On 2012-07-25 15:24, Peter Maydell wrote:
> Instead of assuming that we can use irqfds if and only if
> kvm_irqchip_in_kernel(), add a bool to the KVMState which
> indicates this, and is set only on x86 and only if the
> irqchip is in the kernel.
>
> The kernel documentation implies that the only thing
> you need to use KVM_IRQFD is that KVM_CAP_IRQFD is
> advertised, but this seems to be untrue. In particular
> the kernel does not (alas) return a sensible error if you
> try to set up an irqfd when you haven't created an irqchip.
> If it did we could remove all this nonsense and let the
> kernel return the error code.
>
> Signed-off-by: Peter Maydell <peter.mayd...@linaro.org>
> ---
> kvm-all.c | 3 ++-
> kvm-stub.c | 1 +
> kvm.h | 10 ++++++++++
> target-i386/kvm.c | 4 ++++
> 4 files changed, 17 insertions(+), 1 deletions(-)
>
> diff --git a/kvm-all.c b/kvm-all.c
> index 8e21d81..a88b8ad 100644
> --- a/kvm-all.c
> +++ b/kvm-all.c
> @@ -101,6 +101,7 @@ struct KVMState
> KVMState *kvm_state;
> bool kvm_kernel_irqchip;
> bool kvm_async_interrupt_injection;
> +bool kvm_irqfds_allowed;
Why allowed vs enabled? You only have kvm_async_interrupt_injection as well.
>
> static const KVMCapabilityInfo kvm_required_capabilites[] = {
> KVM_CAP_INFO(USER_MEMORY),
> @@ -1126,7 +1127,7 @@ static int kvm_irqchip_assign_irqfd(KVMState *s, int
> fd, int virq, bool assign)
> .flags = assign ? 0 : KVM_IRQFD_FLAG_DEASSIGN,
> };
>
> - if (!kvm_irqchip_in_kernel()) {
> + if (!kvm_irqfds_enabled()) {
> return -ENOSYS;
> }
>
> diff --git a/kvm-stub.c b/kvm-stub.c
> index af1cb5e..179e5de 100644
> --- a/kvm-stub.c
> +++ b/kvm-stub.c
> @@ -20,6 +20,7 @@
> KVMState *kvm_state;
> bool kvm_kernel_irqchip;
> bool kvm_async_interrupt_injection;
> +bool kvm_irqfds_allowed;
>
> int kvm_init_vcpu(CPUArchState *env)
> {
> diff --git a/kvm.h b/kvm.h
> index e6cbf12..2337eb0 100644
> --- a/kvm.h
> +++ b/kvm.h
> @@ -25,6 +25,7 @@
> extern int kvm_allowed;
> extern bool kvm_kernel_irqchip;
> extern bool kvm_async_interrupt_injection;
> +extern bool kvm_irqfds_allowed;
>
> #if defined CONFIG_KVM || !defined NEED_CPU_H
> #define kvm_enabled() (kvm_allowed)
> @@ -38,10 +39,19 @@ extern bool kvm_async_interrupt_injection;
> * (where the vcpu must be stopped at a suitable point first).
> */
> #define kvm_async_interrupt_injection() (kvm_async_interrupt_injection)
> +/**
> + * kvm_irqfds_enabled:
> + *
> + * Returns: true if we can use irqfds to inject interrupts into
> + * a KVM CPU (ie the kernel supports irqfds and we are running
> + * with a configuration where it is meaningful to use them).
> + */
> +#define kvm_irqfds_enabled() (kvm_irqfds_allowed)
> #else
> #define kvm_enabled() (0)
> #define kvm_irqchip_in_kernel() (false)
> #define kvm_async_interrupt_injection() (false)
> +#define kvm_irqfds_enabled() (false)
> #endif
>
> struct kvm_run;
> diff --git a/target-i386/kvm.c b/target-i386/kvm.c
> index 503abeb..8e19a4d 100644
> --- a/target-i386/kvm.c
> +++ b/target-i386/kvm.c
> @@ -2045,4 +2045,8 @@ void kvm_arch_init_irq_routing(KVMState *s)
> */
> no_hpet = 1;
> }
> + /* We know at this point that we're using the in-kernel
> + * irqchip, so we can use irqfds.
> + */
> + kvm_irqfds_allowed = true;
> }
>
Otherwise:
Acked-by: Jan Kiszka <jan.kis...@siemens.com>
--
Siemens AG, Corporate Technology, CT RTC ITP SDP-DE
Corporate Competence Center Embedded Linux
