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qemu/hw/xen/xen_pt_msi.c
Stefano Stabellini 428c3ece97 fix MSI injection on Xen 
On Xen MSIs can be remapped into pirqs, which are a type of event
channels. It's mostly for the benefit of PCI passthrough devices, to
avoid the overhead of interacting with the emulated lapic.

However remapping interrupts and MSIs is also supported for emulated
devices, such as the e1000 and virtio-net.

When an interrupt or an MSI is remapped into a pirq, masking and
unmasking is done by masking and unmasking the event channel. The
masking bit on the PCI config space or MSI-X table should be ignored,
but it isn't at the moment.

As a consequence emulated devices which use MSI or MSI-X, such as
virtio-net, don't work properly (the guest doesn't receive any
notifications). The mechanism was working properly when xen_apic was
introduced, but I haven't narrowed down which commit in particular is
causing the regression.

Fix the issue by ignoring the masking bit for MSI and MSI-X which have
been remapped into pirqs.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-02-06 20:44:10 +02:00

636 lines
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/*
* Copyright (c) 2007, Intel Corporation.
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*
* Jiang Yunhong <yunhong.jiang@intel.com>
*
* This file implements direct PCI assignment to a HVM guest
*/
#include "qemu/osdep.h"
#include <sys/mman.h>
#include "hw/xen/xen_backend.h"
#include "xen_pt.h"
#include "hw/i386/apic-msidef.h"
#define XEN_PT_AUTO_ASSIGN -1
/* shift count for gflags */
#define XEN_PT_GFLAGS_SHIFT_DEST_ID 0
#define XEN_PT_GFLAGS_SHIFT_RH 8
#define XEN_PT_GFLAGS_SHIFT_DM 9
#define XEN_PT_GFLAGSSHIFT_DELIV_MODE 12
#define XEN_PT_GFLAGSSHIFT_TRG_MODE 15
#define latch(fld) latch[PCI_MSIX_ENTRY_##fld / sizeof(uint32_t)]
/*
* Helpers
*/
static inline uint8_t msi_vector(uint32_t data)
{
return (data & MSI_DATA_VECTOR_MASK) >> MSI_DATA_VECTOR_SHIFT;
}
static inline uint8_t msi_dest_id(uint32_t addr)
{
return (addr & MSI_ADDR_DEST_ID_MASK) >> MSI_ADDR_DEST_ID_SHIFT;
}
static inline uint32_t msi_ext_dest_id(uint32_t addr_hi)
{
return addr_hi & 0xffffff00;
}
static uint32_t msi_gflags(uint32_t data, uint64_t addr)
{
uint32_t result = 0;
int rh, dm, dest_id, deliv_mode, trig_mode;
rh = (addr >> MSI_ADDR_REDIRECTION_SHIFT) & 0x1;
dm = (addr >> MSI_ADDR_DEST_MODE_SHIFT) & 0x1;
dest_id = msi_dest_id(addr);
deliv_mode = (data >> MSI_DATA_DELIVERY_MODE_SHIFT) & 0x7;
trig_mode = (data >> MSI_DATA_TRIGGER_SHIFT) & 0x1;
result = dest_id | (rh << XEN_PT_GFLAGS_SHIFT_RH)
| (dm << XEN_PT_GFLAGS_SHIFT_DM)
| (deliv_mode << XEN_PT_GFLAGSSHIFT_DELIV_MODE)
| (trig_mode << XEN_PT_GFLAGSSHIFT_TRG_MODE);
return result;
}
static inline uint64_t msi_addr64(XenPTMSI *msi)
{
