Don't hang in nvme_poll() if the nvme controller has disconnected from the pcie

bus. i.e. if register reads start returning 0xffffffff.

Feedback/suggestions deraadt@, testing by jca@, ok jmatthew@.

diff --git a/sys/dev/ic/nvme.c b/sys/dev/ic/nvme.c
index 1909fa5..a847eab 100644 (file)
--- a/sys/dev/ic/nvme.c
+++ b/sys/dev/ic/nvme.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: nvme.c,v 1.107 2023/12/20 13:37:25 krw Exp $ */
+/*     $OpenBSD: nvme.c,v 1.108 2024/04/15 13:58:48 krw Exp $ */
 
 /*
  * Copyright (c) 2014 David Gwynne <dlg@openbsd.org>
@@ -197,28 +197,46 @@ nvme_dumpregs(struct nvme_softc *sc)
 int
 nvme_ready(struct nvme_softc *sc, u_int32_t rdy)
 {
-       u_int i = 0;
+       u_int32_t csts;
+       u_int i;
 
-       while ((nvme_read4(sc, NVME_CSTS) & NVME_CSTS_RDY) != rdy) {
-               if (i++ > sc->sc_rdy_to)
-                       return (1);
+       for (i = 0; i <= sc->sc_rdy_to; i++) {
+               csts = nvme_read4(sc, NVME_CSTS);
+               /* enable fails if fatal error, disable succeeds. */
+               if (csts == 0xffffffff || ISSET(csts, NVME_CSTS_CFS))
+                       return (rdy == NVME_CSTS_RDY);
+
+               if ((csts & NVME_CSTS_RDY) == rdy)
+                       return (0);
 
                delay(1000);
                nvme_barrier(sc, NVME_CSTS, 4, BUS_SPACE_BARRIER_READ);
        }
 
-       return (0);
+       return (1);
 }
 
 int
 nvme_enable(struct nvme_softc *sc)
 {
-       u_int32_t cc;
+       u_int32_t cc, csts;
 
        cc = nvme_read4(sc, NVME_CC);
-       if (ISSET(cc, NVME_CC_EN))
+       if (cc != 0xffffffff && ISSET(cc, NVME_CC_EN))
                return (nvme_ready(sc, NVME_CSTS_RDY));
 
+       csts = nvme_read4(sc, NVME_CSTS);
+       if (csts != 0xffffffff && ISSET(csts, NVME_CSTS_RDY)) {
+               /*
+                * Ensure CSTS.RDY is 0.
+                *
+                * Transitioning CC.EN from 0 to 1 when CSTS.RDY is 1
+                * "has undefined results" says NVMe.
+                */
+               if (nvme_ready(sc, 0))
+                       return (1);
+       }
+
        if (sc->sc_ops->op_enable != NULL)
                sc->sc_ops->op_enable(sc);
 
@@ -254,10 +272,18 @@ nvme_disable(struct nvme_softc *sc)
        u_int32_t cc, csts;
 
        cc = nvme_read4(sc, NVME_CC);
-       if (ISSET(cc, NVME_CC_EN)) {
-               csts = nvme_read4(sc, NVME_CSTS);
-               if (!ISSET(csts, NVME_CSTS_CFS) &&
-                   nvme_ready(sc, NVME_CSTS_RDY) != 0)
+       if (!ISSET(cc, NVME_CC_EN))
+               return (nvme_ready(sc, 0));
+
+       csts = nvme_read4(sc, NVME_CSTS);
+       if (!ISSET(csts, NVME_CSTS_RDY)) {
+               /*
+                * Ensure CSTS.RDY is 1.
+                *
+                * Transitioning CC.EN from 1 to 0 when CSTS.RDY is 0
+                * "has undefined results" says NVMe.
+                */
+               if (nvme_ready(sc, NVME_CSTS_RDY))
                        return (1);
        }
 
@@ -509,6 +535,8 @@ nvme_shutdown(struct nvme_softc *sc)
                nvme_barrier(sc, 0, sc->sc_ios,
                    BUS_SPACE_BARRIER_READ | BUS_SPACE_BARRIER_WRITE);
                csts = nvme_read4(sc, NVME_CSTS);
+               if (csts == 0xffffffff)
+                       break;
                if ((csts & NVME_CSTS_SHST_MASK) == NVME_CSTS_SHST_DONE)
                        return (0);
 
@@ -968,6 +996,7 @@ nvme_poll(struct nvme_softc *sc, struct nvme_queue *q, struct nvme_ccb *ccb,
        struct nvme_poll_state state;
        void (*done)(struct nvme_softc *, struct nvme_ccb *, struct nvme_cqe *);
        void *cookie;
+       u_int32_t csts;
        u_int16_t flags;
 
        memset(&state, 0, sizeof(state));
@@ -981,8 +1010,14 @@ nvme_poll(struct nvme_softc *sc, struct nvme_queue *q, struct nvme_ccb *ccb,
 
        nvme_q_submit(sc, q, ccb, nvme_poll_fill);
        while (!ISSET(state.c.flags, htole16(NVME_CQE_PHASE))) {
+               csts = nvme_read4(sc, NVME_CSTS);
+               if (csts == 0xffffffff || ISSET(csts, NVME_CSTS_CFS)) {
+                       SET(state.c.flags, htole16(NVME_CQE_SC_INTERNAL_DEV_ERR));
+                       break;
+               }
                if (nvme_q_complete(sc, q) == 0)
                        delay(10);
+               nvme_barrier(sc, NVME_CSTS, 4, BUS_SPACE_BARRIER_READ);
 
                /* XXX no timeout? */
        }