Re: [PATCH v2 5/5] x86: virtio-mmio: support virtio-mmio with MSI for x86

["Michael S. Tsirkin" <mst@redhat.com>]

On Mon, Feb 10, 2020 at 05:05:21PM +0800, Zha Bin wrote:
> From: Liu Jiang <gerry@linux.alibaba.com>
> 
> virtio-mmio supports a generic MSI irq domain for all archs. This
> patch adds the x86 architecture support.
> 
> Signed-off-by: Liu Jiang <gerry@linux.alibaba.com>
> Co-developed-by: Zha Bin <zhabin@linux.alibaba.com>
> Signed-off-by: Zha Bin <zhabin@linux.alibaba.com>
> Co-developed-by: Jing Liu <jing2.liu@linux.intel.com>
> Signed-off-by: Jing Liu <jing2.liu@linux.intel.com>
> Co-developed-by: Chao Peng <chao.p.peng@linux.intel.com>
> Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com>
> ---
>  arch/x86/kernel/apic/msi.c | 11 ++++++++++-

Patches like this need to CC x86 maintainers.


>  1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kernel/apic/msi.c b/arch/x86/kernel/apic/msi.c
> index 159bd0c..2fcd602 100644
> --- a/arch/x86/kernel/apic/msi.c
> +++ b/arch/x86/kernel/apic/msi.c
> @@ -45,7 +45,11 @@ static void __irq_msi_compose_msg(struct irq_cfg *cfg, struct msi_msg *msg)
>  		MSI_DATA_VECTOR(cfg->vector);
>  }
>  
> -static void irq_msi_compose_msg(struct irq_data *data, struct msi_msg *msg)
> +/*
> + * x86 PCI-MSI/HPET/DMAR related method.
> + * Also can be used as arch specific method for virtio-mmio MSI.
> + */
> +void irq_msi_compose_msg(struct irq_data *data, struct msi_msg *msg)
>  {
>  	__irq_msi_compose_msg(irqd_cfg(data), msg);
>  }
> @@ -166,6 +170,11 @@ static void irq_msi_update_msg(struct irq_data *irqd, struct irq_cfg *cfg)
>  	return ret;
>  }
>  
> +struct irq_domain *arch_msi_root_irq_domain(void)
> +{
> +	return x86_vector_domain;
> +}
> +
>  /*
>   * IRQ Chip for MSI PCI/PCI-X/PCI-Express Devices,
>   * which implement the MSI or MSI-X Capability Structure.


So there's a new non-static functions with no callers here,
and a previously static irq_msi_compose_msg is not longer
static. No callers so how does this help anyone?
And how does this achieve the goal of enabling virtio mmio?


> -- 
> 1.8.3.1