return (uint64_t)msi->addr_hi << 32 | msi->addr_lo;
}
static int msi_msix_enable(XenPCIPassthroughState *s,
uint32_t address,
uint16_t flag,
bool enable)
{
uint16_t val = 0;
int rc;
if (!address) {
return -1;
}
rc = xen_host_pci_get_word(&s->real_device, address, &val);
if (rc) {
XEN_PT_ERR(&s->dev, "Failed to read MSI/MSI-X register (0x%x), rc:%d\n",
address, rc);
return rc;
}
if (enable) {
val |= flag;
} else {
val &= ~flag;
}
rc = xen_host_pci_set_word(&s->real_device, address, val);
if (rc) {
XEN_PT_ERR(&s->dev, "Failed to write MSI/MSI-X register (0x%x), rc:%d\n",
address, rc);
}
return rc;
}
static int msi_msix_setup(XenPCIPassthroughState *s,
uint64_t addr,
uint32_t data,
int *ppirq,
bool is_msix,
int msix_entry,
bool is_not_mapped)
{
uint8_t gvec = msi_vector(data);
int rc = 0;
assert((!is_msix && msix_entry == 0) || is_msix);
if (xen_is_pirq_msi(data)) {
*ppirq = msi_ext_dest_id(addr >> 32) | msi_dest_id(addr);
if (!*ppirq) {
/* this probably identifies an misconfiguration of the guest,
* try the emulated path */
*ppirq = XEN_PT_UNASSIGNED_PIRQ;
} else {
XEN_PT_LOG(&s->dev, "requested pirq %d for MSI%s"
" (vec: %#x, entry: %#x)\n",
*ppirq, is_msix ? "-X" : "", gvec, msix_entry);
}
}
if (is_not_mapped) {
uint64_t table_base = 0;
if (is_msix) {
table_base = s->msix->table_base;
}
rc = xc_physdev_map_pirq_msi(xen_xc, xen_domid, XEN_PT_AUTO_ASSIGN,
ppirq, PCI_DEVFN(s->real_device.dev,
s->real_device.func),
s->real_device.bus,
msix_entry, table_base);
if (rc) {
XEN_PT_ERR(&s->dev,
"Mapping of MSI%s (err: %i, vec: %#x, entry %#x)\n",
is_msix ? "-X" : "", errno, gvec, msix_entry);
return rc;
}
}
return 0;
}
static int msi_msix_update(XenPCIPassthroughState *s,
uint64_t addr,
uint32_t data,
int pirq,
bool is_msix,
int msix_entry,
int *old_pirq)
{
PCIDevice *d = &s->dev;
uint8_t gvec = msi_vector(data);
uint32_t gflags = msi_gflags(data, addr);
int rc = 0;
uint64_t table_addr = 0;
XEN_PT_LOG(d, "Updating MSI%s with pirq %d gvec %#x gflags %#x"
" (entry: %#x)\n",
is_msix ? "-X" : "", pirq, gvec, gflags, msix_entry);
if (is_msix) {
table_addr = s->msix->mmio_base_addr;
}
rc = xc_domain_update_msi_irq(xen_xc, xen_domid, gvec,
pirq, gflags, table_addr);
if (rc) {
XEN_PT_ERR(d, "Updating of MSI%s failed. (err: %d)\n",
is_msix ? "-X" : "", errno);
if (xc_physdev_unmap_pirq(xen_xc, xen_domid, *old_pirq)) {
XEN_PT_ERR(d, "Unmapping of MSI%s pirq %d failed. (err: %d)\n",
is_msix ? "-X" : "", *old_pirq, errno);
}
*old_pirq = XEN_PT_UNASSIGNED_PIRQ;
}
return rc;
}
static int msi_msix_disable(XenPCIPassthroughState *s,
uint64_t addr,
uint32_t data,
int pirq,
bool is_msix,
bool is_binded)
{
PCIDevice *d = &s->dev;
uint8_t gvec = msi_vector(data);
uint32_t gflags = msi_gflags(data, addr);
int rc = 0;
if (pirq == XEN_PT_UNASSIGNED_PIRQ) {
return 0;
}
if (is_binded) {
