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qemu/hw/i386/kvm/xen_evtchn.c
David Woodhouse eeedfe6c63 hw/xen: Simplify emulated Xen platform init 
I initially put the basic platform init (overlay pages, grant tables,
event channels) into mc->kvm_type because that was the earliest place
that could sensibly test for xen_mode==XEN_EMULATE.

The intent was to do this early enough that we could then initialise the
XenBus and other parts which would have depended on them, from a generic
location for both Xen and KVM/Xen in the PC-specific code, as seen in
https://lore.kernel.org/qemu-devel/20230116221919.1124201-16-dwmw2@infradead.org/

However, then the Xen on Arm patches came along, and *they* wanted to
do the XenBus init from a 'generic' Xen-specific location instead:
https://lore.kernel.org/qemu-devel/20230210222729.957168-4-sstabellini@kernel.org/

Since there's no generic location that covers all three, I conceded to
do it for XEN_EMULATE mode in pc_basic_devices_init().

And now there's absolutely no point in having some of the platform init
done from pc_machine_kvm_type(); we can move it all up to live in a
single place in pc_basic_devices_init(). This has the added benefit that
we can drop the separate xen_evtchn_connect_gsis() function completely,
and pass just the system GSIs in directly to xen_evtchn_create().

While I'm at it, it does no harm to explicitly pass in the *number* of
said GSIs, because it does make me twitch a bit to pass an array of
impicit size. During the lifetime of the KVM/Xen patchset, that had
already changed (albeit just cosmetically) from GSI_NUM_PINS to
IOAPIC_NUM_PINS.

And document a bit better that this is for the *output* GSI for raising
CPU0's events when the per-CPU vector isn't available. The fact that
we create a whole set of them and then only waggle the one we're told
to, instead of having a single output and only *connecting* it to the
GSI that it should be connected to, is still non-intuitive for me.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
Message-Id: <20230412185102.441523-2-dwmw2@infradead.org>
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
2023-06-07 15:07:10 +01:00

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/*
* QEMU Xen emulation: Event channel support
*
* Copyright © 2022 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Authors: David Woodhouse <dwmw2@infradead.org>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "qemu/host-utils.h"
#include "qemu/module.h"
#include "qemu/lockable.h"
#include "qemu/main-loop.h"
#include "qemu/log.h"
#include "qemu/error-report.h"
#include "monitor/monitor.h"
#include "monitor/hmp.h"
#include "qapi/error.h"
#include "qapi/qapi-commands-misc-target.h"
#include "qapi/qmp/qdict.h"
#include "qom/object.h"
#include "exec/target_page.h"
#include "exec/address-spaces.h"
#include "migration/vmstate.h"
#include "trace.h"
#include "hw/sysbus.h"
#include "hw/xen/xen.h"
#include "hw/i386/x86.h"
#include "hw/i386/pc.h"
#include "hw/pci/pci.h"
#include "hw/pci/msi.h"
#include "hw/pci/msix.h"
#include "hw/irq.h"
#include "hw/xen/xen_backend_ops.h"
#include "xen_evtchn.h"
#include "xen_overlay.h"
#include "xen_xenstore.h"
#include "sysemu/kvm.h"
#include "sysemu/kvm_xen.h"
#include <linux/kvm.h>
#include <sys/eventfd.h>
#include "hw/xen/interface/memory.h"
#include "hw/xen/interface/hvm/params.h"
/* XX: For kvm_update_msi_routes_all() */
#include "target/i386/kvm/kvm_i386.h"
#define TYPE_XEN_EVTCHN "xen-evtchn"
OBJECT_DECLARE_SIMPLE_TYPE(XenEvtchnState, XEN_EVTCHN)
typedef struct XenEvtchnPort {
uint32_t vcpu; /* Xen/ACPI vcpu_id */
uint16_t type; /* EVTCHNSTAT_xxxx */
uint16_t type_val; /* pirq# / virq# / remote port according to type */
} XenEvtchnPort;
/* 32-bit compatibility definitions, also used natively in 32-bit build */
struct compat_arch_vcpu_info {
unsigned int cr2;
unsigned int pad[5];
};
struct compat_vcpu_info {
uint8_t evtchn_upcall_pending;
uint8_t evtchn_upcall_mask;
uint16_t pad;
uint32_t evtchn_pending_sel;
struct compat_arch_vcpu_info arch;
struct vcpu_time_info time;
}; /* 64 bytes (x86) */
struct compat_arch_shared_info {
unsigned int max_pfn;
unsigned int pfn_to_mfn_frame_list_list;
unsigned int nmi_reason;
unsigned int p2m_cr3;
unsigned int p2m_vaddr;
unsigned int p2m_generation;
uint32_t wc_sec_hi;
};
struct compat_shared_info {
struct compat_vcpu_info vcpu_info[XEN_LEGACY_MAX_VCPUS];
uint32_t evtchn_pending[32];
uint32_t evtchn_mask[32];
uint32_t wc_version; /* Version counter: see vcpu_time_info_t. */
uint32_t wc_sec;
uint32_t wc_nsec;
struct compat_arch_shared_info arch;
};
#define COMPAT_EVTCHN_2L_NR_CHANNELS 1024
/* Local private implementation of struct xenevtchn_handle */
struct xenevtchn_handle {
evtchn_port_t be_port;
evtchn_port_t guest_port; /* Or zero for unbound */
int fd;
};
/*
* For unbound/interdomain ports there are only two possible remote
* domains; self and QEMU. Use a single high bit in type_val for that,
* and the low bits for the remote port number (or 0 for unbound).
