In a kexec reboot scenario, the GPU's Global Graphics Translation Table (GGTT) retains its previous state after the kernel is reloaded, until i915 reinitializes the GGTT.
The simple-framebuffer driver is initialized before i915 and accesses the PCIe memory space (GPU aperture) through outdated GGTT entries. This leads to invalid physical memory accesses, causing GPF or data corruption. To prevent such issues, the Memory Space Enable (MSE) bit in the PCI Command Register is cleared during i915_driver_shutdown. This disables all PCIe memory space access (including MMIO and aperture) at the hardware level. After the kernel is reloaded, access to the PCIe memory space will be forbidden until i915 is re-initialized. Since disabling PCIe memory space affects all MMIO operations, PXP shutdown needs to be completed before this point. Calls intel_pxp_fini() before disabling memory space to ensure PXP cleanup can still access MMIO registers. v2: - follow brace style v3: - revise description Link: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/14598 Cc: Alex Zuo <[email protected]> Cc: Shuicheng Lin <[email protected]> Cc: Askar Safin <[email protected]> Cc: Pingfan Liu <[email protected]> Suggested-by: Chris Wilson <[email protected]> Signed-off-by: Jia Yao <[email protected]> --- drivers/gpu/drm/i915/i915_driver.c | 35 +++++++++++++++++++++++++++--- 1 file changed, 32 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_driver.c b/drivers/gpu/drm/i915/i915_driver.c index b46cb54ef5dc..766f85726b67 100644 --- a/drivers/gpu/drm/i915/i915_driver.c +++ b/drivers/gpu/drm/i915/i915_driver.c @@ -118,6 +118,33 @@ static const struct drm_driver i915_drm_driver; +static int i915_enable_device(struct pci_dev *pdev) +{ + u32 cmd; + int ret; + + ret = pci_enable_device(pdev); + if (ret) + return ret; + + pci_read_config_dword(pdev, PCI_COMMAND, &cmd); + if (!(cmd & PCI_COMMAND_MEMORY)) + pci_write_config_dword(pdev, PCI_COMMAND, cmd | PCI_COMMAND_MEMORY); + + return 0; +} + +static void i915_disable_device(struct pci_dev *pdev) +{ + u32 cmd; + + pci_read_config_dword(pdev, PCI_COMMAND, &cmd); + if (cmd & PCI_COMMAND_MEMORY) + pci_write_config_dword(pdev, PCI_COMMAND, cmd & ~PCI_COMMAND_MEMORY); + + pci_disable_device(pdev); +} + static int i915_workqueues_init(struct drm_i915_private *dev_priv) { /* @@ -788,7 +815,7 @@ int i915_driver_probe(struct pci_dev *pdev, const struct pci_device_id *ent) struct intel_display *display; int ret; - ret = pci_enable_device(pdev); + ret = i915_enable_device(pdev); if (ret) { pr_err("Failed to enable graphics device: %pe\n", ERR_PTR(ret)); return ret; @@ -796,7 +823,7 @@ int i915_driver_probe(struct pci_dev *pdev, const struct pci_device_id *ent) i915 = i915_driver_create(pdev, ent); if (IS_ERR(i915)) { - pci_disable_device(pdev); + i915_disable_device(pdev); return PTR_ERR(i915); } @@ -885,7 +912,7 @@ int i915_driver_probe(struct pci_dev *pdev, const struct pci_device_id *ent) enable_rpm_wakeref_asserts(&i915->runtime_pm); i915_driver_late_release(i915); out_pci_disable: - pci_disable_device(pdev); + i915_disable_device(pdev); i915_probe_error(i915, "Device initialization failed (%d)\n", ret); return ret; } @@ -1003,6 +1030,7 @@ void i915_driver_shutdown(struct drm_i915_private *i915) intel_dmc_suspend(display); + intel_pxp_fini(i915); i915_gem_suspend(i915); /* @@ -1020,6 +1048,7 @@ void i915_driver_shutdown(struct drm_i915_private *i915) enable_rpm_wakeref_asserts(&i915->runtime_pm); intel_runtime_pm_driver_last_release(&i915->runtime_pm); + i915_disable_device(to_pci_dev(i915->drm.dev)); } static bool suspend_to_idle(struct drm_i915_private *dev_priv) -- 2.34.1