XEN_PT_LOG(d, "Unbind MSI%s with pirq %d, gvec %#x\n",
is_msix ? "-X" : "", pirq, gvec);
rc = xc_domain_unbind_msi_irq(xen_xc, xen_domid, gvec, pirq, gflags);
if (rc) {
XEN_PT_ERR(d, "Unbinding of MSI%s failed. (err: %d, pirq: %d, gvec: %#x)\n",
is_msix ? "-X" : "", errno, pirq, gvec);
return rc;
}
}
XEN_PT_LOG(d, "Unmap MSI%s pirq %d\n", is_msix ? "-X" : "", pirq);
rc = xc_physdev_unmap_pirq(xen_xc, xen_domid, pirq);
if (rc) {
XEN_PT_ERR(d, "Unmapping of MSI%s pirq %d failed. (err: %i)\n",
is_msix ? "-X" : "", pirq, errno);
return rc;
}
return 0;
}
/*
* MSI virtualization functions
*/
static int xen_pt_msi_set_enable(XenPCIPassthroughState *s, bool enable)
{
XEN_PT_LOG(&s->dev, "%s MSI.\n", enable ? "enabling" : "disabling");
if (!s->msi) {
return -1;
}
return msi_msix_enable(s, s->msi->ctrl_offset, PCI_MSI_FLAGS_ENABLE,
enable);
}
/* setup physical msi, but don't enable it */
int xen_pt_msi_setup(XenPCIPassthroughState *s)
{
int pirq = XEN_PT_UNASSIGNED_PIRQ;
int rc = 0;
XenPTMSI *msi = s->msi;
if (msi->initialized) {
XEN_PT_ERR(&s->dev,
"Setup physical MSI when it has been properly initialized.\n");
return -1;
}
rc = msi_msix_setup(s, msi_addr64(msi), msi->data, &pirq, false, 0, true);
if (rc) {
return rc;
}
if (pirq < 0) {
XEN_PT_ERR(&s->dev, "Invalid pirq number: %d.\n", pirq);
return -1;
}
msi->pirq = pirq;
XEN_PT_LOG(&s->dev, "MSI mapped with pirq %d.\n", pirq);
return 0;
}
int xen_pt_msi_update(XenPCIPassthroughState *s)
{
XenPTMSI *msi = s->msi;
return msi_msix_update(s, msi_addr64(msi), msi->data, msi->pirq,
false, 0, &msi->pirq);
}
void xen_pt_msi_disable(XenPCIPassthroughState *s)
{
XenPTMSI *msi = s->msi;
if (!msi) {
return;
}
(void)xen_pt_msi_set_enable(s, false);
msi_msix_disable(s, msi_addr64(msi), msi->data, msi->pirq, false,
msi->initialized);
/* clear msi info */
msi->flags &= ~PCI_MSI_FLAGS_ENABLE;
msi->initialized = false;
msi->mapped = false;
msi->pirq = XEN_PT_UNASSIGNED_PIRQ;
}
/*
* MSI-X virtualization functions
*/
static int msix_set_enable(XenPCIPassthroughState *s, bool enabled)
{
XEN_PT_LOG(&s->dev, "%s MSI-X.\n", enabled ? "enabling" : "disabling");
if (!s->msix) {
return -1;
}
return msi_msix_enable(s, s->msix->ctrl_offset, PCI_MSIX_FLAGS_ENABLE,
enabled);
}
static int xen_pt_msix_update_one(XenPCIPassthroughState *s, int entry_nr,
uint32_t vec_ctrl)
{
XenPTMSIXEntry *entry = NULL;
int pirq;
int rc;
if (entry_nr < 0 || entry_nr >= s->msix->total_entries) {
return -EINVAL;
}
entry = &s->msix->msix_entry[entry_nr];
if (!entry->updated) {
return 0;
}
pirq = entry->pirq;
/*
* Update the entry addr and data to the latest values only when the
* entry is masked or they are all masked, as required by the spec.
* Addr and data changes while the MSI-X entry is unmasked get deferred
* until the next masked -> unmasked transition.
