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/*

 * MSI-X device support

 *

 * This module includes support for MSI-X in pci devices.

 *

 * Author: Michael S. Tsirkin <mst@redhat.com>

 *

 *  Copyright (c) 2009, Red Hat Inc, Michael S. Tsirkin (mst@redhat.com)

 *

 * This work is licensed under the terms of the GNU GPL, version 2.  See

 * the COPYING file in the top-level directory.

 */

#include "hw.h"

#include "msix.h"

#include "pci.h"

/* Declaration from linux/pci_regs.h */

#define  PCI_CAP_ID_MSIX 0x11 /* MSI-X */

#define  PCI_MSIX_FLAGS 2     /* Table at lower 11 bits */

#define  PCI_MSIX_FLAGS_QSIZE        0x7FF

#define  PCI_MSIX_FLAGS_ENABLE        (1 << 15)

#define  PCI_MSIX_FLAGS_BIRMASK        (7 << 0)

/* MSI-X capability structure */

#define MSIX_TABLE_OFFSET 4

#define MSIX_PBA_OFFSET 8

#define MSIX_CAP_LENGTH 12

/* MSI enable bit is in byte 1 in FLAGS register */

#define MSIX_ENABLE_OFFSET (PCI_MSIX_FLAGS + 1)

#define MSIX_ENABLE_MASK (PCI_MSIX_FLAGS_ENABLE >> 8)

/* MSI-X table format */

#define MSIX_MSG_ADDR 0

#define MSIX_MSG_UPPER_ADDR 4

#define MSIX_MSG_DATA 8

#define MSIX_VECTOR_CTRL 12

#define MSIX_ENTRY_SIZE 16

#define MSIX_VECTOR_MASK 0x1

/* How much space does an MSIX table need. */

/* The spec requires giving the table structure

 * a 4K aligned region all by itself. Align it to

 * target pages so that drivers can do passthrough

 * on the rest of the region. */

#define MSIX_PAGE_SIZE TARGET_PAGE_ALIGN(0x1000)

/* Reserve second half of the page for pending bits */

#define MSIX_PAGE_PENDING (MSIX_PAGE_SIZE / 2)

#define MSIX_MAX_ENTRIES 32

#ifdef MSIX_DEBUG

#define DEBUG(fmt, ...)                                       \

    do {                                                      \

      fprintf(stderr, "%s: " fmt, __func__ , __VA_ARGS__);    \

    } while (0)

#else

#define DEBUG(fmt, ...) do { } while(0)

#endif

/* Flag for interrupt controller to declare MSI-X support */

int msix_supported;

/* Add MSI-X capability to the config space for the device. */

/* Given a bar and its size, add MSI-X table on top of it

 * and fill MSI-X capability in the config space.

 * Original bar size must be a power of 2 or 0.

 * New bar size is returned. */

static int msix_add_config(struct PCIDevice *pdev, unsigned short nentries,

                           unsigned bar_nr, unsigned bar_size)

{

    int config_offset;

    uint8_t *config;

    uint32_t new_size;

    if (nentries < 1 || nentries > PCI_MSIX_FLAGS_QSIZE + 1)

        return -EINVAL;

    if (bar_size > 0x80000000)

        return -ENOSPC;

    /* Add space for MSI-X structures */

    if (!bar_size)

        new_size = MSIX_PAGE_SIZE;

    else if (bar_size < MSIX_PAGE_SIZE) {

        bar_size = MSIX_PAGE_SIZE;

        new_size = MSIX_PAGE_SIZE * 2;

    } else

        new_size = bar_size * 2;

    pdev->msix_bar_size = new_size;

    config_offset = pci_add_capability(pdev, PCI_CAP_ID_MSIX, MSIX_CAP_LENGTH);

    if (config_offset < 0)

        return config_offset;

    config = pdev->config + config_offset;

    pci_set_word(config + PCI_MSIX_FLAGS, nentries - 1);

    /* Table on top of BAR */

    pci_set_long(config + MSIX_TABLE_OFFSET, bar_size | bar_nr);

    /* Pending bits on top of that */

    pci_set_long(config + MSIX_PBA_OFFSET, (bar_size + MSIX_PAGE_PENDING) |

                 bar_nr);

    pdev->msix_cap = config_offset;

    /* Make flags bit writeable. */

    pdev->wmask[config_offset + MSIX_ENABLE_OFFSET] |= MSIX_ENABLE_MASK;

    return 0;

}

static void msix_free_irq_entries(PCIDevice *dev)

{

    int vector;

    for (vector = 0; vector < dev->msix_entries_nr; ++vector)

        dev->msix_entry_used[vector] = 0;

}

/* Handle MSI-X capability config write. */

void msix_write_config(PCIDevice *dev, uint32_t addr,

                       uint32_t val, int len)

