Re: [PATCH 2/2] drm/xe/xe_survivability: Add support for survivability mode v2

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Thu, Nov 13, 2025 at 01:56:19PM +0530, Riana Tauro wrote:
> Hi Rodrigo
> 
> On 11/12/2025 11:50 PM, Rodrigo Vivi wrote:
> > On Wed, Nov 12, 2025 at 04:03:39PM +0530, Riana Tauro wrote:
> > > v2 survivability breadcrumbs introduces a new mode called
> > > SPI Flash Descriptor Override mode (FDO). This is enabled by
> > > PCODE when MEI itself fails and firmware cannot be updated via
> > > MEI using igsc. This mode provides the ability to update
> > > the firmware directly via SPI driver.
> > > 
> > > Xe KMD initializes the nvm aux driver if FDO mode is enabled.
> > > 
> > > Userspace should check FDO mode entry in survivability info sysfs before
> > > using the SPI driver to update firmware.
> > > 
> > > 	/sys/bus/pci/devices/<device>/survivability_info/fdo_mode
> > > 
> > > v2 also supports survivability mode for critical boot errors.
> > > 
> > > Signed-off-by: Riana Tauro <riana.tauro@intel.com>
> > > ---
> > >   drivers/gpu/drm/xe/xe_pcode_api.h             |  2 +
> > >   drivers/gpu/drm/xe/xe_survivability_mode.c    | 41 +++++++++++++++++--
> > >   .../gpu/drm/xe/xe_survivability_mode_types.h  |  6 +++
> > >   3 files changed, 46 insertions(+), 3 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/xe/xe_pcode_api.h b/drivers/gpu/drm/xe/xe_pcode_api.h
> > > index 92bfcba51e19..d41f07f9194d 100644
> > > --- a/drivers/gpu/drm/xe/xe_pcode_api.h
> > > +++ b/drivers/gpu/drm/xe/xe_pcode_api.h
> > > @@ -77,11 +77,13 @@
> > >   #define PCODE_SCRATCH(x)		XE_REG(0x138320 + ((x) * 4))
> > >   /* PCODE_SCRATCH0 */
> > > +#define   BREADCRUMB_VERSION		REG_GENMASK(31, 29)
> > >   #define   AUXINFO_REG_OFFSET		REG_GENMASK(17, 15)
> > >   #define   OVERFLOW_REG_OFFSET		REG_GENMASK(14, 12)
> > >   #define   HISTORY_TRACKING		REG_BIT(11)
> > >   #define   OVERFLOW_SUPPORT		REG_BIT(10)
> > >   #define   AUXINFO_SUPPORT		REG_BIT(9)
> > > +#define   FDO_MODE			REG_BIT(4)
> > >   #define   BOOT_STATUS			REG_GENMASK(3, 1)
> > >   #define      CRITICAL_FAILURE		4
> > >   #define      NON_CRITICAL_FAILURE	7
> > > diff --git a/drivers/gpu/drm/xe/xe_survivability_mode.c b/drivers/gpu/drm/xe/xe_survivability_mode.c
> > > index 3d9417911c33..d22fdd08d227 100644
> > > --- a/drivers/gpu/drm/xe/xe_survivability_mode.c
> > > +++ b/drivers/gpu/drm/xe/xe_survivability_mode.c
> > > @@ -16,6 +16,7 @@
> > >   #include "xe_heci_gsc.h"
> > >   #include "xe_i2c.h"
> > >   #include "xe_mmio.h"
> > > +#include "xe_nvm.h"
> > >   #include "xe_pcode_api.h"
> > >   #include "xe_vsec.h"
> > > @@ -66,6 +67,11 @@
> > >    *
> > >    * - ``aux_info<n>`` : Some failures have additional debug information
> > >    *
> > > + * - ``fdo_mode`` : To allow recovery in scenarios where MEI itself fails, a new SPI Flash
> > > + *   Descriptor Override (FDO) mode is added in v2 survivability breadcrumbs. This mode is enabled
> > > + *   by PCODE and provides the ability to directly update the firmware via SPI Driver without
> > > + *   any dependency on MEI. Xe KMD initializes the nvm aux driver if FDO mode is enabled.
> > > + *
> > >    * Runtime Survivability
> > >    * =====================
> > >    *
> > > @@ -95,6 +101,8 @@ enum scratch_reg {
> > >   	MAX_SCRATCH_REG,
> > >   };
> > > +#define FDO_INFO	(MAX_SCRATCH_REG + 1)
> > > +
> > >   struct xe_survivability_attribute {
> > >   	struct device_attribute attr;
> > >   	u8 index;
> > > @@ -131,6 +139,11 @@ static void populate_survivability_info(struct xe_device *xe)
> > >   	set_survivability_info(mmio, info, CAPABILITY_INFO, "Capability Info");
> > >   	reg_value = info[CAPABILITY_INFO].value;
> > > +	survivability->version = REG_FIELD_GET(BREADCRUMB_VERSION, reg_value);
> > > +	/* FDO mode is exposed only from version 2 */
> > > +	if (survivability->version >= 2)
> > > +		survivability->fdo_mode = REG_FIELD_GET(FDO_MODE, reg_value);
> > > +
> > >   	if (reg_value & HISTORY_TRACKING) {
> > >   		set_survivability_info(mmio, info, POSTCODE_TRACE, "Postcode Trace");
> > > @@ -193,6 +206,9 @@ static ssize_t survivability_info_show(struct device *dev,
> > >   	struct xe_survivability_info *info = survivability->info;
> > >   	struct xe_survivability_attribute *sa = dev_attr_to_survivability_attr(attr);
> > > +	if (sa->index == FDO_INFO)
> > > +		return sysfs_emit(buff, "%s\n", str_enabled_disabled(survivability->fdo_mode));
> > > +
> > >   	return sysfs_emit(buff, "0x%x\n", info[sa->index].value);
> > >   }
> > > @@ -210,13 +226,18 @@ SURVIVABILITY_ATTR_RO(aux_info1, AUX_INFO1);
> > >   SURVIVABILITY_ATTR_RO(aux_info2, AUX_INFO2);
> > >   SURVIVABILITY_ATTR_RO(aux_info3, AUX_INFO3);
> > >   SURVIVABILITY_ATTR_RO(aux_info4, AUX_INFO4);
> > > +SURVIVABILITY_ATTR_RO(fdo_mode, FDO_INFO);
> > >   static void xe_survivability_mode_fini(void *arg)
> > >   {
> > >   	struct xe_device *xe = arg;
> > > +	struct xe_survivability *survivability = &xe->survivability;
> > >   	struct pci_dev *pdev = to_pci_dev(xe->drm.dev);
> > >   	struct device *dev = &pdev->dev;
> > > +	if (survivability->fdo_mode)
> > > +		xe_nvm_fini(xe);
> > > +
> > >   	device_remove_file(dev, &dev_attr_survivability_mode);
> > >   }
> > > @@ -227,12 +248,16 @@ static umode_t survivability_info_attrs_visible(struct kobject *kobj, struct att
> > >   	struct xe_survivability *survivability = &xe->survivability;
> > >   	struct xe_survivability_info *info = survivability->info;
> > > -	if (info[idx].value)
> > > +	/* FDO mode is visible only when supported */
> > > +	if (idx >= MAX_SCRATCH_REG && survivability->version >= 2)
> > 
> > should we also make the version a file inside survivability_info?
> > for explicit check instead of implicit?
> 
> Are you suggesting that we had version in the sysfs and let the user check
> both version and fdo_mode entry before deciding?

