Re: [Qemu-devel] [PATCH qemu v2] hmp: Print if memory section is registered with an accelerator

[Alexey Kardashevskiy]

On 17/12/2018 23:47, Philippe Mathieu-Daudé wrote:
> On 12/17/18 2:27 AM, Alexey Kardashevskiy wrote:
>> On 14/12/2018 22:07, Philippe Mathieu-Daudé wrote:
>>> Hi Alexey,
>>>
>>> On 12/14/18 3:58 AM, Alexey Kardashevskiy wrote:
>>>> This adds an accelerator name to the "into mtree -f" to tell the user if
>>>> a particular memory section is registered with the accelerator;
>>>> the primary user for this is KVM and such information is useful
>>>> for debugging purposes.
>>>>
>>>> This adds a has_memory() callback to the accelerator class allowing any
>>>> accelerator to have a label in that memory tree dump.
>>>>
>>>> Since memory sections are passed to memory listeners and get registered
>>>> in accelerators (rather than memory regions), this only prints new labels
>>>> for flatviews attached to the system address space.
>>>>
>>>> An example:
>>>>  Root memory region: system
>>>>   0000000000000000-0000002fffffffff (prio 0, ram): /objects/mem0 kvm
>>>>   0000003000000000-0000005fffffffff (prio 0, ram): /objects/mem1 kvm
>>>>   0000200000000020-000020000000003f (prio 1, i/o): virtio-pci
>>>>   0000200080000000-000020008000003f (prio 0, i/o): capabilities
>>>>
>>>> Signed-off-by: Alexey Kardashevskiy <address@hidden>
>>>> ---
>>>>
>>>> This supercedes "[PATCH qemu] hmp: Print if memory section is registered 
>>>> in KVM"
>>>>
>>>> ---
>>>> Changes:
>>>> v2:
>>>> * added an accelerator callback instead of hardcoding it to kvm only
>>>> ---
>>>>  include/sysemu/accel.h |  2 ++
>>>>  accel/kvm/kvm-all.c    | 10 ++++++++++
>>>>  memory.c               | 22 ++++++++++++++++++++++
>>>>  3 files changed, 34 insertions(+)
>>>>
>>>> diff --git a/include/sysemu/accel.h b/include/sysemu/accel.h
>>>> index 637358f..30b456d 100644
>>>> --- a/include/sysemu/accel.h
>>>> +++ b/include/sysemu/accel.h
>>>> @@ -25,6 +25,7 @@
>>>>  
>>>>  #include "qom/object.h"
>>>>  #include "hw/qdev-properties.h"
>>>> +#include "exec/hwaddr.h"
>>>>  
>>>>  typedef struct AccelState {
>>>>      /*< private >*/
>>>> @@ -41,6 +42,7 @@ typedef struct AccelClass {
>>>>      int (*available)(void);
>>>>      int (*init_machine)(MachineState *ms);
>>>>      void (*setup_post)(MachineState *ms, AccelState *accel);
>>>> +    bool (*has_memory)(MachineState *ms, hwaddr start_addr, hwaddr size);
>>>>      bool *allowed;
>>>>      /*
>>>>       * Array of global properties that would be applied when specific
>>>> diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
>>>> index 4880a05..634f386 100644
>>>> --- a/accel/kvm/kvm-all.c
>>>> +++ b/accel/kvm/kvm-all.c
>>>> @@ -2589,11 +2589,21 @@ int kvm_get_one_reg(CPUState *cs, uint64_t id, 
>>>> void *target)
>>>>      return r;
>>>>  }
>>>>  
>>>> +static bool kvm_accel_has_memory(MachineState *ms, hwaddr start_addr,
>>>> +                                 hwaddr size)
>>>> +{
>>>> +    KVMState *kvm = KVM_STATE(ms->accelerator);
>>>> +    KVMMemoryListener *kml = &kvm->memory_listener;
>>>> +
>>>> +    return NULL != kvm_lookup_matching_slot(kml, start_addr, size);
>>>> +}
>>>> +
>>>>  static void kvm_accel_class_init(ObjectClass *oc, void *data)
>>>>  {
>>>>      AccelClass *ac = ACCEL_CLASS(oc);
>>>>      ac->name = "KVM";
>>>>      ac->init_machine = kvm_init;
>>>> +    ac->has_memory = kvm_accel_has_memory;
>>>>      ac->allowed = &kvm_allowed;
>>>>  }
>>>>  
>>>> diff --git a/memory.c b/memory.c
>>>> index d14c6de..61e758a 100644
>>>> --- a/memory.c
>>>> +++ b/memory.c
>>>> @@ -29,7 +29,9 @@
>>>>  #include "exec/ram_addr.h"
>>>>  #include "sysemu/kvm.h"
>>>>  #include "sysemu/sysemu.h"
>>>> +#include "sysemu/accel.h"
>>>>  #include "hw/qdev-properties.h"
>>>> +#include "hw/boards.h"
>>>>  #include "migration/vmstate.h"
>>>>  
>>>>  //#define DEBUG_UNASSIGNED
>>>> @@ -2924,6 +2926,8 @@ struct FlatViewInfo {
>>>>      int counter;
>>>>      bool dispatch_tree;
>>>>      bool owner;
>>>> +    AccelClass *ac;
>>>> +    const char *ac_name;
>>>>  };
>>>>  
>>>>  static void mtree_print_flatview(gpointer key, gpointer value,
>>>> @@ -2939,6 +2943,7 @@ static void mtree_print_flatview(gpointer key, 
>>>> gpointer value,
>>>>      int n = view->nr;
>>>>      int i;
>>>>      AddressSpace *as;
>>>> +    bool system_as = false;
>>>>  
>>>>      p(f, "FlatView #%d\n", fvi->counter);
>>>>      ++fvi->counter;
>>>> @@ -2950,6 +2955,9 @@ static void mtree_print_flatview(gpointer key, 
>>>> gpointer value,
>>>>              p(f, ", alias %s", memory_region_name(as->root->alias));
>>>>          }
>>>>          p(f, "\n");
>>>> +        if (as == &address_space_memory) {
>>>> +            system_as = true;
>>>> +        }
>>>>      }
>>>>  
>>>>      p(f, " Root memory region: %s\n",
>>>> @@ -2985,6 +2993,13 @@ static void mtree_print_flatview(gpointer key, 
>>>> gpointer value,
>>>>          if (fvi->owner) {
>>>>              mtree_print_mr_owner(p, f, mr);
>>>>          }
>>>> +
>>>> +        if (system_as && fvi->ac &&
>>>> +            fvi->ac->has_memory(current_machine,
>>>> +                                int128_get64(range->addr.start),
>>>> +                                MR_SIZE(range->addr.size) + 1)) {
>>>> +            p(f, " %s", fvi->ac_name);
>>>
>>> Why not simply display fvi->ac->name?
>>> You could avoid to add the ac_name field.
>>
>>
>> Well, I thought I better print whatever the user passed via the command
>> line (which is current_machine->accel and equals to "kvm" in my case)
>> rather than robotic, dry and excessive "kvm-accel".
> 
> I have no hit for 'kvm-accel':
> 
> $ git grep kvm-accel
> $
> 
> Names looks human friendly:


