| Message ID | 1356038055-29507-1-git-send-email-stefanha@redhat.com |
|---|---|
| State | New |
| Headers | show |
On Thu, 2012-12-20 at 22:14 +0100, Stefan Hajnoczi wrote: > It's necessary to check kvm_enabled() since a QEMU binary can be > compiled with KVM support but TCG can be used at run-time. > kvm_check_extension() segfaults if kvm_state is NULL. Ugh, this is exactly why we added kvm_irqfds_enabled() which doesn't call kvm_check_extension(). How is it possible to fall through to a kvm_check_extension() with that in place? Thanks, Alex > Reported-by: Joe Terranova <joeterranova@gmail.com> > Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> > --- > hw/vfio_pci.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/hw/vfio_pci.c b/hw/vfio_pci.c > index fbfe670..677dc48 100644 > --- a/hw/vfio_pci.c > +++ b/hw/vfio_pci.c > @@ -275,7 +275,8 @@ static void vfio_enable_intx_kvm(VFIODevice *vdev) > int ret, argsz; > int32_t *pfd; > > - if (!kvm_irqfds_enabled() || > + if (!kvm_enabled() || > + !kvm_irqfds_enabled() || > vdev->intx.route.mode != PCI_INTX_ENABLED || > !kvm_check_extension(kvm_state, KVM_CAP_IRQFD_RESAMPLE)) { > return; > @@ -438,7 +439,8 @@ static int vfio_enable_intx(VFIODevice *vdev) > * Only conditional to avoid generating error messages on platforms > * where we won't actually use the result anyway. > */ > - if (kvm_irqfds_enabled() && > + if (kvm_enabled() && > + kvm_irqfds_enabled() && > kvm_check_extension(kvm_state, KVM_CAP_IRQFD_RESAMPLE)) { > vdev->intx.route = pci_device_route_intx_to_irq(&vdev->pdev, > vdev->intx.pin);
On Thu, Dec 20, 2012 at 11:35 PM, Alex Williamson <alex.williamson@redhat.com> wrote: > On Thu, 2012-12-20 at 22:14 +0100, Stefan Hajnoczi wrote: >> It's necessary to check kvm_enabled() since a QEMU binary can be >> compiled with KVM support but TCG can be used at run-time. >> kvm_check_extension() segfaults if kvm_state is NULL. > > Ugh, this is exactly why we added kvm_irqfds_enabled() which doesn't > call kvm_check_extension(). How is it possible to fall through to a > kvm_check_extension() with that in place? Thanks, Ah, this explains it: Joe was using QEMU 1.3.0 which does not contain the kvm_irqfds_enabled() fix. My patch is unnecessary and can be dropped. Stefan
diff --git a/hw/vfio_pci.c b/hw/vfio_pci.c index fbfe670..677dc48 100644 --- a/hw/vfio_pci.c +++ b/hw/vfio_pci.c @@ -275,7 +275,8 @@ static void vfio_enable_intx_kvm(VFIODevice *vdev) int ret, argsz; int32_t *pfd; - if (!kvm_irqfds_enabled() || + if (!kvm_enabled() || + !kvm_irqfds_enabled() || vdev->intx.route.mode != PCI_INTX_ENABLED || !kvm_check_extension(kvm_state, KVM_CAP_IRQFD_RESAMPLE)) { return; @@ -438,7 +439,8 @@ static int vfio_enable_intx(VFIODevice *vdev) * Only conditional to avoid generating error messages on platforms * where we won't actually use the result anyway. */ - if (kvm_irqfds_enabled() && + if (kvm_enabled() && + kvm_irqfds_enabled() && kvm_check_extension(kvm_state, KVM_CAP_IRQFD_RESAMPLE)) { vdev->intx.route = pci_device_route_intx_to_irq(&vdev->pdev, vdev->intx.pin);
It's necessary to check kvm_enabled() since a QEMU binary can be compiled with KVM support but TCG can be used at run-time. kvm_check_extension() segfaults if kvm_state is NULL. Reported-by: Joe Terranova <joeterranova@gmail.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> --- hw/vfio_pci.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)