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Message-ID: <4fda8fbe-2c65-196e-81ea-fff513a17f11@redhat.com>
Date: Thu, 16 Mar 2017 10:27:03 +0100
From: Auger Eric <eric.auger@...hat.com>
To: Marc Zyngier <marc.zyngier@....com>, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.cs.columbia.edu
Cc: Thomas Gleixner <tglx@...utronix.de>,
Jason Cooper <jason@...edaemon.net>,
Christoffer Dall <christoffer.dall@...aro.org>
Subject: Re: [RFC PATCH 21/33] irqchip/gic-v3-its: Add VPE irq domain
allocation/teardown
Hi,
On 17/01/2017 11:20, Marc Zyngier wrote:
> When creating a VM, the low level GICv4 code is responsible for:
> - allocating each VPE a unique VPEID
> - allocating a doorbell interrupt for each VPE
> - allocating the pending tables for each VPE
> - allocating the property table for the VM
>
> This of course has to be reversed when the VM is brought down.
>
> All of this is wired into the irq domain alloc/free methods.
>
> Signed-off-by: Marc Zyngier <marc.zyngier@....com>
> ---
> drivers/irqchip/irq-gic-v3-its.c | 174 +++++++++++++++++++++++++++++++++++++++
> 1 file changed, 174 insertions(+)
>
> diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
> index ddd8096..54d0075 100644
> --- a/drivers/irqchip/irq-gic-v3-its.c
> +++ b/drivers/irqchip/irq-gic-v3-its.c
> @@ -139,6 +139,7 @@ static struct rdists *gic_rdists;
> static struct irq_domain *its_parent;
>
> static unsigned long its_list_map;
> +static DEFINE_IDA(its_vpeid_ida);
>
> #define gic_data_rdist() (raw_cpu_ptr(gic_rdists->rdist))
> #define gic_data_rdist_rd_base() (gic_data_rdist()->rd_base)
> @@ -1146,6 +1147,11 @@ static struct page *its_allocate_prop_table(gfp_t gfp_flags)
> return prop_page;
> }
>
> +static void its_free_prop_table(struct page *prop_page)
> +{
> + free_pages((unsigned long)page_address(prop_page),
> + get_order(LPI_PROPBASE_SZ));
> +}
>
> static int __init its_alloc_lpi_tables(void)
> {
> @@ -1444,6 +1450,12 @@ static struct page *its_allocate_pending_table(gfp_t gfp_flags)
> return pend_page;
> }
>
> +static void its_free_pending_table(struct page *pt)
> +{
> + free_pages((unsigned long)page_address(pt),
> + get_order(max(LPI_PENDBASE_SZ, SZ_64K)));
> +}
> +
> static void its_cpu_init_lpis(void)
> {
> void __iomem *rbase = gic_data_rdist_rd_base();
> @@ -1666,6 +1678,34 @@ static bool its_alloc_device_table(struct its_node *its, u32 dev_id)
> return its_alloc_table_entry(baser, dev_id);
> }
>
> +static bool its_alloc_vpe_table(u32 vpe_id)
> +{
> + struct its_node *its;
> +
> + /*
> + * Make sure the L2 tables are allocated on *all* v4 ITSs. We
> + * could try and only do it on ITSs corresponding to devices
> + * that have interrupts targeted at this VPE, but the
> + * complexity becomes crazy (and you have tons of memory
> + * anyway, right?).
> + */
> + list_for_each_entry(its, &its_nodes, entry) {
> + struct its_baser *baser;
> +
> + if (!its->is_v4)
> + continue;
> +
> + baser = its_get_baser(its, GITS_BASER_TYPE_VCPU);
> + if (!baser)
> + return false;
don't you need to check the vpe_id doesn't overshoot the BASER caps?
> +
> + if (!its_alloc_table_entry(baser, vpe_id))
> + return false;
> + }
> +
> + return true;
> +}
> +
> static struct its_device *its_create_device(struct its_node *its, u32 dev_id,
> int nvecs)
> {
> @@ -1922,7 +1962,141 @@ static struct irq_chip its_vpe_irq_chip = {
> .name = "GICv4-vpe",
> };
>
> +static int its_vpe_id_alloc(void)
> +{
> + return ida_simple_get(&its_vpeid_ida, 0, 1 << 16, GFP_KERNEL);
> +}
> +
> +static void its_vpe_id_free(u16 id)
> +{
> + ida_simple_remove(&its_vpeid_ida, id);
> +}
> +
> +static int its_vpe_init(struct its_vpe *vpe)
> +{
> + struct page *vpt_page;
> + int vpe_id;
> +
> + /* Allocate vpe_id */
> + vpe_id = its_vpe_id_alloc();
> + if (vpe_id < 0)
> + return vpe_id;
> +
> + /* Allocate VPT */
> + vpt_page = its_allocate_pending_table(GFP_KERNEL);
> + if (vpt_page) {
isn't it !vpt_page?
