[3/4] drm/i915/huc: Prepare for GSC-loaded HuC
Teres Alexis, Alan Previn
alan.previn.teres.alexis at intel.com
Fri Apr 29 18:39:20 UTC 2022
Reviewed-by: Alan Previn <alan.previn.teres.alexis at intel.com>
On Tue, 2022-04-26 at 17:26 -0700, Daniele Ceraolo Spurio wrote:
> HuC loading via GSC is performed via a PXP command sent through the mei
> modules, so we need both MEI_GSC and MEI_PXP to be available. Given that
> the GSC will do both the transfer and the authentication, the legacy HuC
> loading paths can be safely skipped.
> Also note that the GSC-loaded HuC survives GT reset.
>
> Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
> ---
> drivers/gpu/drm/i915/gt/uc/intel_guc_reg.h | 1 +
> drivers/gpu/drm/i915/gt/uc/intel_huc.c | 76 +++++++++++++++++++---
> drivers/gpu/drm/i915/gt/uc/intel_huc.h | 6 ++
> drivers/gpu/drm/i915/gt/uc/intel_huc_fw.c | 5 +-
> drivers/gpu/drm/i915/gt/uc/intel_uc.c | 11 +++-
> 5 files changed, 88 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_reg.h b/drivers/gpu/drm/i915/gt/uc/intel_guc_reg.h
> index 66027a42cda9e..2516705b9f365 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_reg.h
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_reg.h
> @@ -96,6 +96,7 @@
>
> #define GUC_SHIM_CONTROL2 _MMIO(0xc068)
> #define GUC_IS_PRIVILEGED (1<<29)
> +#define GSC_LOADS_HUC (1<<30)
>
> #define GUC_SEND_INTERRUPT _MMIO(0xc4c8)
> #define GUC_SEND_TRIGGER (1<<0)
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_huc.c b/drivers/gpu/drm/i915/gt/uc/intel_huc.c
> index 773020e69589a..76a7df7f136fc 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_huc.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_huc.c
> @@ -6,6 +6,7 @@
> #include <linux/types.h>
>
> #include "gt/intel_gt.h"
> +#include "intel_guc_reg.h"
> #include "intel_huc.h"
> #include "i915_drv.h"
>
> @@ -17,11 +18,15 @@
> * capabilities by adding HuC specific commands to batch buffers.
> *
> * The kernel driver is only responsible for loading the HuC firmware and
> - * triggering its security authentication, which is performed by the GuC. For
> - * The GuC to correctly perform the authentication, the HuC binary must be
> - * loaded before the GuC one. Loading the HuC is optional; however, not using
> - * the HuC might negatively impact power usage and/or performance of media
> - * workloads, depending on the use-cases.
> + * triggering its security authentication, which is performed by the GuC on
> + * older platforms and by the GSC on newer ones. For the GuC to correctly
> + * perform the authentication, the HuC binary must be loaded before the GuC one.
> + * Loading the HuC is optional; however, not using the HuC might negatively
> + * impact power usage and/or performance of media workloads, depending on the
> + * use-cases.
> + * HuC must be reloaded on events that cause the WOPCM to lose its contents
> + * (S3/S4, FLR); GuC-authenticated HuC must also be reloaded on GuC/GT reset,
> + * while GSC-managed HuC will survive that.
> *
> * See https://github.com/intel/media-driver for the latest details on HuC
> * functionality.
> @@ -54,11 +59,51 @@ void intel_huc_init_early(struct intel_huc *huc)
> }
> }
>
> +#define HUC_LOAD_MODE_STRING(x) (x ? "GSC" : "legacy")
> +static int check_huc_loading_mode(struct intel_huc *huc)
> +{
> + struct intel_gt *gt = huc_to_gt(huc);
> + bool fw_needs_gsc = intel_huc_is_loaded_by_gsc(huc);
> + bool hw_uses_gsc = false;
> +
> + /*
> + * The fuse for HuC load via GSC is only valid on platforms that have
> + * GuC deprivilege.
