Gregory Haskins wrote:
> 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
> ]
>
Hmm..it would appear I already released a 'v8' in the past. :(
In any case, this is the latest version to consider
-Greg
> Signed-off-by: Gregory Haskins <ghaskins@xxxxxxxxxx>
> ---
>
> 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 <sys/eventfd.h>
> +
> +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);
>
> --
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