMemoryHotplugDev *mhd = get_sclp_memory_hotplug_dev();
>> +
>> +    if (element != 1) {
>> +        sccb->h.response_code = cpu_to_be16(SCLP_RC_INVALID_SCLP_COMMAND);
>> +        return;
>> +    }
>> +
>> +    assigned = mhd->standby_mem_size >> mhd->increment_size;
>> +    attach_info->assigned = cpu_to_be16(assigned);
>> +    subincrement_id = ((ram_size >> mhd->increment_size) << 16)
>> +                      + SCLP_STARTING_SUBINCREMENT_ID;
>> +    for (i = 0; i < assigned; i++) {
>> +        attach_info->entries[i] = cpu_to_be32(subincrement_id);
>> +        subincrement_id += SCLP_INCREMENT_UNIT;
>> +    }
>> +    sccb->h.response_code = cpu_to_be16(SCLP_RC_NORMAL_COMPLETION);
>> +}
>> +
>> +static void assign_storage(SCCB *sccb)
>> +{
>> +    MemoryRegion *mr = NULL;
>> +    int this_subregion_size;
>> +    AssignStorage *assign_info = (AssignStorage *) sccb;
>> +    sclpMemoryHotplugDev *mhd = get_sclp_memory_hotplug_dev();
>> +    ram_addr_t assign_addr = (assign_info->rn - 1) * mhd->rzm;
>> +    MemoryRegion *sysmem = get_system_memory();
>> +
>> +    if ((assign_addr % MEM_SECTION_SIZE == 0) &&
>> +        (assign_addr >= mhd->padded_ram_size)) {
>> +        /* Re-use existing memory region if found */
>> +        mr = memory_region_find(sysmem, assign_addr, 1).mr;
>> +        if (!mr) {
>> +
>> +            MemoryRegion *standby_ram = g_new(MemoryRegion, 1);
>> +
>> +            /* offset to align to standby_subregion_size for allocation */
>> +            ram_addr_t offset = assign_addr -
>> +                                (assign_addr - mhd->padded_ram_size)
>> +                                % mhd->standby_subregion_size;
>> +
>> +            /* strlen("standby.ram") + 4 (Max of KVM_MEMORY_SLOTS) +  NULL 
>> */
>> +            char id[16];
>> +            snprintf(id, 16, "standby.ram%d",
>> +                     (int)((offset - mhd->padded_ram_size) /
>> +                     mhd->standby_subregion_size) + 1);
>> +
>> +            /* Allocate a subregion of the calculated 
>> standby_subregion_size */
>> +            if (offset + mhd->standby_subregion_size >
>> +                mhd->padded_ram_size + mhd->standby_mem_size) {
>> +                this_subregion_size = mhd->padded_ram_size +
>> +                  mhd->standby_mem_size - offset;
>> +            } else {
>> +                this_subregion_size = mhd->standby_subregion_size;
>> +            }
>> +
>> +            memory_region_init_ram(standby_ram, NULL, id, 
>> this_subregion_size);
>> +            vmstate_register_ram_global(standby_ram);
>> +            memory_region_add_subregion(sysmem, offset, standby_ram);
>> +        }
>> +        /* The specified subregion is no longer in standby */
>> +        mhd->standby_state_map[(assign_addr - mhd->padded_ram_size)
>> +                               / MEM_SECTION_SIZE] = 1;
>> +    }
>> +    sccb->h.response_code = cpu_to_be16(SCLP_RC_NORMAL_COMPLETION);
>> +}
>> +
>> +static void unassign_storage(SCCB *sccb)
>> +{
>> +    MemoryRegion *mr = NULL;
>> +    AssignStorage *assign_info = (AssignStorage *) sccb;
>> +    sclpMemoryHotplugDev *mhd = get_sclp_memory_hotplug_dev();
>> +    ram_addr_t unassign_addr = (assign_info->rn - 1) * mhd->rzm;
>> +    MemoryRegion *sysmem = get_system_memory();
>> +
>> +    /* if the addr is a multiple of 256 MB */
>> +    if ((unassign_addr % MEM_SECTION_SIZE == 0) &&
>> +        (unassign_addr >= mhd->padded_ram_size)) {
>> +        mhd->standby_state_map[(unassign_addr -
>> +                           mhd->padded_ram_size) / MEM_SECTION_SIZE] = 0;
>> +
>> +        /* find the specified memory region and destroy it */
>> +        mr = memory_region_find(sysmem, unassign_addr, 1).mr;
>> +        if (mr) {
>> +            int i;
>> +            int is_removable = 1;
>> +            ram_addr_t map_offset = (unassign_addr - mhd->padded_ram_size -
