From 29e21bff7f056406f0c21507cb67fb55830e9353 Mon Sep 17 00:00:00 2001
From: Johannes Schlatow <johannes.schlatow@genode-labs.com>
Date: Wed, 17 Apr 2024 14:19:24 +0200
Subject: [PATCH] platform/pc: implement IOMMU suspend/resume

genodelabs/genode#5180
---
 .../src/drivers/platform/pc/intel/io_mmu.cc   | 35 +++++++++++++++++++
 .../pc/src/drivers/platform/pc/intel/io_mmu.h | 12 +++++++
 .../drivers/platform/pc/spec/x86_64/main.cc   | 10 ++++++
 3 files changed, 57 insertions(+)

diff --git a/repos/pc/src/drivers/platform/pc/intel/io_mmu.cc b/repos/pc/src/drivers/platform/pc/intel/io_mmu.cc
index 31dfcb7b56..be49fa3291 100644
--- a/repos/pc/src/drivers/platform/pc/intel/io_mmu.cc
+++ b/repos/pc/src/drivers/platform/pc/intel/io_mmu.cc
@@ -403,6 +403,41 @@ void Intel::Io_mmu::default_mappings_complete()
 }
 
 
+void Intel::Io_mmu::suspend()
+{
+	_s3_fec    = read<Fault_event_control>();
+	_s3_fedata = read<Fault_event_data>();
+	_s3_feaddr = read<Fault_event_address>();
+	_s3_rta    = read<Root_table_address>();
+}
+
+
+void Intel::Io_mmu::resume()
+{
+	/* disable queued invalidation interface if it was re-enabled by kernel */
+	if (read<Global_status::Enabled>() && read<Global_status::Qies>())
+		_global_command<Global_command::Qie>(false);
+
+	/* restore fault events only if kernel did not enable IRQ remapping */
+	if (!read<Global_status::Ires>()) {
+		write<Fault_event_control>(_s3_fec);
+		write<Fault_event_data>(_s3_fedata);
+		write<Fault_event_address>(_s3_feaddr);
+	}
+
+	/* issue set root table pointer command */
+	write<Root_table_address>(_s3_rta);
+	_global_command<Global_command::Srtp>(1);
+
+	if (!read<Capability::Esrtps>())
+		invalidate_all();
+
+	/* enable IOMMU */
+	if (!read<Global_status::Enabled>())
+		_global_command<Global_command::Enable>(1);
+}
+
+
 Intel::Io_mmu::Io_mmu(Env                      & env,
                       Io_mmu_devices           & io_mmu_devices,
                       Device::Name       const & name,
diff --git a/repos/pc/src/drivers/platform/pc/intel/io_mmu.h b/repos/pc/src/drivers/platform/pc/intel/io_mmu.h
index b831f4d042..2760073d81 100644
--- a/repos/pc/src/drivers/platform/pc/intel/io_mmu.h
+++ b/repos/pc/src/drivers/platform/pc/intel/io_mmu.h
@@ -408,6 +408,12 @@ class Intel::Io_mmu : private Attached_mmio<0x800>,
 			struct Did  : Bitfield<32,16> { };
 
 		};
+
+		/* saved registers during suspend */
+		Fault_event_control::access_t  _s3_fec { };
+		Fault_event_data ::access_t    _s3_fedata { };
+		Fault_event_address ::access_t _s3_feaddr { };
+		Root_table_address::access_t   _s3_rta { };
 		
 		uint32_t _max_domains() {
 			return 1 << (4 + read<Capability::Domains>()*2); }
@@ -543,6 +549,12 @@ class Intel::Io_mmu : private Attached_mmio<0x800>,
 
 		void flush_write_buffer();
 
+		/**
+		 * Io_mmu suspend/resume interface
+		 */
+		void suspend() override;
+		void resume() override;
+
 		/**
 		 * Io_mmu interface for default mappings
 		 */
diff --git a/repos/pc/src/drivers/platform/pc/spec/x86_64/main.cc b/repos/pc/src/drivers/platform/pc/spec/x86_64/main.cc
index 8df17317eb..b82f6c9934 100644
--- a/repos/pc/src/drivers/platform/pc/spec/x86_64/main.cc
+++ b/repos/pc/src/drivers/platform/pc/spec/x86_64/main.cc
@@ -100,7 +100,17 @@ void Driver::Main::_system_update()
 		_reset();
 
 	if (state == "suspend") {
+		/* save IOMMU state */
+		_common.io_mmu_devices().for_each([&] (Driver::Io_mmu & io_mmu) {
+			io_mmu.suspend();
+		});
+
 		try { _suspend("S3"); } catch (...) { error("suspend failed"); }
+
+		/* re-initialise IOMMU independent of result */
+		_common.io_mmu_devices().for_each([&] (Driver::Io_mmu & io_mmu) {
+			io_mmu.resume();
+		});
 		/* report independent of result */
 		_common.report_resume();
 	}