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qemu/hw/msix.c

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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];
}
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