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[2/5] memory: Flush coalesced MMIO on selected region access

Message ID 714b875f084134ae31596687651e051d4aa3c585.1340607659.git.jan.kiszka@siemens.com
State New
Headers show

Commit Message

Jan Kiszka June 25, 2012, 7 a.m. UTC 
Instead of flushing pending coalesced MMIO requests on every vmexit,
this provides a mechanism to selectively flush when memory regions
related to the coalesced one are accessed. This first of all includes
the coalesced region itself but can also applied to other regions, e.g.
of the same device, by calling memory_region_set_flush_coalesced.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---
 memory.c |   13 +++++++++++++
 memory.h |   13 +++++++++++++
 2 files changed, 26 insertions(+), 0 deletions(-)

Comments

Avi Kivity June 25, 2012, 8:36 a.m. UTC | #1 
On 06/25/2012 10:00 AM, Jan Kiszka wrote:
> Instead of flushing pending coalesced MMIO requests on every vmexit,
> this provides a mechanism to selectively flush when memory regions
> related to the coalesced one are accessed. This first of all includes
> the coalesced region itself but can also applied to other regions, e.g.

> @@ -521,6 +522,18 @@ void memory_region_add_coalescing(MemoryRegion *mr,
>  void memory_region_clear_coalescing(MemoryRegion *mr);
>  
>  /**
> + * memory_region_set_flush_coalesced: Enforce memory coalescing flush before
> + *                                    accesses.
> + *
> + * Ensure that pending coalesced MMIO request are flushed before the memory
> + * region is accessed. This property is automatically enabled for all regions
> + * passed to memory_region_set_coalescing() and memory_region_add_coalescing().
> + *
> + * @mr: the memory region to be updated.
> + */
> +void memory_region_set_flush_coalesced(MemoryRegion *mr);
> +
> +/**


Please provide a way to clear the flag (and autoclear on clear_coalesced).
diff mbox

Patch

diff --git a/memory.c b/memory.c
index aab4a31..ba55b3e 100644
--- a/memory.c
+++ b/memory.c
@@ -311,6 +311,9 @@  static void memory_region_read_accessor(void *opaque,
     MemoryRegion *mr = opaque;
     uint64_t tmp;
 
+    if (mr->flush_coalesced_mmio) {
+        qemu_flush_coalesced_mmio_buffer();
+    }
     tmp = mr->ops->read(mr->opaque, addr, size);
     *value |= (tmp & mask) << shift;
 }
@@ -325,6 +328,9 @@  static void memory_region_write_accessor(void *opaque,
     MemoryRegion *mr = opaque;
     uint64_t tmp;
 
+    if (mr->flush_coalesced_mmio) {
+        qemu_flush_coalesced_mmio_buffer();
+    }
     tmp = (*value >> shift) & mask;
     mr->ops->write(mr->opaque, addr, tmp, size);
 }
@@ -826,6 +832,7 @@  void memory_region_init(MemoryRegion *mr,
     mr->dirty_log_mask = 0;
     mr->ioeventfd_nb = 0;
     mr->ioeventfds = NULL;
+    mr->flush_coalesced_mmio = false;
 }
 
 static bool memory_region_access_valid(MemoryRegion *mr,
@@ -1176,6 +1183,7 @@  void memory_region_add_coalescing(MemoryRegion *mr,
     cmr->addr = addrrange_make(int128_make64(offset), int128_make64(size));
     QTAILQ_INSERT_TAIL(&mr->coalesced, cmr, link);
     memory_region_update_coalesced_range(mr);
+    memory_region_set_flush_coalesced(mr);
 }
 
 void memory_region_clear_coalescing(MemoryRegion *mr)
@@ -1190,6 +1198,11 @@  void memory_region_clear_coalescing(MemoryRegion *mr)
     memory_region_update_coalesced_range(mr);
 }
 
+void memory_region_set_flush_coalesced(MemoryRegion *mr)
+{
+    mr->flush_coalesced_mmio = true;
+}
+
 void memory_region_add_eventfd(MemoryRegion *mr,
                                target_phys_addr_t addr,
                                unsigned size,
diff --git a/memory.h b/memory.h
index 740c48e..dca7a86 100644
--- a/memory.h
+++ b/memory.h
@@ -133,6 +133,7 @@  struct MemoryRegion {
     bool enabled;
     bool rom_device;
     bool warning_printed; /* For reservations */
+    bool flush_coalesced_mmio;
     MemoryRegion *alias;
     target_phys_addr_t alias_offset;
     unsigned priority;
@@ -521,6 +522,18 @@  void memory_region_add_coalescing(MemoryRegion *mr,
 void memory_region_clear_coalescing(MemoryRegion *mr);
 
 /**
+ * memory_region_set_flush_coalesced: Enforce memory coalescing flush before
+ *                                    accesses.
+ *
+ * Ensure that pending coalesced MMIO request are flushed before the memory
+ * region is accessed. This property is automatically enabled for all regions
+ * passed to memory_region_set_coalescing() and memory_region_add_coalescing().
+ *
+ * @mr: the memory region to be updated.
+ */
+void memory_region_set_flush_coalesced(MemoryRegion *mr);
+
+/**
  * memory_region_add_eventfd: Request an eventfd to be triggered when a word
  *                            is written to a location.
  *