{

    unsigned enable_pos = dev->msix_cap + MSIX_ENABLE_OFFSET;

    if (addr + len <= enable_pos || addr > enable_pos)

        return;

    if (msix_enabled(dev))

        qemu_set_irq(dev->irq[0], 0);

}

static uint32_t msix_mmio_readl(void *opaque, target_phys_addr_t addr)

{

    PCIDevice *dev = opaque;

    unsigned int offset = addr & (MSIX_PAGE_SIZE - 1);

    void *page = dev->msix_table_page;

    uint32_t val = 0;

    memcpy(&val, (void *)((char *)page + offset), 4);

    return val;

}

static uint32_t msix_mmio_read_unallowed(void *opaque, target_phys_addr_t addr)

{

    fprintf(stderr, "MSI-X: only dword read is allowed!\n");

    return 0;

}

static uint8_t msix_pending_mask(int vector)

{

    return 1 << (vector % 8);

}

static uint8_t *msix_pending_byte(PCIDevice *dev, int vector)

{

    return dev->msix_table_page + MSIX_PAGE_PENDING + vector / 8;

}

static int msix_is_pending(PCIDevice *dev, int vector)

{

    return *msix_pending_byte(dev, vector) & msix_pending_mask(vector);

}

static void msix_set_pending(PCIDevice *dev, int vector)

{

    *msix_pending_byte(dev, vector) |= msix_pending_mask(vector);

}

static void msix_clr_pending(PCIDevice *dev, int vector)

{

    *msix_pending_byte(dev, vector) &= ~msix_pending_mask(vector);

}

static int msix_is_masked(PCIDevice *dev, int vector)

{

    unsigned offset = vector * MSIX_ENTRY_SIZE + MSIX_VECTOR_CTRL;

    return dev->msix_table_page[offset] & MSIX_VECTOR_MASK;

}

static void msix_mmio_writel(void *opaque, target_phys_addr_t addr,

                             uint32_t val)

{

    PCIDevice *dev = opaque;

    unsigned int offset = addr & (MSIX_PAGE_SIZE - 1);

    int vector = offset / MSIX_ENTRY_SIZE;

    memcpy(dev->msix_table_page + offset, &val, 4);

    if (!msix_is_masked(dev, vector) && msix_is_pending(dev, vector)) {

        msix_clr_pending(dev, vector);

        msix_notify(dev, vector);

    }

}

static void msix_mmio_write_unallowed(void *opaque, target_phys_addr_t addr,

                                      uint32_t val)

{

    fprintf(stderr, "MSI-X: only dword write is allowed!\n");

}

static CPUWriteMemoryFunc *msix_mmio_write[] = {

    msix_mmio_write_unallowed, msix_mmio_write_unallowed, msix_mmio_writel

};

static CPUReadMemoryFunc *msix_mmio_read[] = {

    msix_mmio_read_unallowed, msix_mmio_read_unallowed, msix_mmio_readl

};

/* Should be called from device's map method. */

void msix_mmio_map(PCIDevice *d, int region_num,

                   uint32_t addr, uint32_t size, int type)

{

    uint8_t *config = d->config + d->msix_cap;

    uint32_t table = pci_get_long(config + MSIX_TABLE_OFFSET);

    uint32_t offset = table & ~(MSIX_PAGE_SIZE - 1);

    /* TODO: for assigned devices, we'll want to make it possible to map

     * pending bits separately in case they are in a separate bar. */

    int table_bir = table & PCI_MSIX_FLAGS_BIRMASK;

    if (table_bir != region_num)

        return;

    if (size <= offset)

        return;

    cpu_register_physical_memory(addr + offset, size - offset,

                                 d->msix_mmio_index);

}

/* Initialize the MSI-X structures. Note: if MSI-X is supported, BAR size is

 * modified, it should be retrieved with msix_bar_size. */

int msix_init(struct PCIDevice *dev, unsigned short nentries,

              unsigned bar_nr, unsigned bar_size)

{

    int ret;

    /* Nothing to do if MSI is not supported by interrupt controller */

    if (!msix_supported)

        return -ENOTSUP;

    if (nentries > MSIX_MAX_ENTRIES)

        return -EINVAL;

    dev->msix_entry_used = qemu_mallocz(MSIX_MAX_ENTRIES *

                                        sizeof *dev->msix_entry_used);

    dev->msix_table_page = qemu_mallocz(MSIX_PAGE_SIZE);

    dev->msix_mmio_index = cpu_register_io_memory(msix_mmio_read,

                                                  msix_mmio_write, dev);

    if (dev->msix_mmio_index == -1) {

        ret = -EBUSY;

        goto err_index;

