block/qdev: Allow configuring WCE with qdev properties

As cache.writeback is a BlockBackend property and as such more related
to the guest device than the BlockDriverState, we already removed it
from the blockdev-add interface. This patch adds the new way to set it,
as a qdev property of the corresponding guest device.

For example: -drive if=none,file=test.img,node-name=img
             -device ide-hd,drive=img,write-cache=off
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NMax Reitz <mreitz@redhat.com>

hw/block/block.c

@@ -51,6 +51,22 @@ void blkconf_blocksizes(BlockConf *conf)
     }
 }
 
+void blkconf_apply_backend_options(BlockConf *conf)
+{
+    BlockBackend *blk = conf->blk;
+    bool wce;
+
+    switch (conf->wce) {
+    case ON_OFF_AUTO_ON:    wce = true; break;
+    case ON_OFF_AUTO_OFF:   wce = false; break;
+    case ON_OFF_AUTO_AUTO:  wce = blk_enable_write_cache(blk); break;
+    default:
+        abort();
+    }
+
+    blk_set_enable_write_cache(blk, wce);
+}
+
 void blkconf_geometry(BlockConf *conf, int *ptrans,
                       unsigned cyls_max, unsigned heads_max, unsigned secs_max,
                       Error **errp)

hw/block/nvme.c

@@ -803,6 +803,7 @@ static int nvme_init(PCIDevice *pci_dev)
         return -1;
     }
     blkconf_blocksizes(&n->conf);
+    blkconf_apply_backend_options(&n->conf);
 
     pci_conf = pci_dev->config;
     pci_conf[PCI_INTERRUPT_PIN] = 1;

hw/block/virtio-blk.c

@@ -897,6 +897,7 @@ static void virtio_blk_device_realize(DeviceState *dev, Error **errp)
     }
 
     blkconf_serial(&conf->conf, &conf->serial);
+    blkconf_apply_backend_options(&conf->conf);
     s->original_wce = blk_enable_write_cache(conf->conf.blk);
     blkconf_geometry(&conf->conf, NULL, 65535, 255, 255, &err);
     if (err) {

hw/ide/qdev.c

@@ -180,6 +180,7 @@ static int ide_dev_initfn(IDEDevice *dev, IDEDriveKind kind)
             return -1;
         }
     }
+    blkconf_apply_backend_options(&dev->conf);
 
     if (ide_init_drive(s, dev->conf.blk, kind,
                        dev->version, dev->serial, dev->model, dev->wwn,

hw/scsi/scsi-disk.c

@@ -2309,6 +2309,7 @@ static void scsi_realize(SCSIDevice *dev, Error **errp)
             return;
         }
     }
+    blkconf_apply_backend_options(&dev->conf);
 
     if (s->qdev.conf.discard_granularity == -1) {
         s->qdev.conf.discard_granularity =

hw/usb/dev-storage.c

@@ -603,6 +603,7 @@ static void usb_msd_realize_storage(USBDevice *dev, Error **errp)
 
     blkconf_serial(&s->conf, &dev->serial);
     blkconf_blocksizes(&s->conf);
+    blkconf_apply_backend_options(&s->conf);
 
     /*
      * Hack alert: this pretends to be a block device, but it's really

include/hw/block/block.h

@@ -25,6 +25,7 @@ typedef struct BlockConf {
     uint32_t discard_granularity;
     /* geometry, not all devices use this */
     uint32_t cyls, heads, secs;
+    OnOffAuto wce;
 } BlockConf;
 
 static inline unsigned int get_physical_block_exp(BlockConf *conf)
@@ -49,7 +50,8 @@ static inline unsigned int get_physical_block_exp(BlockConf *conf)
     DEFINE_PROP_UINT16("min_io_size", _state, _conf.min_io_size, 0),  \
     DEFINE_PROP_UINT32("opt_io_size", _state, _conf.opt_io_size, 0),    \
     DEFINE_PROP_UINT32("discard_granularity", _state, \
-                       _conf.discard_granularity, -1)
+                       _conf.discard_granularity, -1), \
+    DEFINE_PROP_ON_OFF_AUTO("write-cache", _state, _conf.wce, ON_OFF_AUTO_AUTO)
 
 #define DEFINE_BLOCK_CHS_PROPERTIES(_state, _conf)      \
     DEFINE_PROP_UINT32("cyls", _state, _conf.cyls, 0),  \
@@ -63,6 +65,7 @@ void blkconf_geometry(BlockConf *conf, int *trans,
                       unsigned cyls_max, unsigned heads_max, unsigned secs_max,
                       Error **errp);
 void blkconf_blocksizes(BlockConf *conf);
+void blkconf_apply_backend_options(BlockConf *conf);
 
 /* Hard disk geometry */