Re: [PATCH kvmtool 15/21] vfio: Refactor ioport trap handler

[Alexandru Elisei <alexandru.elisei@arm.com>]

Hi Andre,

Looks good, one nitpick below.

On 12/10/20 2:29 PM, Andre Przywara wrote:
> With the planned retirement of the special ioport emulation code, we
> need to provide an emulation function compatible with the MMIO prototype.
>
> Adjust the I/O port trap handler to use that new function, and provide
> shims to implement the old ioport interface, for now.
>
> Signed-off-by: Andre Przywara <andre.przywara@arm.com>
> ---
>  vfio/core.c | 51 ++++++++++++++++++++++++++++++++++++---------------
>  1 file changed, 36 insertions(+), 15 deletions(-)
>
> diff --git a/vfio/core.c b/vfio/core.c
> index 0b45e78b..f55f1f87 100644
> --- a/vfio/core.c
> +++ b/vfio/core.c
> @@ -81,15 +81,12 @@ out_free_buf:
>  	return ret;
>  }
>  
> -static bool vfio_ioport_in(struct ioport *ioport, struct kvm_cpu *vcpu,
> -			   u16 port, void *data, int len)
> +static bool _vfio_ioport_in(struct vfio_region *region, u32 offset,
> +			    void *data, int len)
>  {
> -	u32 val;
> -	ssize_t nr;
> -	struct vfio_region *region = ioport->priv;
>  	struct vfio_device *vdev = region->vdev;
> -
> -	u32 offset = port - region->port_base;
> +	ssize_t nr;
> +	u32 val;
>  
>  	if (!(region->info.flags & VFIO_REGION_INFO_FLAG_READ))
>  		return false;
> @@ -97,7 +94,7 @@ static bool vfio_ioport_in(struct ioport *ioport, struct kvm_cpu *vcpu,
>  	nr = pread(vdev->fd, &val, len, region->info.offset + offset);
>  	if (nr != len) {
>  		vfio_dev_err(vdev, "could not read %d bytes from I/O port 0x%x\n",
> -			     len, port);
> +			     len, offset);

To keep things functionally identical, shouldn't that be offset +
region->port_base? I think it's easier to identify the device when we have the PCI
ioport address.

Thanks,

Alex

>  		return false;
>  	}
>  
> @@ -118,15 +115,13 @@ static bool vfio_ioport_in(struct ioport *ioport, struct kvm_cpu *vcpu,
>  	return true;
>  }
>  
> -static bool vfio_ioport_out(struct ioport *ioport, struct kvm_cpu *vcpu,
> -			    u16 port, void *data, int len)
> +static bool _vfio_ioport_out(struct vfio_region *region, u32 offset,
> +			     void *data, int len)
>  {
> -	u32 val;
> -	ssize_t nr;
> -	struct vfio_region *region = ioport->priv;
>  	struct vfio_device *vdev = region->vdev;
> +	ssize_t nr;
> +	u32 val;
>  
> -	u32 offset = port - region->port_base;
>  
>  	if (!(region->info.flags & VFIO_REGION_INFO_FLAG_WRITE))
>  		return false;
> @@ -148,11 +143,37 @@ static bool vfio_ioport_out(struct ioport *ioport, struct kvm_cpu *vcpu,
>  	nr = pwrite(vdev->fd, &val, len, region->info.offset + offset);
>  	if (nr != len)
>  		vfio_dev_err(vdev, "could not write %d bytes to I/O port 0x%x",
> -			     len, port);
> +			     len, offset);
>  
>  	return nr == len;
>  }
>  
> +static void vfio_ioport_mmio(struct kvm_cpu *vcpu, u64 addr, u8 *data, u32 len,
> +			     u8 is_write, void *ptr)
> +{
> +	struct vfio_region *region = ptr;
> +	u32 offset = addr - region->port_base;
> +
> +	if (is_write)
> +		_vfio_ioport_out(region, offset, data, len);
> +	else
> +		_vfio_ioport_in(region, offset, data, len);
> +}
> +
> +static bool vfio_ioport_out(struct ioport *ioport, struct kvm_cpu *vcpu,
> +			    u16 port, void *data, int len)
> +{
> +	vfio_ioport_mmio(vcpu, port, data, len, true, ioport->priv);
> +	return true;
> +}
> +
> +static bool vfio_ioport_in(struct ioport *ioport, struct kvm_cpu *vcpu,
> +			   u16 port, void *data, int len)
> +{
> +	vfio_ioport_mmio(vcpu, port, data, len, false, ioport->priv);
> +	return true;
> +}
> +
>  static struct ioport_operations vfio_ioport_ops = {
>  	.io_in	= vfio_ioport_in,
>  	.io_out	= vfio_ioport_out,