*/
#define PORT_INFO_TYPEVAL_REMOTE_QEMU 0x8000
#define PORT_INFO_TYPEVAL_REMOTE_PORT_MASK 0x7FFF
/*
* These 'emuirq' values are used by Xen in the LM stream... and yes, I am
* insane enough to think about guest-transparent live migration from actual
* Xen to QEMU, and ensuring that we can convert/consume the stream.
*/
#define IRQ_UNBOUND -1
#define IRQ_PT -2
#define IRQ_MSI_EMU -3
struct pirq_info {
int gsi;
uint16_t port;
PCIDevice *dev;
int vector;
bool is_msix;
bool is_masked;
bool is_translated;
};
struct XenEvtchnState {
/*< private >*/
SysBusDevice busdev;
/*< public >*/
uint64_t callback_param;
bool evtchn_in_kernel;
uint32_t callback_gsi;
QEMUBH *gsi_bh;
QemuMutex port_lock;
uint32_t nr_ports;
XenEvtchnPort port_table[EVTCHN_2L_NR_CHANNELS];
/* Connected to the system GSIs for raising callback as GSI / INTx */
unsigned int nr_callback_gsis;
qemu_irq *callback_gsis;
struct xenevtchn_handle *be_handles[EVTCHN_2L_NR_CHANNELS];
uint32_t nr_pirqs;
/* Bitmap of allocated PIRQs (serialized) */
uint16_t nr_pirq_inuse_words;
uint64_t *pirq_inuse_bitmap;
/* GSI → PIRQ mapping (serialized) */
uint16_t gsi_pirq[IOAPIC_NUM_PINS];
/* Per-GSI assertion state (serialized) */
uint32_t pirq_gsi_set;
/* Per-PIRQ information (rebuilt on migration, protected by BQL) */
struct pirq_info *pirq;
};
#define pirq_inuse_word(s, pirq) (s->pirq_inuse_bitmap[((pirq) / 64)])
#define pirq_inuse_bit(pirq) (1ULL << ((pirq) & 63))
#define pirq_inuse(s, pirq) (pirq_inuse_word(s, pirq) & pirq_inuse_bit(pirq))
struct XenEvtchnState *xen_evtchn_singleton;
/* Top bits of callback_param are the type (HVM_PARAM_CALLBACK_TYPE_xxx) */
#define CALLBACK_VIA_TYPE_SHIFT 56
static void unbind_backend_ports(XenEvtchnState *s);
static int xen_evtchn_pre_load(void *opaque)
{
XenEvtchnState *s = opaque;
/* Unbind all the backend-side ports; they need to rebind */
unbind_backend_ports(s);
/* It'll be leaked otherwise. */
g_free(s->pirq_inuse_bitmap);
s->pirq_inuse_bitmap = NULL;
return 0;
}
static int xen_evtchn_post_load(void *opaque, int version_id)
{
XenEvtchnState *s = opaque;
uint32_t i;
if (s->callback_param) {
xen_evtchn_set_callback_param(s->callback_param);
}
/* Rebuild s->pirq[].port mapping */
for (i = 0; i < s->nr_ports; i++) {
XenEvtchnPort *p = &s->port_table[i];
if (p->type == EVTCHNSTAT_pirq) {
assert(p->type_val);
assert(p->type_val < s->nr_pirqs);
/*
* Set the gsi to IRQ_UNBOUND; it may be changed to an actual
* GSI# below, or to IRQ_MSI_EMU when the MSI table snooping
* catches up with it.
