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[src/trunk]: src/sys/dev/pci Make ld_virtio aware of a possible device-side w...



details:   https://anonhg.NetBSD.org/src/rev/e2009f4af126
branches:  trunk
changeset: 323300:e2009f4af126
user:      jakllsch <jakllsch%NetBSD.org@localhost>
date:      Thu Jun 07 23:32:30 2018 +0000

description:
Make ld_virtio aware of a possible device-side write cache.

diffstat:

 sys/dev/pci/ld_virtio.c |  182 ++++++++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 175 insertions(+), 7 deletions(-)

diffs (256 lines):

diff -r 9b7cf844ef3a -r e2009f4af126 sys/dev/pci/ld_virtio.c
--- a/sys/dev/pci/ld_virtio.c   Thu Jun 07 18:16:55 2018 +0000
+++ b/sys/dev/pci/ld_virtio.c   Thu Jun 07 23:32:30 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: ld_virtio.c,v 1.19 2018/06/03 19:50:20 jakllsch Exp $  */
+/*     $NetBSD: ld_virtio.c,v 1.20 2018/06/07 23:32:30 jakllsch Exp $  */
 
 /*
  * Copyright (c) 2010 Minoura Makoto.
@@ -26,7 +26,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: ld_virtio.c,v 1.19 2018/06/03 19:50:20 jakllsch Exp $");
+__KERNEL_RCSID(0, "$NetBSD: ld_virtio.c,v 1.20 2018/06/07 23:32:30 jakllsch Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -120,6 +120,7 @@
        struct virtio_blk_req_hdr       vr_hdr;
        uint8_t                         vr_status;
        struct buf                      *vr_bp;
+#define DUMMY_VR_BP                            ((void *)1)
        bus_dmamap_t                    vr_cmdsts;
        bus_dmamap_t                    vr_payload;
 };
@@ -135,6 +136,13 @@
        bus_dma_segment_t       sc_reqs_seg;
 
        int                     sc_readonly;
+
+       enum {
+               SYNC_FREE, SYNC_BUSY, SYNC_DONE
+       }                       sc_sync_use;
+       kcondvar_t              sc_sync_wait;
+       kmutex_t                sc_sync_wait_lock;
+       uint8_t                 sc_sync_status;
 };
 
 static int     ld_virtio_match(device_t, cfdata_t, void *);
@@ -158,6 +166,7 @@
 static int ld_virtio_vq_done(struct virtqueue *);
 static int ld_virtio_dump(struct ld_softc *, void *, int, int);
 static int ld_virtio_start(struct ld_softc *, struct buf *);
+static int ld_virtio_ioctl(struct ld_softc *, u_long, void *, int32_t, bool);
 
 static int
 ld_virtio_alloc_reqs(struct ld_virtio_softc *sc, int qsize)
@@ -270,7 +279,8 @@
        virtio_child_attach_start(vsc, self, IPL_BIO, &sc->sc_vq,
            NULL, virtio_vq_intr, 0,
            (VIRTIO_BLK_F_SIZE_MAX | VIRTIO_BLK_F_SEG_MAX |
-            VIRTIO_BLK_F_GEOMETRY | VIRTIO_BLK_F_RO | VIRTIO_BLK_F_BLK_SIZE),
+            VIRTIO_BLK_F_GEOMETRY | VIRTIO_BLK_F_RO | VIRTIO_BLK_F_BLK_SIZE |
+            VIRTIO_BLK_F_FLUSH | VIRTIO_BLK_F_CONFIG_WCE),
            VIRTIO_BLK_FLAG_BITS);
 
        features = virtio_features(vsc);
@@ -344,13 +354,18 @@
                ld->sc_nsectors   = virtio_read_device_config_1(vsc,
                                        VIRTIO_BLK_CONFIG_GEOMETRY_S);
        }
-       ld->sc_maxqueuecnt = qsize;
+       ld->sc_maxqueuecnt = qsize - 1; /* reserve slot for dumps, flushes */
 
        if (ld_virtio_alloc_reqs(sc, qsize) < 0)
                goto err;
 
