Re: [Qemu-devel] xhci migration breakage

[Gerd Hoffmann <kraxel@redhat.com>]

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  Hi,

> dest:
> (qemu) red_dispatcher_loadvm_commands: 
> usb-storage msd post_load 0x7f45f510ee50 sig=0 tag=0
> 
> I added these as debug on the 'usb-storage' vmsd element; but
> the signature/tag being 0 I assume they're not the culprit.

Yep, no inflight transfer, so highly unlikely (also note that ehci works
fine according to bugzilla).

> #6  0x00007febabacae27 in xhci_kick_epctx (epctx=<optimized out>, xfer=<optimized out>, xhci=<optimized out>)
>     at /root/1436616/qemu/hw/usb/hcd-xhci.c:2103 <- right at the end of xhci_submit
> #7  0x00007febabacae27 in xhci_kick_epctx (epctx=<optimized out>, xfer=<optimized out>, xhci=<optimized out>)
>     at /root/1436616/qemu/hw/usb/hcd-xhci.c:2112 right at end of xhci_fire_transfer
> #8  0x00007febabacae27 in xhci_kick_epctx (epctx=0x7febaec395a0, streamid=0)
>     at /root/1436616/qemu/hw/usb/hcd-xhci.c:2240

Recursive xhci_kick_epctx calls, not good.

Does the attached patch (not tested yet) make any difference?

cheers,
  Gerd


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From 1b10b10445ab438c3fa1107f9962add3ae0716c6 Mon Sep 17 00:00:00 2001
From: Gerd Hoffmann <kraxel@redhat.com>
Date: Fri, 31 Mar 2017 07:40:45 +0200
Subject: [PATCH] xhci: set kick_active for retried xfers too

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 hw/usb/hcd-xhci.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/hw/usb/hcd-xhci.c b/hw/usb/hcd-xhci.c
index f0af852..8958f95 100644
--- a/hw/usb/hcd-xhci.c
+++ b/hw/usb/hcd-xhci.c
@@ -2083,6 +2083,7 @@ static void xhci_kick_epctx(XHCIEPContext *epctx, unsigned int streamid)
         return;
     }
 
+    epctx->kick_active++;
     if (epctx->retry) {
         XHCITransfer *xfer = epctx->retry;
 
@@ -2093,6 +2094,7 @@ static void xhci_kick_epctx(XHCIEPContext *epctx, unsigned int streamid)
             mfindex = xhci_mfindex_get(xhci);
             xhci_check_intr_iso_kick(xhci, xfer, epctx, mfindex);
             if (xfer->running_retry) {
+                epctx->kick_active--;
                 return;
             }
             xfer->timed_xfer = 0;
@@ -2101,6 +2103,7 @@ static void xhci_kick_epctx(XHCIEPContext *epctx, unsigned int streamid)
         if (xfer->iso_xfer) {
             /* retry iso transfer */
             if (xhci_setup_packet(xfer) < 0) {
+                epctx->kick_active--;
                 return;
             }
             usb_handle_packet(xfer->packet.ep->dev, &xfer->packet);
@@ -2109,10 +2112,12 @@ static void xhci_kick_epctx(XHCIEPContext *epctx, unsigned int streamid)
         } else {
             /* retry nak'ed transfer */
             if (xhci_setup_packet(xfer) < 0) {
+                epctx->kick_active--;
                 return;
             }
             usb_handle_packet(xfer->packet.ep->dev, &xfer->packet);
             if (xfer->packet.status == USB_RET_NAK) {
+                epctx->kick_active--;
                 return;
             }
             xhci_try_complete_packet(xfer);
@@ -2126,6 +2131,7 @@ static void xhci_kick_epctx(XHCIEPContext *epctx, unsigned int streamid)
 
     if (epctx->state == EP_HALTED) {
         DPRINTF("xhci: ep halted, not running schedule\n");
+        epctx->kick_active--;
         return;
     }
 
@@ -2134,6 +2140,7 @@ static void xhci_kick_epctx(XHCIEPContext *epctx, unsigned int streamid)
         uint32_t err;
         stctx = xhci_find_stream(epctx, streamid, &err);
         if (stctx == NULL) {
+            epctx->kick_active--;
             return;
         }
         ring = &stctx->ring;
@@ -2145,7 +2152,6 @@ static void xhci_kick_epctx(XHCIEPContext *epctx, unsigned int streamid)
     }
     assert(ring->dequeue != 0);
 
-    epctx->kick_active++;
     while (1) {
         length = xhci_ring_chain_length(xhci, ring);
         if (length <= 0) {
-- 
1.8.3.1