virtio-mem: Simplify bitmap handling and virtio_mem_set_block_state()
Let's separate plug and unplug handling to prepare for future changes
and make the code a bit easier to read -- working on block states
(plugged/unplugged) instead of on a bitmap.
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Gavin Shan <gshan@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20230523183036.517957-1-david@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
diff --git a/hw/virtio/virtio-mem.c b/hw/virtio/virtio-mem.c
index 12ea58d..ec0ae32 100644
--- a/hw/virtio/virtio-mem.c
+++ b/hw/virtio/virtio-mem.c
@@ -398,33 +398,46 @@
}
}
-static bool virtio_mem_test_bitmap(const VirtIOMEM *vmem, uint64_t start_gpa,
- uint64_t size, bool plugged)
+static bool virtio_mem_is_range_plugged(const VirtIOMEM *vmem,
+ uint64_t start_gpa, uint64_t size)
{
const unsigned long first_bit = (start_gpa - vmem->addr) / vmem->block_size;
const unsigned long last_bit = first_bit + (size / vmem->block_size) - 1;
unsigned long found_bit;
/* We fake a shorter bitmap to avoid searching too far. */
- if (plugged) {
- found_bit = find_next_zero_bit(vmem->bitmap, last_bit + 1, first_bit);
- } else {
- found_bit = find_next_bit(vmem->bitmap, last_bit + 1, first_bit);
- }
+ found_bit = find_next_zero_bit(vmem->bitmap, last_bit + 1, first_bit);
return found_bit > last_bit;
}
-static void virtio_mem_set_bitmap(VirtIOMEM *vmem, uint64_t start_gpa,
- uint64_t size, bool plugged)
+static bool virtio_mem_is_range_unplugged(const VirtIOMEM *vmem,
+ uint64_t start_gpa, uint64_t size)
+{
+ const unsigned long first_bit = (start_gpa - vmem->addr) / vmem->block_size;
+ const unsigned long last_bit = first_bit + (size / vmem->block_size) - 1;
+ unsigned long found_bit;
+
+ /* We fake a shorter bitmap to avoid searching too far. */
+ found_bit = find_next_bit(vmem->bitmap, last_bit + 1, first_bit);
+ return found_bit > last_bit;
+}
+
+static void virtio_mem_set_range_plugged(VirtIOMEM *vmem, uint64_t start_gpa,
+ uint64_t size)
{
const unsigned long bit = (start_gpa - vmem->addr) / vmem->block_size;
const unsigned long nbits = size / vmem->block_size;
- if (plugged) {
- bitmap_set(vmem->bitmap, bit, nbits);
- } else {
- bitmap_clear(vmem->bitmap, bit, nbits);
- }
+ bitmap_set(vmem->bitmap, bit, nbits);
+}
+
+static void virtio_mem_set_range_unplugged(VirtIOMEM *vmem, uint64_t start_gpa,
+ uint64_t size)
+{
+ const unsigned long bit = (start_gpa - vmem->addr) / vmem->block_size;
+ const unsigned long nbits = size / vmem->block_size;
+
+ bitmap_clear(vmem->bitmap, bit, nbits);
}
static void virtio_mem_send_response(VirtIOMEM *vmem, VirtQueueElement *elem,
@@ -474,6 +487,7 @@
{
const uint64_t offset = start_gpa - vmem->addr;
RAMBlock *rb = vmem->memdev->mr.ram_block;
+ int ret = 0;
if (virtio_mem_is_busy()) {
return -EBUSY;
@@ -484,42 +498,43 @@
return -EBUSY;
}
virtio_mem_notify_unplug(vmem, offset, size);
- } else {
- int ret = 0;
+ virtio_mem_set_range_unplugged(vmem, start_gpa, size);
+ return 0;
+ }
- if (vmem->prealloc) {
- void *area = memory_region_get_ram_ptr(&vmem->memdev->mr) + offset;
- int fd = memory_region_get_fd(&vmem->memdev->mr);
- Error *local_err = NULL;
+ if (vmem->prealloc) {
+ void *area = memory_region_get_ram_ptr(&vmem->memdev->mr) + offset;
+ int fd = memory_region_get_fd(&vmem->memdev->mr);
+ Error *local_err = NULL;
- qemu_prealloc_mem(fd, area, size, 1, NULL, &local_err);
- if (local_err) {
- static bool warned;
+ qemu_prealloc_mem(fd, area, size, 1, NULL, &local_err);
+ if (local_err) {
+ static bool warned;
- /*
- * Warn only once, we don't want to fill the log with these
- * warnings.
- */
- if (!warned) {
- warn_report_err(local_err);
- warned = true;
- } else {
- error_free(local_err);
- }
- ret = -EBUSY;
+ /*
+ * Warn only once, we don't want to fill the log with these
+ * warnings.
+ */
+ if (!warned) {
+ warn_report_err(local_err);
+ warned = true;
+ } else {
+ error_free(local_err);
}
- }
- if (!ret) {
- ret = virtio_mem_notify_plug(vmem, offset, size);
- }
-
- if (ret) {
- /* Could be preallocation or a notifier populated memory. */
- ram_block_discard_range(vmem->memdev->mr.ram_block, offset, size);
- return -EBUSY;
+ ret = -EBUSY;
}
}
- virtio_mem_set_bitmap(vmem, start_gpa, size, plug);
+
+ if (!ret) {
+ ret = virtio_mem_notify_plug(vmem, offset, size);
+ }
+ if (ret) {
+ /* Could be preallocation or a notifier populated memory. */
+ ram_block_discard_range(vmem->memdev->mr.ram_block, offset, size);
+ return -EBUSY;
+ }
+
+ virtio_mem_set_range_plugged(vmem, start_gpa, size);
return 0;
}
@@ -538,7 +553,8 @@
}
/* test if really all blocks are in the opposite state */
- if (!virtio_mem_test_bitmap(vmem, gpa, size, !plug)) {
+ if ((plug && !virtio_mem_is_range_unplugged(vmem, gpa, size)) ||
+ (!plug && !virtio_mem_is_range_plugged(vmem, gpa, size))) {
return VIRTIO_MEM_RESP_ERROR;
}
@@ -651,9 +667,9 @@
return;
}
- if (virtio_mem_test_bitmap(vmem, gpa, size, true)) {
+ if (virtio_mem_is_range_plugged(vmem, gpa, size)) {
resp.u.state.state = cpu_to_le16(VIRTIO_MEM_STATE_PLUGGED);
- } else if (virtio_mem_test_bitmap(vmem, gpa, size, false)) {
+ } else if (virtio_mem_is_range_unplugged(vmem, gpa, size)) {
resp.u.state.state = cpu_to_le16(VIRTIO_MEM_STATE_UNPLUGGED);
} else {
resp.u.state.state = cpu_to_le16(VIRTIO_MEM_STATE_MIXED);
@@ -1372,7 +1388,7 @@
return false;
}
- return virtio_mem_test_bitmap(vmem, start_gpa, end_gpa - start_gpa, true);
+ return virtio_mem_is_range_plugged(vmem, start_gpa, end_gpa - start_gpa);
}
struct VirtIOMEMReplayData {