>> +                                     (unassign_addr - mhd->padded_ram_size)
>> +                                     % mhd->standby_subregion_size);
>> +            /* Mark all affected subregions as 'standby' once again */
>> +            for (i = 0;
>> +                 i < (mhd->standby_subregion_size / MEM_SECTION_SIZE);
>> +                 i++) {
>> +
>> +                if (mhd->standby_state_map[i + map_offset / 
>> MEM_SECTION_SIZE]) {
>> +                    is_removable = 0;
>> +                    break;
>> +                }
>> +            }
>> +            if (is_removable) {
>> +                memory_region_del_subregion(sysmem, mr);
>> +                memory_region_destroy(mr);
>> +                g_free(mr);
>> +            }
>> +        }
>> +    }
>> +    sccb->h.response_code = cpu_to_be16(SCLP_RC_NORMAL_COMPLETION);
>> +}
>> +
>>  /* Provide information about the CPU */
>>  static void sclp_read_cpu_info(SCCB *sccb)
>>  {
>> @@ -103,6 +318,22 @@ static void sclp_execute(SCCB *sccb, uint32_t code)
>>      case SCLP_CMDW_READ_CPU_INFO:
>>          sclp_read_cpu_info(sccb);
>>          break;
>> +    case SCLP_READ_STORAGE_ELEMENT_INFO:
>> +        if (code & 0xff00) {
>> +            read_storage_element1_info(sccb);
>> +        } else {
>> +            read_storage_element0_info(sccb);
>> +        }
>> +        break;
>> +    case SCLP_ATTACH_STORAGE_ELEMENT:
>> +        attach_storage_element(sccb, (code & 0xff00) >> 8);
>> +        break;
>> +    case SCLP_ASSIGN_STORAGE:
>> +        assign_storage(sccb);
>> +        break;
>> +    case SCLP_UNASSIGN_STORAGE:
>> +        unassign_storage(sccb);
>> +        break;
>>      default:
>>          efc->command_handler(ef, sccb, code);
>>          break;
>> diff --git a/target-s390x/cpu.h b/target-s390x/cpu.h
>> index 193eac3..ec9879a 100644
>> --- a/target-s390x/cpu.h
>> +++ b/target-s390x/cpu.h
>> @@ -1049,6 +1049,7 @@ static inline void cpu_inject_crw_mchk(S390CPU *cpu)
>>
>>  /* from s390-virtio-ccw */
>>  #define MEM_SECTION_SIZE             0x10000000UL
>> +#define MAX_AVAIL_SLOTS              32
>>
>>  /* fpu_helper.c */
>>  uint32_t set_cc_nz_f32(float32 v);
>> @@ -1072,6 +1073,7 @@ void kvm_s390_enable_css_support(S390CPU *cpu);
>>  int kvm_s390_assign_subch_ioeventfd(EventNotifier *notifier, uint32_t sch,
>>                                      int vq, bool assign);
>>  int kvm_s390_cpu_restart(S390CPU *cpu);
>> +int kvm_s390_get_memslot_count(KVMState *s);
>>  #else
>>  static inline void kvm_s390_io_interrupt(S390CPU *cpu,
>>                                          uint16_t subchannel_id,
>> @@ -1096,6 +1098,10 @@ static inline int kvm_s390_cpu_restart(S390CPU *cpu)
>>  {
>>      return -ENOSYS;
>>  }
>> +static inline int kvm_s390_get_memslot_count(KVMState *s)
>> +{
>> +  return MAX_AVAIL_SLOTS;
>> +}
>>  #endif
>>
>>  static inline int s390_cpu_restart(S390CPU *cpu)
>> @@ -1106,6 +1112,15 @@ static inline int s390_cpu_restart(S390CPU *cpu)
>>      return -ENOSYS;
>>  }
>>
>> +static inline int s390_get_memslot_count(KVMState *s)
>> +{
>> +    if (kvm_enabled()) {
>> +        return kvm_s390_get_memslot_count(s);
>> +    } else {
>> +        return MAX_AVAIL_SLOTS;
>> +    }
>> +}
>> +
>>  static inline void s390_io_interrupt(S390CPU *cpu,
>>                                       uint16_t subchannel_id,
>>                                       uint16_t subchannel_nr,
>> diff --git a/target-s390x/kvm.c b/target-s390x/kvm.c
>> index b7b0edc..ea6123c 100644
>> --- a/target-s390x/kvm.c
>> +++ b/target-s390x/kvm.c
>> @@ -959,3 +959,8 @@ int kvm_s390_assign_subch_ioeventfd(EventNotifier 
>> *notifier, uint32_t sch,
>>      }
>>      return kvm_vm_ioctl(kvm_state, KVM_IOEVENTFD, &kick);
>>  }
>> +
>> +int kvm_s390_get_memslot_count(KVMState *s)
>> +{
>> +    return kvm_check_extension(s, KVM_CAP_NR_MEMSLOTS);
>> +}
>>
> 
> 
> 
>