+       cv_init(&sc->sc_sync_wait, "vblksync");
+       mutex_init(&sc->sc_sync_wait_lock, MUTEX_DEFAULT, IPL_BIO);
+       sc->sc_sync_use = SYNC_FREE;
+
        ld->sc_dump = ld_virtio_dump;
        ld->sc_start = ld_virtio_start;
+       ld->sc_ioctl = ld_virtio_ioctl;
 
        ld->sc_flags = LDF_ENABLED | LDF_MPSAFE;
        ldattach(ld, BUFQ_DISK_DEFAULT_STRAT);
@@ -443,14 +458,23 @@
        bus_dmamap_sync(virtio_dmat(vsc), vr->vr_cmdsts,
                        0, sizeof(struct virtio_blk_req_hdr),
                        BUS_DMASYNC_POSTWRITE);
+       bus_dmamap_sync(virtio_dmat(vsc), vr->vr_cmdsts,
+                       sizeof(struct virtio_blk_req_hdr), sizeof(uint8_t),
+                       BUS_DMASYNC_POSTREAD);
+       if (bp == DUMMY_VR_BP) {
+               mutex_enter(&sc->sc_sync_wait_lock);
+               sc->sc_sync_status = vr->vr_status;
+               sc->sc_sync_use = SYNC_DONE;
+               cv_signal(&sc->sc_sync_wait);
+               mutex_exit(&sc->sc_sync_wait_lock);
+               virtio_dequeue_commit(vsc, vq, slot);
+               return;
+       }
        bus_dmamap_sync(virtio_dmat(vsc), vr->vr_payload,
                        0, bp->b_bcount,
                        (bp->b_flags & B_READ)?BUS_DMASYNC_POSTREAD
                                              :BUS_DMASYNC_POSTWRITE);
        bus_dmamap_unload(virtio_dmat(vsc), vr->vr_payload);
-       bus_dmamap_sync(virtio_dmat(vsc), vr->vr_cmdsts,
-                       sizeof(struct virtio_blk_req_hdr), sizeof(uint8_t),
-                       BUS_DMASYNC_POSTREAD);
 
        if (vr->vr_status != VIRTIO_BLK_S_OK) {
                bp->b_error = EIO;
@@ -609,6 +633,150 @@
        return 0;
 }
 
