From: Auger Eric <eric.auger@redhat.com>
To: Marc Zyngier <maz@kernel.org>,
linux-arm-kernel@lists.infradead.org,
kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Jason Cooper <jason@lakedaemon.net>,
Robert Richter <rrichter@marvell.com>,
Thomas Gleixner <tglx@linutronix.de>,
Zenghui Yu <yuzenghui@huawei.com>,
James Morse <james.morse@arm.com>,
Julien Thierry <julien.thierry.kdev@gmail.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>
Subject: Re: [PATCH v5 11/23] irqchip/gic-v4.1: Plumb get/set_irqchip_state SGI callbacks
Date: Mon, 16 Mar 2020 22:43:18 +0100 [thread overview]
Message-ID: <d6b95eeb-b1c7-802b-e29e-a6c6ecf9ea33@redhat.com> (raw)
In-Reply-To: <20200304203330.4967-12-maz@kernel.org>
Hi Marc,
On 3/4/20 9:33 PM, Marc Zyngier wrote:
> To implement the get/set_irqchip_state callbacks (limited to the
> PENDING state), we have to use a particular set of hacks:
>
> - Reading the pending state is done by using a pair of new redistributor
> registers (GICR_VSGIR, GICR_VSGIPENDR), which allow the 16 interrupts
> state to be retrieved.
> - Setting the pending state is done by generating it as we'd otherwise do
> for a guest (writing to GITS_SGIR).
> - Clearing the pending state is done by emiting a VSGI command with the
emitting
> "clear" bit set.
>
> This requires some interesting locking though:
> - When talking to the redistributor, we must make sure that the VPE
> affinity doesn't change, hence taking the VPE lock.
> - At the same time, we must ensure that nobody accesses the same
> redistributor's GICR_VSGI*R registers for a different VPE, which
GICR_VSGIR
> would corrupt the reading of the pending bits. We thus take the
> per-RD spinlock. Much fun.
>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> ---
> drivers/irqchip/irq-gic-v3-its.c | 73 ++++++++++++++++++++++++++++++
> include/linux/irqchip/arm-gic-v3.h | 14 ++++++
> 2 files changed, 87 insertions(+)
>
> diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
> index c93f178914ee..fb2b836c31ff 100644
> --- a/drivers/irqchip/irq-gic-v3-its.c
> +++ b/drivers/irqchip/irq-gic-v3-its.c
> @@ -3962,11 +3962,84 @@ static int its_sgi_set_affinity(struct irq_data *d,
> return -EINVAL;
> }
>
> +static int its_sgi_set_irqchip_state(struct irq_data *d,
> + enum irqchip_irq_state which,
> + bool state)
> +{
> + if (which != IRQCHIP_STATE_PENDING)
> + return -EINVAL;
> +
> + if (state) {
> + struct its_vpe *vpe = irq_data_get_irq_chip_data(d);
> + struct its_node *its = find_4_1_its();
> + u64 val;
> +
> + val = FIELD_PREP(GITS_SGIR_VPEID, vpe->vpe_id);
> + val |= FIELD_PREP(GITS_SGIR_VINTID, d->hwirq);
> + writeq_relaxed(val, its->sgir_base + GITS_SGIR - SZ_128K);
> + } else {
> + its_configure_sgi(d, true);
> + }
> +
> + return 0;
> +}
> +
> +static int its_sgi_get_irqchip_state(struct irq_data *d,
> + enum irqchip_irq_state which, bool *val)
> +{
> + struct its_vpe *vpe = irq_data_get_irq_chip_data(d);
> + void __iomem *base;
> + unsigned long flags;
> + u32 count = 1000000; /* 1s! */
where does it come from? I did not find any info in the spec about this
delay.
> + u32 status;
> + int cpu;
> +
> + if (which != IRQCHIP_STATE_PENDING)
> + return -EINVAL;
> +
> + /*
> + * Locking galore! We can race against two different events:
> + *
> + * - Concurent vPE affinity change: we must make sure it cannot
> + * happen, or we'll talk to the wrong redistributor. This is
> + * identical to what happens with vLPIs.
> + *
> + * - Concurrent VSGIPENDR access: As it involves accessing two
> + * MMIO registers, this must be made atomic one way or another.
