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SubjectRe: [PATCH v1 1/2] x86/msi: Enhance x86 to support platform_msi
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On 2019/12/25 上午10:50, Zha Bin wrote:
> From: Liu Jiang <gerry@linux.alibaba.com>
>
> The x86 platform currently only supports specific MSI/MSI-x for PCI
> devices. To enable MSI to the platform devices such as virtio-mmio
> device, this patch enhances x86 with platform MSI by leveraging the
> already built-in platform-msi driver (drivers/base/platform-msi.c)
> and makes it as a configurable option.
>
> Signed-off-by: Liu Jiang <gerry@linux.alibaba.com>
> Signed-off-by: Zha Bin <zhabin@linux.alibaba.com>
> Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com>
> Signed-off-by: Jing Liu <jing2.liu@linux.intel.com>
> ---
> arch/x86/Kconfig | 6 ++++
> arch/x86/include/asm/hw_irq.h | 5 +++
> arch/x86/include/asm/irqdomain.h | 9 +++++
> arch/x86/kernel/apic/msi.c | 74 ++++++++++++++++++++++++++++++++++++++++
> drivers/base/platform-msi.c | 4 +--
> include/linux/msi.h | 1 +
> 6 files changed, 97 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 5e89499..c1178f2 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -1074,6 +1074,12 @@ config X86_IO_APIC
> def_bool y
> depends on X86_LOCAL_APIC || X86_UP_IOAPIC
>
> +config X86_PLATFORM_MSI
> + def_bool y
> + depends on X86_LOCAL_APIC && X86_64
> + select GENERIC_MSI_IRQ
> + select GENERIC_MSI_IRQ_DOMAIN
> +
> config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
> bool "Reroute for broken boot IRQs"
> depends on X86_IO_APIC
> diff --git a/arch/x86/include/asm/hw_irq.h b/arch/x86/include/asm/hw_irq.h
> index 4154bc5..5c96b49 100644
> --- a/arch/x86/include/asm/hw_irq.h
> +++ b/arch/x86/include/asm/hw_irq.h
> @@ -113,6 +113,11 @@ struct irq_alloc_info {
> struct msi_desc *desc;
> };
> #endif
> +#ifdef CONFIG_X86_PLATFORM_MSI
> + struct {
> + irq_hw_number_t platform_msi_hwirq;
> + };
> +#endif
> };
> };
>
> diff --git a/arch/x86/include/asm/irqdomain.h b/arch/x86/include/asm/irqdomain.h
> index c066ffa..b53f51f 100644
> --- a/arch/x86/include/asm/irqdomain.h
> +++ b/arch/x86/include/asm/irqdomain.h
> @@ -56,4 +56,13 @@ extern void mp_irqdomain_deactivate(struct irq_domain *domain,
> static inline void arch_init_msi_domain(struct irq_domain *domain) { }
> #endif
>
> +#ifdef CONFIG_X86_PLATFORM_MSI
> +extern struct irq_domain *platform_msi_get_def_irq_domain(void);
> +#else
> +static inline struct irq_domain *platform_msi_get_def_irq_domain(void)
> +{
> + return NULL;
> +}
> +#endif
> +
> #endif
> diff --git a/arch/x86/kernel/apic/msi.c b/arch/x86/kernel/apic/msi.c
> index 7f75334..ef558c7 100644
> --- a/arch/x86/kernel/apic/msi.c
> +++ b/arch/x86/kernel/apic/msi.c
> @@ -22,6 +22,10 @@
> #include <asm/irq_remapping.h>
>
> static struct irq_domain *msi_default_domain;
> +#ifdef CONFIG_X86_PLATFORM_MSI
> +static struct irq_domain *platform_msi_default_domain;
> +static struct msi_domain_info platform_msi_domain_info;
> +#endif
>
> static void irq_msi_compose_msg(struct irq_data *data, struct msi_msg *msg)
> {
> @@ -146,6 +150,17 @@ void __init arch_init_msi_domain(struct irq_domain *parent)
> }
> if (!msi_default_domain)
> pr_warn("failed to initialize irqdomain for MSI/MSI-x.\n");
> +#ifdef CONFIG_X86_PLATFORM_MSI
> + fn = irq_domain_alloc_named_fwnode("PLATFORM-MSI");
> + if (fn) {
> + platform_msi_default_domain =
> + platform_msi_create_irq_domain(fn,
> + &platform_msi_domain_info, parent);
> + irq_domain_free_fwnode(fn);
> + }
> + if (!platform_msi_default_domain)
> + pr_warn("failed to initialize irqdomain for PLATFORM-MSI.\n");
> +#endif
> }
>
> #ifdef CONFIG_IRQ_REMAP
> @@ -384,3 +399,62 @@ int hpet_assign_irq(struct irq_domain *domain, struct hpet_channel *hc,
> return irq_domain_alloc_irqs(domain, 1, NUMA_NO_NODE, &info);
> }
> #endif
> +
> +#ifdef CONFIG_X86_PLATFORM_MSI
> +static void platform_msi_mask_irq(struct irq_data *data)
> +{
> +}
> +
> +static void platform_msi_unmask_irq(struct irq_data *data)
> +{
> +}
> +
> +static struct irq_chip platform_msi_controller = {
> + .name = "PLATFORM-MSI",
> + .irq_mask = platform_msi_mask_irq,
> + .irq_unmask = platform_msi_unmask_irq,
> + .irq_ack = irq_chip_ack_parent,
> + .irq_retrigger = irq_chip_retrigger_hierarchy,
> + .irq_compose_msi_msg = irq_msi_compose_msg,
> + .flags = IRQCHIP_SKIP_SET_WAKE,