nevermind, I think I might had missunderstood the flow...

> 
> > 
> > > +		return 0400;
> > > +	else if (info[idx].value)
> > >   		return 0400;
> > >   	return 0;
> > >   }
> > > +/* Attributes are ordered according to enum scratch_reg */
> > >   static struct attribute *survivability_info_attrs[] = {
> > >   	&attr_capability_info.attr.attr,
> > >   	&attr_postcode_trace.attr.attr,
> > > @@ -242,6 +267,7 @@ static struct attribute *survivability_info_attrs[] = {
> > >   	&attr_aux_info2.attr.attr,
> > >   	&attr_aux_info3.attr.attr,
> > >   	&attr_aux_info4.attr.attr,
> > > +	&attr_fdo_mode.attr.attr,
> > >   	NULL,
> > >   };
> > > @@ -301,11 +327,18 @@ static int enable_boot_survivability_mode(struct pci_dev *pdev)
> > >   	if (ret)
> > >   		goto err;
> > > +	if (survivability->fdo_mode) {
> > > +		ret = xe_nvm_init(xe);
> > > +		if (ret)
> > > +			goto err;
> > 
> > should we really fail the survivability mode here?
> > Or keep the survivability mode with some indication that fdo/nvm has failed?
> 
> FDO mode is only enabled when MEI path to update firmware is not available
> due to some error in MEI.
> 
> If initializing SPI also fails then user cannot update firmware in
> survivability mode. Staying in survivability mode will not be helpful
> since both paths are unavailabe. That's why added the fail

But then you also fail the probe anyway right?

> 
> I should remove failing on mei_init instead. Missed that. Thank you for
> the review comment. Will fix it in new rev
> 
> Thanks
> Riana
> > 
> > > +	}
> > > +
> > >   	dev_err(dev, "In Survivability Mode\n");
> > >   	return 0;
> > >   err:
> > > +	dev_err(dev, "Failed to enable Survivability Mode\n");
> > >   	survivability->mode = false;
> > >   	return ret;
> > >   }
> > > @@ -436,8 +469,10 @@ int xe_survivability_mode_boot_enable(struct xe_device *xe)
> > >   	if (ret)
> > >   		return ret;
> > > -	/* Log breadcrumbs but do not enter survivability mode for Critical boot errors */
> > > -	if (survivability->boot_status == CRITICAL_FAILURE) {
> > > +	/*
> > > +	 * v2 supports survivability mode for critical errors
> > > +	 */
> > > +	if (survivability->version < 2  && survivability->boot_status == CRITICAL_FAILURE) {
> > >   		log_survivability_info(pdev);
> > >   		return -ENXIO;
> > >   	}
> > > diff --git a/drivers/gpu/drm/xe/xe_survivability_mode_types.h b/drivers/gpu/drm/xe/xe_survivability_mode_types.h
> > > index 1ed122cf62f2..d887b443b397 100644
> > > --- a/drivers/gpu/drm/xe/xe_survivability_mode_types.h
> > > +++ b/drivers/gpu/drm/xe/xe_survivability_mode_types.h
> > > @@ -37,6 +37,12 @@ struct xe_survivability {
> > >   	/** @type: survivability type */
> > >   	enum xe_survivability_type type;
> > > +
> > > +	/** @fdo_mode: indicates if FDO mode is enabled */
> > > +	bool fdo_mode;
> > > +
> > > +	/** @version: breadcrumb version of survivability mode  */
> > > +	u8 version;
> > >   };
> > >   #endif /* _XE_SURVIVABILITY_MODE_TYPES_H_ */
> > > -- 
> > > 2.47.1
> > > 
>