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SubjectRe: [PATCH 31/35] irqchip/gic-v4.1: Eagerly vmap vPEs
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On 2019/9/24 2:26, Marc Zyngier wrote:
> Now that we have HW-accelerated SGIs being delivered to VPEs, it
> becomes required to map the VPEs on all ITSs instead of relying
> on the lazy approach that we would use when using the ITS-list
> mechanism.
>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> ---
> drivers/irqchip/irq-gic-v3-its.c | 39 +++++++++++++++++++++++++-------
> 1 file changed, 31 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
> index 4aae9582182b..a1e8c4c2598a 100644
> --- a/drivers/irqchip/irq-gic-v3-its.c
> +++ b/drivers/irqchip/irq-gic-v3-its.c
> @@ -1417,12 +1417,31 @@ static int its_irq_set_irqchip_state(struct irq_data *d,
> return 0;
> }
>
> +/*
> + * Two favourable cases:
> + *
> + * (a) Either we have a GICv4.1, and all vPEs have to be mapped at all times
> + * for vSGI delivery
> + *
> + * (b) Or the ITSs do not use a list map, meaning that VMOVP is cheap enough
> + * and we're better off mapping all VPEs always
> + *
> + * If neither (a) nor (b) is true, then we map VLPIs on demand.
^^^^^
vPEs

> + *
> + */
> +static bool gic_requires_eager_mapping(void)
> +{
> + if (!its_list_map || gic_rdists->has_rvpeid)
> + return true;
> +
> + return false;
> +}
> +
> static void its_map_vm(struct its_node *its, struct its_vm *vm)
> {
> unsigned long flags;
>
> - /* Not using the ITS list? Everything is always mapped. */
> - if (!its_list_map)
> + if (gic_requires_eager_mapping())
> return;
>
> raw_spin_lock_irqsave(&vmovp_lock, flags);
> @@ -1456,7 +1475,7 @@ static void its_unmap_vm(struct its_node *its, struct its_vm *vm)
> unsigned long flags;
>
> /* Not using the ITS list? Everything is always mapped. */
> - if (!its_list_map)
> + if (gic_requires_eager_mapping())
> return;
>
> raw_spin_lock_irqsave(&vmovp_lock, flags);
> @@ -3957,8 +3976,12 @@ static int its_vpe_irq_domain_activate(struct irq_domain *domain,
> struct its_vpe *vpe = irq_data_get_irq_chip_data(d);
> struct its_node *its;
>
> - /* If we use the list map, we issue VMAPP on demand... */
> - if (its_list_map)
> + /*
> + * If we use the list map, we issue VMAPP on demand... Unless
> + * we're on a GICv4.1 and we eagerly map the VPE on all ITSs
> + * so that VSGIs can work.
> + */
> + if (!gic_requires_eager_mapping())
> return 0;
>
> /* Map the VPE to the first possible CPU */
> @@ -3984,10 +4007,10 @@ static void its_vpe_irq_domain_deactivate(struct irq_domain *domain,
> struct its_node *its;
>
> /*
> - * If we use the list map, we unmap the VPE once no VLPIs are
> - * associated with the VM.
> + * If we use the list map on GICv4.0, we unmap the VPE once no
> + * VLPIs are associated with the VM.
> */
> - if (its_list_map)
> + if (!gic_requires_eager_mapping())
> return;
>
> list_for_each_entry(its, &its_nodes, entry) {
>


Thanks,
zenghui

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