On Mon, Jan 07, 2019 at 07:39:45PM +0100, Cédric Le Goater wrote:
> The IRQ number space of the XIVE and XICS interrupt mode are aligned
> when using the dual interrupt mode for the machine. This means that
> the ICS offset is set to zero in QEMU and that the KVM XICS device
> should be informed of this new value. Unfortunately, there is now way
> to do so and KVM still maintains the XICS_IRQ_BASE (0x1000) offset.
>
> Ignore the lower 4K which are not used under the XICS interrupt
> mode. These IRQ numbers are only claimed by XIVE for the CPU IPIs.
>
> Signed-off-by: Cédric Le Goater <c...@kaod.org>
> ---
> hw/intc/xics_kvm.c | 18 ++++++++++++++++++
> 1 file changed, 18 insertions(+)
>
> diff --git a/hw/intc/xics_kvm.c b/hw/intc/xics_kvm.c
> index 651bbfdf6966..1d21ff217b82 100644
> --- a/hw/intc/xics_kvm.c
> +++ b/hw/intc/xics_kvm.c
> @@ -238,6 +238,15 @@ static void ics_get_kvm_state(ICSState *ics)
> for (i = 0; i < ics->nr_irqs; i++) {
> ICSIRQState *irq = &ics->irqs[i];
>
> + /*
> + * The KVM XICS device considers that the IRQ numbers should
> + * start at XICS_IRQ_BASE (0x1000). Ignore the lower 4K
> + * numbers (only claimed by XIVE for the CPU IPIs).
> + */
> + if (i + ics->offset < XICS_IRQ_BASE) {
> + continue;
> + }
> +
This seems bogus to me. The guest-visible irq numbers need to line up
between xics and xive mode, yes, but that doesn't mean we need to keep
around a great big array of unused array of ICS irq states, even in
TCG mode.
> kvm_device_access(kernel_xics_fd, KVM_DEV_XICS_GRP_SOURCES,
> i + ics->offset, &state, false, &error_fatal);
>
> @@ -303,6 +312,15 @@ static int ics_set_kvm_state(ICSState *ics, int
> version_id)
> ICSIRQState *irq = &ics->irqs[i];
> int ret;
>
> + /*
> + * The KVM XICS device considers that the IRQ numbers should
> + * start at XICS_IRQ_BASE (0x1000). Ignore the lower 4K
> + * numbers (only claimed by XIVE for the CPU IPIs).
> + */
> + if (i + ics->offset < XICS_IRQ_BASE) {
> + continue;
> + }
> +
> state = irq->server;
> state |= (uint64_t)(irq->saved_priority & KVM_XICS_PRIORITY_MASK)
> << KVM_XICS_PRIORITY_SHIFT;
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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