Kernel: Add base support for VirtIO devices

Based on pull #3236 by tomuta, this adds helper methods for generic
device initialization, and partily-broken virtqueue helper methods

Co-authored-by: Tom <tomut@yahoo.com>
Co-authored-by: Sahan <sahan.h.fernando@gmail.com>

Kernel/VirtIO/VirtIO.h

@@ -0,0 +1,249 @@
+/*
+ * Copyright (c) 2020, the SerenityOS developers.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <AK/NonnullOwnPtrVector.h>
+#include <Kernel/IO.h>
+#include <Kernel/Interrupts/IRQHandler.h>
+#include <Kernel/PCI/Access.h>
+#include <Kernel/PCI/Device.h>
+#include <Kernel/VM/MemoryManager.h>
+#include <Kernel/VirtIO/VirtIOQueue.h>
+
+namespace Kernel {
+
+#define VIRTIO_PCI_VENDOR_ID 0x1AF4
+
+#define REG_DEVICE_FEATURES 0x0
+#define REG_GUEST_FEATURES 0x4
+#define REG_QUEUE_ADDRESS 0x8
+#define REG_QUEUE_SIZE 0xc
+#define REG_QUEUE_SELECT 0xe
+#define REG_QUEUE_NOTIFY 0x10
+#define REG_DEVICE_STATUS 0x12
+#define REG_ISR_STATUS 0x13
+
+#define DEVICE_STATUS_ACKNOWLEDGE (1 << 0)
+#define DEVICE_STATUS_DRIVER (1 << 1)
+#define DEVICE_STATUS_DRIVER_OK (1 << 2)
+#define DEVICE_STATUS_FEATURES_OK (1 << 3)
+#define DEVICE_STATUS_DEVICE_NEEDS_RESET (1 << 6)
+#define DEVICE_STATUS_FAILED (1 << 7)
+
+#define VIRTIO_F_VERSION_1 ((u64)1 << 32)
+#define VIRTIO_F_RING_PACKED ((u64)1 << 34)
+
+#define VIRTIO_PCI_CAP_COMMON_CFG 1
+#define VIRTIO_PCI_CAP_NOTIFY_CFG 2
+#define VIRTIO_PCI_CAP_ISR_CFG 3
+#define VIRTIO_PCI_CAP_DEVICE_CFG 4
+#define VIRTIO_PCI_CAP_PCI_CFG 5
+
+// virtio_pci_common_cfg
+#define COMMON_CFG_DEVICE_FEATURE_SELECT 0x0
+#define COMMON_CFG_DEVICE_FEATURE 0x4
+#define COMMON_CFG_DRIVER_FEATURE_SELECT 0x8
+#define COMMON_CFG_DRIVER_FEATURE 0xc
+#define COMMON_CFG_MSIX_CONFIG 0x10
+#define COMMON_CFG_NUM_QUEUES 0x12
+#define COMMON_CFG_DEVICE_STATUS 0x14
+#define COMMON_CFG_CONFIG_GENERATION 0x15
+#define COMMON_CFG_QUEUE_SELECT 0x16
+#define COMMON_CFG_QUEUE_SIZE 0x18
+#define COMMON_CFG_QUEUE_MSIX_VECTOR 0x1a
+#define COMMON_CFG_QUEUE_ENABLE 0x1c
+#define COMMON_CFG_QUEUE_NOTIFY_OFF 0x1e
+#define COMMON_CFG_QUEUE_DESC 0x20
+#define COMMON_CFG_QUEUE_DRIVER 0x28
+#define COMMON_CFG_QUEUE_DEVICE 0x30
+
+#define QUEUE_INTERRUPT 0x1
+#define DEVICE_CONFIG_INTERRUPT 0x2
+
+class VirtIO {
+public:
+    static void detect();
+};
+
+class VirtIODevice : public PCI::Device {
+public:
+    VirtIODevice(PCI::Address, const char*);
+    virtual ~VirtIODevice() override;
+
+protected:
+    const char* const m_class_name;
+
+    struct MappedMMIO {
+        OwnPtr<Region> base;
+        size_t size { 0 };
+
+        template<typename T>
+        T read(u32 offset) const
+        {
+            if (!base)
+                return 0;
+            VERIFY(size >= sizeof(T));
+            VERIFY(offset + sizeof(T) <= size);
+            return *(volatile T*)(base->vaddr().offset(offset).get());
+        }
+
+        template<typename T>
+        void write(u32 offset, T value)
+        {
+            if (!base)
+                return;
+            VERIFY(size >= sizeof(T));
+            VERIFY(offset + sizeof(T) <= size);
+            *(volatile T*)(base->vaddr().offset(offset).get()) = value;
+        }
+    };
+
+    struct Configuration {
+        u8 cfg_type;
+        u8 bar;
+        u32 offset;
+        u32 length;
+    };
+
+    const Configuration* get_config(u8 cfg_type, u32 index = 0) const
+    {
+        for (const auto& cfg : m_configs) {
+            if (cfg.cfg_type != cfg_type)
