(applies to kvm-userspace.git 84474e4f39) This adds userspace support for the irqfd mechanism in the kernel, published here: http://lkml.org/lkml/2009/4/24/6 This is v2. Changes since v1: *) bug-fix to prevent returning "0" for success on allocation --------------------- There are no current users, though the future virtual-bus v4 has plans to adopt it. Signed-off-by: Gregory Haskins <ghaskins@xxxxxxxxxx> --- libkvm/libkvm.c | 33 +++++++++++++++++++++++++++++++++ libkvm/libkvm.h | 13 +++++++++++++ 2 files changed, 46 insertions(+), 0 deletions(-) diff --git a/libkvm/libkvm.c b/libkvm/libkvm.c index 0610e3f..8c994a3 100644 --- a/libkvm/libkvm.c +++ b/libkvm/libkvm.c @@ -35,6 +35,7 @@ #include <errno.h> #include <sys/ioctl.h> #include <inttypes.h> +#include <sys/eventfd.h> #include "libkvm.h" #if defined(__x86_64__) || defined(__i386__) @@ -1440,3 +1441,35 @@ int kvm_assign_set_msix_entry(kvm_context_t kvm, return ret; } #endif + +static int assign_irqfd(kvm_context_t kvm, int fd, int gsi) +{ + int r; + struct kvm_irqfd data = { + .fd = fd, + .gsi = gsi, + }; + + r = ioctl(kvm->vm_fd, KVM_ASSIGN_IRQFD, &data); + if (r == -1) + r = -errno; + return r; +} + +int kvm_irqfd(kvm_context_t kvm, int gsi) +{ + int fd, r; + + if (!kvm_check_extension(kvm, KVM_CAP_IRQFD)) + return -ENOENT; + + fd = eventfd(0, 0); + if (fd < 0) + return fd; + + r = assign_irqfd(kvm, fd, gsi); + if (r < 0) + return r; + + return fd; +} diff --git a/libkvm/libkvm.h b/libkvm/libkvm.h index ce6f054..404c028 100644 --- a/libkvm/libkvm.h +++ b/libkvm/libkvm.h @@ -856,6 +856,19 @@ 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 + */ +int kvm_irqfd(kvm_context_t kvm, int gsi); + #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 majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
