[Qemu-devel] [PATCH qemu v3] hmp: Print if memory section is registered with an accelerator

[Alexey Kardashevskiy <aik@ozlabs.ru>]

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 <aik@ozlabs.ru>
---
Changes:
v3:
* added support for multiple ASes per accelerator (KVM can do 2 at least)
as Paolo suggested

v2:
* added an accelerator callback instead of hardcoding it to kvm only
---
 include/sysemu/accel.h |  3 +++
 accel/kvm/kvm-all.c    | 38 ++++++++++++++++++++++++++++++++++++++
 memory.c               | 22 ++++++++++++++++++++++
 3 files changed, 63 insertions(+)

diff --git a/include/sysemu/accel.h b/include/sysemu/accel.h
index 81293cdb08f9..89ce57e404ca 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 >*/
@@ -39,6 +40,8 @@ typedef struct AccelClass {
     const char *name;
     int (*init_machine)(MachineState *ms);
     void (*setup_post)(MachineState *ms, AccelState *accel);
+    bool (*has_memory)(MachineState *ms, AddressSpace *as,
+                       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 b0c4bed6e367..948b7e53df47 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -109,6 +109,13 @@ struct KVMState
     /* memory encryption */
     void *memcrypt_handle;
     int (*memcrypt_encrypt_data)(void *handle, uint8_t *ptr, uint64_t len);
+
+    /* For "info mtree -f" to tell if an MR is registered in KVM */
+    int nr_as;
+    struct KVMAs {
+        KVMMemoryListener *ml;
+        AddressSpace *as;
+    } *as;
 };
 
 KVMState *kvm_state;
@@ -940,6 +947,14 @@ void kvm_memory_listener_register(KVMState *s, KVMMemoryListener *kml,
     kml->listener.priority = 10;
 
     memory_listener_register(&kml->listener, as);
+
+    for (i = 0; i < s->nr_as; ++i) {
+        if (!s->as[i].as) {
+            s->as[i].as = as;
+            s->as[i].ml = kml;
+            break;
+        }
+    }
 }
 
 static MemoryListener kvm_io_listener = {
@@ -1590,6 +1605,12 @@ static int kvm_init(MachineState *ms)
         s->nr_slots = 32;
     }
 
+    s->nr_as = kvm_check_extension(s, KVM_CAP_MULTI_ADDRESS_SPACE);
+    if (s->nr_as <= 1) {
+        s->nr_as = 1;
+    }
+    s->as = g_new0(struct KVMAs, s->nr_as);
+
     kvm_type = qemu_opt_get(qemu_get_machine_opts(), "kvm-type");
     if (mc->kvm_type) {
         type = mc->kvm_type(ms, kvm_type);
@@ -2591,11 +2612,28 @@ int kvm_get_one_reg(CPUState *cs, uint64_t id, void *target)
     return r;
 }
 
+static bool kvm_accel_has_memory(MachineState *ms, AddressSpace *as,
+                                 hwaddr start_addr, hwaddr size)
+{
+    KVMState *kvm = KVM_STATE(ms->accelerator);
+    int i;
+
+    for (i = 0; i < kvm->nr_as; ++i) {
+        if (kvm->as[i].as == as && kvm->as[i].ml) {
+            return NULL != kvm_lookup_matching_slot(kvm->as[i].ml,
+                                                    start_addr, size);
+        }
+    }
+
+    return false;
+}
+
 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 0a089a73ae1a..61524156a1ce 100644
--- a/memory.c
+++ b/memory.c
@@ -30,7 +30,9 @@
 #include "sysemu/kvm.h"
 #include "sysemu/sysemu.h"
 #include "sysemu/tcg.h"
+#include "sysemu/accel.h"
 #include "hw/qdev-properties.h"
+#include "hw/boards.h"
 #include "migration/vmstate.h"
 
 //#define DEBUG_UNASSIGNED
@@ -2939,6 +2941,8 @@ struct FlatViewInfo {
     int counter;
     bool dispatch_tree;
     bool owner;
+    AccelClass *ac;
+    const char *ac_name;
 };
 
 static void mtree_print_flatview(gpointer key, gpointer value,
@@ -3001,6 +3005,17 @@ static void mtree_print_flatview(gpointer key, gpointer value,
         if (fvi->owner) {
             mtree_print_mr_owner(mr);
         }
+
+        if (fvi->ac) {
+            for (i = 0; i < fv_address_spaces->len; ++i) {
+                as = g_array_index(fv_address_spaces, AddressSpace*, i);
+                if (fvi->ac->has_memory(current_machine, as,
+                                        int128_get64(range->addr.start),
+                                        MR_SIZE(range->addr.size) + 1)) {
+                    qemu_printf(" %s", fvi->ac_name);
+                }
+            }
+        }
         qemu_printf("\n");
         range++;
     }
@@ -3041,6 +3056,13 @@ void mtree_info(bool flatview, bool dispatch_tree, bool owner)
         };
         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) {
-- 
2.17.1