From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gregory Haskins Subject: [PATCH v8] qemu-kvm: add irqfd support Date: Tue, 02 Jun 2009 11:45:24 -0400 Message-ID: <20090602154233.30489.81627.stgit@dev.haskins.net> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: avi@redhat.com To: kvm@vger.kernel.org Return-path: Received: from victor.provo.novell.com ([137.65.250.26]:56344 "EHLO victor.provo.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754861AbZFBPp3 (ORCPT ); Tue, 2 Jun 2009 11:45:29 -0400 Sender: kvm-owner@vger.kernel.org List-ID: irqfd lets you create an eventfd based file-desriptor to inject interrupts to a kvm guest. We associate one gsi per fd for fine-grained routing. [note: this is meant to work in conjunction with the POLLHUP version of irqfd, which has not yet been accepted into kvm.git] [ Changelog: v8: *) removed deassign() verb in favor of POLLHUP support on close() *) only include sys/eventfd.h if CAP_IRQFD is defined to properly support older kernels *) s/ENOENT/ENOSYS ] Signed-off-by: Gregory Haskins --- kvm/libkvm/libkvm.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++++ kvm/libkvm/libkvm.h | 14 ++++++++++++++ 2 files changed, 63 insertions(+), 0 deletions(-) diff --git a/kvm/libkvm/libkvm.c b/kvm/libkvm/libkvm.c index ba0a5d1..10cb2ac 100644 --- a/kvm/libkvm/libkvm.c +++ b/kvm/libkvm/libkvm.c @@ -1444,3 +1444,52 @@ int kvm_assign_set_msix_entry(kvm_context_t kvm, return ret; } #endif + +#ifdef KVM_CAP_IRQFD + +#include + +static int _kvm_irqfd(kvm_context_t kvm, int fd, int gsi, int flags) +{ + int r; + struct kvm_irqfd data = { + .fd = fd, + .gsi = gsi, + .flags = flags, + }; + + r = ioctl(kvm->vm_fd, KVM_IRQFD, &data); + if (r == -1) + r = -errno; + return r; +} + +int kvm_irqfd(kvm_context_t kvm, int gsi, int flags) +{ + int r; + int fd; + + if (!kvm_check_extension(kvm, KVM_CAP_IRQFD)) + return -ENOENT; + + fd = eventfd(0, 0); + if (fd < 0) + return -errno; + + r = _kvm_irqfd(kvm, fd, gsi, 0); + if (r < 0) { + close(fd); + return -errno; + } + + return fd; +} + +#else /* KVM_CAP_IRQFD */ + +int kvm_irqfd(kvm_context_t kvm, int gsi, int flags) +{ + return -ENOSYS; +} + +#endif /* KVM_CAP_IRQFD */ diff --git a/kvm/libkvm/libkvm.h b/kvm/libkvm/libkvm.h index 4821a1e..aca8ed6 100644 --- a/kvm/libkvm/libkvm.h +++ b/kvm/libkvm/libkvm.h @@ -856,6 +856,20 @@ int kvm_commit_irq_routes(kvm_context_t kvm); */ int kvm_get_irq_route_gsi(kvm_context_t kvm); +/*! + * \brief Create a file descriptor for injecting interrupts + * + * Creates an eventfd based file-descriptor that maps to a specific GSI + * in the guest. eventfd compliant signaling (write() from userspace, or + * eventfd_signal() from kernelspace) will cause the GSI to inject + * itself into the guest at the next available window. + * + * \param kvm Pointer to the current kvm_context + * \param gsi GSI to assign to this fd + * \param flags reserved, must be zero + */ +int kvm_irqfd(kvm_context_t kvm, int gsi, int flags); + #ifdef KVM_CAP_DEVICE_MSIX int kvm_assign_set_msix_nr(kvm_context_t kvm, struct kvm_assigned_msix_nr *msix_nr);