From 0aafec038d258ca0b3dcfae8b6ecb47b9bdb98c5 Mon Sep 17 00:00:00 2001
From: Johannes Schlatow <johannes.schlatow@genode-labs.com>
Date: Mon, 10 Jun 2024 18:15:13 +0200
Subject: [PATCH] platform: pass reserved memory update to IOMMU

Only add default mappings on IOMMU construction and on reserved-memory
updates.

Issue #5232
---
 repos/os/src/driver/platform/common.h         | 52 ++++++++++---------
 repos/os/src/driver/platform/device.h         |  9 ++++
 repos/os/src/driver/platform/root.cc          | 18 +++++++
 .../src/driver/platform/session_component.cc  |  8 +--
 4 files changed, 56 insertions(+), 31 deletions(-)

diff --git a/repos/os/src/driver/platform/common.h b/repos/os/src/driver/platform/common.h
index 929d2d584b..411cce8b90 100644
--- a/repos/os/src/driver/platform/common.h
+++ b/repos/os/src/driver/platform/common.h
@@ -90,6 +90,28 @@ class Driver::Common : Device_reporter,
 
 void Driver::Common::acquire_io_mmu_devices()
 {
+	auto init_default_mappings = [&] (Io_mmu & io_mmu_dev) {
+		_devices.for_each([&] (Device const & device) {
+			device.with_optional_io_mmu(io_mmu_dev.name(), [&] () {
+				bool has_reserved_mem = false;
+				device.for_each_reserved_memory([&] (unsigned,
+				                                     Io_mmu::Range range) {
+					io_mmu_dev.add_default_range(range, range.start);
+					has_reserved_mem = true;
+				});
+
+				if (!has_reserved_mem)
+					return;
+
+				/* enable default mappings for corresponding pci devices */
+				device.for_pci_config([&] (Device::Pci_config const & cfg) {
+					io_mmu_dev.enable_default_mappings(
+						{cfg.bus_num, cfg.dev_num, cfg.func_num});
+				});
+			});
+		});
+	};
+
 	_io_mmu_factories.for_each([&] (Io_mmu_factory & factory) {
 
 		_devices.for_each([&] (Device & dev) {
@@ -99,6 +121,11 @@ void Driver::Common::acquire_io_mmu_devices()
 			if (factory.matches(dev)) {
 				dev.acquire(*this);
 				factory.create(_heap, _io_mmu_devices, dev);
+
+				_io_mmu_devices.for_each([&] (Io_mmu & io_mmu_dev) {
+					if (io_mmu_dev.name() == dev.name())
+						init_default_mappings(io_mmu_dev);
+				});
 			}
 		});
 
@@ -117,31 +144,6 @@ void Driver::Common::acquire_io_mmu_devices()
 	if (device_present && !mpu_present)
 		_root.enable_dma_remapping();
 
-	/* iterate devices and add default mappings */
-	_devices.for_each([&] (Device & device) {
-		device.for_each_io_mmu([&] (Device::Io_mmu const & io_mmu) {
-			_io_mmu_devices.for_each([&] (Io_mmu & io_mmu_dev) {
-				if (io_mmu_dev.name() == io_mmu.name) {
-					bool has_reserved_mem = false;
-					device.for_each_reserved_memory([&] (unsigned,
-					                                     Io_mmu::Range range) {
-						io_mmu_dev.add_default_range(range, range.start);
-						has_reserved_mem = true;
-					});
-
-					if (!has_reserved_mem)
-						return;
-
-					/* enable default mappings for corresponding pci devices */
-					device.for_pci_config([&] (Device::Pci_config const & cfg) {
-						io_mmu_dev.enable_default_mappings(
-							 {cfg.bus_num, cfg.dev_num, cfg.func_num});
-					});
-				}
-			});
-		}, [&] () { /* empty list fn */ });
-	});
-
 	bool kernel_iommu_present { false };
 	_io_mmu_devices.for_each([&] (Io_mmu & io_mmu_dev) {
 		io_mmu_dev.default_mappings_complete();
diff --git a/repos/os/src/driver/platform/device.h b/repos/os/src/driver/platform/device.h
index 1780898e2c..873198e644 100644
--- a/repos/os/src/driver/platform/device.h
+++ b/repos/os/src/driver/platform/device.h
@@ -417,6 +417,15 @@ class Driver::Device : private List_model<Device>::Element
 				empty_fn();
 		}
 
+		template <typename FN>
+		void with_optional_io_mmu(Io_mmu::Name const & name, FN && fn) const
+		{
+			_io_mmu_list.for_each([&] (Io_mmu const & io_mmu) {
+				if (io_mmu.name == name)
+					fn();
+			});
+		}
+
 		void generate(Xml_generator &, bool) const;
 
 		void update(Allocator &, Xml_node const &, Reserved_memory_handler &);
diff --git a/repos/os/src/driver/platform/root.cc b/repos/os/src/driver/platform/root.cc
index 03a905ff57..092566f4d7 100644
--- a/repos/os/src/driver/platform/root.cc
+++ b/repos/os/src/driver/platform/root.cc
@@ -76,6 +76,18 @@ void Driver::Root::add_range(Device const & dev, Range const & range)
 		sc._dma_allocator.reserve(range.start, range.size);
 	});
 
+	/* add default mapping and enable for corresponding pci device */
+	_io_mmu_devices.for_each([&] (Io_mmu & io_mmu_dev) {
+		dev.with_optional_io_mmu(io_mmu_dev.name(), [&] () {
+
+			io_mmu_dev.add_default_range(range, range.start);
+			dev.for_pci_config([&] (Device::Pci_config const & cfg) {
+				io_mmu_dev.enable_default_mappings(
+					{cfg.bus_num, cfg.dev_num, cfg.func_num});
+			});
+
+		});
+	});
 }
 
 
@@ -85,6 +97,12 @@ void Driver::Root::remove_range(Device const & dev, Range const & range)
 		if (!sc.matches(dev)) return;
 		sc._dma_allocator.unreserve(range.start, range.size);
 	});
+
+	/*
+	 * remark: There is no need to remove default mappings since once known
+	 *         default mappings should be preserved. Double-insertion in case
+	 *         mapping are re-added at a later point in time is taken care of.
+	 */
 }
 
 
diff --git a/repos/os/src/driver/platform/session_component.cc b/repos/os/src/driver/platform/session_component.cc
index 7af77553ba..2de8cb521a 100644
--- a/repos/os/src/driver/platform/session_component.cc
+++ b/repos/os/src/driver/platform/session_component.cc
@@ -132,12 +132,8 @@ void Session_component::update_io_mmu_devices()
 			if (used_by_owned_device)
 				return;
 
-			dev.for_each_io_mmu(
-				[&] (Device::Io_mmu const & io_mmu) {
-					if (io_mmu.name == io_mmu_dev.name())
-						used_by_owned_device = true;
-				},
-				[&] () { });
+			dev.with_optional_io_mmu(io_mmu_dev.name(), [&] () {
+				used_by_owned_device = true; });
 		});
 
 		/* synchronise with IOMMU domains */