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Message-ID: <d40dc34f-c5cf-1091-c20d-f2c02a906964@redhat.com>
Date: Tue, 17 Mar 2020 09:36:41 +0100
From: Auger Eric <eric.auger@...hat.com>
To: Zenghui Yu <yuzenghui@...wei.com>, Marc Zyngier <maz@...nel.org>,
linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.cs.columbia.edu,
kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
Jason Cooper <jason@...edaemon.net>,
Robert Richter <rrichter@...vell.com>,
Thomas Gleixner <tglx@...utronix.de>,
James Morse <james.morse@....com>,
Julien Thierry <julien.thierry.kdev@...il.com>,
Suzuki K Poulose <suzuki.poulose@....com>
Subject: Re: [PATCH v5 09/23] irqchip/gic-v4.1: Add initial SGI configuration
Hi Zenghui,
On 3/17/20 3:02 AM, Zenghui Yu wrote:
> Hi Eric,
>
> On 2020/3/17 1:53, Auger Eric wrote:
>> Hi Marc,
>>
>> On 3/4/20 9:33 PM, Marc Zyngier wrote:
>>> The GICv4.1 ITS has yet another new command (VSGI) which allows
>>> a VPE-targeted SGI to be configured (or have its pending state
>>> cleared). Add support for this command and plumb it into the
>>> activate irqdomain callback so that it is ready to be used.
>>>
>>> Signed-off-by: Marc Zyngier <maz@...nel.org>
>>> Reviewed-by: Zenghui Yu <yuzenghui@...wei.com>
>>> ---
>>> drivers/irqchip/irq-gic-v3-its.c | 79 +++++++++++++++++++++++++++++-
>>> include/linux/irqchip/arm-gic-v3.h | 3 +-
>>> 2 files changed, 80 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/irqchip/irq-gic-v3-its.c
>>> b/drivers/irqchip/irq-gic-v3-its.c
>>> index 112b452fcb40..e0db3f906f87 100644
>>> --- a/drivers/irqchip/irq-gic-v3-its.c
>>> +++ b/drivers/irqchip/irq-gic-v3-its.c
>>> @@ -380,6 +380,15 @@ struct its_cmd_desc {
>>> struct {
>>> struct its_vpe *vpe;
>>> } its_invdb_cmd;
>>> +
>>> + struct {
>>> + struct its_vpe *vpe;
>>> + u8 sgi;
>>> + u8 priority;
>>> + bool enable;
>>> + bool group;
>>> + bool clear;
>>> + } its_vsgi_cmd;
>>> };
>>> };
>>> @@ -528,6 +537,31 @@ static void its_encode_db(struct its_cmd_block
>>> *cmd, bool db)
>>> its_mask_encode(&cmd->raw_cmd[2], db, 63, 63);
>>> }
>>> +static void its_encode_sgi_intid(struct its_cmd_block *cmd, u8 sgi)
>>> +{
>>> + its_mask_encode(&cmd->raw_cmd[0], sgi, 35, 32);
>>> +}
>>> +
>>> +static void its_encode_sgi_priority(struct its_cmd_block *cmd, u8 prio)
>>> +{
>>> + its_mask_encode(&cmd->raw_cmd[0], prio >> 4, 23, 20);
>>> +}
>>> +
>>> +static void its_encode_sgi_group(struct its_cmd_block *cmd, bool grp)
>>> +{
>>> + its_mask_encode(&cmd->raw_cmd[0], grp, 10, 10);
>>> +}
>>> +
>>> +static void its_encode_sgi_clear(struct its_cmd_block *cmd, bool clr)
>>> +{
>>> + its_mask_encode(&cmd->raw_cmd[0], clr, 9, 9);
>>> +}
>>> +
>>> +static void its_encode_sgi_enable(struct its_cmd_block *cmd, bool en)
>>> +{
>>> + its_mask_encode(&cmd->raw_cmd[0], en, 8, 8);
>>> +}
>>> +
>>> static inline void its_fixup_cmd(struct its_cmd_block *cmd)
>>> {
>>> /* Let's fixup BE commands */
>>> @@ -893,6 +927,26 @@ static struct its_vpe
>>> *its_build_invdb_cmd(struct its_node *its,
>>> return valid_vpe(its, desc->its_invdb_cmd.vpe);
>>> }
>>> +static struct its_vpe *its_build_vsgi_cmd(struct its_node *its,
>>> + struct its_cmd_block *cmd,
>>> + struct its_cmd_desc *desc)
>>> +{
>>> + if (WARN_ON(!is_v4_1(its)))
>>> + return NULL;
>>> +
>>> + its_encode_cmd(cmd, GITS_CMD_VSGI);
>>> + its_encode_vpeid(cmd, desc->its_vsgi_cmd.vpe->vpe_id);
>>> + its_encode_sgi_intid(cmd, desc->its_vsgi_cmd.sgi);
>>> + its_encode_sgi_priority(cmd, desc->its_vsgi_cmd.priority);
>>> + its_encode_sgi_group(cmd, desc->its_vsgi_cmd.group);
>>> + its_encode_sgi_clear(cmd, desc->its_vsgi_cmd.clear);
>>> + its_encode_sgi_enable(cmd, desc->its_vsgi_cmd.enable);
>>> +
>>> + its_fixup_cmd(cmd);
>>> +
>>> + return valid_vpe(its, desc->its_vsgi_cmd.vpe);