*/
if (pirq == XEN_PT_UNASSIGNED_PIRQ || s->msix->maskall ||
(vec_ctrl & PCI_MSIX_ENTRY_CTRL_MASKBIT)) {
entry->addr = entry->latch(LOWER_ADDR) |
((uint64_t)entry->latch(UPPER_ADDR) << 32);
entry->data = entry->latch(DATA);
}
rc = msi_msix_setup(s, entry->addr, entry->data, &pirq, true, entry_nr,
entry->pirq == XEN_PT_UNASSIGNED_PIRQ);
if (rc) {
return rc;
}
if (entry->pirq == XEN_PT_UNASSIGNED_PIRQ) {
entry->pirq = pirq;
}
rc = msi_msix_update(s, entry->addr, entry->data, pirq, true,
entry_nr, &entry->pirq);
if (!rc) {
entry->updated = false;
}
return rc;
}
int xen_pt_msix_update(XenPCIPassthroughState *s)
{
XenPTMSIX *msix = s->msix;
int i;
for (i = 0; i < msix->total_entries; i++) {
xen_pt_msix_update_one(s, i, msix->msix_entry[i].latch(VECTOR_CTRL));
}
return 0;
}
void xen_pt_msix_disable(XenPCIPassthroughState *s)
{
int i = 0;
msix_set_enable(s, false);
for (i = 0; i < s->msix->total_entries; i++) {
XenPTMSIXEntry *entry = &s->msix->msix_entry[i];
msi_msix_disable(s, entry->addr, entry->data, entry->pirq, true, true);
/* clear MSI-X info */
entry->pirq = XEN_PT_UNASSIGNED_PIRQ;
entry->updated = false;
}
}
int xen_pt_msix_update_remap(XenPCIPassthroughState *s, int bar_index)
{
XenPTMSIXEntry *entry;
int i, ret;
if (!(s->msix && s->msix->bar_index == bar_index)) {
return 0;
}
for (i = 0; i < s->msix->total_entries; i++) {
entry = &s->msix->msix_entry[i];
if (entry->pirq != XEN_PT_UNASSIGNED_PIRQ) {
ret = xc_domain_unbind_pt_irq(xen_xc, xen_domid, entry->pirq,
PT_IRQ_TYPE_MSI, 0, 0, 0, 0);
if (ret) {
XEN_PT_ERR(&s->dev, "unbind MSI-X entry %d failed (err: %d)\n",
entry->pirq, errno);
}
entry->updated = true;
}
}
return xen_pt_msix_update(s);
}
static uint32_t get_entry_value(XenPTMSIXEntry *e, int offset)
{
assert(!(offset % sizeof(*e->latch)));
return e->latch[offset / sizeof(*e->latch)];
}
static void set_entry_value(XenPTMSIXEntry *e, int offset, uint32_t val)
{
assert(!(offset % sizeof(*e->latch)));
e->latch[offset / sizeof(*e->latch)] = val;
}
static void pci_msix_write(void *opaque, hwaddr addr,
uint64_t val, unsigned size)
{
XenPCIPassthroughState *s = opaque;
XenPTMSIX *msix = s->msix;
XenPTMSIXEntry *entry;
unsigned int entry_nr, offset;
entry_nr = addr / PCI_MSIX_ENTRY_SIZE;
if (entry_nr >= msix->total_entries) {
return;
}
entry = &msix->msix_entry[entry_nr];
offset = addr % PCI_MSIX_ENTRY_SIZE;
if (offset != PCI_MSIX_ENTRY_VECTOR_CTRL) {
if (get_entry_value(entry, offset) == val
&& entry->pirq != XEN_PT_UNASSIGNED_PIRQ) {
return;
}
entry->updated = true;
} else if (msix->enabled && entry->updated &&
!(val & PCI_MSIX_ENTRY_CTRL_MASKBIT)) {
const volatile uint32_t *vec_ctrl;
/*
* If Xen intercepts the mask bit access, entry->vec_ctrl may not be
* up-to-date. Read from hardware directly.
*/
vec_ctrl = s->msix->phys_iomem_base + entry_nr * PCI_MSIX_ENTRY_SIZE
+ PCI_MSIX_ENTRY_VECTOR_CTRL;
xen_pt_msix_update_one(s, entry_nr, *vec_ctrl);
}
set_entry_value(entry, offset, val);
}
static uint64_t pci_msix_read(void *opaque, hwaddr addr,
unsigned size)
{
XenPCIPassthroughState *s = opaque;
XenPTMSIX *msix = s->msix;
int entry_nr, offset;
entry_nr = addr / PCI_MSIX_ENTRY_SIZE;
if (entry_nr < 0) {
XEN_PT_ERR(&s->dev, "asked MSI-X entry '%i' invalid!\n", entry_nr);
return 0;
}
offset = addr % PCI_MSIX_ENTRY_SIZE;
if (addr < msix->total_entries * PCI_MSIX_ENTRY_SIZE) {
return get_entry_value(&msix->msix_entry[entry_nr], offset);
} else {
/* Pending Bit Array (PBA) */
