qemu/hw/msix.c
Michael S. Tsirkin ae392c416c msix: avoid mask updates if mask is unchanged
Check pending bit only if vector mask status changed.
This is not really important for qemu.git but helps
fix a bug in qemu-kvm.git.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2011-11-21 15:05:59 -06:00

415 lines
12 KiB
C

/*
* 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"
#include "range.h"
#define MSIX_CAP_LENGTH 12
/* MSI enable bit and maskall bit are in byte 1 in FLAGS register */
#define MSIX_CONTROL_OFFSET (PCI_MSIX_FLAGS + 1)
#define MSIX_ENABLE_MASK (PCI_MSIX_FLAGS_ENABLE >> 8)
#define MSIX_MASKALL_MASK (PCI_MSIX_FLAGS_MASKALL >> 8)
/* How much space does an MSIX table need. */
/* The spec requires giving the table structure
* a 4K aligned region all by itself. */
#define MSIX_PAGE_SIZE 0x1000
/* Reserve second half of the page for pending bits */
#define MSIX_PAGE_PENDING (MSIX_PAGE_SIZE / 2)
#define MSIX_MAX_ENTRIES 32
/* 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,
0, 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 + PCI_MSIX_TABLE, bar_size | bar_nr);
/* Pending bits on top of that */
pci_set_long(config + PCI_MSIX_PBA, (bar_size + MSIX_PAGE_PENDING) |
bar_nr);
pdev->msix_cap = config_offset;
/* Make flags bit writable. */
pdev->wmask[config_offset + MSIX_CONTROL_OFFSET] |= MSIX_ENABLE_MASK |
MSIX_MASKALL_MASK;
pdev->msix_function_masked = true;
return 0;
}
static uint64_t msix_mmio_read(void *opaque, target_phys_addr_t addr,
unsigned size)
{
PCIDevice *dev = opaque;
unsigned int offset = addr & (MSIX_PAGE_SIZE - 1) & ~0x3;
void *page = dev->msix_table_page;
return pci_get_long(page + offset);
}
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 bool msix_vector_masked(PCIDevice *dev, int vector, bool fmask)
{
unsigned offset = vector * PCI_MSIX_ENTRY_SIZE + PCI_MSIX_ENTRY_VECTOR_CTRL;
return fmask || dev->msix_table_page[offset] & PCI_MSIX_ENTRY_CTRL_MASKBIT;
}
static bool msix_is_masked(PCIDevice *dev, int vector)
{
return msix_vector_masked(dev, vector, dev->msix_function_masked);
}
static void msix_handle_mask_update(PCIDevice *dev, int vector, bool was_masked)
{
bool is_masked = msix_is_masked(dev, vector);
if (is_masked == was_masked) {
return;
}
if (!is_masked && msix_is_pending(dev, vector)) {
msix_clr_pending(dev, vector);
msix_notify(dev, vector);
}
}
static void msix_update_function_masked(PCIDevice *dev)
{
dev->msix_function_masked = !msix_enabled(dev) ||
(dev->config[dev->msix_cap + MSIX_CONTROL_OFFSET] & MSIX_MASKALL_MASK);
}
/* 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_CONTROL_OFFSET;
int vector;
bool was_masked;
if (!range_covers_byte(addr, len, enable_pos)) {
return;
}
was_masked = dev->msix_function_masked;
msix_update_function_masked(dev);
if (!msix_enabled(dev)) {
return;
}
pci_device_deassert_intx(dev);
if (dev->msix_function_masked == was_masked) {
return;
}
for (vector = 0; vector < dev->msix_entries_nr; ++vector) {
msix_handle_mask_update(dev, vector,
msix_vector_masked(dev, vector, was_masked));
}
}
static void msix_mmio_write(void *opaque, target_phys_addr_t addr,
uint64_t val, unsigned size)
{
PCIDevice *dev = opaque;
unsigned int offset = addr & (MSIX_PAGE_SIZE - 1) & ~0x3;
int vector = offset / PCI_MSIX_ENTRY_SIZE;
bool was_masked;
/* MSI-X page includes a read-only PBA and a writeable Vector Control. */
