[PATCH 1/6] drm/xe/vf: Use register values obtained from the PF

[Matt Roper]

On Thu, May 23, 2024 at 09:22:35PM +0200, Michal Wajdeczko wrote:
> As part of the its initialization, the VF driver has already
> obtained a list of the runtime (fuse) register values from the
> PF driver. When VF driver is attempting to read register that is
> inaccessible to the VF, use the values from this list instead.
> 
> Signed-off-by: Michal Wajdeczko <michal.wajdeczko at intel.com>

Reviewed-by: Matt Roper <matthew.d.roper at intel.com>

> ---
>  drivers/gpu/drm/xe/xe_gt_sriov_vf.c | 53 +++++++++++++++++++++++++++++
>  drivers/gpu/drm/xe/xe_gt_sriov_vf.h |  2 ++
>  drivers/gpu/drm/xe/xe_mmio.c        |  4 +++
>  3 files changed, 59 insertions(+)
> 
> diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_vf.c b/drivers/gpu/drm/xe/xe_gt_sriov_vf.c
> index bab3858b423e..237486a80fb5 100644
> --- a/drivers/gpu/drm/xe/xe_gt_sriov_vf.c
> +++ b/drivers/gpu/drm/xe/xe_gt_sriov_vf.c
> @@ -4,6 +4,7 @@
>   */
>  
>  #include <linux/bitfield.h>
> +#include <linux/bsearch.h>
>  
>  #include <drm/drm_managed.h>
>  #include <drm/drm_print.h>
> @@ -21,6 +22,7 @@
>  #include "xe_guc.h"
>  #include "xe_guc_hxg_helpers.h"
>  #include "xe_guc_relay.h"
> +#include "xe_mmio.h"
>  #include "xe_sriov.h"
>  
>  #define make_u64_from_u32(hi, lo) ((u64)((u64)(u32)(hi) << 32 | (u32)(lo)))
> @@ -677,6 +679,57 @@ int xe_gt_sriov_vf_query_runtime(struct xe_gt *gt)
>  	return err;
>  }
>  
> +static int vf_runtime_reg_cmp(const void *a, const void *b)
> +{
> +	const struct vf_runtime_reg *ra = a;
> +	const struct vf_runtime_reg *rb = b;
> +
> +	return (int)ra->offset - (int)rb->offset;
> +}
> +
> +static struct vf_runtime_reg *vf_lookup_reg(struct xe_gt *gt, u32 addr)
> +{
> +	struct xe_gt_sriov_vf_runtime *runtime = &gt->sriov.vf.runtime;
> +	struct vf_runtime_reg key = { .offset = addr };
> +
> +	xe_gt_assert(gt, IS_SRIOV_VF(gt_to_xe(gt)));
> +
> +	return bsearch(&key, runtime->regs, runtime->regs_size, sizeof(key),
> +		       vf_runtime_reg_cmp);
> +}
> +
> +/**
> + * xe_gt_sriov_vf_read32 - Get a register value from the runtime data.
> + * @gt: the &xe_gt
> + * @reg: the register to read
> + *
> + * This function is for VF use only.
> + * This function shall be called after VF has connected to PF.
> + * This function is dedicated for registers that VFs can't read directly.
> + *
> + * Return: register value obtained from the PF or 0 if not found.
> + */
> +u32 xe_gt_sriov_vf_read32(struct xe_gt *gt, struct xe_reg reg)
> +{
> +	u32 addr = xe_mmio_adjusted_addr(gt, reg.addr);
> +	struct vf_runtime_reg *rr;
> +
> +	xe_gt_assert(gt, IS_SRIOV_VF(gt_to_xe(gt)));
> +	xe_gt_assert(gt, gt->sriov.vf.pf_version.major);
> +	xe_gt_assert(gt, !reg.vf);
> +
> +	rr = vf_lookup_reg(gt, addr);
> +	if (!rr) {
> +		xe_gt_WARN(gt, IS_ENABLED(CONFIG_DRM_XE_DEBUG),
> +			   "VF is trying to read an inaccessible register %#x+%#x\n",
> +			   reg.addr, addr - reg.addr);
> +		return 0;
> +	}
> +
> +	xe_gt_sriov_dbg_verbose(gt, "runtime[%#x] = %#x\n", addr, rr->value);
> +	return rr->value;
> +}
> +
>  /**
>   * xe_gt_sriov_vf_print_config - Print VF self config.
>   * @gt: the &xe_gt
> diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_vf.h b/drivers/gpu/drm/xe/xe_gt_sriov_vf.h
> index d6d37b193d17..be69c1025320 100644
> --- a/drivers/gpu/drm/xe/xe_gt_sriov_vf.h
> +++ b/drivers/gpu/drm/xe/xe_gt_sriov_vf.h
> @@ -10,6 +10,7 @@
>  
>  struct drm_printer;
>  struct xe_gt;
> +struct xe_reg;
>  
>  int xe_gt_sriov_vf_bootstrap(struct xe_gt *gt);
>  int xe_gt_sriov_vf_query_config(struct xe_gt *gt);
> @@ -17,6 +18,7 @@ int xe_gt_sriov_vf_connect(struct xe_gt *gt);
>  int xe_gt_sriov_vf_query_runtime(struct xe_gt *gt);
>  
>  u16 xe_gt_sriov_vf_guc_ids(struct xe_gt *gt);
> +u32 xe_gt_sriov_vf_read32(struct xe_gt *gt, struct xe_reg reg);
>  
>  void xe_gt_sriov_vf_print_config(struct xe_gt *gt, struct drm_printer *p);
>  void xe_gt_sriov_vf_print_runtime(struct xe_gt *gt, struct drm_printer *p);
> diff --git a/drivers/gpu/drm/xe/xe_mmio.c b/drivers/gpu/drm/xe/xe_mmio.c
> index 8a39d4c18554..16c94f118119 100644
> --- a/drivers/gpu/drm/xe/xe_mmio.c
> +++ b/drivers/gpu/drm/xe/xe_mmio.c
> @@ -22,6 +22,7 @@
>  #include "xe_gt.h"
>  #include "xe_gt_mcr.h"
>  #include "xe_gt_printk.h"
> +#include "xe_gt_sriov_vf.h"
>  #include "xe_macros.h"
>  #include "xe_module.h"
>  #include "xe_sriov.h"
> @@ -479,6 +480,9 @@ u32 xe_mmio_read32(struct xe_gt *gt, struct xe_reg reg)
>  	struct xe_tile *tile = gt_to_tile(gt);
>  	u32 addr = xe_mmio_adjusted_addr(gt, reg.addr);
>  
> +	if (!reg.vf && IS_SRIOV_VF(gt_to_xe(gt)))
> +		return xe_gt_sriov_vf_read32(gt, reg);
> +
>  	return readl((reg.ext ? tile->mmio_ext.regs : tile->mmio.regs) + addr);
>  }
>  
> -- 
> 2.43.0
> 

-- 
Matt Roper
Graphics Software Engineer
Linux GPU Platform Enablement
Intel Corporation