Except for irq_msi_compose_msg all the rest were arch independent. Can
we have allow arch to specify irq_compose_msi_msg then we can unfiy the
rest for all archs?


> +};
> +
> +static int platform_msi_prepare(struct irq_domain *domain, struct device *dev,
> + int nvec, msi_alloc_info_t *arg)
> +{
> + memset(arg, 0, sizeof(*arg));
> + return 0;
> +}
> +
> +static void platform_msi_set_desc(msi_alloc_info_t *arg, struct msi_desc *desc)
> +{
> + arg->platform_msi_hwirq = platform_msi_calc_hwirq(desc);
> +}
> +
> +static irq_hw_number_t platform_msi_get_hwirq(struct msi_domain_info *info,
> + msi_alloc_info_t *arg)
> +{
> + return arg->platform_msi_hwirq;
> +}
> +
> +static struct msi_domain_ops platform_msi_domain_ops = {
> + .msi_prepare = platform_msi_prepare,
> + .set_desc = platform_msi_set_desc,
> + .get_hwirq = platform_msi_get_hwirq,
> +};
> +
> +static struct msi_domain_info platform_msi_domain_info = {
> + .flags = MSI_FLAG_USE_DEF_DOM_OPS |
> + MSI_FLAG_USE_DEF_CHIP_OPS |
> + MSI_FLAG_ACTIVATE_EARLY,
> + .ops = &platform_msi_domain_ops,
> + .chip = &platform_msi_controller,
> + .handler = handle_edge_irq,
> + .handler_name = "edge",
> +};


Is this better to have a virtio-mmio specific domain and irq_chip? It
looks to me the advantages are:

- works for all archs
- allow virtio-mmio specific method to do e.g mask/unmask.

Thanks


> +
> +struct irq_domain *platform_msi_get_def_irq_domain(void)
> +{
> + return platform_msi_default_domain;
> +}
> +#endif
> diff --git a/drivers/base/platform-msi.c b/drivers/base/platform-msi.c
> index 8da314b..45752f1 100644
> --- a/drivers/base/platform-msi.c
> +++ b/drivers/base/platform-msi.c
> @@ -31,12 +31,11 @@ struct platform_msi_priv_data {
> /* The devid allocator */
> static DEFINE_IDA(platform_msi_devid_ida);
>
> -#ifdef GENERIC_MSI_DOMAIN_OPS
> /*
> * Convert an msi_desc to a globaly unique identifier (per-device
> * devid + msi_desc position in the msi_list).
> */
> -static irq_hw_number_t platform_msi_calc_hwirq(struct msi_desc *desc)
> +irq_hw_number_t platform_msi_calc_hwirq(struct msi_desc *desc)
> {
> u32 devid;
>
> @@ -45,6 +44,7 @@ static irq_hw_number_t platform_msi_calc_hwirq(struct msi_desc *desc)
> return (devid << (32 - DEV_ID_SHIFT)) | desc->platform.msi_index;
> }
>
> +#ifdef GENERIC_MSI_DOMAIN_OPS
> static void platform_msi_set_desc(msi_alloc_info_t *arg, struct msi_desc *desc)
> {
> arg->desc = desc;
> diff --git a/include/linux/msi.h b/include/linux/msi.h
> index 8ad679e..ee5f566 100644
> --- a/include/linux/msi.h
> +++ b/include/linux/msi.h
> @@ -362,6 +362,7 @@ int platform_msi_domain_alloc(struct irq_domain *domain, unsigned int virq,
> void platform_msi_domain_free(struct irq_domain *domain, unsigned int virq,
> unsigned int nvec);
> void *platform_msi_get_host_data(struct irq_domain *domain);
> +irq_hw_number_t platform_msi_calc_hwirq(struct msi_desc *desc);
> #endif /* CONFIG_GENERIC_MSI_IRQ_DOMAIN */
>
> #ifdef CONFIG_PCI_MSI_IRQ_DOMAIN

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