Ah, I confused with object_class_get_name(). Anyway, I'd still show the
user provided accelerator name than some internal name.


> 
> $ git grep 'ac->name ='
> accel/kvm/kvm-all.c:2595:    ac->name = "KVM";
> accel/tcg/tcg-all.c:74:    ac->name = "tcg";
> hw/xen/xen-common.c:184:    ac->name = "Xen";
> target/i386/hax-all.c:1088:    ac->name = "HAX";
> target/i386/hvf/hvf.c:959:    ac->name = "HVF";
> target/i386/whpx-all.c:1477:    ac->name = "WHPX";
> qtest.c:755:    ac->name = "QTest";
> 
>>>
>>>> +        }
>>>>          p(f, "\n");
>>>>          range++;
>>>>      }
>>>> @@ -3028,6 +3043,13 @@ void mtree_info(fprintf_function mon_printf, void 
>>>> *f, bool flatview,
>>>>          };
>>>>          GArray *fv_address_spaces;
>>>>          GHashTable *views = g_hash_table_new(g_direct_hash, 
>>>> g_direct_equal);
>>>> +        AccelClass *ac = ACCEL_GET_CLASS(current_machine->accelerator);
>>>> +
>>>> +        if (ac->has_memory) {
>>>> +            fvi.ac = ac;
>>>> +            fvi.ac_name = current_machine->accel ? current_machine->accel 
>>>> :
>>>> +                object_class_get_name(OBJECT_CLASS(ac));
>>>> +        }
>>>>  
>>>>          /* Gather all FVs in one table */
>>>>          QTAILQ_FOREACH(as, &address_spaces, address_spaces_link) {
>>>>

-- 
Alexey