[src/trunk]: src/sys/dev/pci Fix vmx(4) receive workqueue problem on qemu, re...

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

details:   https://anonhg.NetBSD.org/src/rev/56eb8b4122fc
branches:  trunk
changeset: 1024232:56eb8b4122fc
user:      knakahara <knakahara%NetBSD.org@localhost>
date:      Wed Oct 13 01:11:29 2021 +0000

description:
Fix vmx(4) receive workqueue problem on qemu, reported by ozaki-r@n.o, thanks.

ESXi stops interrupt by vmxnet3_disable_intr() immediately.  In contrast, qemu
does not stop interrupt soon.  Hmm, qemu's behavior seems not to be correct,
however, there is no explicit specification of vmxnet3.  So, we have to accept
that behavior.

diffstat:

 sys/dev/pci/if_vmx.c |  17 +++++++++++++----
 1 files changed, 13 insertions(+), 4 deletions(-)

diffs (52 lines):

diff -r 56ff89c50dab -r 56eb8b4122fc sys/dev/pci/if_vmx.c
--- a/sys/dev/pci/if_vmx.c      Tue Oct 12 23:40:38 2021 +0000
+++ b/sys/dev/pci/if_vmx.c      Wed Oct 13 01:11:29 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: if_vmx.c,v 1.4 2020/10/15 04:37:48 ryo Exp $   */
+/*     $NetBSD: if_vmx.c,v 1.5 2021/10/13 01:11:29 knakahara Exp $     */
 /*     $OpenBSD: if_vmx.c,v 1.16 2014/01/22 06:04:17 brad Exp $        */
 
 /*
@@ -19,7 +19,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if_vmx.c,v 1.4 2020/10/15 04:37:48 ryo Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_vmx.c,v 1.5 2021/10/13 01:11:29 knakahara Exp $");
 
 #include <sys/param.h>
 #include <sys/cpu.h>
@@ -253,6 +253,7 @@
 
        void *vxq_si;
        bool vxq_workqueue;
+       bool vxq_wq_enqueued;
        struct work vxq_wq_cookie;
 };
 
@@ -2484,8 +2485,15 @@
 {
 
        if (vmxq->vxq_workqueue) {
-               workqueue_enqueue(sc->vmx_queue_wq, &vmxq->vxq_wq_cookie,
-                   curcpu());
+               /*
+                * When this function is called, "vmxq" is owned by one CPU.
+                * so, atomic operation is not required here.
+                */
+               if (!vmxq->vxq_wq_enqueued) {
+                       vmxq->vxq_wq_enqueued = true;
+                       workqueue_enqueue(sc->vmx_queue_wq,
+                           &vmxq->vxq_wq_cookie, curcpu());
+               }
        } else {
                softint_schedule(vmxq->vxq_si);
        }
@@ -2625,6 +2633,7 @@
        struct vmxnet3_queue *vmxq;
 
        vmxq = container_of(wk, struct vmxnet3_queue, vxq_wq_cookie);
+       vmxq->vxq_wq_enqueued = false;
        vmxnet3_handle_queue(vmxq);
 }