(Applies to qemu-kvm.git:92a37a021) 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.
Signed-off-by: Gregory Haskins <[email protected]> --- kvm/libkvm/libkvm.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++ kvm/libkvm/libkvm.h | 14 ++++++++++++++ 2 files changed, 61 insertions(+), 0 deletions(-) diff --git a/kvm/libkvm/libkvm.c b/kvm/libkvm/libkvm.c index ba0a5d1..ff25f3b 100644 --- a/kvm/libkvm/libkvm.c +++ b/kvm/libkvm/libkvm.c @@ -34,6 +34,7 @@ #include <string.h> #include <errno.h> #include <sys/ioctl.h> +#include <sys/eventfd.h> #include <inttypes.h> #include "libkvm.h" @@ -1444,3 +1445,49 @@ int kvm_assign_set_msix_entry(kvm_context_t kvm, return ret; } #endif + +#ifdef KVM_CAP_IRQFD +static int _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 = _irqfd(kvm, fd, gsi, flags); + 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 -ENOENT; +} + +#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); -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