> + its_vpe_id_free(vpe_id);
> + return -ENOMEM;
> + }
> +
> + if (!its_alloc_vpe_table(vpe_id)) {
> + its_vpe_id_free(vpe_id);
> + its_free_pending_table(vpe->vpt_page);
> + return -ENOMEM;
> + }
> +
> + vpe->vpe_id = vpe_id;
> + vpe->vpt_page = vpt_page;
> +
> + return 0;
> +}
> +
> +static void its_vpe_teardown(struct its_vpe *vpe)
> +{
> + its_vpe_id_free(vpe->vpe_id);
> + its_free_pending_table(vpe->vpt_page);
don't you need to remove the VPE entry as well?
> +}
> +
> +static int its_vpe_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
> + unsigned int nr_irqs, void *args)
> +{
> + msi_alloc_info_t *info = args;
> + struct its_vpe **vpes = info->scratchpad[0].ptr;
> + struct its_vm *vm = vpes[0]->its_vm;
> + unsigned long *bitmap;
> + struct page *vprop_page;
> + int base, nr_ids, i, err = 0;
> +
> + bitmap = its_lpi_alloc_chunks(nr_irqs, &base, &nr_ids);
> + if (!bitmap)
> + return -ENOMEM;
> +
> + if (nr_ids < nr_irqs) {
> + its_lpi_free_chunks(bitmap, base, nr_ids);
> + return -ENOMEM;
> + }
> +
> + vprop_page = its_allocate_prop_table(GFP_KERNEL);
> + if (!vprop_page) {
> + its_lpi_free_chunks(bitmap, base, nr_ids);
> + return ENOMEM;
-ENOMEM
> + }
> +
> + for (i = 0; i < nr_irqs; i++) {
> + vpes[i]->vpe_db_lpi = base + i;
> + err = its_vpe_init(vpes[i]);
> + if (err)
> + break;
> + irq_domain_set_hwirq_and_chip(domain,
> + virq + i, vpes[i]->vpe_db_lpi,
> + &its_vpe_irq_chip, vpes[i]);
> + set_bit(i, bitmap);
> + }
> +
> + if (err) {
> + while (--i >= 0) {
> + its_vpe_teardown(vpes[i]);
> + clear_bit(i, bitmap);
> + }
> +
> + its_lpi_free_chunks(bitmap, base, nr_ids);
> + its_free_prop_table(vprop_page);
> +
> + return err;
> + }
> +
> + vm->db_bitmap = bitmap;
> + vm->db_lpi_base = base;
> + vm->nr_db_lpis = nr_ids;
> + vm->vprop_page = vprop_page;
> +
> + return 0;
> +}
> +
> +static void its_vpe_irq_domain_free(struct irq_domain *domain,
> + unsigned int virq,
> + unsigned int nr_irqs)
> +{
> + struct its_vm *vm = NULL;
> + int i;
> +
> + for (i = 0; i < nr_irqs; i++) {
> + struct irq_data *data = irq_domain_get_irq_data(domain, virq);
> + struct its_vpe *vpe = irq_data_get_irq_chip_data(data);
> +
> + BUG_ON(vm && vm != vpe->its_vm);
> + if (!vm)
> + vm = vpe->its_vm;
I don't get the above. actually I missed who does set its_vm field on
the vpe.
Thanks
Eric
> +
> + clear_bit(vpe->vpe_db_lpi - vm->db_lpi_base, vm->db_bitmap);
> + its_vpe_teardown(vpe);
> + irq_domain_reset_irq_data(data);
> + }
> +
> + if (!vm)
> + return;
> +
> + if (bitmap_empty(vm->db_bitmap, vm->nr_db_lpis)) {
> + its_lpi_free_chunks(vm->db_bitmap, vm->db_lpi_base, vm->nr_db_lpis);
> + its_free_prop_table(vm->vprop_page);
> + }
> +
> + irq_domain_free_irqs_parent(domain, virq, nr_irqs);
> +}
> +
> static const struct irq_domain_ops its_vpe_domain_ops = {
> + .alloc = its_vpe_irq_domain_alloc,
> + .free = its_vpe_irq_domain_free,
> };
>
> static int its_force_quiescent(void __iomem *base)
>
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