Messages in this thread | | | Subject | Re: [PATCH v2 13/36] irqchip/gic-v4.1: Don't use the VPE proxy if RVPEID is set | From | Zenghui Yu <> | Date | Fri, 1 Nov 2019 19:05:56 +0800 |
| |
Hi Marc,
On 2019/10/27 22:42, Marc Zyngier wrote: > The infamous VPE proxy device isn't used with GICv4.1 because: > - we can invalidate any LPI from the DirectLPI MMIO interface > - the ITS and redistributors understand the life cycle of > the doorbell, so we don't need to enable/disable it all > the time > > So let's escape early from the proxy related functions. > > Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Zenghui Yu <yuzenghui@huawei.com>
> --- > drivers/irqchip/irq-gic-v3-its.c | 23 ++++++++++++++++++++++- > 1 file changed, 22 insertions(+), 1 deletion(-) > > diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c > index 220d490d516e..999e61a9b2c3 100644 > --- a/drivers/irqchip/irq-gic-v3-its.c > +++ b/drivers/irqchip/irq-gic-v3-its.c > @@ -3069,7 +3069,7 @@ static const struct irq_domain_ops its_domain_ops = { > /* > * This is insane. > * > - * If a GICv4 doesn't implement Direct LPIs (which is extremely > + * If a GICv4.0 doesn't implement Direct LPIs (which is extremely > * likely), the only way to perform an invalidate is to use a fake > * device to issue an INV command, implying that the LPI has first > * been mapped to some event on that device. Since this is not exactly > @@ -3077,9 +3077,18 @@ static const struct irq_domain_ops its_domain_ops = { > * only issue an UNMAP if we're short on available slots. > * > * Broken by design(tm). > + * > + * GICv4.1 actually mandates that we're able to invalidate by writing to a > + * MMIO register. It doesn't implement the whole of DirectLPI, but that's > + * good enough. And most of the time, we don't even have to invalidate > + * anything, so that's actually pretty good!
I can't understand the meaning of this last sentence. May I ask for an explanation? :)
Thanks, Zenghui
> */ > static void its_vpe_db_proxy_unmap_locked(struct its_vpe *vpe) > { > + /* GICv4.1 doesn't use a proxy, so nothing to do here */ > + if (gic_rdists->has_rvpeid) > + return; > + > /* Already unmapped? */ > if (vpe->vpe_proxy_event == -1) > return; > @@ -3102,6 +3111,10 @@ static void its_vpe_db_proxy_unmap_locked(struct its_vpe *vpe) > > static void its_vpe_db_proxy_unmap(struct its_vpe *vpe) > { > + /* GICv4.1 doesn't use a proxy, so nothing to do here */ > + if (gic_rdists->has_rvpeid) > + return; > + > if (!gic_rdists->has_direct_lpi) { > unsigned long flags; > > @@ -3113,6 +3126,10 @@ static void its_vpe_db_proxy_unmap(struct its_vpe *vpe) > > static void its_vpe_db_proxy_map_locked(struct its_vpe *vpe) > { > + /* GICv4.1 doesn't use a proxy, so nothing to do here */ > + if (gic_rdists->has_rvpeid) > + return; > + > /* Already mapped? */ > if (vpe->vpe_proxy_event != -1) > return; > @@ -3135,6 +3152,10 @@ static void its_vpe_db_proxy_move(struct its_vpe *vpe, int from, int to) > unsigned long flags; > struct its_collection *target_col; > > + /* GICv4.1 doesn't use a proxy, so nothing to do here */ > + if (gic_rdists->has_rvpeid) > + return; > + > if (gic_rdists->has_direct_lpi) { > void __iomem *rdbase; > >
| |