| Message ID | 20090507170834.26367.91907.stgit@dl380g6-3.ned.telco.ned.telco (mailing list archive) |
|---|---|
| State | New, archived |
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On Thu, 2009-05-07 at 11:09 -0600, Alex Williamson wrote: > Fix the index at which we return -ENOSPC since the kernel side will > reject a GSI >= KVM_MAX_IRQ_ROUTES. Also, mask as a signed int before > testing for error. Even with this, there still seems to be a fundamental problem with our consumption of GSIs in kvm. For example, every time a guest writes to the MSI capabilities area and enables MSI support, we call kvm_get_irq_route_gsi() to get a new max_used_gsi + 1 value, then call kvm_add_routing_entry(), which updates max_used_gsi. It doesn't take too long before we exhaust the GSI space and the device no longer works. This seems to happen within a minute or two of booting a guest with an e1000e device sitting idle on a busy network. Do we need to keep a bitmap of used GSIs or maybe just attempt to reuse the GSI we've gotten previously for the device? Thanks, Alex -- 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 Friday 08 May 2009 01:16:53 Alex Williamson wrote: > On Thu, 2009-05-07 at 11:09 -0600, Alex Williamson wrote: > > Fix the index at which we return -ENOSPC since the kernel side will > > reject a GSI >= KVM_MAX_IRQ_ROUTES. Also, mask as a signed int before > > testing for error. > > Even with this, there still seems to be a fundamental problem with our > consumption of GSIs in kvm. For example, every time a guest writes to > the MSI capabilities area and enables MSI support, we call > kvm_get_irq_route_gsi() to get a new max_used_gsi + 1 value, then call > kvm_add_routing_entry(), which updates max_used_gsi. It doesn't take > too long before we exhaust the GSI space and the device no longer works. > This seems to happen within a minute or two of booting a guest with an > e1000e device sitting idle on a busy network. Do we need to keep a > bitmap of used GSIs or maybe just attempt to reuse the GSI we've gotten > previously for the device? Thanks, Yes, I think a bitmap is much better here. Thanks.
diff --git a/hw/device-assignment.c b/hw/device-assignment.c index a7365c8..e06dd08 100644 --- a/hw/device-assignment.c +++ b/hw/device-assignment.c @@ -796,7 +796,7 @@ static void assigned_dev_update_msi(PCIDevice *pci_dev, unsigned int ctrl_pos) pci_dev->cap.start + PCI_MSI_DATA_32); assigned_dev->entry->type = KVM_IRQ_ROUTING_MSI; assigned_dev->entry->gsi = kvm_get_irq_route_gsi(kvm_context); - if (assigned_dev->entry->gsi < 0) { + if ((int)(assigned_dev->entry->gsi) < 0) { perror("assigned_dev_update_msi: kvm_get_irq_route_gsi"); return; } diff --git a/kvm/libkvm/libkvm.c b/kvm/libkvm/libkvm.c index ba0a5d1..2a4165a 100644 --- a/kvm/libkvm/libkvm.c +++ b/kvm/libkvm/libkvm.c @@ -1408,7 +1408,7 @@ int kvm_get_irq_route_gsi(kvm_context_t kvm) { #ifdef KVM_CAP_IRQ_ROUTING if (kvm->max_used_gsi >= KVM_IOAPIC_NUM_PINS) { - if (kvm->max_used_gsi <= kvm_get_gsi_count(kvm)) + if (kvm->max_used_gsi + 1 < kvm_get_gsi_count(kvm)) return kvm->max_used_gsi + 1; else return -ENOSPC;
Fix the index at which we return -ENOSPC since the kernel side will reject a GSI >= KVM_MAX_IRQ_ROUTES. Also, mask as a signed int before testing for error. Signed-off-by: Alex Williamson <alex.williamson@hp.com> --- hw/device-assignment.c | 2 +- kvm/libkvm/libkvm.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) -- 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