RE: [PATCH v5 1/4] pci: add non-merged Linux uAPI changes

[Wathsala Wathawana Vithanage <wathsala.vithanage@arm.com>]

Hi Maxim,

Here is the link to the kernel VFIO patch you have asked earlier (v4).
https://lore.kernel.org/kvm/20250221224638.1836909-1-wathsala.vithanage@arm.com/T/#me73cf9b9c87da97d7d9461dfb97863b78ca1755b

Thanks

--wathsala

> -----Original Message-----
> From: Wathsala Vithanage <wathsala.vithanage@arm.com>
> Sent: Monday, June 2, 2025 5:38 PM
> To: Chenbo Xia <chenbox@nvidia.com>; Nipun Gupta <nipun.gupta@amd.com>;
> Maxime Coquelin <maxime.coquelin@redhat.com>
> Cc: dev@dpdk.org; nd <nd@arm.com>; Wathsala Wathawana Vithanage
> <wathsala.vithanage@arm.com>; Dhruv Tripathi <Dhruv.Tripathi@arm.com>
> Subject: [PATCH v5 1/4] pci: add non-merged Linux uAPI changes
> 
> This commit is a hack to prevent build failures the next commit in this patch series
> causes due to missing vfio uapi definitions.
> This commit should NEVER BE MERGED.
> Next commit in this patch series depends on additions to vfio uapi that enable
> TPH icotl in the vfio-pci driver in the Linux kernel.
> These additions have not yet been merged into the upstream kernel.
> 
> Signed-off-by: Wathsala Vithanage <wathsala.vithanage@arm.com>
> Reviewed-by: Dhruv Tripathi <dhruv.tripathi@arm.com>
> ---
>  drivers/bus/pci/linux/pci_init.h   |   1 +
>  kernel/linux/uapi/linux/vfio_tph.h | 102 +++++++++++++++++++++++++++++
>  2 files changed, 103 insertions(+)
>  create mode 100644 kernel/linux/uapi/linux/vfio_tph.h
> 
> diff --git a/drivers/bus/pci/linux/pci_init.h b/drivers/bus/pci/linux/pci_init.h
> index a4d37c0d0a..25b901f460 100644
> --- a/drivers/bus/pci/linux/pci_init.h
> +++ b/drivers/bus/pci/linux/pci_init.h
> @@ -6,6 +6,7 @@
>  #define EAL_PCI_INIT_H_
> 
>  #include <rte_vfio.h>
> +#include <uapi/linux/vfio_tph.h>
> 
>  #include "private.h"
> 
> diff --git a/kernel/linux/uapi/linux/vfio_tph.h
> b/kernel/linux/uapi/linux/vfio_tph.h
> new file mode 100644
> index 0000000000..9336c2e5af
> --- /dev/null
> +++ b/kernel/linux/uapi/linux/vfio_tph.h
> @@ -0,0 +1,102 @@
> +
> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
> +/*
> + * VFIO API definition
> + *
> + * WARNING: CONTENTS OF THIS HEADER NEEDS TO BE MERGED INTO
> KERNEL'S
> + * uapi/linux/vifo.h IN A FUTURE KERNEL RELEASE. UNTIL THEN IT'S TACKED
> + * ON TO DPDK'S kernel/linux/uapi DIRECTORY TO PREVENT BUILD FAILURES.
> + *
> + * Copyright (C) 2012 Red Hat, Inc.  All rights reserved.
> + *     Author: Alex Williamson <alex.williamson@redhat.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +#ifndef _UAPIVFIO_TPH_H
> +#define _UAPIVFIO_TPH_H
> +
> +/**
> + * VFIO_DEVICE_PCI_TPH	- _IO(VFIO_TYPE, VFIO_BASE + 22)
> + *
> + * This command is used to control PCIe TLP Processing Hints (TPH)
> + * capability in a PCIe device.
> + * It supports following operations on a PCIe device with respect to
> +TPH
> + * capability.
> + *
> + * - Enabling/disabling TPH capability in a PCIe device.
> + *
> + *   Setting VFIO_DEVICE_TPH_ENABLE flag enables TPH in no-steering-tag,