> + */
> + cpu = vpe_to_cpuid_lock(vpe, &flags);
> + raw_spin_lock(&gic_data_rdist_cpu(cpu)->rd_lock);
> + base = gic_data_rdist_cpu(cpu)->rd_base + SZ_128K;
> + writel_relaxed(vpe->vpe_id, base + GICR_VSGIR);
> + do {
> + status = readl_relaxed(base + GICR_VSGIPENDR);
> + if (!(status & GICR_VSGIPENDR_BUSY))
> + goto out;
> +
> + count--;
> + if (!count) {
> + pr_err_ratelimited("Unable to get SGI status\n");
> + goto out;
> + }
> + cpu_relax();
> + udelay(1);
> + } while(count);
> +
> +out:
> + raw_spin_unlock(&gic_data_rdist_cpu(cpu)->rd_lock);
> + vpe_to_cpuid_unlock(vpe, flags);
> + *val = !!(status & (1 << d->hwirq));
> +
> + return 0;
cascade an error on timeout?
> +}
> +
> static struct irq_chip its_sgi_irq_chip = {
> .name = "GICv4.1-sgi",
> .irq_mask = its_sgi_mask_irq,
> .irq_unmask = its_sgi_unmask_irq,
> .irq_set_affinity = its_sgi_set_affinity,
> + .irq_set_irqchip_state = its_sgi_set_irqchip_state,
> + .irq_get_irqchip_state = its_sgi_get_irqchip_state,
> };
>
> static int its_sgi_irq_domain_alloc(struct irq_domain *domain,
> diff --git a/include/linux/irqchip/arm-gic-v3.h b/include/linux/irqchip/arm-gic-v3.h
> index fd3be49ac9a5..830d2abf14b3 100644
> --- a/include/linux/irqchip/arm-gic-v3.h
> +++ b/include/linux/irqchip/arm-gic-v3.h
> @@ -345,6 +345,15 @@
> #define GICR_VPENDBASER_4_1_VGRP1EN (1ULL << 58)
> #define GICR_VPENDBASER_4_1_VPEID GENMASK_ULL(15, 0)
>
> +#define GICR_VSGIR 0x0080
> +
> +#define GICR_VSGIR_VPEID GENMASK(15, 0)
> +
> +#define GICR_VSGIPENDR 0x0088
> +
> +#define GICR_VSGIPENDR_BUSY (1U << 31)
> +#define GICR_VSGIPENDR_PENDING GENMASK(15, 0)
> +
> /*
> * ITS registers, offsets from ITS_base
> */
> @@ -368,6 +377,11 @@
>
> #define GITS_TRANSLATER 0x10040
>
> +#define GITS_SGIR 0x20020
> +
> +#define GITS_SGIR_VPEID GENMASK_ULL(47, 32)
> +#define GITS_SGIR_VINTID GENMASK_ULL(7, 0)
as spotted by Zenghui 3, 0
> +
> #define GITS_CTLR_ENABLE (1U << 0)
> #define GITS_CTLR_ImDe (1U << 1)
> #define GITS_CTLR_ITS_NUMBER_SHIFT 4
>
Thanks
Eric
next prev parent reply other threads:[~2020-03-16 21:43 UTC|newest]
Thread overview: 114+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-04 20:33 [PATCH v5 00/23] irqchip/gic-v4: GICv4.1 architecture support Marc Zyngier
2020-03-04 20:33 ` [PATCH v5 01/23] irqchip/gic-v3: Use SGIs without active state if offered Marc Zyngier
2020-03-12 6:30 ` Zenghui Yu
2020-03-12 9:28 ` Marc Zyngier
2020-03-12 12:05 ` Marc Zyngier
2020-03-13 1:39 ` Zenghui Yu
2020-03-12 17:16 ` Auger Eric
2020-03-12 17:23 ` Marc Zyngier
2020-03-29 20:26 ` [tip: irq/core] " tip-bot2 for Marc Zyngier
2020-03-04 20:33 ` [PATCH v5 02/23] irqchip/gic-v4.1: Skip absent CPUs while iterating over redistributors Marc Zyngier
