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From: Peter Xu <peterx@redhat.com>
To: qemu-devel@nongnu.org
Cc: Paolo Bonzini <pbonzini@redhat.com>,
	"Dr . David Alan Gilbert" <dgilbert@redhat.com>,
	peterx@redhat.com, "Michael S . Tsirkin" <mst@redhat.com>
Subject: [PATCH RFC 5/9] KVM: Provide helper to get kvm dirty log
Date: Wed,  5 Feb 2020 09:17:45 -0500
Message-ID: <20200205141749.378044-6-peterx@redhat.com> (raw)
In-Reply-To: <20200205141749.378044-1-peterx@redhat.com>

Provide a helper kvm_slot_get_dirty_log() to make the function
kvm_physical_sync_dirty_bitmap() clearer.  We can even cache the as_id
into KVMSlot when it is created, so that we don't even need to pass it
down every time.

Since at it, remove return value of kvm_physical_sync_dirty_bitmap()
because it should never fail.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 accel/kvm/kvm-all.c      | 39 +++++++++++++++++++--------------------
 include/sysemu/kvm_int.h |  2 ++
 2 files changed, 21 insertions(+), 20 deletions(-)

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index bb635c775f..608216fd53 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -553,6 +553,18 @@ static void kvm_slot_init_dirty_bitmap(KVMSlot *mem)
     mem->dirty_bmap = g_malloc0(bitmap_size);
 }
 
+/* Sync dirty bitmap from kernel to KVMSlot.dirty_bmap */
+static void kvm_slot_get_dirty_log(KVMState *s, KVMSlot *slot)
+{
+    struct kvm_dirty_log d = {};
+    int ret;
+
+    d.dirty_bitmap = slot->dirty_bmap;
+    d.slot = slot->slot | (slot->as_id << 16);
+    ret = kvm_vm_ioctl(s, KVM_GET_DIRTY_LOG, &d);
+    assert(ret != -1);
+}
+
 /**
  * kvm_physical_sync_dirty_bitmap - Sync dirty bitmap from kernel space
  *
@@ -564,15 +576,13 @@ static void kvm_slot_init_dirty_bitmap(KVMSlot *mem)
  * @kml: the KVM memory listener object
  * @section: the memory section to sync the dirty bitmap with
  */
-static int kvm_physical_sync_dirty_bitmap(KVMMemoryListener *kml,
-                                          MemoryRegionSection *section)
+static void kvm_physical_sync_dirty_bitmap(KVMMemoryListener *kml,
+                                           MemoryRegionSection *section)
 {
     KVMState *s = kvm_state;
-    struct kvm_dirty_log d = {};
     KVMSlot *mem;
     hwaddr start_addr, size;
     hwaddr slot_size, slot_offset = 0;
-    int ret = 0;
 
     size = kvm_align_section(section, &start_addr);
     while (size) {
@@ -582,27 +592,19 @@ static int kvm_physical_sync_dirty_bitmap(KVMMemoryListener *kml,
         mem = kvm_lookup_matching_slot(kml, start_addr, slot_size);
         if (!mem) {
             /* We don't have a slot if we want to trap every access. */
-            goto out;
+            return;
         }
 
-        d.dirty_bitmap = mem->dirty_bmap;
-        d.slot = mem->slot | (kml->as_id << 16);
-        if (kvm_vm_ioctl(s, KVM_GET_DIRTY_LOG, &d) == -1) {
-            DPRINTF("ioctl failed %d\n", errno);
-            ret = -1;
-            goto out;
-        }
+        kvm_slot_get_dirty_log(s, mem);
 
         subsection.offset_within_region += slot_offset;
         subsection.size = int128_make64(slot_size);
-        kvm_get_dirty_pages_log_range(&subsection, d.dirty_bitmap);
+        kvm_get_dirty_pages_log_range(&subsection, mem->dirty_bmap);
 
         slot_offset += slot_size;
         start_addr += slot_size;
         size -= slot_size;
     }
-out:
-    return ret;
 }
 