>>> +}
>>> +
>>> static u64 its_cmd_ptr_to_offset(struct its_node *its,
>>> struct its_cmd_block *ptr)
>>> {
>>> @@ -3870,6 +3924,21 @@ static struct irq_chip its_vpe_4_1_irq_chip = {
>>> .irq_set_vcpu_affinity = its_vpe_4_1_set_vcpu_affinity,
>>> };
>>> +static void its_configure_sgi(struct irq_data *d, bool clear)
>>> +{
>>> + struct its_vpe *vpe = irq_data_get_irq_chip_data(d);
>>> + struct its_cmd_desc desc;
>>> +
>>> + desc.its_vsgi_cmd.vpe = vpe;
>>> + desc.its_vsgi_cmd.sgi = d->hwirq;
>>> + desc.its_vsgi_cmd.priority = vpe->sgi_config[d->hwirq].priority;
>>> + desc.its_vsgi_cmd.enable = vpe->sgi_config[d->hwirq].enabled;
>>> + desc.its_vsgi_cmd.group = vpe->sgi_config[d->hwirq].group;
>>> + desc.its_vsgi_cmd.clear = clear;
>>> +
>>> + its_send_single_vcommand(find_4_1_its(), its_build_vsgi_cmd,
>>> &desc);
>> I see we pick up the first 4.1 ITS with find_4_1_its(). Can it happen
>> that not all of them have a mapping for that vPEID and if so we should
>> rather use one that has this mapping?
>
> It can't happen in GICv4.1, and you may find the answer in patch #16
> ("Eagerly vmap vPEs"). I also failed to follow this logic the first
> time looking at it [*], so I think it may worth adding some comments
> on top of find_4_1_its()?
>
> [*]
> https://lore.kernel.org/lkml/c94061be-d029-69c8-d34f-4d21081d5aba@huawei.com/
OK thank you for the pointer. Slowly moving forward ... ;-)
Eric
>
>
>>
>> The spec says:
>> The ITS controls must only be used on an ITS that has a mapping for that
>> vPEID.
>> Where multiple ITSs have a mapping for the vPEID, any ITS with a mapping
>> may be used.
>>
>>> +}
>>> +
>>> static int its_sgi_set_affinity(struct irq_data *d,
>>> const struct cpumask *mask_val,
>>> bool force)
>>> @@ -3915,13 +3984,21 @@ static void its_sgi_irq_domain_free(struct
>>> irq_domain *domain,
>>> static int its_sgi_irq_domain_activate(struct irq_domain *domain,
>>> struct irq_data *d, bool reserve)
>>> {
>>> + /* Write out the initial SGI configuration */
>>> + its_configure_sgi(d, false);
>>> return 0;
>>> }
>>> static void its_sgi_irq_domain_deactivate(struct irq_domain *domain,
>>> struct irq_data *d)
>>> {
>>> - /* Nothing to do */
>>> + struct its_vpe *vpe = irq_data_get_irq_chip_data(d);
>>> +
>>> + /* First disable the SGI */
>>> + vpe->sgi_config[d->hwirq].enabled = false;
>>> + its_configure_sgi(d, false);
>>> + /* Now clear the potential pending bit (yes, this is clunky) */
>> nit: Without carefuly reading the VSGI cmd notes, it is difficult to
>> understand why those 2 steps are needed: maybe replace this comment by
>> something like:
>> to change the config, clear must be set to false. Then clear is set and
>> this leaves the config unchanged. Both steps cannot be done concurrently.
>>
>> "
>
> I think it makes sense.
>
>
> Thanks,
> Zenghui
>
>>> + its_configure_sgi(d, true);
>>> }
>>> static struct irq_domain_ops its_sgi_domain_ops = {
>>> diff --git a/include/linux/irqchip/arm-gic-v3.h
>>> b/include/linux/irqchip/arm-gic-v3.h
>>> index b28acfa71f82..fd3be49ac9a5 100644
>>> --- a/include/linux/irqchip/arm-gic-v3.h
>>> +++ b/include/linux/irqchip/arm-gic-v3.h
>>> @@ -502,8 +502,9 @@
>>> #define GITS_CMD_VMAPTI GITS_CMD_GICv4(GITS_CMD_MAPTI)
>>> #define GITS_CMD_VMOVI GITS_CMD_GICv4(GITS_CMD_MOVI)
>>> #define GITS_CMD_VSYNC GITS_CMD_GICv4(GITS_CMD_SYNC)
>>> -/* VMOVP and INVDB are the odd ones, as they dont have a physical
>>> counterpart */
>>> +/* VMOVP, VSGI and INVDB are the odd ones, as they dont have a
>>> physical counterpart */
>>> #define GITS_CMD_VMOVP GITS_CMD_GICv4(2)
>>> +#define GITS_CMD_VSGI GITS_CMD_GICv4(3)
>>> #define GITS_CMD_INVDB GITS_CMD_GICv4(0xe)
>>> /*
>>>
>> Thanks
>>
>> Eric
>>
>>
>> .
>>
>
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