*/
s->pirq[p->type_val].gsi = IRQ_UNBOUND;
s->pirq[p->type_val].port = i;
}
}
/* Rebuild s->pirq[].gsi mapping */
for (i = 0; i < IOAPIC_NUM_PINS; i++) {
if (s->gsi_pirq[i]) {
s->pirq[s->gsi_pirq[i]].gsi = i;
}
}
return 0;
}
static bool xen_evtchn_is_needed(void *opaque)
{
return xen_mode == XEN_EMULATE;
}
static const VMStateDescription xen_evtchn_port_vmstate = {
.name = "xen_evtchn_port",
.version_id = 1,
.minimum_version_id = 1,
.fields = (VMStateField[]) {
VMSTATE_UINT32(vcpu, XenEvtchnPort),
VMSTATE_UINT16(type, XenEvtchnPort),
VMSTATE_UINT16(type_val, XenEvtchnPort),
VMSTATE_END_OF_LIST()
}
};
static const VMStateDescription xen_evtchn_vmstate = {
.name = "xen_evtchn",
.version_id = 1,
.minimum_version_id = 1,
.needed = xen_evtchn_is_needed,
.pre_load = xen_evtchn_pre_load,
.post_load = xen_evtchn_post_load,
.fields = (VMStateField[]) {
VMSTATE_UINT64(callback_param, XenEvtchnState),
VMSTATE_UINT32(nr_ports, XenEvtchnState),
VMSTATE_STRUCT_VARRAY_UINT32(port_table, XenEvtchnState, nr_ports, 1,
xen_evtchn_port_vmstate, XenEvtchnPort),
VMSTATE_UINT16_ARRAY(gsi_pirq, XenEvtchnState, IOAPIC_NUM_PINS),
VMSTATE_VARRAY_UINT16_ALLOC(pirq_inuse_bitmap, XenEvtchnState,
nr_pirq_inuse_words, 0,
vmstate_info_uint64, uint64_t),
VMSTATE_UINT32(pirq_gsi_set, XenEvtchnState),
VMSTATE_END_OF_LIST()
}
};
static void xen_evtchn_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
dc->vmsd = &xen_evtchn_vmstate;
}
static const TypeInfo xen_evtchn_info = {
.name = TYPE_XEN_EVTCHN,
.parent = TYPE_SYS_BUS_DEVICE,
.instance_size = sizeof(XenEvtchnState),
.class_init = xen_evtchn_class_init,
};
static struct evtchn_backend_ops emu_evtchn_backend_ops = {
.open = xen_be_evtchn_open,
.bind_interdomain = xen_be_evtchn_bind_interdomain,
.unbind = xen_be_evtchn_unbind,
.close = xen_be_evtchn_close,
.get_fd = xen_be_evtchn_fd,
.notify = xen_be_evtchn_notify,
.unmask = xen_be_evtchn_unmask,
.pending = xen_be_evtchn_pending,
};
static void gsi_assert_bh(void *opaque)
{
struct vcpu_info *vi = kvm_xen_get_vcpu_info_hva(0);
if (vi) {
xen_evtchn_set_callback_level(!!vi->evtchn_upcall_pending);
}
}
void xen_evtchn_create(unsigned int nr_gsis, qemu_irq *system_gsis)
{
XenEvtchnState *s = XEN_EVTCHN(sysbus_create_simple(TYPE_XEN_EVTCHN,
-1, NULL));
int i;
xen_evtchn_singleton = s;
qemu_mutex_init(&s->port_lock);
s->gsi_bh = aio_bh_new(qemu_get_aio_context(), gsi_assert_bh, s);
/*
* These are the *output* GSI from event channel support, for
* signalling CPU0's events via GSI or PCI INTx instead of the
* per-CPU vector. We create a *set* of irqs and connect one to
* each of the system GSIs which were passed in from the platform
* code, and then just trigger the right one as appropriate from
* xen_evtchn_set_callback_level().
*/
s->nr_callback_gsis = nr_gsis;
s->callback_gsis = g_new0(qemu_irq, nr_gsis);
for (i = 0; i < nr_gsis; i++) {
sysbus_init_irq(SYS_BUS_DEVICE(s), &s->callback_gsis[i]);
sysbus_connect_irq(SYS_BUS_DEVICE(s), i, system_gsis[i]);
}
/*
* The Xen scheme for encoding PIRQ# into an MSI message is not
* compatible with 32-bit MSI, as it puts the high bits of the
* PIRQ# into the high bits of the MSI message address, instead of
* using the Extended Destination ID in address bits 4-11 which
* perhaps would have been a better choice.
*
* To keep life simple, kvm_accel_instance_init() initialises the
* default to 256. which conveniently doesn't need to set anything
* outside the low 32 bits of the address. It can be increased by
* setting the xen-evtchn-max-pirq property.
*/
s->nr_pirqs = kvm_xen_get_evtchn_max_pirq();
s->nr_pirq_inuse_words = DIV_ROUND_UP(s->nr_pirqs, 64);
s->pirq_inuse_bitmap = g_new0(uint64_t, s->nr_pirq_inuse_words);
s->pirq = g_new0(struct pirq_info, s->nr_pirqs);
/* Set event channel functions for backend drivers to use */
xen_evtchn_ops = &emu_evtchn_backend_ops;
}
static void xen_evtchn_register_types(void)
{
type_register_static(&xen_evtchn_info);
}
type_init(xen_evtchn_register_types)
static int set_callback_pci_intx(XenEvtchnState *s, uint64_t param)
{
PCMachineState *pcms = PC_MACHINE(qdev_get_machine());
uint8_t pin = param & 3;
uint8_t devfn = (param >> 8) & 0xff;
uint16_t bus = (param >> 16) & 0xffff;
uint16_t domain = (param >> 32) & 0xffff;
PCIDevice *pdev;
PCIINTxRoute r;
if (domain || !pcms) {
return 0;
}
pdev = pci_find_device(pcms->bus, bus, devfn);
if (!pdev) {
return 0;
}
r = pci_device_route_intx_to_irq(pdev, pin);
if (r.mode != PCI_INTX_ENABLED) {
return 0;
}
/*
* Hm, can we be notified of INTX routing changes? Not without
* *owning* the device and being allowed to overwrite its own
* ->intx_routing_notifier, AFAICT. So let's not.
