[PATCH 2/5] virtio: Don't expose legacy block features when VIRTIO_BLK_NO_LEGACY defined.

From: Rusty Russell
Date: Fri Feb 06 2015 - 00:13:01 EST


This allows modern implementations to ensure they don't use legacy
feature bits or SCSI commands (which are not used in v1.0 non-legacy).

Signed-off-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
---
include/uapi/linux/virtio_blk.h | 17 +++++++++++++----
1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/include/uapi/linux/virtio_blk.h b/include/uapi/linux/virtio_blk.h
index 247c8ba8544a..3c53eec4ae22 100644
--- a/include/uapi/linux/virtio_blk.h
+++ b/include/uapi/linux/virtio_blk.h
@@ -31,22 +31,25 @@
#include <linux/virtio_types.h>

/* Feature bits */
-#define VIRTIO_BLK_F_BARRIER 0 /* Does host support barriers? */
#define VIRTIO_BLK_F_SIZE_MAX 1 /* Indicates maximum segment size */
#define VIRTIO_BLK_F_SEG_MAX 2 /* Indicates maximum # of segments */
#define VIRTIO_BLK_F_GEOMETRY 4 /* Legacy geometry available */
#define VIRTIO_BLK_F_RO 5 /* Disk is read-only */
#define VIRTIO_BLK_F_BLK_SIZE 6 /* Block size of disk is available*/
-#define VIRTIO_BLK_F_SCSI 7 /* Supports scsi command passthru */
-#define VIRTIO_BLK_F_WCE 9 /* Writeback mode enabled after reset */
#define VIRTIO_BLK_F_TOPOLOGY 10 /* Topology information is available */
-#define VIRTIO_BLK_F_CONFIG_WCE 11 /* Writeback mode available in config */
#define VIRTIO_BLK_F_MQ 12 /* support more than one vq */

+/* Legacy feature bits */
+#ifndef VIRTIO_BLK_NO_LEGACY
+#define VIRTIO_BLK_F_BARRIER 0 /* Does host support barriers? */
+#define VIRTIO_BLK_F_SCSI 7 /* Supports scsi command passthru */
+#define VIRTIO_BLK_F_WCE 9 /* Writeback mode enabled after reset */
+#define VIRTIO_BLK_F_CONFIG_WCE 11 /* Writeback mode available in config */
#ifndef __KERNEL__
/* Old (deprecated) name for VIRTIO_BLK_F_WCE. */
#define VIRTIO_BLK_F_FLUSH VIRTIO_BLK_F_WCE
#endif
+#endif /* !VIRTIO_BLK_NO_LEGACY */

#define VIRTIO_BLK_ID_BYTES 20 /* ID string length */

@@ -100,8 +103,10 @@ struct virtio_blk_config {
#define VIRTIO_BLK_T_IN 0
#define VIRTIO_BLK_T_OUT 1

+#ifndef VIRTIO_BLK_NO_LEGACY
/* This bit says it's a scsi command, not an actual read or write. */
#define VIRTIO_BLK_T_SCSI_CMD 2
+#endif /* VIRTIO_BLK_NO_LEGACY */

/* Cache flush command */
#define VIRTIO_BLK_T_FLUSH 4
@@ -109,8 +114,10 @@ struct virtio_blk_config {
/* Get device ID command */
#define VIRTIO_BLK_T_GET_ID 8

+#ifndef VIRTIO_BLK_NO_LEGACY
/* Barrier before this op. */
#define VIRTIO_BLK_T_BARRIER 0x80000000
+#endif /* !VIRTIO_BLK_NO_LEGACY */

/* This is the first element of the read scatter-gather list. */
struct virtio_blk_outhdr {
@@ -122,12 +129,14 @@ struct virtio_blk_outhdr {
__virtio64 sector;
};

+#ifndef VIRTIO_BLK_NO_LEGACY
struct virtio_scsi_inhdr {
__virtio32 errors;
__virtio32 data_len;
__virtio32 sense_len;
__virtio32 residual;
};
+#endif /* !VIRTIO_BLK_NO_LEGACY */

/* And this is the final byte of the write scatter-gather list. */
#define VIRTIO_BLK_S_OK 0
--
2.1.0

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