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qemu-e2k/hw/pci/msi.c
Jan Beulich 7611dae8a6 xen: don't allow guest to control MSI mask register 
It's being used by the hypervisor. For now simply mimic a device not
capable of masking, and fully emulate any accesses a guest may issue
nevertheless as simple reads/writes without side effects.

This is XSA-129.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
2015-06-02 15:07:00 +00:00

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/*
* msi.c
*
* Copyright (c) 2010 Isaku Yamahata <yamahata at valinux co jp>
* VA Linux Systems Japan K.K.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
* You should have received a copy of the GNU General Public License along
* with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include "hw/pci/msi.h"
#include "qemu/range.h"
/* PCI_MSI_ADDRESS_LO */
#define PCI_MSI_ADDRESS_LO_MASK (~0x3)
/* If we get rid of cap allocator, we won't need those. */
#define PCI_MSI_32_SIZEOF 0x0a
#define PCI_MSI_64_SIZEOF 0x0e
#define PCI_MSI_32M_SIZEOF 0x14
#define PCI_MSI_64M_SIZEOF 0x18
#define PCI_MSI_VECTORS_MAX 32
/* Flag for interrupt controller to declare MSI/MSI-X support */
bool msi_supported;
/* If we get rid of cap allocator, we won't need this. */
static inline uint8_t msi_cap_sizeof(uint16_t flags)
{
switch (flags & (PCI_MSI_FLAGS_MASKBIT | PCI_MSI_FLAGS_64BIT)) {
case PCI_MSI_FLAGS_MASKBIT | PCI_MSI_FLAGS_64BIT:
return PCI_MSI_64M_SIZEOF;
case PCI_MSI_FLAGS_64BIT:
return PCI_MSI_64_SIZEOF;
case PCI_MSI_FLAGS_MASKBIT:
return PCI_MSI_32M_SIZEOF;
case 0:
return PCI_MSI_32_SIZEOF;
default:
abort();
break;
}
return 0;
}
//#define MSI_DEBUG
#ifdef MSI_DEBUG
# define MSI_DPRINTF(fmt, ...) \
fprintf(stderr, "%s:%d " fmt, __func__, __LINE__, ## __VA_ARGS__)
#else
# define MSI_DPRINTF(fmt, ...) do { } while (0)
#endif
#define MSI_DEV_PRINTF(dev, fmt, ...) \
MSI_DPRINTF("%s:%x " fmt, (dev)->name, (dev)->devfn, ## __VA_ARGS__)
static inline unsigned int msi_nr_vectors(uint16_t flags)
{
return 1U <<
((flags & PCI_MSI_FLAGS_QSIZE) >> ctz32(PCI_MSI_FLAGS_QSIZE));
}
static inline uint8_t msi_flags_off(const PCIDevice* dev)
{
return dev->msi_cap + PCI_MSI_FLAGS;
}
static inline uint8_t msi_address_lo_off(const PCIDevice* dev)
{
return dev->msi_cap + PCI_MSI_ADDRESS_LO;
}
static inline uint8_t msi_address_hi_off(const PCIDevice* dev)
{
return dev->msi_cap + PCI_MSI_ADDRESS_HI;
}
static inline uint8_t msi_data_off(const PCIDevice* dev, bool msi64bit)
{
return dev->msi_cap + (msi64bit ? PCI_MSI_DATA_64 : PCI_MSI_DATA_32);
}
static inline uint8_t msi_mask_off(const PCIDevice* dev, bool msi64bit)
{
return dev->msi_cap + (msi64bit ? PCI_MSI_MASK_64 : PCI_MSI_MASK_32);
}
static inline uint8_t msi_pending_off(const PCIDevice* dev, bool msi64bit)
{
return dev->msi_cap + (msi64bit ? PCI_MSI_PENDING_64 : PCI_MSI_PENDING_32);
}
/*
* Special API for POWER to configure the vectors through
* a side channel. Should never be used by devices.