*/
return r.irq;
}
void xen_evtchn_set_callback_level(int level)
{
XenEvtchnState *s = xen_evtchn_singleton;
if (!s) {
return;
}
/*
* We get to this function in a number of ways:
*
* • From I/O context, via PV backend drivers sending a notification to
* the guest.
*
* • From guest vCPU context, via loopback interdomain event channels
* (or theoretically even IPIs but guests don't use those with GSI
* delivery because that's pointless. We don't want a malicious guest
* to be able to trigger a deadlock though, so we can't rule it out.)
*
* • From guest vCPU context when the HVM_PARAM_CALLBACK_IRQ is being
* configured.
*
* • From guest vCPU context in the KVM exit handler, if the upcall
* pending flag has been cleared and the GSI needs to be deasserted.
*
* • Maybe in future, in an interrupt ack/eoi notifier when the GSI has
* been acked in the irqchip.
*
* Whichever context we come from if we aren't already holding the BQL
* then e can't take it now, as we may already hold s->port_lock. So
* trigger the BH to set the IRQ for us instead of doing it immediately.
*
* In the HVM_PARAM_CALLBACK_IRQ and KVM exit handler cases, the caller
* will deliberately take the BQL because they want the change to take
* effect immediately. That just leaves interdomain loopback as the case
* which uses the BH.
*/
if (!qemu_mutex_iothread_locked()) {
qemu_bh_schedule(s->gsi_bh);
return;
}
if (s->callback_gsi && s->callback_gsi < s->nr_callback_gsis) {
qemu_set_irq(s->callback_gsis[s->callback_gsi], level);
if (level) {
/* Ensure the vCPU polls for deassertion */
kvm_xen_set_callback_asserted();
}
}
}
int xen_evtchn_set_callback_param(uint64_t param)
{
XenEvtchnState *s = xen_evtchn_singleton;
struct kvm_xen_hvm_attr xa = {
.type = KVM_XEN_ATTR_TYPE_UPCALL_VECTOR,
.u.vector = 0,
};
bool in_kernel = false;
uint32_t gsi = 0;
int type = param >> CALLBACK_VIA_TYPE_SHIFT;
int ret;
if (!s) {
return -ENOTSUP;
}
/*
* We need the BQL because set_callback_pci_intx() may call into PCI code,
* and because we may need to manipulate the old and new GSI levels.
*/
assert(qemu_mutex_iothread_locked());
qemu_mutex_lock(&s->port_lock);
switch (type) {
case HVM_PARAM_CALLBACK_TYPE_VECTOR: {
xa.u.vector = (uint8_t)param,
ret = kvm_vm_ioctl(kvm_state, KVM_XEN_HVM_SET_ATTR, &xa);
if (!ret && kvm_xen_has_cap(EVTCHN_SEND)) {
in_kernel = true;
}
gsi = 0;
break;
}
case HVM_PARAM_CALLBACK_TYPE_PCI_INTX:
gsi = set_callback_pci_intx(s, param);
ret = gsi ? 0 : -EINVAL;
break;
case HVM_PARAM_CALLBACK_TYPE_GSI:
gsi = (uint32_t)param;
ret = 0;
break;
default:
/* Xen doesn't return error even if you set something bogus */
ret = 0;
break;
}
if (!ret) {
/* If vector delivery was turned *off* then tell the kernel */
if ((s->callback_param >> CALLBACK_VIA_TYPE_SHIFT) ==
HVM_PARAM_CALLBACK_TYPE_VECTOR && !xa.u.vector) {
kvm_vm_ioctl(kvm_state, KVM_XEN_HVM_SET_ATTR, &xa);
}
s->callback_param = param;
s->evtchn_in_kernel = in_kernel;
if (gsi != s->callback_gsi) {
struct vcpu_info *vi = kvm_xen_get_vcpu_info_hva(0);
xen_evtchn_set_callback_level(0);
s->callback_gsi = gsi;
if (gsi && vi && vi->evtchn_upcall_pending) {
kvm_xen_inject_vcpu_callback_vector(0, type);
}
}
}
qemu_mutex_unlock(&s->port_lock);
return ret;
}
static void inject_callback(XenEvtchnState *s, uint32_t vcpu)
{
int type = s->callback_param >> CALLBACK_VIA_TYPE_SHIFT;
