[kvmtool PATCH v2 4/6] riscv: Add IRQFD support for in-kernel AIA irqchip

[Anup Patel]

On Wed, Oct 25, 2023 at 6:47 PM Andrew Jones <ajones at ventanamicro.com> wrote:
>
> On Mon, Sep 18, 2023 at 06:27:28PM +0530, Anup Patel wrote:
> > To use irqfd with in-kernel AIA irqchip, we add custom
> > irq__add_irqfd and irq__del_irqfd functions. This allows
> > us to defer actual KVM_IRQFD ioctl() until AIA irqchip
> > is initialized by KVMTOOL.
> >
> > Signed-off-by: Anup Patel <apatel at ventanamicro.com>
> > ---
> >  riscv/include/kvm/kvm-arch.h | 11 ++++++
> >  riscv/irq.c                  | 73 ++++++++++++++++++++++++++++++++++++
> >  2 files changed, 84 insertions(+)
> >
> > diff --git a/riscv/include/kvm/kvm-arch.h b/riscv/include/kvm/kvm-arch.h
> > index cd37fc6..1a8af6a 100644
> > --- a/riscv/include/kvm/kvm-arch.h
> > +++ b/riscv/include/kvm/kvm-arch.h
> > @@ -98,11 +98,22 @@ extern void (*riscv_irqchip_generate_fdt_node)(void *fdt, struct kvm *kvm);
> >  extern u32 riscv_irqchip_phandle;
> >  extern u32 riscv_irqchip_msi_phandle;
> >  extern bool riscv_irqchip_line_sensing;
> > +extern bool riscv_irqchip_irqfd_ready;
> >
> >  void plic__create(struct kvm *kvm);
> >
> >  void pci__generate_fdt_nodes(void *fdt);
> >
> > +int riscv__add_irqfd(struct kvm *kvm, unsigned int gsi, int trigger_fd,
> > +                  int resample_fd);
> > +
> > +void riscv__del_irqfd(struct kvm *kvm, unsigned int gsi, int trigger_fd);
> > +
> > +#define irq__add_irqfd riscv__add_irqfd
> > +#define irq__del_irqfd riscv__del_irqfd
> > +
> > +int riscv__setup_irqfd_lines(struct kvm *kvm);
> > +
> >  void riscv__generate_irq_prop(void *fdt, u8 irq, enum irq_type irq_type);
> >
> >  void riscv__irqchip_create(struct kvm *kvm);
> > diff --git a/riscv/irq.c b/riscv/irq.c
> > index b608a2f..e6c0939 100644
> > --- a/riscv/irq.c
> > +++ b/riscv/irq.c
> > @@ -12,6 +12,7 @@ void (*riscv_irqchip_generate_fdt_node)(void *fdt, struct kvm *kvm) = NULL;
> >  u32 riscv_irqchip_phandle = PHANDLE_RESERVED;
> >  u32 riscv_irqchip_msi_phandle = PHANDLE_RESERVED;
> >  bool riscv_irqchip_line_sensing = false;
> > +bool riscv_irqchip_irqfd_ready = false;
> >
> >  void kvm__irq_line(struct kvm *kvm, int irq, int level)
> >  {
> > @@ -46,6 +47,78 @@ void kvm__irq_trigger(struct kvm *kvm, int irq)
> >       }
> >  }
> >
> > +struct riscv_irqfd_line {
> > +     unsigned int            gsi;
> > +     int                     trigger_fd;
> > +     int                     resample_fd;
> > +     struct list_head        list;
> > +};
> > +
> > +static LIST_HEAD(irqfd_lines);
> > +
> > +int riscv__add_irqfd(struct kvm *kvm, unsigned int gsi, int trigger_fd,
> > +                  int resample_fd)
> > +{
> > +     struct riscv_irqfd_line *line;
> > +
> > +     if (riscv_irqchip_irqfd_ready)
> > +             return irq__common_add_irqfd(kvm, gsi, trigger_fd,
> > +                                          resample_fd);
> > +
> > +     /* Postpone the routing setup until we have a distributor */
>
> This comment comes from the Arm code. We probably want to replace
> distributor with "until the AIA is initialized" or something.

Okay, I will update.

>
> > +     line = malloc(sizeof(*line));
> > +     if (!line)
> > +             return -ENOMEM;
> > +
> > +     *line = (struct riscv_irqfd_line) {
> > +             .gsi            = gsi,
> > +             .trigger_fd     = trigger_fd,
> > +             .resample_fd    = resample_fd,
> > +     };
> > +     list_add(&line->list, &irqfd_lines);
> > +
> > +     return 0;
> > +}
> > +
> > +void riscv__del_irqfd(struct kvm *kvm, unsigned int gsi, int trigger_fd)
> > +{
> > +     struct riscv_irqfd_line *line;
> > +
> > +     if (riscv_irqchip_irqfd_ready) {
> > +             irq__common_del_irqfd(kvm, gsi, trigger_fd);
> > +             return;
> > +     }
> > +
> > +     list_for_each_entry(line, &irqfd_lines, list) {
> > +             if (line->gsi != gsi)
> > +                     continue;
> > +
> > +             list_del(&line->list);
> > +             free(line);
> > +             break;
> > +     }
> > +}
> > +
> > +int riscv__setup_irqfd_lines(struct kvm *kvm)
> > +{
> > +     int ret;
> > +     struct riscv_irqfd_line *line, *tmp;
> > +
> > +     list_for_each_entry_safe(line, tmp, &irqfd_lines, list) {
> > +             ret = irq__common_add_irqfd(kvm, line->gsi, line->trigger_fd,
> > +                                         line->resample_fd);
> > +             if (ret < 0) {
> > +                     pr_err("Failed to register IRQFD");
> > +                     return ret;
> > +             }
> > +
> > +             list_del(&line->list);
> > +             free(line);
> > +     }
> > +
> > +     return 0;
> > +}
> > +
> >  void riscv__generate_irq_prop(void *fdt, u8 irq, enum irq_type irq_type)
> >  {
> >       u32 prop[2], size;
> > --
> > 2.34.1
> >
>
> Other than the comment,
>
> Reviewed-by: Andrew Jones <ajones at ventanamicro.com>

Regards,
Anup