*/
void msi_set_message(PCIDevice *dev, MSIMessage msg)
{
uint16_t flags = pci_get_word(dev->config + msi_flags_off(dev));
bool msi64bit = flags & PCI_MSI_FLAGS_64BIT;
if (msi64bit) {
pci_set_quad(dev->config + msi_address_lo_off(dev), msg.address);
} else {
pci_set_long(dev->config + msi_address_lo_off(dev), msg.address);
}
pci_set_word(dev->config + msi_data_off(dev, msi64bit), msg.data);
}
MSIMessage msi_get_message(PCIDevice *dev, unsigned int vector)
{
uint16_t flags = pci_get_word(dev->config + msi_flags_off(dev));
bool msi64bit = flags & PCI_MSI_FLAGS_64BIT;
unsigned int nr_vectors = msi_nr_vectors(flags);
MSIMessage msg;
assert(vector < nr_vectors);
if (msi64bit) {
msg.address = pci_get_quad(dev->config + msi_address_lo_off(dev));
} else {
msg.address = pci_get_long(dev->config + msi_address_lo_off(dev));
}
/* upper bit 31:16 is zero */
msg.data = pci_get_word(dev->config + msi_data_off(dev, msi64bit));
if (nr_vectors > 1) {
msg.data &= ~(nr_vectors - 1);
msg.data |= vector;
}
return msg;
}
bool msi_enabled(const PCIDevice *dev)
{
return msi_present(dev) &&
(pci_get_word(dev->config + msi_flags_off(dev)) &
PCI_MSI_FLAGS_ENABLE);
}
int msi_init(struct PCIDevice *dev, uint8_t offset,
unsigned int nr_vectors, bool msi64bit, bool msi_per_vector_mask)
{
unsigned int vectors_order;
uint16_t flags;
uint8_t cap_size;
int config_offset;
if (!msi_supported) {
return -ENOTSUP;
}
MSI_DEV_PRINTF(dev,
"init offset: 0x%"PRIx8" vector: %"PRId8
" 64bit %d mask %d\n",
offset, nr_vectors, msi64bit, msi_per_vector_mask);
assert(!(nr_vectors & (nr_vectors - 1))); /* power of 2 */
assert(nr_vectors > 0);
assert(nr_vectors <= PCI_MSI_VECTORS_MAX);
/* the nr of MSI vectors is up to 32 */
vectors_order = ctz32(nr_vectors);
flags = vectors_order << ctz32(PCI_MSI_FLAGS_QMASK);
if (msi64bit) {
flags |= PCI_MSI_FLAGS_64BIT;
}
if (msi_per_vector_mask) {
flags |= PCI_MSI_FLAGS_MASKBIT;
}
cap_size = msi_cap_sizeof(flags);
config_offset = pci_add_capability(dev, PCI_CAP_ID_MSI, offset, cap_size);
if (config_offset < 0) {
return config_offset;
}
dev->msi_cap = config_offset;
dev->cap_present |= QEMU_PCI_CAP_MSI;
pci_set_word(dev->config + msi_flags_off(dev), flags);
pci_set_word(dev->wmask + msi_flags_off(dev),
PCI_MSI_FLAGS_QSIZE | PCI_MSI_FLAGS_ENABLE);
pci_set_long(dev->wmask + msi_address_lo_off(dev),
PCI_MSI_ADDRESS_LO_MASK);
if (msi64bit) {
pci_set_long(dev->wmask + msi_address_hi_off(dev), 0xffffffff);
}
pci_set_word(dev->wmask + msi_data_off(dev, msi64bit), 0xffff);
if (msi_per_vector_mask) {
/* Make mask bits 0 to nr_vectors - 1 writable. */
pci_set_long(dev->wmask + msi_mask_off(dev, msi64bit),
0xffffffff >> (PCI_MSI_VECTORS_MAX - nr_vectors));
}
return config_offset;
}
void msi_uninit(struct PCIDevice *dev)
{
uint16_t flags;
uint8_t cap_size;
if (!msi_present(dev)) {
return;
}
flags = pci_get_word(dev->config + msi_flags_off(dev));
cap_size = msi_cap_sizeof(flags);
pci_del_capability(dev, PCI_CAP_ID_MSI, cap_size);
dev->cap_present &= ~QEMU_PCI_CAP_MSI;
MSI_DEV_PRINTF(dev, "uninit\n");
}
void msi_reset(PCIDevice *dev)
{
uint16_t flags;
bool msi64bit;
if (!msi_present(dev)) {
return;
}
flags = pci_get_word(dev->config + msi_flags_off(dev));
flags &= ~(PCI_MSI_FLAGS_QSIZE | PCI_MSI_FLAGS_ENABLE);
msi64bit = flags & PCI_MSI_FLAGS_64BIT;
pci_set_word(dev->config + msi_flags_off(dev), flags);
pci_set_long(dev->config + msi_address_lo_off(dev), 0);
if (msi64bit) {
pci_set_long(dev->config + msi_address_hi_off(dev), 0);
}
pci_set_word(dev->config + msi_data_off(dev, msi64bit), 0);
if (flags & PCI_MSI_FLAGS_MASKBIT) {
pci_set_long(dev->config + msi_mask_off(dev, msi64bit), 0);
pci_set_long(dev->config + msi_pending_off(dev, msi64bit), 0);
}
MSI_DEV_PRINTF(dev, "reset\n");
}
static bool msi_is_masked(const PCIDevice *dev, unsigned int vector)
{
uint16_t flags = pci_get_word(dev->config + msi_flags_off(dev));
uint32_t mask;
assert(vector < PCI_MSI_VECTORS_MAX);
if (!(flags & PCI_MSI_FLAGS_MASKBIT)) {
return false;
}
mask = pci_get_long(dev->config +
msi_mask_off(dev, flags & PCI_MSI_FLAGS_64BIT));