2020-03-16 17:10 ` Auger Eric
2020-03-29 20:26 ` [tip: irq/core] " tip-bot2 for Marc Zyngier
2020-03-04 20:33 ` [PATCH v5 03/23] irqchip/gic-v4.1: Ensure mutual exclusion between vPE affinity change and RD access Marc Zyngier
2020-03-12 6:56 ` Zenghui Yu
2020-03-29 20:26 ` [tip: irq/core] " tip-bot2 for Marc Zyngier
2020-03-04 20:33 ` [PATCH v5 04/23] irqchip/gic-v4.1: Wait for completion of redistributor's INVALL operation Marc Zyngier
2020-03-20 14:23 ` Auger Eric
2020-03-04 20:33 ` [PATCH v5 05/23] irqchip/gic-v4.1: Ensure mutual exclusion betwen invalidations on the same RD Marc Zyngier
2020-03-12 7:11 ` Zenghui Yu
2020-03-20 14:23 ` Auger Eric
2020-03-29 20:26 ` [tip: irq/core] " tip-bot2 for Marc Zyngier
2020-03-04 20:33 ` [PATCH v5 06/23] irqchip/gic-v4.1: Advertise support v4.1 to KVM Marc Zyngier
2020-03-16 17:10 ` Auger Eric
2020-03-29 20:26 ` [tip: irq/core] " tip-bot2 for Marc Zyngier
2020-03-04 20:33 ` [PATCH v5 07/23] irqchip/gic-v4.1: Map the ITS SGIR register page Marc Zyngier
2020-03-16 17:10 ` Auger Eric
2020-03-29 20:26 ` [tip: irq/core] " tip-bot2 for Marc Zyngier
2020-03-04 20:33 ` [PATCH v5 08/23] irqchip/gic-v4.1: Plumb skeletal VSGI irqchip Marc Zyngier
2020-03-16 17:10 ` Auger Eric
2020-03-19 10:03 ` Marc Zyngier
2020-03-29 20:26 ` [tip: irq/core] " tip-bot2 for Marc Zyngier
2020-03-04 20:33 ` [PATCH v5 09/23] irqchip/gic-v4.1: Add initial SGI configuration Marc Zyngier
2020-03-16 17:53 ` Auger Eric
2020-03-17 2:02 ` Zenghui Yu
2020-03-17 8:36 ` Auger Eric
2020-03-19 10:20 ` Marc Zyngier
2020-03-29 20:26 ` [tip: irq/core] " tip-bot2 for Marc Zyngier
2020-03-04 20:33 ` [PATCH v5 10/23] irqchip/gic-v4.1: Plumb mask/unmask SGI callbacks Marc Zyngier
2020-03-16 18:15 ` Auger Eric
2020-03-29 20:26 ` [tip: irq/core] " tip-bot2 for Marc Zyngier
2020-03-04 20:33 ` [PATCH v5 11/23] irqchip/gic-v4.1: Plumb get/set_irqchip_state " Marc Zyngier
2020-03-12 7:41 ` Zenghui Yu
2020-03-16 21:43 ` Auger Eric [this message]
2020-03-19 10:27 ` Marc Zyngier
2020-03-29 20:26 ` [tip: irq/core] " tip-bot2 for Marc Zyngier
2020-03-04 20:33 ` [PATCH v5 12/23] irqchip/gic-v4.1: Plumb set_vcpu_affinity " Marc Zyngier
2020-03-17 10:35 ` Auger Eric
2020-03-29 20:26 ` [tip: irq/core] " tip-bot2 for Marc Zyngier
2020-03-04 20:33 ` [PATCH v5 13/23] irqchip/gic-v4.1: Move doorbell management to the GICv4 abstraction layer Marc Zyngier
2020-03-12 8:20 ` Zenghui Yu
2020-03-29 20:26 ` [tip: irq/core] " tip-bot2 for Marc Zyngier
2020-03-04 20:33 ` [PATCH v5 14/23] irqchip/gic-v4.1: Add VSGI allocation/teardown Marc Zyngier
2020-03-12 8:06 ` Zenghui Yu
2020-03-29 20:26 ` [tip: irq/core] " tip-bot2 for Marc Zyngier