 /* Alignment requirement for KVM_CLEAR_DIRTY_LOG - 64 pages */
@@ -1077,6 +1079,7 @@ static void kvm_set_phys_mem(KVMMemoryListener *kml,
     do {
         slot_size = MIN(kvm_max_slot_size, size);
         mem = kvm_alloc_slot(kml);
+        mem->as_id = kml->as_id;
         mem->memory_size = slot_size;
         mem->start_addr = start_addr;
         mem->ram = ram;
@@ -1119,14 +1122,10 @@ static void kvm_log_sync(MemoryListener *listener,
                          MemoryRegionSection *section)
 {
     KVMMemoryListener *kml = container_of(listener, KVMMemoryListener, listener);
-    int r;
 
     kvm_slots_lock(kml);
-    r = kvm_physical_sync_dirty_bitmap(kml, section);
+    kvm_physical_sync_dirty_bitmap(kml, section);
     kvm_slots_unlock(kml);
-    if (r < 0) {
-        abort();
-    }
 }
 
 static void kvm_log_clear(MemoryListener *listener,
diff --git a/include/sysemu/kvm_int.h b/include/sysemu/kvm_int.h
index ac2d1f8b56..4434e15ec7 100644
--- a/include/sysemu/kvm_int.h
+++ b/include/sysemu/kvm_int.h
@@ -23,6 +23,8 @@ typedef struct KVMSlot
     int old_flags;
     /* Dirty bitmap cache for the slot */
     unsigned long *dirty_bmap;
+    /* Cache of the address space ID */
+    int as_id;
 } KVMSlot;
 
 typedef struct KVMMemoryListener {
-- 
2.24.1



  parent reply index

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-05 14:17 [PATCH RFC 0/9] KVM: Dirty ring support (QEMU part) Peter Xu
2020-02-05 14:17 ` [PATCH RFC 1/9] KVM: Fixup kvm_log_clear_one_slot() ioctl return check Peter Xu
2020-03-25 16:34   ` Dr. David Alan Gilbert
2020-03-25 17:43   ` Peter Xu
2020-02-05 14:17 ` [PATCH RFC 2/9] linux-headers: Update Peter Xu
2020-02-05 14:17 ` [PATCH RFC 3/9] memory: Introduce log_sync_global() to memory listener Peter Xu
2020-03-25 16:52   ` Dr. David Alan Gilbert
2020-03-25 17:02     ` Peter Xu
2020-02-05 14:17 ` [PATCH RFC 4/9] KVM: Create the KVMSlot dirty bitmap on flag changes Peter Xu
2020-03-25 17:44   ` Dr. David Alan Gilbert
2020-02-05 14:17 ` Peter Xu [this message]
2020-03-25 17:52   ` [PATCH RFC 5/9] KVM: Provide helper to get kvm dirty log Dr. David Alan Gilbert
2020-03-25 18:15     ` Peter Xu
2020-02-05 14:17 ` [PATCH RFC 6/9] KVM: Provide helper to sync dirty bitmap from slot to ramblock Peter Xu
2020-03-25 18:47   ` Dr. David Alan Gilbert
2020-02-05 14:17 ` [PATCH RFC 7/9] KVM: Cache kvm slot dirty bitmap size Peter Xu
2020-03-25 18:49   ` Dr. David Alan Gilbert
2020-02-05 14:17 ` [PATCH RFC 8/9] KVM: Add dirty-ring-size property Peter Xu
2020-03-25 20:00   ` Dr. David Alan Gilbert
2020-03-25 20:42     ` Peter Xu
2020-03-26 13:41       ` Dr. David Alan Gilbert
2020-03-26 16:03         ` Peter Xu
2020-03-25 20:14   ` Dr. David Alan Gilbert
2020-03-25 20:48     ` Peter Xu
2020-02-05 14:17 ` [PATCH RFC 9/9] KVM: Dirty ring support Peter Xu
2020-03-25 20:41   ` Dr. David Alan Gilbert
2020-03-25 21:32     ` Peter Xu
2020-03-26 14:14       ` Dr. David Alan Gilbert
2020-03-26 16:10         ` Peter Xu
2020-02-05 14:51 ` [PATCH RFC 0/9] KVM: Dirty ring support (QEMU part) no-reply
2020-03-03 17:32 ` Peter Xu

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