return mask & (1U << vector);
}
void msi_notify(PCIDevice *dev, unsigned int vector)
{
uint16_t flags = pci_get_word(dev->config + msi_flags_off(dev));
bool msi64bit = flags & PCI_MSI_FLAGS_64BIT;
unsigned int nr_vectors = msi_nr_vectors(flags);
MSIMessage msg;
assert(vector < nr_vectors);
if (msi_is_masked(dev, vector)) {
assert(flags & PCI_MSI_FLAGS_MASKBIT);
pci_long_test_and_set_mask(
dev->config + msi_pending_off(dev, msi64bit), 1U << vector);
MSI_DEV_PRINTF(dev, "pending vector 0x%x\n", vector);
return;
}
msg = msi_get_message(dev, vector);
MSI_DEV_PRINTF(dev,
"notify vector 0x%x"
" address: 0x%"PRIx64" data: 0x%"PRIx32"\n",
vector, msg.address, msg.data);
msi_send_message(dev, msg);
}
void msi_send_message(PCIDevice *dev, MSIMessage msg)
{
MemTxAttrs attrs = {};
attrs.stream_id = (pci_bus_num(dev->bus) << 8) | dev->devfn;
address_space_stl_le(&dev->bus_master_as, msg.address, msg.data,
attrs, NULL);
}
/* Normally called by pci_default_write_config(). */
void msi_write_config(PCIDevice *dev, uint32_t addr, uint32_t val, int len)
{
uint16_t flags = pci_get_word(dev->config + msi_flags_off(dev));
bool msi64bit = flags & PCI_MSI_FLAGS_64BIT;
bool msi_per_vector_mask = flags & PCI_MSI_FLAGS_MASKBIT;
unsigned int nr_vectors;
uint8_t log_num_vecs;
uint8_t log_max_vecs;
unsigned int vector;
uint32_t pending;
if (!msi_present(dev) ||
!ranges_overlap(addr, len, dev->msi_cap, msi_cap_sizeof(flags))) {
return;
}
#ifdef MSI_DEBUG
MSI_DEV_PRINTF(dev, "addr 0x%"PRIx32" val 0x%"PRIx32" len %d\n",
addr, val, len);
MSI_DEV_PRINTF(dev, "ctrl: 0x%"PRIx16" address: 0x%"PRIx32,
flags,
pci_get_long(dev->config + msi_address_lo_off(dev)));
if (msi64bit) {
fprintf(stderr, " address-hi: 0x%"PRIx32,
pci_get_long(dev->config + msi_address_hi_off(dev)));
}
fprintf(stderr, " data: 0x%"PRIx16,
pci_get_word(dev->config + msi_data_off(dev, msi64bit)));
if (flags & PCI_MSI_FLAGS_MASKBIT) {
fprintf(stderr, " mask 0x%"PRIx32" pending 0x%"PRIx32,
pci_get_long(dev->config + msi_mask_off(dev, msi64bit)),
pci_get_long(dev->config + msi_pending_off(dev, msi64bit)));
}
fprintf(stderr, "\n");
#endif
if (!(flags & PCI_MSI_FLAGS_ENABLE)) {
return;
}
/*
* Now MSI is enabled, clear INTx# interrupts.
* the driver is prohibited from writing enable bit to mask
* a service request. But the guest OS could do this.
* So we just discard the interrupts as moderate fallback.
*
* 6.8.3.3. Enabling Operation
* While enabled for MSI or MSI-X operation, a function is prohibited
* from using its INTx# pin (if implemented) to request
* service (MSI, MSI-X, and INTx# are mutually exclusive).
*/
pci_device_deassert_intx(dev);
/*
* nr_vectors might be set bigger than capable. So clamp it.
* This is not legal by spec, so we can do anything we like,
* just don't crash the host
*/
log_num_vecs =
(flags & PCI_MSI_FLAGS_QSIZE) >> ctz32(PCI_MSI_FLAGS_QSIZE);
log_max_vecs =
(flags & PCI_MSI_FLAGS_QMASK) >> ctz32(PCI_MSI_FLAGS_QMASK);
if (log_num_vecs > log_max_vecs) {
flags &= ~PCI_MSI_FLAGS_QSIZE;
flags |= log_max_vecs << ctz32(PCI_MSI_FLAGS_QSIZE);
pci_set_word(dev->config + msi_flags_off(dev), flags);
}
if (!msi_per_vector_mask) {
/* if per vector masking isn't supported,
there is no pending interrupt. */
return;
}
nr_vectors = msi_nr_vectors(flags);
/* This will discard pending interrupts, if any. */
pending = pci_get_long(dev->config + msi_pending_off(dev, msi64bit));
pending &= 0xffffffff >> (PCI_MSI_VECTORS_MAX - nr_vectors);
pci_set_long(dev->config + msi_pending_off(dev, msi64bit), pending);
/* deliver pending interrupts which are unmasked */
for (vector = 0; vector < nr_vectors; ++vector) {
if (msi_is_masked(dev, vector) || !(pending & (1U << vector))) {
continue;
}
pci_long_test_and_clear_mask(
dev->config + msi_pending_off(dev, msi64bit), 1U << vector);
msi_notify(dev, vector);
}
}
unsigned int msi_nr_vectors_allocated(const PCIDevice *dev)
{
uint16_t flags = pci_get_word(dev->config + msi_flags_off(dev));
return msi_nr_vectors(flags);
}
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