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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 6/9] KVM: Provide helper to sync dirty bitmap from slot to ramblock
Date: Wed,  5 Feb 2020 09:17:46 -0500
Message-ID: <20200205141749.378044-7-peterx@redhat.com> (raw)
In-Reply-To: <20200205141749.378044-1-peterx@redhat.com>

kvm_physical_sync_dirty_bitmap() calculates the ramblock offset in an
awkward way from the MemoryRegionSection that passed in from the
caller.  The truth is for each KVMSlot the ramblock offset never
change for the lifecycle.  Cache the ramblock offset for each KVMSlot
into the structure when the KVMSlot is created.

With that, we can further simplify kvm_physical_sync_dirty_bitmap()
with a helper to sync KVMSlot dirty bitmap to the ramblock dirty
bitmap of a specific KVMSlot.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 accel/kvm/kvm-all.c      | 37 +++++++++++++++++--------------------
 include/sysemu/kvm_int.h |  2 ++
 2 files changed, 19 insertions(+), 20 deletions(-)

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index 608216fd53..f81e7a644b 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -515,15 +515,12 @@ static void kvm_log_stop(MemoryListener *listener,
 }
 
 /* get kvm's dirty pages bitmap and update qemu's */
-static int kvm_get_dirty_pages_log_range(MemoryRegionSection *section,
-                                         unsigned long *bitmap)
+static void kvm_slot_sync_dirty_pages(KVMSlot *slot)
 {
-    ram_addr_t start = section->offset_within_region +
-                       memory_region_get_ram_addr(section->mr);
-    ram_addr_t pages = int128_get64(section->size) / qemu_real_host_page_size;
+    ram_addr_t start = slot->ram_start_offset;
+    ram_addr_t pages = slot->memory_size / qemu_real_host_page_size;
 
-    cpu_physical_memory_set_dirty_lebitmap(bitmap, start, pages);
-    return 0;
+    cpu_physical_memory_set_dirty_lebitmap(slot->dirty_bmap, start, pages);
 }
 
 #define ALIGN(x, y)  (((x)+(y)-1) & ~((y)-1))
@@ -582,12 +579,10 @@ static void kvm_physical_sync_dirty_bitmap(KVMMemoryListener *kml,
     KVMState *s = kvm_state;
     KVMSlot *mem;
     hwaddr start_addr, size;
-    hwaddr slot_size, slot_offset = 0;
+    hwaddr slot_size;
 
     size = kvm_align_section(section, &start_addr);
     while (size) {
-        MemoryRegionSection subsection = *section;
-
         slot_size = MIN(kvm_max_slot_size, size);
         mem = kvm_lookup_matching_slot(kml, start_addr, slot_size);
         if (!mem) {
@@ -596,12 +591,7 @@ static void kvm_physical_sync_dirty_bitmap(KVMMemoryListener *kml,
         }
 
         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, mem->dirty_bmap);
-
-        slot_offset += slot_size;
+        kvm_slot_sync_dirty_pages(mem);
         start_addr += slot_size;
         size -= slot_size;
     }
@@ -1023,7 +1013,8 @@ static void kvm_set_phys_mem(KVMMemoryListener *kml,
     int err;
     MemoryRegion *mr = section->mr;
     bool writeable = !mr->readonly && !mr->rom_device;
-    hwaddr start_addr, size, slot_size;
+    hwaddr start_addr, size, slot_size, mr_offset;
+    ram_addr_t ram_start_offset;
     void *ram;
 
     if (!memory_region_is_ram(mr)) {
@@ -1041,9 +1032,13 @@ static void kvm_set_phys_mem(KVMMemoryListener *kml,
         return;
     }
 
-    /* use aligned delta to align the ram address */
-    ram = memory_region_get_ram_ptr(mr) + section->offset_within_region +
-          (start_addr - section->offset_within_address_space);
+    /* The offset of the kvmslot within the memory region */
+    mr_offset = section->offset_within_region + start_addr -
+        section->offset_within_address_space;
+
+    /* use aligned delta to align the ram address and offset */
+    ram = memory_region_get_ram_ptr(mr) + mr_offset;
+    ram_start_offset = memory_region_get_ram_addr(mr) + mr_offset;
 
     kvm_slots_lock(kml);
 
@@ -1082,6 +1077,7 @@ static void kvm_set_phys_mem(KVMMemoryListener *kml,
         mem->as_id = kml->as_id;
         mem->memory_size = slot_size;
         mem->start_addr = start_addr;
+        mem->ram_start_offset = ram_start_offset;
         mem->ram = ram;
         mem->flags = kvm_mem_flags(mr);
         kvm_slot_init_dirty_bitmap(mem);
@@ -1092,6 +1088,7 @@ static void kvm_set_phys_mem(KVMMemoryListener *kml,
             abort();
         }
         start_addr += slot_size;
+        ram_start_offset += slot_size;
         ram += slot_size;
         size -= slot_size;
     } while (size);
diff --git a/include/sysemu/kvm_int.h b/include/sysemu/kvm_int.h
index 4434e15ec7..1a19bfef80 100644
--- a/include/sysemu/kvm_int.h
+++ b/include/sysemu/kvm_int.h
@@ -25,6 +25,8 @@ typedef struct KVMSlot
     unsigned long *dirty_bmap;
     /* Cache of the address space ID */
     int as_id;
+    /* Cache of the offset in ram address space */
+    ram_addr_t ram_start_offset;
 } 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 ` [PATCH RFC 5/9] KVM: Provide helper to get kvm dirty log Peter Xu
2020-03-25 17:52   ` Dr. David Alan Gilbert
2020-03-25 18:15     ` Peter Xu
2020-02-05 14:17 ` Peter Xu [this message]
2020-03-25 18:47   ` [PATCH RFC 6/9] KVM: Provide helper to sync dirty bitmap from slot to ramblock 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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