[PATCH v12 22/25] platform/x86/intel/pmt: Inform resctrl when MMIO maps are being removed

[Tony Luck]

Before destroying devices, tell resctrl that the virtual addresses
supplied by an earlier call to intel_pmt_get_regions_by_feature()
are about to be invalidated and should not be used again.

Avoid A-B deadlock between ep_lock and aet_register_lock.

Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx>
---
v12:
	Ilpo: Downgrade "can't happen" dev_warn() to dev_debug()
	Ilpo's suggestion to use guard(mutex) moot due to refactor.
	Reinette: Refactor and eliminate "u32 ret" and s/packages/package/
	Reinette: Explain ep_lock release/acquire.
---
 drivers/platform/x86/intel/pmt/telemetry.c | 31 ++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/drivers/platform/x86/intel/pmt/telemetry.c b/drivers/platform/x86/intel/pmt/telemetry.c
index bf0c9295feb3..527563043777 100644
--- a/drivers/platform/x86/intel/pmt/telemetry.c
+++ b/drivers/platform/x86/intel/pmt/telemetry.c
@@ -366,12 +366,43 @@ pmt_telem_find_and_register_endpoint(struct device *dev, u32 guid, u16 pos)
 }
 EXPORT_SYMBOL_NS_GPL(pmt_telem_find_and_register_endpoint, "INTEL_PMT_TELEMETRY");
 
+static int pmt_telem_get_package_id(struct pmt_telem_priv *priv)
+{
+	int i;
+
+	for (i = 0; i < priv->num_entries; i++) {
+		struct intel_pmt_entry *entry = &priv->entry[i];
+		struct pci_dev *pdev = to_pci_dev(entry->ep->dev);
+		struct oobmsm_plat_info *plat_info;
+
+		plat_info = intel_vsec_get_mapping(pdev);
+		if (!IS_ERR(plat_info))
+			return plat_info->package_id;
+	}
+
+	return -ENODEV;
+}
+
 static void pmt_telem_remove(struct auxiliary_device *auxdev)
 {
 	struct pmt_telem_priv *priv = auxiliary_get_drvdata(auxdev);
+	int package_id;
 	int i;
 
 	mutex_lock(&ep_lock);
+	package_id = pmt_telem_get_package_id(priv);
+	/*
+	 * Tell resctrl/AET that virtual mappings for MMIO space in a CPU
+	 * package are about to be torn down.
+	 */
+	if (package_id < 0) {
+		dev_dbg(&auxdev->dev, "Unable to determine package ID for removed device\n");
+	} else {
+		mutex_unlock(&ep_lock);
+		intel_aet_invalidate(package_id);
+		mutex_lock(&ep_lock);
+	}
+
 	for (i = 0; i < priv->num_entries; i++) {
 		struct intel_pmt_entry *entry = &priv->entry[i];
 
-- 
2.55.0