return *(uint32_t *)(msix->phys_iomem_base + addr);
}
}
static bool pci_msix_accepts(void *opaque, hwaddr addr,
unsigned size, bool is_write)
{
return !(addr & (size - 1));
}
static const MemoryRegionOps pci_msix_ops = {
.read = pci_msix_read,
.write = pci_msix_write,
.endianness = DEVICE_NATIVE_ENDIAN,
.valid = {
.min_access_size = 4,
.max_access_size = 4,
.unaligned = false,
.accepts = pci_msix_accepts
},
.impl = {
.min_access_size = 4,
.max_access_size = 4,
.unaligned = false
}
};
int xen_pt_msix_init(XenPCIPassthroughState *s, uint32_t base)
{
uint8_t id = 0;
uint16_t control = 0;
uint32_t table_off = 0;
int i, total_entries, bar_index;
XenHostPCIDevice *hd = &s->real_device;
PCIDevice *d = &s->dev;
int fd = -1;
XenPTMSIX *msix = NULL;
int rc = 0;
rc = xen_host_pci_get_byte(hd, base + PCI_CAP_LIST_ID, &id);
if (rc) {
return rc;
}
if (id != PCI_CAP_ID_MSIX) {
XEN_PT_ERR(d, "Invalid id %#x base %#x\n", id, base);
return -1;
}
xen_host_pci_get_word(hd, base + PCI_MSIX_FLAGS, &control);
total_entries = control & PCI_MSIX_FLAGS_QSIZE;
total_entries += 1;
s->msix = g_malloc0(sizeof (XenPTMSIX)
+ total_entries * sizeof (XenPTMSIXEntry));
msix = s->msix;
msix->total_entries = total_entries;
for (i = 0; i < total_entries; i++) {
msix->msix_entry[i].pirq = XEN_PT_UNASSIGNED_PIRQ;
}
memory_region_init_io(&msix->mmio, OBJECT(s), &pci_msix_ops,
s, "xen-pci-pt-msix",
(total_entries * PCI_MSIX_ENTRY_SIZE
+ XC_PAGE_SIZE - 1)
& XC_PAGE_MASK);
xen_host_pci_get_long(hd, base + PCI_MSIX_TABLE, &table_off);
bar_index = msix->bar_index = table_off & PCI_MSIX_FLAGS_BIRMASK;
table_off = table_off & ~PCI_MSIX_FLAGS_BIRMASK;
msix->table_base = s->real_device.io_regions[bar_index].base_addr;
XEN_PT_LOG(d, "get MSI-X table BAR base 0x%"PRIx64"\n", msix->table_base);
fd = open("/dev/mem", O_RDWR);
if (fd == -1) {
rc = -errno;
XEN_PT_ERR(d, "Can't open /dev/mem: %s\n", strerror(errno));
goto error_out;
}
XEN_PT_LOG(d, "table_off = %#x, total_entries = %d\n",
table_off, total_entries);
msix->table_offset_adjust = table_off & 0x0fff;
msix->phys_iomem_base =
mmap(NULL,
total_entries * PCI_MSIX_ENTRY_SIZE + msix->table_offset_adjust,
PROT_READ,
MAP_SHARED | MAP_LOCKED,
fd,
msix->table_base + table_off - msix->table_offset_adjust);
close(fd);
if (msix->phys_iomem_base == MAP_FAILED) {
rc = -errno;
XEN_PT_ERR(d, "Can't map physical MSI-X table: %s\n", strerror(errno));
goto error_out;
}
msix->phys_iomem_base = (char *)msix->phys_iomem_base
+ msix->table_offset_adjust;
XEN_PT_LOG(d, "mapping physical MSI-X table to %p\n",
msix->phys_iomem_base);
memory_region_add_subregion_overlap(&s->bar[bar_index], table_off,
&msix->mmio,
2); /* Priority: pci default + 1 */
return 0;
error_out:
g_free(s->msix);
s->msix = NULL;
return rc;
}
void xen_pt_msix_unmap(XenPCIPassthroughState *s)
{
XenPTMSIX *msix = s->msix;
if (!msix) {
return;
}
/* unmap the MSI-X memory mapped register area */
if (msix->phys_iomem_base) {
XEN_PT_LOG(&s->dev, "unmapping physical MSI-X table from %p\n",
msix->phys_iomem_base);
munmap(msix->phys_iomem_base, msix->total_entries * PCI_MSIX_ENTRY_SIZE
+ msix->table_offset_adjust);
}
memory_region_del_subregion(&s->bar[msix->bar_index], &msix->mmio);
}
void xen_pt_msix_delete(XenPCIPassthroughState *s)
{
XenPTMSIX *msix = s->msix;
if (!msix) {
return;
}
object_unparent(OBJECT(&msix->mmio));
g_free(s->msix);
s->msix = NULL;
}
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