> -----Original Message-----
> From: Wei Liu [mailto:wei.l...@citrix.com]
> Sent: Wednesday, March 30, 2016 12:58 AM
> To: Konrad Rzeszutek Wilk <konrad.w...@oracle.com>
> Cc: Hao, Xudong <xudong....@intel.com>; wei.l...@citrix.com;
> samuel.thiba...@ens-lyon.org; stefano.stabell...@eu.citrix.com; xen-
> de...@lists.xen.org
> Subject: Re: [Xen-devel] pv-grub guest booting fail with recent qemu-xen
>
> On Mon, Mar 28, 2016 at 09:21:14AM -0400, Konrad Rzeszutek Wilk wrote:
> > On Mon, Mar 28, 2016 at 02:03:35AM +0000, Hao, Xudong wrote:
> > > > -----Original Message-----
> > > > From: Xen-devel [mailto:xen-devel-boun...@lists.xen.org] On Behalf
> > > > Of Konrad Rzeszutek Wilk
> > > > Sent: Saturday, March 26, 2016 2:58 AM
> > > > To: Hao, Xudong <xudong....@intel.com>
> > > > Cc: stefano.stabell...@eu.citrix.com; xen-devel@lists.xen.org
> > > > Subject: Re: [Xen-devel] pv-grub guest booting fail with recent
> > > > qemu-xen
> > > >
> > > > On Wed, Mar 02, 2016 at 07:16:40AM +0000, Hao, Xudong wrote:
> > > > > Hi,
> > > > > For Xen upstream master branch with commit 1949868d, After
> > > > > updating qemu-
> > > > xen version from fcf6ac57 to 2ce1d30e, booting a pv-grub guest will
> > > > fail.
> >
>
> pv-grub should be using qemu-traditional, not qemu-xen
>
Never hear this limitation.
> The log message you posted in your original post doesn't seem to reveal much.
> Can you have a look at relevant QEMU logs under /var/log/xen?
There is not valuable qemu log, only one line: "qemu: terminating on signal 1
from pid 36642".
Bisect and the bad commit of qemu-xen is:
commit 2ce1d30ef2858dfed72a281872579e5a26b090dd
Author: Stefano Stabellini <stefano.stabell...@eu.citrix.com>
Date: Wed Jan 6 16:32:22 2016 +0000
xenfb.c: avoid expensive loops when prod <= out_cons
If the frontend sets out_cons to a value higher than out_prod, it will
cause xenfb_handle_events to loop about 2^32 times. Avoid that by using
better checks at the beginning of the function.
upstream-commit-id: ac0487e1d2ae811cd4d035741a109a4ecfb013f1
Signed-off-by: Stefano Stabellini <stefano.stabell...@eu.citrix.com>
Reported-by: Ling Liu <liuling...@360.cn>
diff --git a/hw/display/xenfb.c b/hw/display/xenfb.c
index 4e2a27a..8eb3046 100644
--- a/hw/display/xenfb.c
+++ b/hw/display/xenfb.c
@@ -789,8 +789,9 @@ static void xenfb_handle_events(struct XenFB *xenfb)
prod = page->out_prod;
out_cons = page->out_cons;
- if (prod == out_cons)
- return;
+ if (prod - out_cons >= XENFB_OUT_RING_LEN) {
+ return;
+ }
xen_rmb(); /* ensure we see ring contents up to prod */
for (cons = out_cons; cons != prod; cons++) {
union xenfb_out_event *event = &XENFB_OUT_RING_REF(page, cons);
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