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

[Philippe Mathieu-Daudé]

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:

$ 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) {
>>>