kvm_xen_inject_vcpu_callback_vector(vcpu, type);
}
static void deassign_kernel_port(evtchn_port_t port)
{
struct kvm_xen_hvm_attr ha;
int ret;
ha.type = KVM_XEN_ATTR_TYPE_EVTCHN;
ha.u.evtchn.send_port = port;
ha.u.evtchn.flags = KVM_XEN_EVTCHN_DEASSIGN;
ret = kvm_vm_ioctl(kvm_state, KVM_XEN_HVM_SET_ATTR, &ha);
if (ret) {
qemu_log_mask(LOG_GUEST_ERROR, "Failed to unbind kernel port %d: %s\n",
port, strerror(ret));
}
}
static int assign_kernel_port(uint16_t type, evtchn_port_t port,
uint32_t vcpu_id)
{
CPUState *cpu = qemu_get_cpu(vcpu_id);
struct kvm_xen_hvm_attr ha;
if (!cpu) {
return -ENOENT;
}
ha.type = KVM_XEN_ATTR_TYPE_EVTCHN;
ha.u.evtchn.send_port = port;
ha.u.evtchn.type = type;
ha.u.evtchn.flags = 0;
ha.u.evtchn.deliver.port.port = port;
ha.u.evtchn.deliver.port.vcpu = kvm_arch_vcpu_id(cpu);
ha.u.evtchn.deliver.port.priority = KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL;
return kvm_vm_ioctl(kvm_state, KVM_XEN_HVM_SET_ATTR, &ha);
}
static int assign_kernel_eventfd(uint16_t type, evtchn_port_t port, int fd)
{
struct kvm_xen_hvm_attr ha;
ha.type = KVM_XEN_ATTR_TYPE_EVTCHN;
ha.u.evtchn.send_port = port;
ha.u.evtchn.type = type;
ha.u.evtchn.flags = 0;
ha.u.evtchn.deliver.eventfd.port = 0;
ha.u.evtchn.deliver.eventfd.fd = fd;
return kvm_vm_ioctl(kvm_state, KVM_XEN_HVM_SET_ATTR, &ha);
}
static bool valid_port(evtchn_port_t port)
{
if (!port) {
return false;
}
if (xen_is_long_mode()) {
return port < EVTCHN_2L_NR_CHANNELS;
} else {
return port < COMPAT_EVTCHN_2L_NR_CHANNELS;
}
}
static bool valid_vcpu(uint32_t vcpu)
{
return !!qemu_get_cpu(vcpu);
}
static void unbind_backend_ports(XenEvtchnState *s)
{
XenEvtchnPort *p;
int i;
for (i = 1; i < s->nr_ports; i++) {
p = &s->port_table[i];
if (p->type == EVTCHNSTAT_interdomain &&
(p->type_val & PORT_INFO_TYPEVAL_REMOTE_QEMU)) {
evtchn_port_t be_port = p->type_val & PORT_INFO_TYPEVAL_REMOTE_PORT_MASK;
if (s->be_handles[be_port]) {
/* This part will be overwritten on the load anyway. */
p->type = EVTCHNSTAT_unbound;
p->type_val = PORT_INFO_TYPEVAL_REMOTE_QEMU;
/* Leave the backend port open and unbound too. */
if (kvm_xen_has_cap(EVTCHN_SEND)) {
deassign_kernel_port(i);
}
s->be_handles[be_port]->guest_port = 0;
}
}
}
}
int xen_evtchn_status_op(struct evtchn_status *status)
{
XenEvtchnState *s = xen_evtchn_singleton;
XenEvtchnPort *p;
if (!s) {
return -ENOTSUP;
}
if (status->dom != DOMID_SELF && status->dom != xen_domid) {
return -ESRCH;
}
if (!valid_port(status->port)) {
return -EINVAL;
}
qemu_mutex_lock(&s->port_lock);
p = &s->port_table[status->port];
status->status = p->type;
status->vcpu = p->vcpu;
switch (p->type) {
case EVTCHNSTAT_unbound:
if (p->type_val & PORT_INFO_TYPEVAL_REMOTE_QEMU) {
status->u.unbound.dom = DOMID_QEMU;
} else {
status->u.unbound.dom = xen_domid;
}
break;
case EVTCHNSTAT_interdomain:
if (p->type_val & PORT_INFO_TYPEVAL_REMOTE_QEMU) {
status->u.interdomain.dom = DOMID_QEMU;
} else {
status->u.interdomain.dom = xen_domid;
}
status->u.interdomain.port = p->type_val &
PORT_INFO_TYPEVAL_REMOTE_PORT_MASK;
break;
case EVTCHNSTAT_pirq:
status->u.pirq = p->type_val;
break;
case EVTCHNSTAT_virq:
status->u.virq = p->type_val;
break;
}
qemu_mutex_unlock(&s->port_lock);
return 0;
}
/*
* Never thought I'd hear myself say this, but C++ templates would be
* kind of nice here.
