platform_drv: provide Virtio PCI information

Ref genodelabs/genode#4578

repos/os/src/drivers/platform/device.h

@@ -228,7 +228,7 @@ class Driver::Device : private List_model<Device>::Element
 		{
 			unsigned idx = 0;
 			_io_mem_list.for_each([&] (Io_mem const & iomem) {
-				fn(idx++, iomem.range); });
+				fn(idx++, iomem.range, iomem.bar); });
 		}
 
 		template <typename FN> void for_each_io_port_range(FN const & fn) const

repos/os/src/drivers/platform/device_component.cc

@@ -159,7 +159,7 @@ Device_component::Device_component(Registry<Device_component> & registry,
 			new (session.heap()) Irq(_irq_registry, idx, nr, type, polarity, mode);
 		});
 
-		device.for_each_io_mem([&] (unsigned idx, Range range)
+		device.for_each_io_mem([&] (unsigned idx, Range range, Device::Pci_bar)
 		{
 			session.ram_quota_guard().withdraw(Ram_quota{Io_mem_session::RAM_QUOTA});
 			_ram_quota += Io_mem_session::RAM_QUOTA;

repos/os/src/drivers/platform/pci.cc

@@ -21,6 +21,7 @@
 #include <pci_uhci.h>
 #include <pci_intel_graphics.h>
 #include <pci_hd_audio.h>
+#include <pci_virtio.h>
 
 using namespace Genode;
 using namespace Pci;
@@ -51,7 +52,8 @@ struct Config_helper
 		Config::Command::Bus_master_enable::set(cmd, 1);
 
 		/* enable memory space when I/O mem is defined */
-		_dev.for_each_io_mem([&] (unsigned, Driver::Device::Io_mem::Range) {
+		_dev.for_each_io_mem([&] (unsigned, Driver::Device::Io_mem::Range,
+		                          Driver::Device::Pci_bar) {
 			Config::Command::Memory_space_enable::set(cmd, 1); });
 
 		/* enable i/o space when I/O ports are defined */
@@ -182,6 +184,9 @@ void Driver::pci_device_specific_info(Device const  & dev,
                                       Device_model  & model,
                                       Xml_generator & xml)
 {
-	dev.for_pci_config([&] (Device::Pci_config const cfg) {
+	dev.for_pci_config([&] (Device::Pci_config const cfg)
-		Driver::pci_intel_graphics_info(cfg, env, model, xml); });
+	{
+		Driver::pci_intel_graphics_info(cfg, env, model, xml);
+		Driver::pci_virtio_info(dev, cfg, env, xml);
+	});
 }

repos/os/src/drivers/platform/pci_virtio.h

@@ -0,0 +1,119 @@
+/*
+ * \brief  Platform driver - PCI Virtio utilities
+ * \author Stefan Kalkowski
+ * \date   2022-09-19
+ */
+
+/*
+ * Copyright (C) 2022 Genode Labs GmbH
+ *
+ * This file is part of the Genode OS framework, which is distributed
+ * under the terms of the GNU Affero General Public License version 3.
+ */
+
+#include <util/mmio.h>
+#include <pci/config.h>
+#include <device.h>
+
+namespace Driver {
+	void pci_virtio_info(Device const     & dev,
+	                     Device::Pci_config cfg,
+	                     Env              & env,
+	                     Xml_generator    & xml);
+}
+
+
+void Driver::pci_virtio_info(Device const     & dev,
+                             Device::Pci_config cfg,
+                             Env              & env,
+                             Xml_generator    & xml)
+{
+	enum { VENDOR_RED_HAT = 0x1af4 };
+
+	if (cfg.vendor_id != VENDOR_RED_HAT)
+		return;
+
+	struct Virtio : Pci::Config
+	{
+		struct Capability : Pci::Config::Pci_capability
+		{
+			enum { COMMON = 1, NOTIFY = 2, ISR = 3, DEVICE = 4 };
+
+			struct Type          : Register<0x3, 8>  {};
+			struct Bar           : Register<0x4, 8>  {};
+			struct Offset        : Register<0x8, 32> {};
+			struct Length        : Register<0xc, 32> {};
+			struct Offset_factor : Register<0x10, 32> {};
+
+			using Pci::Config::Pci_capability::Pci_capability;
+
+			bool valid()
+			{
+				switch (read<Type>()) {
+					case COMMON:
+					case NOTIFY:
+					case ISR:
+					case DEVICE:
+						return true;
+				};
+				return false;
+			}
+
+			String<16> name()
+			{
+				switch (read<Type>()) {
+					case COMMON: return "common";
+					case NOTIFY: return "notify";
+					case ISR:    return "irq_status";
+					case DEVICE: return "device";
+				};
+				return "unknown";
+			}
+		};
+
+		using Pci::Config::Config;
+
+		void capability(Capability           & cap,
+		                Driver::Device const & dev,
+		                Xml_generator        & xml)
+		{
+			unsigned idx = ~0U;
+			dev.for_each_io_mem([&] (unsigned i,
+			                         Driver::Device::Io_mem::Range,
+			                         Driver::Device::Pci_bar bar) {
+				if (bar.number == cap.read<Capability::Bar>()) idx = i; });
+
+			xml.node("virtio_range", [&] () {
+				xml.attribute("type",   cap.name());
+				xml.attribute("index",  idx);
+				xml.attribute("offset", cap.read<Capability::Offset>());
+				xml.attribute("size",   cap.read<Capability::Length>());
+				if (cap.read<Capability::Type>() == Capability::NOTIFY)
+					xml.attribute("factor",
+					              cap.read<Capability::Offset_factor>());
+			});
+		}
+
+		void for_each_capability(Driver::Device const & dev,
+		                         Xml_generator        & xml)
+		{
+			if (!read<Status::Capabilities>())
+				return;
+
+			uint16_t off = read<Capability_pointer>();
+			while (off) {
+				Capability cap(base() + off);
+				if (cap.read<Pci_capability::Id>() ==
+				    Pci_capability::Id::VENDOR &&
+				    cap.valid())
+					capability(cap, dev, xml);
+				off = cap.read<Pci_capability::Pointer>();
+			}
+		}
+	};
+
+	Attached_io_mem_dataspace io_mem(env, cfg.addr, 0x1000);
+	Virtio                    config((addr_t)io_mem.local_addr<void>());
+	config.for_each_capability(dev, xml);
+}
+