> + */
> + if (HAS_GUC_DEPRIVILEGE(gt->i915))
> + hw_uses_gsc = intel_uncore_read(gt->uncore, GUC_SHIM_CONTROL2) &
> + GSC_LOADS_HUC;
> +
> + if (fw_needs_gsc != hw_uses_gsc) {
> + drm_err(>->i915->drm,
> + "mismatch between HuC FW (%s) and HW (%s) load modes\n",
> + HUC_LOAD_MODE_STRING(fw_needs_gsc),
> + HUC_LOAD_MODE_STRING(hw_uses_gsc));
> + return -ENOEXEC;
> + }
> +
> + /* make sure we can access the GSC via the mei driver if we need it */
> + if (!(IS_ENABLED(CONFIG_INTEL_MEI_PXP) && IS_ENABLED(CONFIG_INTEL_MEI_GSC)) &&
> + fw_needs_gsc) {
> + drm_info(>->i915->drm,
> + "Can't load HuC due to missing MEI modules\n");
> + return -EIO;
> + }
> +
> + drm_dbg(>->i915->drm, "GSC loads huc=%s\n", str_yes_no(fw_needs_gsc));
> +
> + return 0;
> +}
> +
> int intel_huc_init(struct intel_huc *huc)
> {
> struct drm_i915_private *i915 = huc_to_gt(huc)->i915;
> int err;
>
> + err = check_huc_loading_mode(huc);
> + if (err)
> + goto out;
> +
> err = intel_uc_fw_init(&huc->fw);
> if (err)
> goto out;
> @@ -108,17 +153,20 @@ int intel_huc_auth(struct intel_huc *huc)
> struct intel_guc *guc = >->uc.guc;
> int ret;
>
> - GEM_BUG_ON(huc_is_authenticated(huc));
> -
> if (!intel_uc_fw_is_loaded(&huc->fw))
> return -ENOEXEC;
>
> + /* GSC will do the auth */
> + if (intel_huc_is_loaded_by_gsc(huc))
> + return -ENODEV;
> +
> ret = i915_inject_probe_error(gt->i915, -ENXIO);
> if (ret)
> goto fail;
>
> - ret = intel_guc_auth_huc(guc,
> - intel_guc_ggtt_offset(guc, huc->fw.rsa_data));
> + GEM_BUG_ON(huc_is_authenticated(huc));
> +
> + ret = intel_guc_auth_huc(guc, intel_guc_ggtt_offset(guc, huc->fw.rsa_data));
> if (ret) {
> DRM_ERROR("HuC: GuC did not ack Auth request %d\n", ret);
> goto fail;
> @@ -178,6 +226,16 @@ int intel_huc_check_status(struct intel_huc *huc)
> return huc_is_authenticated(huc);
> }
>
> +void intel_huc_update_auth_status(struct intel_huc *huc)
> +{
> + if (!intel_uc_fw_is_loadable(&huc->fw))
> + return;
> +
> + if (huc_is_authenticated(huc))
> + intel_uc_fw_change_status(&huc->fw,
> + INTEL_UC_FIRMWARE_RUNNING);
> +}
> +
> /**
> * intel_huc_load_status - dump information about HuC load status
> * @huc: the HuC
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_huc.h b/drivers/gpu/drm/i915/gt/uc/intel_huc.h
> index 77d813840d76c..d7e25b6e879eb 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_huc.h
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_huc.h
> @@ -27,6 +27,7 @@ int intel_huc_init(struct intel_huc *huc);
> void intel_huc_fini(struct intel_huc *huc);
> int intel_huc_auth(struct intel_huc *huc);
> int intel_huc_check_status(struct intel_huc *huc);
> +void intel_huc_update_auth_status(struct intel_huc *huc);
>
> static inline int intel_huc_sanitize(struct intel_huc *huc)
> {
> @@ -50,6 +51,11 @@ static inline bool intel_huc_is_used(struct intel_huc *huc)
> return intel_uc_fw_is_available(&huc->fw);
> }
>
> +static inline bool intel_huc_is_loaded_by_gsc(const struct intel_huc *huc)
> +{
> + return huc->fw.loaded_via_gsc;
> +}
> +
> void intel_huc_load_status(struct intel_huc *huc, struct drm_printer *p);
>
> #endif
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_huc_fw.c b/drivers/gpu/drm/i915/gt/uc/intel_huc_fw.c
> index e5ef509c70e89..9d6ab1e016395 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_huc_fw.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_huc_fw.c
> @@ -8,7 +8,7 @@
> #include "i915_drv.h"
>
> /**
> - * intel_huc_fw_upload() - load HuC uCode to device
> + * intel_huc_fw_upload() - load HuC uCode to device via DMA transfer
> * @huc: intel_huc structure
> *
> * Called from intel_uc_init_hw() during driver load, resume from sleep and
> @@ -21,6 +21,9 @@
> */
> int intel_huc_fw_upload(struct intel_huc *huc)
> {
> + if (intel_huc_is_loaded_by_gsc(huc))
> + return -ENODEV;
> +
> /* HW doesn't look at destination address for HuC, so set it to 0 */
> return intel_uc_fw_upload(&huc->fw, 0, HUC_UKERNEL);
> }
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_uc.c b/drivers/gpu/drm/i915/gt/uc/intel_uc.c
> index 8c9ef690ac9d8..0dce94f896a8c 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_uc.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_uc.c
> @@ -509,7 +509,16 @@ static int __uc_init_hw(struct intel_uc *uc)
> if (ret)
> goto err_log_capture;
>
> - intel_huc_auth(huc);
> + /*
> + * GSC-loaded HuC is authenticated by the GSC, so we don't need to
> + * trigger the auth here. However, given that the HuC loaded this way
> + * survive GT reset, we still need to update our SW bookkeeping to make
> + * sure it reflects the correct HW status.
> + */
> + if (intel_huc_is_loaded_by_gsc(huc))
> + intel_huc_update_auth_status(huc);
> + else
> + intel_huc_auth(huc);
>
> if (intel_uc_uses_guc_submission(uc))
> intel_guc_submission_enable(guc);
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