| Message ID | d9c105ea0909041238j26d85cb1ndb7dc89315159e93@mail.gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, 4 Sep 2009 14:38:30 -0500 Dustin Kirkland <kirkland@canonical.com> wrote: > On Fri, Sep 4, 2009 at 11:36 AM, Marcelo Tosatti<mtosatti@redhat.com> wrote: > > On Fri, Sep 04, 2009 at 11:06:38AM -0500, Dustin Kirkland wrote: > >> On Fri, 2009-09-04 at 08:22 +0100, Mark McLoughlin wrote: > >> > On Thu, 2009-09-03 at 19:18 -0300, Glauber Costa wrote: > >> > > On Thu, Sep 3, 2009 at 6:48 PM, Dustin Kirkland<kirkland@canonical.com> wrote: > >> > > > On Thu, Sep 3, 2009 at 3:01 PM, Mark McLoughlin<markmc@redhat.com> wrote: > >> > > >> On Thu, 2009-09-03 at 12:31 -0500, Dustin Kirkland wrote: > >> > > >>> qemu-kvm: fix segfault when running kvm without /dev/kvm, falling back > >> > > >>> to non-accelerated mode > >> > > >>> > >> > > >>> We're seeing segfaults on systems without access to /dev/kvm.  It > >> > > >>> looks like the global kvm_allowed is being set just a little too late > >> > > >>> in vl.c.  This patch moves the kvm initialization a bit higher in the > >> > > >>> vl.c main, just after options processing, and solves the segfaults. > >> > > >>> We're carrying this patch in Ubuntu 9.10 Alpha.  Please apply > >> > > >>> upstream, or advise if and why this might not be the optimal solution. > >> > > >> > >> > > >> Ah discussion about an alternative fix for this fizzled out recently: > >> > > >> > >> > > >>  http://www.mail-archive.com/kvm@vger.kernel.org/msg19890.html > >> > > > > >> > > > Ah, thanks Mark.  In that thread, I found Daniel's suggestion the most > >> > > > reasonable, and user-friendly: > >> > > > > >> > > > On Mon, Jul 27, 2009 at 1:44 PM, Daniel P. Berrange<berrange@redhat.com> wrote: > >> > > >> Well, we could go for logic like: > >> > > >> > >> > > >>  * No arg given      => try kvm, try kqemu, try tcg > >> > > >>  * --accelmode arg given => try $arg, and fail if unavailable > >> > > >> > >> > > >> then libvirt would simply always supply --accelmode for all VMs, > >> > > >> while people running qemu manually would get best available > >> > > I sent some patches to do that, but they were incomplete, and I was > >> > > preempted by something else. > >> > > If you want, you can wait for my cycles to come back, or pick from where I left > >> > >> Thanks for the pointer, Glauber.  My cycles a bit constrained too, but > >> I'll have a look when I get a chance. > >> > >> > In the meantime, can we commit to stable-0.11 either Dustin's fix or > >> > this: > >> > > >> >  http://git.et.redhat.com/?p=qemu-fedora.git;a=commitdiff;h=aa1620047b > >> > >> +1.  We're looking for something agreeable in stable-0.11, that solves > >> the segfault and proceeds without VT acceleration. > > > > Dustin, > > > > Can you please resend the patch with the suggestion i made earlier, for > > stable-0.11? > > Sure, Marcelo. It's attached. > > I tested it, and it still does avoid the segfault. > > Luiz, could you re-test this patch on your side too? I'm getting rejections, are you sure it's against upstream? -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
qemu-kvm: fix segfault when running kvm without /dev/kvm qemu-kvm segfaults on systems without access to /dev/kvm. The global kvm_allowed is being set too late in vl.c. This patch moves the kvm initialization a bit higher in the vl.c main, just after the daemonize fork. This fix is intended to be a short term solution, solving the segfaults. In the longer term, the suggested approach requires a bit more development and testing: * If no arg given => try kvm, try kqemu, try tcg * If --accelmode arg given => try $arg, and fail if unavailable Signed-off-by: Dustin Kirkland <kirkland@canonical.com> diff --git a/vl.c b/vl.c index db75470..26bced8 100644 --- a/vl.c +++ b/vl.c @@ -5831,6 +5831,20 @@ int main(int argc, char **argv, char **envp) } #endif + if (kvm_enabled()) { + int ret; + + ret = kvm_init(smp_cpus); + if (ret < 0) { +#if defined(KVM_UPSTREAM) || defined(NO_CPU_EMULATION) + fprintf(stderr, "failed to initialize KVM\n"); + exit(1); +#endif + fprintf(stderr, "Could not initialize KVM, will disable KVM support\n"); + kvm_allowed = 0; + } + } + #ifdef CONFIG_KQEMU if (smp_cpus > 1) kqemu_allowed = 0; @@ -6002,20 +6016,6 @@ int main(int argc, char **argv, char **envp) } } - if (kvm_enabled()) { - int ret; - - ret = kvm_init(smp_cpus); - if (ret < 0) { -#if defined(KVM_UPSTREAM) || defined(NO_CPU_EMULATION) - fprintf(stderr, "failed to initialize KVM\n"); - exit(1); -#endif - fprintf(stderr, "Could not initialize KVM, will disable KVM support\n"); - kvm_allowed = 0; - } - } - if (monitor_device) { monitor_hd = qemu_chr_open("monitor", monitor_device, NULL); if (!monitor_hd) {