> + *   interrupt-vector, or device-specific mode defined in the PCIe specficiation
> + *   when feature flags TPH_ST_NS_MODE, TPH_ST_IV_MODE, and
> TPH_ST_DS_MODE are
> + *   set respectively. TPH_ST_xx_MODE macros are defined in
> + *   uapi/linux/pci_regs.h.
> + *
> + *   VFIO_DEVICE_TPH_DISABLE disables PCIe TPH on the device.
> + *
> + * - Writing STs to MSI-X or ST table in a PCIe device.
> + *
> + *   VFIO_DEVICE_TPH_SET_ST flag set steering tags on a device at an index in
> + *   MSI-X or ST-table depending on the VFIO_TPH_ST_x_MODE flag used and
> device
> + *   capabilities. The caller can set one or more steering tags by passing an
> + *   array of vfio_pci_tph_entry objects containing cpu_id, cache_level, and
> + *   MSI-X/ST-table index. The caller can also set the intended memory type and
> + *   the processing hint by setting VFIO_TPH_MEM_TYPE_x and
> VFIO_TPH_HINT_x
> + *   flags, respectively.
> + *
> + * - Reading Steering Tags (ST) from the host platform.
> + *
> + *   VFIO_DEVICE_TPH_GET_ST flags returns steering tags to the caller. Caller
> + *   can request one or more steering tags by passing an array of
> + *   vfio_pci_tph_entry objects. Steering Tag for each request is returned via
> + *   the st field in vfio_pci_tph_entry.
> + */
> +struct vfio_pci_tph_entry {
> +	/* in */
> +	__u32 cpu_id;			/* CPU logical ID */
> +	__u32 cache_level;		/* Cache level. L1 D= 0, L2D = 2, ...*/
> +	__u8  flags;
> +#define VFIO_TPH_MEM_TYPE_MASK		0x1
> +#define VFIO_TPH_MEM_TYPE_SHIFT		0
> +#define VFIO_TPH_MEM_TYPE_VMEM		0   /* Request volatile memory
> ST */
> +#define VFIO_TPH_MEM_TYPE_PMEM		1   /* Request persistent
> memory ST */
> +
> +#define VFIO_TPH_HINT_MASK		0x3
> +#define VFIO_TPH_HINT_SHIFT		1
> +#define VFIO_TPH_HINT_BIDIR		0
> +#define VFIO_TPH_HINT_REQSTR		(1 << VFIO_TPH_HINT_SHIFT)
> +#define VFIO_TPH_HINT_TARGET		(2 << VFIO_TPH_HINT_SHIFT)
> +#define VFIO_TPH_HINT_TARGET_PRIO	(3 << VFIO_TPH_HINT_SHIFT)
> +	__u8  pad0;
> +	__u16 index;			/* MSI-X/ST-table index to set ST */
> +	/* out */
> +	__u16 st;			/* Steering-Tag */
> +	__u8  ph_ignore;		/* Platform ignored the Processing */
> +	__u8  pad1;
> +};
> +
> +struct vfio_pci_tph {
> +	__u32 argsz;			/* Size of vfio_pci_tph and info[] */
> +	__u32 flags;
> +#define VFIO_TPH_ST_MODE_MASK		0x7
> +
> +#define VFIO_DEVICE_TPH_OP_SHIFT	3
> +#define VFIO_DEVICE_TPH_OP_MASK		(0x7 <<
> VFIO_DEVICE_TPH_OP_SHIFT)
> +/* Enable TPH on device */
> +#define VFIO_DEVICE_TPH_ENABLE		0
> +/* Disable TPH on device */
> +#define VFIO_DEVICE_TPH_DISABLE		(1 <<
> VFIO_DEVICE_TPH_OP_SHIFT)
> +/* Get steering-tags */
> +#define VFIO_DEVICE_TPH_GET_ST		(2 <<
> VFIO_DEVICE_TPH_OP_SHIFT)
> +/* Set steering-tags */
> +#define VFIO_DEVICE_TPH_SET_ST		(4 <<
> VFIO_DEVICE_TPH_OP_SHIFT)
> +	__u32 count;			/* Number of entries in ents[] */
> +	struct vfio_pci_tph_entry ents[];
> +#define VFIO_TPH_INFO_MAX	2048	/* Max entries in ents[] */
> +};
> +
> +#define VFIO_DEVICE_PCI_TPH	_IO(VFIO_TYPE, VFIO_BASE + 22)
> +
> +#endif /* _UAPIVFIO_TPH_H */
> --
> 2.43.0