+                continue;
+            if (index > 0) {
+                index--;
+                continue;
+            }
+            return &cfg;
+        }
+        return nullptr;
+    }
+    const Configuration* get_common_config(u32 index = 0) const;
+    const Configuration* get_device_config(u32 index = 0) const;
+
+    template<typename F>
+    void read_config_atomic(F f)
+    {
+        if (m_common_cfg) {
+            u8 generation_before, generation_after;
+            do {
+                generation_before = config_read8(m_common_cfg, 0x15);
+                f();
+                generation_after = config_read8(m_common_cfg, 0x15);
+            } while (generation_before != generation_after);
+        } else {
+            f();
+        }
+    }
+
+    u8 config_read8(const Configuration*, u32);
+    u16 config_read16(const Configuration*, u32);
+    u32 config_read32(const Configuration*, u32);
+    void config_write8(const Configuration*, u32, u8);
+    void config_write16(const Configuration*, u32, u16);
+    void config_write32(const Configuration*, u32, u32);
+    void config_write64(const Configuration*, u32, u64);
+
+    auto mapping_for_bar(u8) -> MappedMMIO&;
+
+    u8 read_status_bits();
+    void clear_status_bit(u8);
+    void set_status_bit(u8);
+    u64 get_device_features();
+    bool finish_init();
+
+    VirtIOQueue* get_queue(u16 queue_index)
+    {
+        return &m_queues[queue_index];
+    }
+    void set_requested_queue_count(u16);
+
+    template<typename F>
+    bool negotiate_features(F f)
+    {
+        u64 device_features = get_device_features();
+        u64 accept_features = f(device_features);
+        VERIFY(!(~device_features & accept_features));
+        return accept_device_features(device_features, accept_features);
+    }
+
+    static bool is_feature_set(u64 feature_set, u64 test_feature)
+    {
+        // features can have more than one bit
+        return (feature_set & test_feature) == test_feature;
+    }
+    bool is_feature_accepted(u64 feature) const
+    {
+        VERIFY(m_did_accept_features);
+        return is_feature_set(m_accepted_features, feature);
+    }
+
+    void supply_buffer_and_notify(u16 queue_index, const u8* buffer, u32 len, BufferType);
+
+    virtual void handle_irq(const RegisterState&) override;
+    virtual void handle_device_config_change() = 0;
+
+private:
+    template<typename T>
+    void out(u16 address, T value)
+    {
+        m_io_base.offset(address).out(value);
+    }
+
+    template<typename T>
+    T in(u16 address)
+    {
+        return m_io_base.offset(address).in<T>();
+    }
+
+    bool accept_device_features(u64 device_features, u64 accepted_features);
+
+    bool setup_queues();
+    bool setup_queue(u16 queue_index);
+    void notify_queue(u16 queue_index);
+
+    void reset_device();
+
+    u8 isr_status();
+
+    NonnullOwnPtrVector<VirtIOQueue> m_queues;
+    Vector<Configuration> m_configs;
+    const Configuration* m_common_cfg { nullptr }; // Cached due to high usage
+    const Configuration* m_notify_cfg { nullptr }; // Cached due to high usage
+    const Configuration* m_isr_cfg { nullptr };    // Cached due to high usage
+
+    IOAddress m_io_base;
+    MappedMMIO m_mmio[6];
+    u16 m_queue_count { 0 };
+    bool m_use_mmio { false };
+    u8 m_status { 0 };
+    u64 m_accepted_features { 0 };
+    bool m_did_accept_features { false };
+    u32 m_notify_multiplier { 0 };
+};
+
+}