virtio: fixes and features 4.3

virtio-mmio can now be auto-loaded through acpi.
 virtio blk supports extended partitions.
 total memory is better reported when using virtio balloon with auto-deflate.
 cache control is re-enabled when using virtio-blk in modern mode.
 
 Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost

Pull virtio updates from Michael Tsirkin:
 "Virtio fixes and features for 4.3:

   - virtio-mmio can now be auto-loaded through acpi.
   - virtio blk supports extended partitions.
   - total memory is better reported when using virtio balloon with
     auto-deflate.
   - cache control is re-enabled when using virtio-blk in modern mode"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  virtio_balloon: do not change memory amount visible via /proc/meminfo
  virtio_ballon: change stub of release_pages_by_pfn
  virtio-blk: Allow extended partitions
  virtio_mmio: add ACPI probing
  virtio-blk: use VIRTIO_BLK_F_WCE and VIRTIO_BLK_F_CONFIG_WCE in virtio1

drivers/block/virtio_blk.c

@@ -478,8 +478,7 @@ static int virtblk_get_cache_mode(struct virtio_device *vdev)
 				   struct virtio_blk_config, wce,
 				   &writeback);
 	if (err)
-		writeback = virtio_has_feature(vdev, VIRTIO_BLK_F_WCE) ||
-		            virtio_has_feature(vdev, VIRTIO_F_VERSION_1);
+		writeback = virtio_has_feature(vdev, VIRTIO_BLK_F_WCE);
 
 	return writeback;
 }
@@ -657,6 +656,7 @@ static int virtblk_probe(struct virtio_device *vdev)
 	vblk->disk->private_data = vblk;
 	vblk->disk->fops = &virtblk_fops;
 	vblk->disk->driverfs_dev = &vdev->dev;
+	vblk->disk->flags |= GENHD_FL_EXT_DEVT;
 	vblk->index = index;
 
 	/* configure queue flush support */
@@ -840,7 +840,7 @@ static unsigned int features_legacy[] = {
 static unsigned int features[] = {
 	VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY,
 	VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE,
-	VIRTIO_BLK_F_TOPOLOGY,
+	VIRTIO_BLK_F_WCE, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE,
 	VIRTIO_BLK_F_MQ,
 };
 

drivers/virtio/virtio_balloon.c

@@ -157,6 +157,8 @@ static void fill_balloon(struct virtio_balloon *vb, size_t num)
 		}
 		set_page_pfns(vb->pfns + vb->num_pfns, page);
 		vb->num_pages += VIRTIO_BALLOON_PAGES_PER_PAGE;
+		if (!virtio_has_feature(vb->vdev,
+					VIRTIO_BALLOON_F_DEFLATE_ON_OOM))
 			adjust_managed_page_count(page, -1);
 	}
 
@@ -166,13 +168,15 @@ static void fill_balloon(struct virtio_balloon *vb, size_t num)
 	mutex_unlock(&vb->balloon_lock);
 }
 
-static void release_pages_by_pfn(const u32 pfns[], unsigned int num)
+static void release_pages_balloon(struct virtio_balloon *vb)
 {
 	unsigned int i;
 
 	/* Find pfns pointing at start of each page, get pages and free them. */
-	for (i = 0; i < num; i += VIRTIO_BALLOON_PAGES_PER_PAGE) {
-		struct page *page = balloon_pfn_to_page(pfns[i]);
+	for (i = 0; i < vb->num_pfns; i += VIRTIO_BALLOON_PAGES_PER_PAGE) {
+		struct page *page = balloon_pfn_to_page(vb->pfns[i]);
+		if (!virtio_has_feature(vb->vdev,
+					VIRTIO_BALLOON_F_DEFLATE_ON_OOM))
 			adjust_managed_page_count(page, 1);
 		put_page(page); /* balloon reference */
 	}
@@ -206,7 +210,7 @@ static unsigned leak_balloon(struct virtio_balloon *vb, size_t num)
 	if (vb->num_pfns != 0)
 		tell_host(vb, vb->deflate_vq);
 	mutex_unlock(&vb->balloon_lock);
-	release_pages_by_pfn(vb->pfns, vb->num_pfns);
+	release_pages_balloon(vb);
 	return num_freed_pages;
 }
 

drivers/virtio/virtio_mmio.c

@@ -58,6 +58,7 @@
 
 #define pr_fmt(fmt) "virtio-mmio: " fmt
 
+#include <linux/acpi.h>
 #include <linux/highmem.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
@@ -732,12 +733,21 @@ static struct of_device_id virtio_mmio_match[] = {
 };
 MODULE_DEVICE_TABLE(of, virtio_mmio_match);
 
+#ifdef CONFIG_ACPI
+static const struct acpi_device_id virtio_mmio_acpi_match[] = {
+	{ "LNRO0005", },
+	{ }
+};
+MODULE_DEVICE_TABLE(acpi, virtio_mmio_acpi_match);
+#endif
+
 static struct platform_driver virtio_mmio_driver = {
 	.probe		= virtio_mmio_probe,
 	.remove		= virtio_mmio_remove,
 	.driver		= {
 		.name	= "virtio-mmio",
 		.of_match_table	= virtio_mmio_match,
+		.acpi_match_table = ACPI_PTR(virtio_mmio_acpi_match),
 	},
 };