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c08c364102
On MTL accessing stolen memory via the BARs is somehow borked,
and it can hang the machine. As a workaround let's bypass the
BARs and just go straight to DSMBASE/GSMBASE instead.
Note that on every other platform this itself would hang the
machine, but on MTL the system firmware is expected to relax
the access permission guarding stolen memory to enable this
workaround, and thus direct CPU accesses should be fine.
The raw stolen memory areas won't be passed to VMs so we'll
need to risk using the BAR there for the initial setup. Once
command submission is up we should switch to MI_UPDATE_GTT
which at least shouldn't hang the whole machine.
v2: Don't use direct GSM/DSM access on guests
Add w/a number
v3: Check register 0x138914 to see if pcode did its job
Add some debug prints
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
Reviewed-by: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
Reviewed-by: Nirmoy Das <nirmoy.das@intel.com>
Tested-by: Paz Zcharya <pazz@chromium.org>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240202224340.30647-5-ville.syrjala@linux.intel.com
144 lines
3.5 KiB
C
144 lines
3.5 KiB
C
// SPDX-License-Identifier: MIT
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/*
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* Copyright © 2019 Intel Corporation
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*/
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#include <linux/device.h>
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#include <drm/drm_drv.h>
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#include "i915_drv.h"
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#include "i915_reg.h"
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#include "i915_utils.h"
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#define FDO_BUG_MSG "Please file a bug on drm/i915; see " FDO_BUG_URL " for details."
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void
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__i915_printk(struct drm_i915_private *dev_priv, const char *level,
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const char *fmt, ...)
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{
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static bool shown_bug_once;
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struct device *kdev = dev_priv->drm.dev;
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bool is_error = level[1] <= KERN_ERR[1];
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bool is_debug = level[1] == KERN_DEBUG[1];
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struct va_format vaf;
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va_list args;
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if (is_debug && !drm_debug_enabled(DRM_UT_DRIVER))
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return;
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va_start(args, fmt);
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vaf.fmt = fmt;
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vaf.va = &args;
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if (is_error)
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dev_printk(level, kdev, "%pV", &vaf);
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else
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dev_printk(level, kdev, "[" DRM_NAME ":%ps] %pV",
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__builtin_return_address(0), &vaf);
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va_end(args);
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if (is_error && !shown_bug_once) {
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/*
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* Ask the user to file a bug report for the error, except
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* if they may have caused the bug by fiddling with unsafe
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* module parameters.
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*/
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if (!test_taint(TAINT_USER))
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dev_notice(kdev, "%s", FDO_BUG_MSG);
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shown_bug_once = true;
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}
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}
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void add_taint_for_CI(struct drm_i915_private *i915, unsigned int taint)
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{
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__i915_printk(i915, KERN_NOTICE, "CI tainted:%#x by %pS\n",
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taint, (void *)_RET_IP_);
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/* Failures that occur during fault injection testing are expected */
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if (!i915_error_injected())
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__add_taint_for_CI(taint);
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}
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#if IS_ENABLED(CONFIG_DRM_I915_DEBUG)
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static unsigned int i915_probe_fail_count;
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int __i915_inject_probe_error(struct drm_i915_private *i915, int err,
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const char *func, int line)
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{
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if (i915_probe_fail_count >= i915_modparams.inject_probe_failure)
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return 0;
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if (++i915_probe_fail_count < i915_modparams.inject_probe_failure)
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return 0;
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__i915_printk(i915, KERN_INFO,
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"Injecting failure %d at checkpoint %u [%s:%d]\n",
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err, i915_modparams.inject_probe_failure, func, line);
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i915_modparams.inject_probe_failure = 0;
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return err;
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}
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bool i915_error_injected(void)
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{
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return i915_probe_fail_count && !i915_modparams.inject_probe_failure;
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}
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#endif
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void cancel_timer(struct timer_list *t)
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{
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if (!timer_active(t))
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return;
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del_timer(t);
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WRITE_ONCE(t->expires, 0);
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}
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void set_timer_ms(struct timer_list *t, unsigned long timeout)
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{
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if (!timeout) {
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cancel_timer(t);
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return;
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}
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timeout = msecs_to_jiffies(timeout);
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/*
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* Paranoia to make sure the compiler computes the timeout before
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* loading 'jiffies' as jiffies is volatile and may be updated in
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* the background by a timer tick. All to reduce the complexity
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* of the addition and reduce the risk of losing a jiffie.
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*/
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barrier();
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/* Keep t->expires = 0 reserved to indicate a canceled timer. */
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mod_timer(t, jiffies + timeout ?: 1);
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}
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bool i915_vtd_active(struct drm_i915_private *i915)
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{
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if (device_iommu_mapped(i915->drm.dev))
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return true;
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/* Running as a guest, we assume the host is enforcing VT'd */
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return i915_run_as_guest();
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}
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bool i915_direct_stolen_access(struct drm_i915_private *i915)
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{
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/*
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* Wa_22018444074
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*
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* Access via BAR can hang MTL, go directly to GSM/DSM,
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* except for VM guests which won't have access to it.
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*
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* Normally this would not work but on MTL the system firmware
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* should have relaxed the access permissions sufficiently.
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* 0x138914==0x1 indicates that the firmware has done its job.
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*/
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return IS_METEORLAKE(i915) && !i915_run_as_guest() &&
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intel_uncore_read(&i915->uncore, MTL_PCODE_STOLEN_ACCESS) == STOLEN_ACCESS_ALLOWED;
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}
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