[RFC PATCH 4/9] irqchip: GIC: add support for forwarded interrupts
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From: Will Deacon <hidden>
Date: 2014-06-27 13:18:20
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Hi Marc, On Wed, Jun 25, 2014 at 10:28:45AM +0100, Marc Zyngier wrote:
Now that we've switched to EOImode == 1, prevent a forwarded interrupt from being deactivated after its priority has been dropped. Also add support for the interrupt state to be saved/restored. Signed-off-by: Marc Zyngier <redacted> --- drivers/irqchip/irq-gic.c | 48 +++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 42 insertions(+), 6 deletions(-)
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quoted hunk ↗ jump to hunk
+static void gic_irq_set_fwd_state(struct irq_data *d, u32 val, u32 mask) +{ + if (mask & IRQ_FWD_STATE_PENDING) + gic_poke_irq(d, (val & IRQ_FWD_STATE_PENDING) ? GIC_DIST_ENABLE_SET : GIC_DIST_ENABLE_CLEAR); + if (mask & IRQ_FWD_STATE_ACTIVE) + gic_poke_irq(d, (val & IRQ_FWD_STATE_ACTIVE) ? GIC_DIST_ACTIVE_SET : GIC_DIST_ACTIVE_CLEAR); + if (mask & IRQ_FWD_STATE_MASKED) + gic_poke_irq(d, (val & IRQ_FWD_STATE_MASKED) ? GIC_DIST_ENABLE_CLEAR : GIC_DIST_ENABLE_SET);
Given that this isn't atomic and KVM only cares about ACTIVE, why not change mask to be a single state only? Renumbering the states so that's not bits would help to enforce this (i.e. make IRQ_FWD_STATE_ACTIVE 0, PENDING 1, ...). That would also allow you to switch on the state and return early.
quoted hunk ↗ jump to hunk
+static u32 gic_irq_get_fwd_state(struct irq_data *d, u32 mask) +{ + u32 val = 0; + + if (mask & IRQ_FWD_STATE_PENDING && gic_peek_irq(d, GIC_DIST_ENABLE_SET)) + val |= IRQ_FWD_STATE_PENDING; + if (mask & IRQ_FWD_STATE_ACTIVE && gic_peek_irq(d, GIC_DIST_ACTIVE_SET)) + val |= IRQ_FWD_STATE_ACTIVE; + if (mask & IRQ_FWD_STATE_MASKED && !gic_peek_irq(d, GIC_DIST_ENABLE_SET)) + val |= IRQ_FWD_STATE_MASKED;
*and* you could peek GIC_DIST_ENABLE_SET in one place here. Will