linux-kernel - Re: [RFC v4 3/3] vfio: platform: reset: add msi support

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Date:   Mon, 8 Feb 2021 16:27:45 +0100
From:   Auger Eric <eric.auger@...hat.com>
To:     Vikas Gupta <vikas.gupta@...adcom.com>, alex.williamson@...hat.com,
        cohuck@...hat.com, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     vikram.prakash@...adcom.com, srinath.mannam@...adcom.com,
        ashwin.kamath@...adcom.com, zachary.schroff@...adcom.com,
        manish.kurup@...adcom.com
Subject: Re: [RFC v4 3/3] vfio: platform: reset: add msi support

Hi Vikas,

On 1/29/21 6:24 PM, Vikas Gupta wrote:
> Add msi support for Broadcom FlexRm device.
> 
> Signed-off-by: Vikas Gupta <vikas.gupta@...adcom.com>
> ---
>  .../platform/reset/vfio_platform_bcmflexrm.c  | 72 ++++++++++++++++++-
>  1 file changed, 70 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/vfio/platform/reset/vfio_platform_bcmflexrm.c b/drivers/vfio/platform/reset/vfio_platform_bcmflexrm.c
> index 96064ef8f629..6ca4ca12575b 100644
> --- a/drivers/vfio/platform/reset/vfio_platform_bcmflexrm.c
> +++ b/drivers/vfio/platform/reset/vfio_platform_bcmflexrm.c
> @@ -21,7 +21,9 @@
>  #include <linux/init.h>
>  #include <linux/io.h>
>  #include <linux/kernel.h>
> +#include <linux/msi.h>
>  #include <linux/module.h>
> +#include <linux/vfio.h>
>  
>  #include "../vfio_platform_private.h"
>  
> @@ -33,6 +35,9 @@
>  #define RING_VER					0x000
>  #define RING_CONTROL					0x034
>  #define RING_FLUSH_DONE					0x038
> +#define RING_MSI_ADDR_LS				0x03c
> +#define RING_MSI_ADDR_MS				0x040
> +#define RING_MSI_DATA_VALUE				0x064
>  
>  /* Register RING_CONTROL fields */
>  #define CONTROL_FLUSH_SHIFT				5
> @@ -105,8 +110,71 @@ static int vfio_platform_bcmflexrm_reset(struct vfio_platform_device *vdev)
>  	return ret;
>  }
>  
> -module_vfio_reset_handler("brcm,iproc-flexrm-mbox",
> -			  vfio_platform_bcmflexrm_reset);
> +static u32 bcm_num_msi(struct vfio_platform_device *vdev)
Please use the same prefix as for reset, ie. vfio_platform_bcmflexrm_get_msi
> +{
> +	struct vfio_platform_region *reg = &vdev->regions[0];> +
> +	return (reg->size / RING_REGS_SIZE);
> +}
> +
> +static void bcm_write_msi(struct vfio_platform_device *vdev,
vfio_platform_bcmflexrm_msi_write?
> +		struct msi_desc *desc,
> +		struct msi_msg *msg)
> +{
> +	int i;
> +	int hwirq = -1;
> +	int msi_src;
> +	void __iomem *ring;
> +	struct vfio_platform_region *reg = &vdev->regions[0];
> +
> +	if (!reg)
> +		return;
why do you need this check? For this to be called, SET_IRQ IOCTL must
have been called. This can only happen after vfio_platform_open which
first calls vfio_platform_regions_init and then vfio_platform_irq_init
> +
> +	for (i = 0; i < vdev->num_irqs; i++)
> +		if (vdev->irqs[i].type == VFIO_IRQ_TYPE_MSI)
> +			hwirq = vdev->irqs[i].ctx[0].hwirq;
nit: It would have been easier to record in vdev the last index of wired
interrupts and just add the index of the MSI
> +
> +	if (hwirq < 0)
> +		return;
> +
> +	msi_src = desc->irq - hwirq;
> +
> +	if (!reg->ioaddr) {
> +		reg->ioaddr = ioremap(reg->addr, reg->size);
> +		if (!reg->ioaddr)
pr_warn_once("")?
> +			return;
> +	}
> +
> +	ring = reg->ioaddr + msi_src * RING_REGS_SIZE;
> +
> +	writel_relaxed(msg->address_lo, ring + RING_MSI_ADDR_LS);
> +	writel_relaxed(msg->address_hi, ring + RING_MSI_ADDR_MS);
> +	writel_relaxed(msg->data, ring + RING_MSI_DATA_VALUE);
> +}
> +
> +static struct vfio_platform_reset_node vfio_platform_bcmflexrm_reset_node = {
> +	.owner = THIS_MODULE,
> +	.compat = "brcm,iproc-flexrm-mbox",
> +	.of_reset = vfio_platform_bcmflexrm_reset,
> +	.of_get_msi = bcm_num_msi,
> +	.of_msi_write = bcm_write_msi
> +};
> +
> +static int __init vfio_platform_bcmflexrm_reset_module_init(void)
> +{
> +	__vfio_platform_register_reset(&vfio_platform_bcmflexrm_reset_node);
> +
> +	return 0;
> +}
> +
> +static void __exit vfio_platform_bcmflexrm_reset_module_exit(void)
> +{
> +	vfio_platform_unregister_reset("brcm,iproc-flexrm-mbox",
> +				       vfio_platform_bcmflexrm_reset);
> +}
> +
> +module_init(vfio_platform_bcmflexrm_reset_module_init);
> +module_exit(vfio_platform_bcmflexrm_reset_module_exit);
>  
>  MODULE_LICENSE("GPL v2");
>  MODULE_AUTHOR("Anup Patel <anup.patel@...adcom.com>");
> 

I think you should move the whole series in PATCH now.

Thanks

Eric