2020-03-04 20:33 ` [PATCH v5 15/23] irqchip/gic-v4.1: Add VSGI property setup Marc Zyngier
2020-03-12 8:09 ` Zenghui Yu
2020-03-17 10:30 ` Auger Eric
2020-03-19 10:57 ` Marc Zyngier
2020-03-29 20:26 ` [tip: irq/core] " tip-bot2 for Marc Zyngier
2020-03-04 20:33 ` [PATCH v5 16/23] irqchip/gic-v4.1: Eagerly vmap vPEs Marc Zyngier
2020-03-12 8:12 ` Zenghui Yu
2020-03-17 2:49 ` Zenghui Yu
2020-03-19 10:55 ` Marc Zyngier
2020-03-20 2:31 ` Zenghui Yu
2020-03-29 20:26 ` [tip: irq/core] " tip-bot2 for Marc Zyngier
2020-03-04 20:33 ` [PATCH v5 17/23] KVM: arm64: GICv4.1: Let doorbells be auto-enabled Marc Zyngier
2020-03-12 8:15 ` Zenghui Yu
2020-03-17 11:04 ` Auger Eric
2020-03-04 20:33 ` [PATCH v5 18/23] KVM: arm64: GICv4.1: Add direct injection capability to SGI registers Marc Zyngier
2020-03-18 3:28 ` Zenghui Yu
2020-03-20 8:11 ` Auger Eric
2020-03-20 10:05 ` Marc Zyngier
2020-03-20 10:56 ` Auger Eric
2020-03-04 20:33 ` [PATCH v5 19/23] KVM: arm64: GICv4.1: Allow SGIs to switch between HW and SW interrupts Marc Zyngier
2020-03-19 16:16 ` Auger Eric
2020-03-19 19:52 ` Marc Zyngier
2020-03-19 20:13 ` Auger Eric
2020-03-20 9:17 ` Marc Zyngier
2020-03-20 4:22 ` Zenghui Yu
2020-03-04 20:33 ` [PATCH v5 20/23] KVM: arm64: GICv4.1: Plumb SGI implementation selection in the distributor Marc Zyngier
2020-03-18 6:34 ` Zenghui Yu
2020-03-19 12:10 ` Marc Zyngier
2020-03-19 20:38 ` Auger Eric
2020-03-20 3:08 ` Zenghui Yu
2020-03-20 7:59 ` Auger Eric
2020-03-20 9:46 ` Marc Zyngier
2020-03-20 11:09 ` Auger Eric
2020-03-20 11:20 ` Marc Zyngier
2020-03-20 3:53 ` Zenghui Yu
2020-03-20 9:01 ` Marc Zyngier
2020-03-23 8:11 ` Zenghui Yu
2020-03-23 8:25 ` Marc Zyngier
2020-03-23 12:40 ` Zenghui Yu
2020-03-04 20:33 ` [PATCH v5 21/23] KVM: arm64: GICv4.1: Reload VLPI configuration on distributor enable/disable Marc Zyngier
2020-03-18 3:17 ` Zenghui Yu
2020-03-19 12:18 ` Marc Zyngier
2020-03-04 20:33 ` [PATCH v5 22/23] KVM: arm64: GICv4.1: Allow non-trapping WFI when using HW SGIs Marc Zyngier
2020-03-20 4:23 ` Zenghui Yu
2020-03-20 8:12 ` Auger Eric
2020-03-04 20:33 ` [PATCH v5 23/23] KVM: arm64: GICv4.1: Expose HW-based SGIs in debugfs Marc Zyngier
2020-03-18 3:19 ` Zenghui Yu
2020-03-19 15:05 ` Auger Eric
2020-03-19 15:21 ` Marc Zyngier
2020-03-19 15:43 ` Auger Eric
2020-03-19 16:16 ` Marc Zyngier
2020-03-19 16:17 ` Auger Eric
2020-03-20 4:38 ` Zenghui Yu
2020-03-20 9:09 ` Marc Zyngier
2020-03-20 11:35 ` Zenghui Yu
2020-03-20 11:46 ` Marc Zyngier
2020-03-20 12:09 ` Zenghui Yu
2020-03-05 3:39 ` [PATCH v5 00/23] irqchip/gic-v4: GICv4.1 architecture support Zenghui Yu
2020-03-09 8:17 ` Zenghui Yu
2020-03-09 8:46 ` Marc Zyngier
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