[src/trunk]: src/sys/dev/nvmm Don't allow unloading when there are still VMs ...

[maxv <maxv%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/eec724b0e68a
branches:  trunk
changeset: 455601:eec724b0e68a
user:      maxv <maxv%NetBSD.org@localhost>
date:      Sun Apr 07 14:05:15 2019 +0000

description:
Don't allow unloading when there are still VMs registered, and don't allow
auto-unloading at all. Not a big problem actually, because since I changed
the module class it's not auto-loadable anymore.

diffstat:

 sys/dev/nvmm/nvmm.c |  14 +++++++++++---
 1 files changed, 11 insertions(+), 3 deletions(-)

diffs (70 lines):

diff -r 3c0d7c64935f -r eec724b0e68a sys/dev/nvmm/nvmm.c
--- a/sys/dev/nvmm/nvmm.c       Sun Apr 07 13:50:29 2019 +0000
+++ b/sys/dev/nvmm/nvmm.c       Sun Apr 07 14:05:15 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: nvmm.c,v 1.12 2019/03/28 19:00:40 maxv Exp $   */
+/*     $NetBSD: nvmm.c,v 1.13 2019/04/07 14:05:15 maxv Exp $   */
 
 /*
  * Copyright (c) 2018 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: nvmm.c,v 1.12 2019/03/28 19:00:40 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: nvmm.c,v 1.13 2019/04/07 14:05:15 maxv Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -53,6 +53,7 @@
 #include <dev/nvmm/nvmm_ioctl.h>
 
 static struct nvmm_machine machines[NVMM_MAX_MACHINES];
+static volatile unsigned int nmachines __cacheline_aligned;
 
 static const struct nvmm_impl *nvmm_impl_list[] = {
        &nvmm_x86_svm,  /* x86 AMD SVM */
@@ -80,6 +81,7 @@
 
                mach->present = true;
                *ret = mach;
+               atomic_inc_uint(&nmachines);
                return 0;
        }
 
@@ -92,6 +94,7 @@
        KASSERT(rw_write_held(&mach->lock));
        KASSERT(mach->present);
        mach->present = false;
+       atomic_dec_uint(&nmachines);
 }
 
 static int
@@ -845,7 +848,6 @@
                for (n = 0; n < NVMM_MAX_VCPUS; n++) {
                        mutex_destroy(&machines[i].cpus[n].lock);
                }
-               /* TODO need to free stuff, etc */
        }
 
        (*nvmm_impl->fini)();
@@ -963,6 +965,9 @@
                return 0;
 
        case MODULE_CMD_FINI:
+               if (nmachines > 0) {
+                       return EBUSY;
+               }
 #if defined(_MODULE)
                {
                        error = devsw_detach(NULL, &nvmm_cdevsw);
@@ -974,6 +979,9 @@
                nvmm_fini();
                return 0;
 
+       case MODULE_CMD_AUTOUNLOAD:
+               return EBUSY;
+
        default:
                return ENOTTY;
        }