*
* template<class T> static int do_unmask_port(T *shinfo, ...);
*/
static int do_unmask_port_lm(XenEvtchnState *s, evtchn_port_t port,
bool do_unmask, struct shared_info *shinfo,
struct vcpu_info *vcpu_info)
{
const int bits_per_word = BITS_PER_BYTE * sizeof(shinfo->evtchn_pending[0]);
typeof(shinfo->evtchn_pending[0]) mask;
int idx = port / bits_per_word;
int offset = port % bits_per_word;
mask = 1UL << offset;
if (idx >= bits_per_word) {
return -EINVAL;
}
if (do_unmask) {
/*
* If this is a true unmask operation, clear the mask bit. If
* it was already unmasked, we have nothing further to do.
*/
if (!((qatomic_fetch_and(&shinfo->evtchn_mask[idx], ~mask) & mask))) {
return 0;
}
} else {
/*
* This is a pseudo-unmask for affinity changes. We don't
* change the mask bit, and if it's *masked* we have nothing
* else to do.
*/
if (qatomic_fetch_or(&shinfo->evtchn_mask[idx], 0) & mask) {
return 0;
}
}
/* If the event was not pending, we're done. */
if (!(qatomic_fetch_or(&shinfo->evtchn_pending[idx], 0) & mask)) {
return 0;
}
/* Now on to the vcpu_info evtchn_pending_sel index... */
mask = 1UL << idx;
/* If a port in this word was already pending for this vCPU, all done. */
if (qatomic_fetch_or(&vcpu_info->evtchn_pending_sel, mask) & mask) {
return 0;
}
/* Set evtchn_upcall_pending for this vCPU */
if (qatomic_fetch_or(&vcpu_info->evtchn_upcall_pending, 1)) {
return 0;
}
inject_callback(s, s->port_table[port].vcpu);
return 0;
}
static int do_unmask_port_compat(XenEvtchnState *s, evtchn_port_t port,
bool do_unmask,
struct compat_shared_info *shinfo,
struct compat_vcpu_info *vcpu_info)
{
const int bits_per_word = BITS_PER_BYTE * sizeof(shinfo->evtchn_pending[0]);
typeof(shinfo->evtchn_pending[0]) mask;
int idx = port / bits_per_word;
int offset = port % bits_per_word;
mask = 1UL << offset;
if (idx >= bits_per_word) {
return -EINVAL;
}
if (do_unmask) {
/*
* If this is a true unmask operation, clear the mask bit. If
* it was already unmasked, we have nothing further to do.
*/
if (!((qatomic_fetch_and(&shinfo->evtchn_mask[idx], ~mask) & mask))) {
return 0;
}
} else {
/*
* This is a pseudo-unmask for affinity changes. We don't
* change the mask bit, and if it's *masked* we have nothing
* else to do.
*/
if (qatomic_fetch_or(&shinfo->evtchn_mask[idx], 0) & mask) {
return 0;
}
}
/* If the event was not pending, we're done. */
if (!(qatomic_fetch_or(&shinfo->evtchn_pending[idx], 0) & mask)) {
return 0;
}
/* Now on to the vcpu_info evtchn_pending_sel index... */
mask = 1UL << idx;
/* If a port in this word was already pending for this vCPU, all done. */
if (qatomic_fetch_or(&vcpu_info->evtchn_pending_sel, mask) & mask) {
return 0;
}
/* Set evtchn_upcall_pending for this vCPU */
if (qatomic_fetch_or(&vcpu_info->evtchn_upcall_pending, 1)) {
return 0;
}
inject_callback(s, s->port_table[port].vcpu);
return 0;
}
static int unmask_port(XenEvtchnState *s, evtchn_port_t port, bool do_unmask)
{
void *vcpu_info, *shinfo;
if (s->port_table[port].type == EVTCHNSTAT_closed) {
return -EINVAL;
}
shinfo = xen_overlay_get_shinfo_ptr();
if (!shinfo) {
return -ENOTSUP;
}
vcpu_info = kvm_xen_get_vcpu_info_hva(s->port_table[port].vcpu);
if (!vcpu_info) {
return -EINVAL;
}
if (xen_is_long_mode()) {
return do_unmask_port_lm(s, port, do_unmask, shinfo, vcpu_info);
} else {
return do_unmask_port_compat(s, port, do_unmask, shinfo, vcpu_info);
}
}
static int do_set_port_lm(XenEvtchnState *s, evtchn_port_t port,
struct shared_info *shinfo,
struct vcpu_info *vcpu_info)
{
const int bits_per_word = BITS_PER_BYTE * sizeof(shinfo->evtchn_pending[0]);