+static int
+ld_virtio_flush(struct ld_softc *ld, bool poll)
+{
+       struct ld_virtio_softc * const sc = device_private(ld->sc_dv);
+       struct virtio_softc * const vsc = sc->sc_virtio;
+       const uint32_t features = virtio_features(vsc);
+       struct virtqueue *vq = &sc->sc_vq;
+       struct virtio_blk_req *vr;
+       int slot;
+       int r;
+
+       if ((features & VIRTIO_BLK_F_FLUSH) == 0)
+               return 0;
+
+       mutex_enter(&sc->sc_sync_wait_lock);
+       while (sc->sc_sync_use != SYNC_FREE) {
+               if (poll) {
+                       mutex_exit(&sc->sc_sync_wait_lock);
+                       ld_virtio_vq_done(vq);
+                       mutex_enter(&sc->sc_sync_wait_lock);
+                       continue;
+               }
+               cv_wait(&sc->sc_sync_wait, &sc->sc_sync_wait_lock);
+       }
+       sc->sc_sync_use = SYNC_BUSY;
+       mutex_exit(&sc->sc_sync_wait_lock);
+
+       r = virtio_enqueue_prep(vsc, vq, &slot);
+       if (r != 0) {
+               return r;
+       }
+
+       vr = &sc->sc_reqs[slot];
+       KASSERT(vr->vr_bp == NULL);
+
+       r = virtio_enqueue_reserve(vsc, vq, slot, VIRTIO_BLK_MIN_SEGMENTS);
+       if (r != 0) {
+               return r;
+       }
+
+       vr->vr_bp = DUMMY_VR_BP;
+       vr->vr_hdr.type = VIRTIO_BLK_T_FLUSH;
+       vr->vr_hdr.ioprio = 0;
+       vr->vr_hdr.sector = 0;
+
+       bus_dmamap_sync(virtio_dmat(vsc), vr->vr_cmdsts,
+                       0, sizeof(struct virtio_blk_req_hdr),
+                       BUS_DMASYNC_PREWRITE);
+       bus_dmamap_sync(virtio_dmat(vsc), vr->vr_cmdsts,
+                       offsetof(struct virtio_blk_req, vr_status),
+                       sizeof(uint8_t),
+                       BUS_DMASYNC_PREREAD);
+
+       virtio_enqueue_p(vsc, vq, slot, vr->vr_cmdsts,
+                        0, sizeof(struct virtio_blk_req_hdr),
+                        true);
+       virtio_enqueue_p(vsc, vq, slot, vr->vr_cmdsts,
+                        offsetof(struct virtio_blk_req, vr_status),
+                        sizeof(uint8_t),
+                        false);
+       virtio_enqueue_commit(vsc, vq, slot, true);
+
+       mutex_enter(&sc->sc_sync_wait_lock);
+       while (sc->sc_sync_use != SYNC_DONE) {
+               if (poll) {
+                       mutex_exit(&sc->sc_sync_wait_lock);
+                       ld_virtio_vq_done(vq);
+                       mutex_enter(&sc->sc_sync_wait_lock);
+                       continue;
+               }
+               cv_wait(&sc->sc_sync_wait, &sc->sc_sync_wait_lock);
+       }
+
+       if (sc->sc_sync_status == VIRTIO_BLK_S_OK)
+               r = 0;
+       else
+               r = EIO;
+
+       sc->sc_sync_use = SYNC_FREE;
+       cv_signal(&sc->sc_sync_wait);
+       mutex_exit(&sc->sc_sync_wait_lock);
+
+       return r;
+}
+
+static int
+ld_virtio_getcache(struct ld_softc *ld, int *bitsp)
+{
+       struct ld_virtio_softc * const sc = device_private(ld->sc_dv);
+       struct virtio_softc * const vsc = sc->sc_virtio;
+       const uint32_t features = virtio_features(vsc);
+
+       *bitsp = DKCACHE_READ;
+       if ((features & VIRTIO_BLK_F_CONFIG_WCE) != 0)
+               *bitsp |= DKCACHE_WCHANGE;
+       if (virtio_read_device_config_1(vsc,
+           VIRTIO_BLK_CONFIG_WRITEBACK) != 0x00)
+               *bitsp |= DKCACHE_WRITE;
+
+       return 0;
+}
+
+static int
+ld_virtio_setcache(struct ld_softc *ld, int bits)
+{
+       struct ld_virtio_softc * const sc = device_private(ld->sc_dv);
+       struct virtio_softc * const vsc = sc->sc_virtio;
+       const uint8_t wce = (bits & DKCACHE_WRITE) ? 0x01 : 0x00;
+
+       virtio_write_device_config_1(vsc,
+           VIRTIO_BLK_CONFIG_WRITEBACK, wce);
+       if (virtio_read_device_config_1(vsc,
+           VIRTIO_BLK_CONFIG_WRITEBACK) != wce)
+               return EIO;
+
+       return 0;
+}
+
+static int
+ld_virtio_ioctl(struct ld_softc *ld, u_long cmd, void *addr, int32_t flag, bool poll)
+{
+       int error;
+
+       switch (cmd) {
+       case DIOCCACHESYNC:
+               error = ld_virtio_flush(ld, poll);
+               break;
+
+       case DIOCGCACHE:
+               error = ld_virtio_getcache(ld, (int *)addr);
+               break;
+
+       case DIOCSCACHE:
+               error = ld_virtio_setcache(ld, *(int *)addr);
+               break;
+
+       default:
+               error = EPASSTHROUGH;
+               break;
+       }
+
+       return error;
+}
+
 MODULE(MODULE_CLASS_DRIVER, ld_virtio, "ld,virtio");
 
 #ifdef _MODULE



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