From: Zenghui Yu <yuzenghui@huawei.com>
To: Marc Zyngier <maz@kernel.org>
Cc: <linux-arm-kernel@lists.infradead.org>,
<kvmarm@lists.cs.columbia.edu>, <kvm@vger.kernel.org>,
<linux-kernel@vger.kernel.org>,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Jason Cooper <jason@lakedaemon.net>,
"Robert Richter" <rrichter@marvell.com>,
Thomas Gleixner <tglx@linutronix.de>,
"Eric Auger" <eric.auger@redhat.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 16/23] irqchip/gic-v4.1: Eagerly vmap vPEs
Date: Fri, 20 Mar 2020 10:31:20 +0800 [thread overview]
Message-ID: <2f667113-8241-dce6-0a5e-3acb5ef9cf7f@huawei.com> (raw)
In-Reply-To: <d45e7ddfd51d4d8229e02efc42c8da04@kernel.org>
Hi Marc,
On 2020/3/19 18:55, Marc Zyngier wrote:
> On 2020-03-17 02:49, Zenghui Yu wrote:
>> Hi Marc,
>>
>> On 2020/3/5 4:33, 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>
>>
>> Before GICv4.1, we use vlpi_count to evaluate whether the vPE has been
>> mapped on the specified ITS, and use this refcount to only issue VMOVP
>> to those involved ITSes. It's broken after this patch.
>>
>> We may need to re-evaluate "whether the vPE is mapped" now that we're at
>> GICv4.1, otherwise *no* VMOVP will be issued on the v4.1 capable machine
>> (I mean those without single VMOVP support).
>>
>> What I'm saying is something like below (only an idea, it even can't
>> compile), any thoughts?
>>
>>
>> diff --git a/drivers/irqchip/irq-gic-v3-its.c
>> b/drivers/irqchip/irq-gic-v3-its.c
>> index 2e12bc52e3a2..3450b5e847ca 100644
>> --- a/drivers/irqchip/irq-gic-v3-its.c
>> +++ b/drivers/irqchip/irq-gic-v3-its.c
>> @@ -198,7 +198,8 @@ static u16 get_its_list(struct its_vm *vm)
>> if (!is_v4(its))
>> continue;
>>
>> - if (vm->vlpi_count[its->list_nr])
>> + if (vm->vlpi_count[its->list_nr] ||
>> + gic_requires_eager_mapping())
>> __set_bit(its->list_nr, &its_list);
>> }
>>
>> @@ -1295,7 +1296,8 @@ static void its_send_vmovp(struct its_vpe *vpe)
>> if (!is_v4(its))
>> continue;
>>
>> - if (!vpe->its_vm->vlpi_count[its->list_nr])
>> + if (!vpe->its_vm->vlpi_count[its->list_nr] &&
>> + !gic_requires_eager_mapping())
>> continue;
>>
>> desc.its_vmovp_cmd.col = &its->collections[col_id];
>
> It took me a while to wrap my head around that one, but you're as usual
> spot on.
>
> The use of gic_requires_eager_mapping() is a bit confusing here, as it
> isn't
> so much that the VPE is eagerly mapped, but the predicate on which we
> evaluate
> the need for a VMOVP. How about this:
>
> diff --git a/drivers/irqchip/irq-gic-v3-its.c
> b/drivers/irqchip/irq-gic-v3-its.c
> index cd6451e190c9..348f7a909a69 100644
> --- a/drivers/irqchip/irq-gic-v3-its.c
> +++ b/drivers/irqchip/irq-gic-v3-its.c
> @@ -189,6 +189,15 @@ static DEFINE_IDA(its_vpeid_ida);
> #define gic_data_rdist_rd_base() (gic_data_rdist()->rd_base)
> #define gic_data_rdist_vlpi_base() (gic_data_rdist_rd_base() +
> SZ_128K)
>
> +/*
> + * Skip ITSs that have no vLPIs mapped, unless we're on GICv4.1, as we
> + * always have vSGIs mapped.
> + */
> +static bool require_its_list_vmovp(struct its_vm *vm, struct its_node
> *its)
> +{
> + return (gic_rdists->has_rvpeid || vm->vlpi_count[its->list_nr]);
> +}
> +
> static u16 get_its_list(struct its_vm *vm)
> {
> struct its_node *its;
> @@ -198,7 +207,7 @@ static u16 get_its_list(struct its_vm *vm)
> if (!is_v4(its))
> continue;
>
> - if (vm->vlpi_count[its->list_nr])
> + if (require_its_list_vmovp(vm, its))
> __set_bit(its->list_nr, &its_list);
> }
>
> @@ -1295,7 +1304,7 @@ static void its_send_vmovp(struct its_vpe *vpe)
> if (!is_v4(its))
> continue;
>
> - if (!vpe->its_vm->vlpi_count[its->list_nr])
> + if (!require_its_list_vmovp(vpe->its_vm, its))
> continue;
>
> desc.its_vmovp_cmd.col = &its->collections[col_id];
Indeed this looks much clearer. We're actually evaluating the need
for issuing VMOVP to a specified ITS, on system using its_list_map
feature (though we evaluate it by checking whether the vPE is mapped
on this ITS).
Thanks,
Zenghui
next prev parent reply other threads:[~2020-03-20 2:31 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
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 [this message]
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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