typeof(shinfo->evtchn_pending[0]) mask;
int idx = port / bits_per_word;
int offset = port % bits_per_word;
mask = 1UL << offset;
if (idx >= bits_per_word) {
return -EINVAL;
}
/* Update the pending bit itself. If it was already set, we're done. */
if (qatomic_fetch_or(&shinfo->evtchn_pending[idx], mask) & mask) {
return 0;
}
/* Check if it's masked. */
if (qatomic_fetch_or(&shinfo->evtchn_mask[idx], 0) & mask) {
return 0;
}
/* Now on to the vcpu_info evtchn_pending_sel index... */
mask = 1UL << idx;
/* If a port in this word was already pending for this vCPU, all done. */
if (qatomic_fetch_or(&vcpu_info->evtchn_pending_sel, mask) & mask) {
return 0;
}
/* Set evtchn_upcall_pending for this vCPU */
if (qatomic_fetch_or(&vcpu_info->evtchn_upcall_pending, 1)) {
return 0;
}
inject_callback(s, s->port_table[port].vcpu);
return 0;
}
static int do_set_port_compat(XenEvtchnState *s, evtchn_port_t port,
struct compat_shared_info *shinfo,
struct compat_vcpu_info *vcpu_info)
{
const int bits_per_word = BITS_PER_BYTE * sizeof(shinfo->evtchn_pending[0]);
typeof(shinfo->evtchn_pending[0]) mask;
int idx = port / bits_per_word;
int offset = port % bits_per_word;
mask = 1UL << offset;
if (idx >= bits_per_word) {
return -EINVAL;
}
/* Update the pending bit itself. If it was already set, we're done. */
if (qatomic_fetch_or(&shinfo->evtchn_pending[idx], mask) & mask) {
return 0;
}
/* Check if it's masked. */
if (qatomic_fetch_or(&shinfo->evtchn_mask[idx], 0) & mask) {
return 0;
}
/* Now on to the vcpu_info evtchn_pending_sel index... */
mask = 1UL << idx;
/* If a port in this word was already pending for this vCPU, all done. */
if (qatomic_fetch_or(&vcpu_info->evtchn_pending_sel, mask) & mask) {
return 0;
}
/* Set evtchn_upcall_pending for this vCPU */
if (qatomic_fetch_or(&vcpu_info->evtchn_upcall_pending, 1)) {
return 0;
}
inject_callback(s, s->port_table[port].vcpu);
return 0;
}
static int set_port_pending(XenEvtchnState *s, evtchn_port_t port)
{
void *vcpu_info, *shinfo;
if (s->port_table[port].type == EVTCHNSTAT_closed) {
return -EINVAL;
}
if (s->evtchn_in_kernel) {
XenEvtchnPort *p = &s->port_table[port];
CPUState *cpu = qemu_get_cpu(p->vcpu);
struct kvm_irq_routing_xen_evtchn evt;
if (!cpu) {
return 0;
}
evt.port = port;
evt.vcpu = kvm_arch_vcpu_id(cpu);
evt.priority = KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL;
return kvm_vm_ioctl(kvm_state, KVM_XEN_HVM_EVTCHN_SEND, &evt);
}
shinfo = xen_overlay_get_shinfo_ptr();
if (!shinfo) {
return -ENOTSUP;
}
vcpu_info = kvm_xen_get_vcpu_info_hva(s->port_table[port].vcpu);
if (!vcpu_info) {
return -EINVAL;
}
if (xen_is_long_mode()) {
return do_set_port_lm(s, port, shinfo, vcpu_info);
} else {
return do_set_port_compat(s, port, shinfo, vcpu_info);
}
}
static int clear_port_pending(XenEvtchnState *s, evtchn_port_t port)
{
void *p = xen_overlay_get_shinfo_ptr();
if (!p) {
return -ENOTSUP;
}
if (xen_is_long_mode()) {
struct shared_info *shinfo = p;
const int bits_per_word = BITS_PER_BYTE * sizeof(shinfo->evtchn_pending[0]);
typeof(shinfo->evtchn_pending[0]) mask;
int idx = port / bits_per_word;
int offset = port % bits_per_word;
mask = 1UL << offset;
qatomic_fetch_and(&shinfo->evtchn_pending[idx], ~mask);
} else {
struct compat_shared_info *shinfo = p;
const int bits_per_word = BITS_PER_BYTE * sizeof(shinfo->evtchn_pending[0]);
typeof(shinfo->evtchn_pending[0]) mask;
int idx = port / bits_per_word;
int offset = port % bits_per_word;
mask = 1UL << offset;
qatomic_fetch_and(&shinfo->evtchn_pending[idx], ~mask);
}
return 0;
}
static void free_port(XenEvtchnState *s, evtchn_port_t port)
