[Intel-xe] [PATCH 2/3] drm/xe: Prepare for running in different SR-IOV modes
Matt Roper
matthew.d.roper at intel.com
Wed Nov 22 19:47:40 UTC 2023
On Wed, Nov 15, 2023 at 08:38:03AM +0100, Michal Wajdeczko wrote:
> We will be adding support for the SR-IOV and driver might be then
> running, in addition to existing non-virtualized bare-metal mode,
> also in Physical Function (PF) or Virtual Function (VF) mode.
>
> Since these additional modes require some changes to the driver,
> define enum flag to represent different SR-IOV modes and add a
> function where we will detect the actual mode in the runtime.
>
> We start with a forced bare-metal mode as it is sufficient to
> enable basic functionality and ensures no impact to existing code.
For platforms that support SRIOV, can you describe what the benefit is
of running in bare-metal mode vs just running in PF mode with no VFs
active? Will we wind up needing to do extra initialization in PF mode
that could be counter-productive if someone didn't actually want to use
any virtualization? Will the system have additional limitations in PF
mode that we can avoid in bare-metal mode?
Aside from adding some explanation for that,
Reviewed-by: Matt Roper <matthew.d.roper at intel.com>
>
> Signed-off-by: Michal Wajdeczko <michal.wajdeczko at intel.com>
> ---
> drivers/gpu/drm/xe/Makefile | 3 ++
> drivers/gpu/drm/xe/xe_device_types.h | 7 ++++
> drivers/gpu/drm/xe/xe_pci.c | 3 ++
> drivers/gpu/drm/xe/xe_sriov.c | 55 ++++++++++++++++++++++++++++
> drivers/gpu/drm/xe/xe_sriov.h | 42 +++++++++++++++++++++
> drivers/gpu/drm/xe/xe_sriov_types.h | 28 ++++++++++++++
> 6 files changed, 138 insertions(+)
> create mode 100644 drivers/gpu/drm/xe/xe_sriov.c
> create mode 100644 drivers/gpu/drm/xe/xe_sriov.h
> create mode 100644 drivers/gpu/drm/xe/xe_sriov_types.h
>
> diff --git a/drivers/gpu/drm/xe/Makefile b/drivers/gpu/drm/xe/Makefile
> index cb41b4fead08..fbba74d9a330 100644
> --- a/drivers/gpu/drm/xe/Makefile
> +++ b/drivers/gpu/drm/xe/Makefile
> @@ -123,6 +123,9 @@ xe-y += xe_bb.o \
> # graphics hardware monitoring (HWMON) support
> xe-$(CONFIG_HWMON) += xe_hwmon.o
>
> +# graphics virtualization (SR-IOV) support
> +xe-y += xe_sriov.o
> +
> # i915 Display compat #defines and #includes
> subdir-ccflags-$(CONFIG_DRM_XE_DISPLAY) += \
> -I$(srctree)/$(src)/display/ext \
> diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h
> index f2ba4f746fa2..2712905c7a91 100644
> --- a/drivers/gpu/drm/xe/xe_device_types.h
> +++ b/drivers/gpu/drm/xe/xe_device_types.h
> @@ -18,6 +18,7 @@
> #include "xe_platform_types.h"
> #include "xe_pt_types.h"
> #include "xe_pmu.h"
> +#include "xe_sriov_types.h"
> #include "xe_step_types.h"
>
> #if IS_ENABLED(CONFIG_DRM_XE_DISPLAY)
> @@ -299,6 +300,12 @@ struct xe_device {
> struct ttm_resource_manager sys_mgr;
> } mem;
>
> + /** @sriov: device level virtualization data */
> + struct {
> + /** @sriov.__mode: SR-IOV mode (Don't access directly!) */
> + enum xe_sriov_mode __mode;
> + } sriov;
> +
> /** @usm: unified memory state */
> struct {
> /** @asid: convert a ASID to VM */
> diff --git a/drivers/gpu/drm/xe/xe_pci.c b/drivers/gpu/drm/xe/xe_pci.c
> index c1c8048bbc0f..3030b223e4a0 100644
> --- a/drivers/gpu/drm/xe/xe_pci.c
> +++ b/drivers/gpu/drm/xe/xe_pci.c
> @@ -24,6 +24,7 @@
> #include "xe_module.h"
> #include "xe_pci_types.h"
> #include "xe_pm.h"
> +#include "xe_sriov.h"
> #include "xe_step.h"
>
> enum toggle_d3cold {
> @@ -706,6 +707,8 @@ static int xe_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
>
> pci_set_master(pdev);
>
> + xe_sriov_probe_early(xe, desc->has_sriov);
> +
> err = xe_info_init(xe, desc, subplatform_desc);
> if (err)
> goto err_pci_disable;
> diff --git a/drivers/gpu/drm/xe/xe_sriov.c b/drivers/gpu/drm/xe/xe_sriov.c
> new file mode 100644
> index 000000000000..42a0e0c917a0
> --- /dev/null
> +++ b/drivers/gpu/drm/xe/xe_sriov.c
> @@ -0,0 +1,55 @@
> +// SPDX-License-Identifier: MIT
> +/*
> + * Copyright © 2023 Intel Corporation
> + */
> +
> +#include "xe_assert.h"
> +#include "xe_sriov.h"
> +
> +/**
> + * xe_sriov_mode_to_string - Convert enum value to string.
