| Message ID | 20090921145136.GA29405@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 09/21/2009 05:51 PM, Michael S. Tsirkin wrote: > When running on host kernel which does not let the guest manupulate the > gsi routing, and user requested MSI-X to be enabled, we get the > following warnings: > kvm_msix_add: kvm_get_irq_route_gsi failed: No space left on device > kvm_msix_update: kvm_update_routing_entry failed: Invalid argument > > What really happens is that we report a failure to allocate > a vector to the guest, it will retry and finally disable MSI. > > Make this clearer by checking for gsi capability and warning about > the error in a readable form. > > Can we disable msix (or, abort qemu at startup and request that the user disable msix) if the kernel doesn't provide required features? It's better than a runtime error.
On Mon, Sep 21, 2009 at 05:56:13PM +0300, Avi Kivity wrote: > On 09/21/2009 05:51 PM, Michael S. Tsirkin wrote: >> When running on host kernel which does not let the guest manupulate the >> gsi routing, and user requested MSI-X to be enabled, we get the >> following warnings: >> kvm_msix_add: kvm_get_irq_route_gsi failed: No space left on device >> kvm_msix_update: kvm_update_routing_entry failed: Invalid argument >> >> What really happens is that we report a failure to allocate >> a vector to the guest, it will retry and finally disable MSI. >> >> Make this clearer by checking for gsi capability and warning about >> the error in a readable form. >> >> > > Can we disable msix What we do effectively disables msix. > (or, abort qemu at startup and request that the user > disable msix) if the kernel doesn't provide required features? > It's > better than a runtime error. Note it's a warning, not an error. We have a similar failure mode when we run out of gsi entries, and that can not be checked upfront. I prefer having it fail in the same way, so that this failure path in guest drivers is excercised and tested. > -- > error compiling committee.c: too many arguments to function -- 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
On 09/21/2009 10:50 PM, Michael S. Tsirkin wrote: > On Mon, Sep 21, 2009 at 05:56:13PM +0300, Avi Kivity wrote: > >> On 09/21/2009 05:51 PM, Michael S. Tsirkin wrote: >> >>> When running on host kernel which does not let the guest manupulate the >>> gsi routing, and user requested MSI-X to be enabled, we get the >>> following warnings: >>> kvm_msix_add: kvm_get_irq_route_gsi failed: No space left on device >>> kvm_msix_update: kvm_update_routing_entry failed: Invalid argument >>> >>> What really happens is that we report a failure to allocate >>> a vector to the guest, it will retry and finally disable MSI. >>> >>> Make this clearer by checking for gsi capability and warning about >>> the error in a readable form. >>> >>> >>> >> Can we disable msix >> > What we do effectively disables msix. > > >> (or, abort qemu at startup and request that the user >> disable msix) if the kernel doesn't provide required features? >> It's >> better than a runtime error. >> > Note it's a warning, not an error. > > We have a similar failure mode when we run out of gsi entries, and that > can not be checked upfront. I prefer having it fail in the same way, so > that this failure path in guest drivers is excercised and tested. > I see, applied the patch, thanks.
diff --git a/hw/msix.c b/hw/msix.c index fcd425f..5695582 100644 --- a/hw/msix.c +++ b/hw/msix.c @@ -129,6 +129,13 @@ static int kvm_msix_add(PCIDevice *dev, unsigned vector) struct kvm_irq_routing_entry *entry = dev->msix_irq_entries + vector; int r; + if (!kvm_has_gsi_routing(kvm_context)) { + fprintf(stderr, "Warning: no MSI-X support found. " + "At least kernel 2.6.30 is required for MSI-X support.\n" + ); + return -EOPNOTSUPP; + } + r = kvm_get_irq_route_gsi(kvm_context); if (r < 0) { fprintf(stderr, "%s: kvm_get_irq_route_gsi failed: %s\n", __func__, strerror(-r));
When running on host kernel which does not let the guest manupulate the gsi routing, and user requested MSI-X to be enabled, we get the following warnings: kvm_msix_add: kvm_get_irq_route_gsi failed: No space left on device kvm_msix_update: kvm_update_routing_entry failed: Invalid argument What really happens is that we report a failure to allocate a vector to the guest, it will retry and finally disable MSI. Make this clearer by checking for gsi capability and warning about the error in a readable form. Reported-by: Juan Quintela <quintela@redhat.com> Suggested-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> --- hw/msix.c | 7 +++++++ 1 files changed, 7 insertions(+), 0 deletions(-)