if (vector >= dev->msix_entries_nr) {
return;
}
was_masked = msix_is_masked(dev, vector);
pci_set_long(dev->msix_table_page + offset, val);
msix_handle_mask_update(dev, vector, was_masked);
}
static const MemoryRegionOps msix_mmio_ops = {
.read = msix_mmio_read,
.write = msix_mmio_write,
.endianness = DEVICE_NATIVE_ENDIAN,
.valid = {
.min_access_size = 4,
.max_access_size = 4,
},
};
static void msix_mmio_setup(PCIDevice *d, MemoryRegion *bar)
{
uint8_t *config = d->config + d->msix_cap;
uint32_t table = pci_get_long(config + PCI_MSIX_TABLE);
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. */
memory_region_add_subregion(bar, offset, &d->msix_mmio);
}
static void msix_mask_all(struct PCIDevice *dev, unsigned nentries)
{
int vector;
for (vector = 0; vector < nentries; ++vector) {
unsigned offset =
vector * PCI_MSIX_ENTRY_SIZE + PCI_MSIX_ENTRY_VECTOR_CTRL;
dev->msix_table_page[offset] |= PCI_MSIX_ENTRY_CTRL_MASKBIT;
}
}
/* 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,
MemoryRegion *bar,
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 = g_malloc0(MSIX_MAX_ENTRIES *
sizeof *dev->msix_entry_used);
dev->msix_table_page = g_malloc0(MSIX_PAGE_SIZE);
msix_mask_all(dev, nentries);
memory_region_init_io(&dev->msix_mmio, &msix_mmio_ops, dev,
"msix", MSIX_PAGE_SIZE);
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;
msix_mmio_setup(dev, bar);
return 0;
err_config:
dev->msix_entries_nr = 0;
memory_region_destroy(&dev->msix_mmio);
g_free(dev->msix_table_page);
dev->msix_table_page = NULL;
g_free(dev->msix_entry_used);
dev->msix_entry_used = NULL;
return ret;
}
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;
msix_clr_pending(dev, vector);
}
}
/* Clean up resources for the device. */
int msix_uninit(PCIDevice *dev, MemoryRegion *bar)
{
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;
memory_region_del_subregion(bar, &dev->msix_mmio);
memory_region_destroy(&dev->msix_mmio);
g_free(dev->msix_table_page);
dev->msix_table_page = NULL;
g_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 n = dev->msix_entries_nr;
if (!(dev->cap_present & QEMU_PCI_CAP_MSIX)) {
return;
}
qemu_put_buffer(f, dev->msix_table_page, n * PCI_MSIX_ENTRY_SIZE);
qemu_put_buffer(f, dev->msix_table_page + MSIX_PAGE_PENDING, (n + 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;
}
msix_free_irq_entries(dev);
qemu_get_buffer(f, dev->msix_table_page, n * PCI_MSIX_ENTRY_SIZE);
qemu_get_buffer(f, dev->msix_table_page + MSIX_PAGE_PENDING, (n + 7) / 8);
msix_update_function_masked(dev);
}
/* 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_CONTROL_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 * PCI_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_quad(table_entry + PCI_MSIX_ENTRY_LOWER_ADDR);
data = pci_get_long(table_entry + PCI_MSIX_ENTRY_DATA);
stl_le_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_CONTROL_OFFSET] &=
~dev->wmask[dev->msix_cap + MSIX_CONTROL_OFFSET];
memset(dev->msix_table_page, 0, MSIX_PAGE_SIZE);
msix_mask_all(dev, dev->msix_entries_nr);
}
/* 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]) {
return;
}
if (--dev->msix_entry_used[vector]) {
return;
}
msix_clr_pending(dev, vector);
}
void msix_unuse_all_vectors(PCIDevice *dev)
{
if (!(dev->cap_present & QEMU_PCI_CAP_MSIX))
return;
msix_free_irq_entries(dev);
}