    }

    dev->msix_entries_nr = nentries;

    ret = msix_add_config(dev, nentries, bar_nr, bar_size);

    if (ret)

        goto err_config;

    dev->cap_present |= QEMU_PCI_CAP_MSIX;

    return 0;

err_config:

    cpu_unregister_io_memory(dev->msix_mmio_index);

err_index:

    qemu_free(dev->msix_table_page);

    dev->msix_table_page = NULL;

    qemu_free(dev->msix_entry_used);

    dev->msix_entry_used = NULL;

    return ret;

}

/* Clean up resources for the device. */

int msix_uninit(PCIDevice *dev)

{

    if (!(dev->cap_present & QEMU_PCI_CAP_MSIX))

        return 0;

    pci_del_capability(dev, PCI_CAP_ID_MSIX, MSIX_CAP_LENGTH);

    dev->msix_cap = 0;

    msix_free_irq_entries(dev);

    dev->msix_entries_nr = 0;

    cpu_unregister_io_memory(dev->msix_mmio_index);

    qemu_free(dev->msix_table_page);

    dev->msix_table_page = NULL;

    qemu_free(dev->msix_entry_used);

    dev->msix_entry_used = NULL;

    dev->cap_present &= ~QEMU_PCI_CAP_MSIX;

    return 0;

}

void msix_save(PCIDevice *dev, QEMUFile *f)

{

    unsigned nentries = (pci_get_word(dev->config + PCI_MSIX_FLAGS) &

                         PCI_MSIX_FLAGS_QSIZE) + 1;

    qemu_put_buffer(f, dev->msix_table_page, nentries * MSIX_ENTRY_SIZE);

    qemu_put_buffer(f, dev->msix_table_page + MSIX_PAGE_PENDING,

                    (nentries + 7) / 8);

}

/* Should be called after restoring the config space. */

void msix_load(PCIDevice *dev, QEMUFile *f)

{

    unsigned n = dev->msix_entries_nr;

    if (!dev->cap_present & QEMU_PCI_CAP_MSIX)

        return;

    qemu_get_buffer(f, dev->msix_table_page, n * MSIX_ENTRY_SIZE);

    qemu_get_buffer(f, dev->msix_table_page + MSIX_PAGE_PENDING, (n + 7) / 8);

}

/* Does device support MSI-X? */

int msix_present(PCIDevice *dev)

{

    return dev->cap_present & QEMU_PCI_CAP_MSIX;

}

/* Is MSI-X enabled? */

int msix_enabled(PCIDevice *dev)

{

    return (dev->cap_present & QEMU_PCI_CAP_MSIX) &&

        (dev->config[dev->msix_cap + MSIX_ENABLE_OFFSET] &

         MSIX_ENABLE_MASK);

}

/* Size of bar where MSI-X table resides, or 0 if MSI-X not supported. */

uint32_t msix_bar_size(PCIDevice *dev)

{

    return (dev->cap_present & QEMU_PCI_CAP_MSIX) ?

        dev->msix_bar_size : 0;

}

/* Send an MSI-X message */

void msix_notify(PCIDevice *dev, unsigned vector)

{

    uint8_t *table_entry = dev->msix_table_page + vector * MSIX_ENTRY_SIZE;

    uint64_t address;

    uint32_t data;

    if (vector >= dev->msix_entries_nr || !dev->msix_entry_used[vector])

        return;

    if (msix_is_masked(dev, vector)) {

        msix_set_pending(dev, vector);

        return;

    }

    address = pci_get_long(table_entry + MSIX_MSG_UPPER_ADDR);

    address = (address << 32) | pci_get_long(table_entry + MSIX_MSG_ADDR);

    data = pci_get_long(table_entry + MSIX_MSG_DATA);

    stl_phys(address, data);

}

void msix_reset(PCIDevice *dev)

{

    if (!(dev->cap_present & QEMU_PCI_CAP_MSIX))

        return;

    msix_free_irq_entries(dev);

    dev->config[dev->msix_cap + MSIX_ENABLE_OFFSET] &= MSIX_ENABLE_MASK;

    memset(dev->msix_table_page, 0, MSIX_PAGE_SIZE);

}

/* PCI spec suggests that devices make it possible for software to configure

 * less vectors than supported by the device, but does not specify a standard

 * mechanism for devices to do so.

 *

 * We support this by asking devices to declare vectors software is going to

 * actually use, and checking this on the notification path. Devices that

 * don't want to follow the spec suggestion can declare all vectors as used. */

/* Mark vector as used. */

int msix_vector_use(PCIDevice *dev, unsigned vector)

{

    if (vector >= dev->msix_entries_nr)

        return -EINVAL;

    dev->msix_entry_used[vector]++;

    return 0;

}

/* Mark vector as unused. */

void msix_vector_unuse(PCIDevice *dev, unsigned vector)

{

    if (vector < dev->msix_entries_nr && dev->msix_entry_used[vector])

        --dev->msix_entry_used[vector];

}