> + * @mode: the &xe_sriov_mode to convert
> + *
> + * Returns: SR-IOV mode as a user friendly string.
> + */
> +const char *xe_sriov_mode_to_string(enum xe_sriov_mode mode)
> +{
> + switch (mode) {
> + case XE_SRIOV_MODE_NONE:
> + return "none";
> + case XE_SRIOV_MODE_PF:
> + return "SR-IOV PF";
> + case XE_SRIOV_MODE_VF:
> + return "SR-IOV VF";
> + default:
> + return "<invalid>";
> + }
> +}
> +
> +/**
> + * xe_sriov_probe_early - Probe a SR-IOV mode.
> + * @xe: the &xe_device to probe mode on
> + * @has_sriov: flag indicating hardware support for SR-IOV
> + *
> + * This function should be called only once and as soon as possible during
> + * driver probe to detect whether we are running a SR-IOV Physical Function
> + * (PF) or a Virtual Function (VF) device.
> + *
> + * SR-IOV PF mode detection is based on PCI @dev_is_pf() function.
> + * SR-IOV VF mode detection is based on dedicated MMIO register read.
> + */
> +void xe_sriov_probe_early(struct xe_device *xe, bool has_sriov)
> +{
> + enum xe_sriov_mode mode = XE_SRIOV_MODE_NONE;
> +
> + /* TODO: replace with proper mode detection */
> + xe_assert(xe, !has_sriov);
> +
> + xe_assert(xe, !xe->sriov.__mode);
> + xe->sriov.__mode = mode;
> + xe_assert(xe, xe->sriov.__mode);
> +
> + if (has_sriov)
> + drm_info(&xe->drm, "Running in %s mode\n",
> + xe_sriov_mode_to_string(xe_device_sriov_mode(xe)));
> +}
> diff --git a/drivers/gpu/drm/xe/xe_sriov.h b/drivers/gpu/drm/xe/xe_sriov.h
> new file mode 100644
> index 000000000000..5af73a3172b0
> --- /dev/null
> +++ b/drivers/gpu/drm/xe/xe_sriov.h
> @@ -0,0 +1,42 @@
> +/* SPDX-License-Identifier: MIT */
> +/*
> + * Copyright © 2023 Intel Corporation
> + */
> +
> +#ifndef _XE_SRIOV_H_
> +#define _XE_SRIOV_H_
> +
> +#include "xe_assert.h"
> +#include "xe_device_types.h"
> +#include "xe_sriov_types.h"
> +
> +const char *xe_sriov_mode_to_string(enum xe_sriov_mode mode);
> +
> +void xe_sriov_probe_early(struct xe_device *xe, bool has_sriov);
> +
> +static inline enum xe_sriov_mode xe_device_sriov_mode(struct xe_device *xe)
> +{
> + xe_assert(xe, xe->sriov.__mode);
> + return xe->sriov.__mode;
> +}
> +
> +static inline bool xe_device_is_sriov_pf(struct xe_device *xe)
> +{
> + return xe_device_sriov_mode(xe) == XE_SRIOV_MODE_PF;
> +}
> +
> +static inline bool xe_device_is_sriov_vf(struct xe_device *xe)
> +{
> + return xe_device_sriov_mode(xe) == XE_SRIOV_MODE_VF;
> +}
> +
> +#ifdef CONFIG_PCI_IOV
> +#define IS_SRIOV_PF(xe) xe_device_is_sriov_pf(xe)
> +#else
> +#define IS_SRIOV_PF(xe) (typecheck(struct xe_device *, (xe)) && false)
> +#endif
> +#define IS_SRIOV_VF(xe) xe_device_is_sriov_vf(xe)
> +
> +#define IS_SRIOV(xe) (IS_SRIOV_PF(xe) || IS_SRIOV_VF(xe))
> +
> +#endif
> diff --git a/drivers/gpu/drm/xe/xe_sriov_types.h b/drivers/gpu/drm/xe/xe_sriov_types.h
> new file mode 100644
> index 000000000000..999a4311b98b
> --- /dev/null
> +++ b/drivers/gpu/drm/xe/xe_sriov_types.h
> @@ -0,0 +1,28 @@
> +/* SPDX-License-Identifier: MIT */
> +/*
> + * Copyright © 2023 Intel Corporation
> + */
> +
> +#ifndef _XE_SRIOV_TYPES_H_
> +#define _XE_SRIOV_TYPES_H_
> +
> +#include <linux/build_bug.h>
> +
> +/**
> + * enum xe_sriov_mode - SR-IOV mode
> + * @XE_SRIOV_MODE_NONE: bare-metal mode (non-virtualized)
> + * @XE_SRIOV_MODE_PF: SR-IOV Physical Function (PF) mode
> + * @XE_SRIOV_MODE_VF: SR-IOV Virtual Function (VF) mode
> + */
> +enum xe_sriov_mode {
> + /*
> + * Note: We don't use default enum value 0 to allow catch any too early
> + * attempt of checking the SR-IOV mode prior to the actual mode probe.
> + */
> + XE_SRIOV_MODE_NONE = 1,
> + XE_SRIOV_MODE_PF,
> + XE_SRIOV_MODE_VF,
> +};
> +static_assert(XE_SRIOV_MODE_NONE);
> +
> +#endif
> --
> 2.25.1
>
--
Matt Roper
Graphics Software Engineer
Linux GPU Platform Enablement
Intel Corporation
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