{
s->port_table[port].type = EVTCHNSTAT_closed;
s->port_table[port].type_val = 0;
s->port_table[port].vcpu = 0;
if (s->nr_ports == port + 1) {
do {
s->nr_ports--;
} while (s->nr_ports &&
s->port_table[s->nr_ports - 1].type == EVTCHNSTAT_closed);
}
/* Clear pending event to avoid unexpected behavior on re-bind. */
clear_port_pending(s, port);
}
static int allocate_port(XenEvtchnState *s, uint32_t vcpu, uint16_t type,
uint16_t val, evtchn_port_t *port)
{
evtchn_port_t p = 1;
for (p = 1; valid_port(p); p++) {
if (s->port_table[p].type == EVTCHNSTAT_closed) {
s->port_table[p].vcpu = vcpu;
s->port_table[p].type = type;
s->port_table[p].type_val = val;
*port = p;
if (s->nr_ports < p + 1) {
s->nr_ports = p + 1;
}
return 0;
}
}
return -ENOSPC;
}
static bool virq_is_global(uint32_t virq)
{
switch (virq) {
case VIRQ_TIMER:
case VIRQ_DEBUG:
case VIRQ_XENOPROF:
case VIRQ_XENPMU:
return false;
default:
return true;
}
}
static int close_port(XenEvtchnState *s, evtchn_port_t port,
bool *flush_kvm_routes)
{
XenEvtchnPort *p = &s->port_table[port];
/* Because it *might* be a PIRQ port */
assert(qemu_mutex_iothread_locked());
switch (p->type) {
case EVTCHNSTAT_closed:
return -ENOENT;
case EVTCHNSTAT_pirq:
s->pirq[p->type_val].port = 0;
if (s->pirq[p->type_val].is_translated) {
*flush_kvm_routes = true;
}
break;
case EVTCHNSTAT_virq:
kvm_xen_set_vcpu_virq(virq_is_global(p->type_val) ? 0 : p->vcpu,
p->type_val, 0);
break;
case EVTCHNSTAT_ipi:
if (s->evtchn_in_kernel) {
deassign_kernel_port(port);
}
break;
case EVTCHNSTAT_interdomain:
if (p->type_val & PORT_INFO_TYPEVAL_REMOTE_QEMU) {
uint16_t be_port = p->type_val & ~PORT_INFO_TYPEVAL_REMOTE_QEMU;
struct xenevtchn_handle *xc = s->be_handles[be_port];
if (xc) {
if (kvm_xen_has_cap(EVTCHN_SEND)) {
deassign_kernel_port(port);
}
xc->guest_port = 0;
}
} else {
/* Loopback interdomain */
XenEvtchnPort *rp = &s->port_table[p->type_val];
if (!valid_port(p->type_val) || rp->type_val != port ||
rp->type != EVTCHNSTAT_interdomain) {
error_report("Inconsistent state for interdomain unbind");
} else {
/* Set the other end back to unbound */
rp->type = EVTCHNSTAT_unbound;
rp->type_val = 0;
}
}
break;
default:
break;
}
free_port(s, port);
return 0;
}
int xen_evtchn_soft_reset(void)
{
XenEvtchnState *s = xen_evtchn_singleton;
bool flush_kvm_routes;
int i;
if (!s) {
return -ENOTSUP;
}
assert(qemu_mutex_iothread_locked());
qemu_mutex_lock(&s->port_lock);
for (i = 0; i < s->nr_ports; i++) {
close_port(s, i, &flush_kvm_routes);
}
qemu_mutex_unlock(&s->port_lock);
if (flush_kvm_routes) {
kvm_update_msi_routes_all(NULL, true, 0, 0);
}
return 0;
}
int xen_evtchn_reset_op(struct evtchn_reset *reset)
{
if (reset->dom != DOMID_SELF && reset->dom != xen_domid) {
return -ESRCH;
}
return xen_evtchn_soft_reset();
}
int xen_evtchn_close_op(struct evtchn_close *close)
{
XenEvtchnState *s = xen_evtchn_singleton;
bool flush_kvm_routes = false;
int ret;
if (!s) {
return -ENOTSUP;
}
if (!valid_port(close->port)) {
return -EINVAL;
}
QEMU_IOTHREAD_LOCK_GUARD();
qemu_mutex_lock(&s->port_lock);
ret = close_port(s, close->port, &flush_kvm_routes);
qemu_mutex_unlock(&s->port_lock);
if (flush_kvm_routes) {
kvm_update_msi_routes_all(NULL, true, 0, 0);
}
return ret;
}
int xen_evtchn_unmask_op(struct evtchn_unmask *unmask)
{
XenEvtchnState *s = xen_evtchn_singleton;
int ret;
if (!s) {
return -ENOTSUP;
}
if (!valid_port(unmask->port)) {
return -EINVAL;
}
qemu_mutex_lock(&s->port_lock);
ret = unmask_port(s, unmask->port, true);
qemu_mutex_unlock(&s->port_lock);
return ret;
}
int xen_evtchn_bind_vcpu_op(struct evtchn_bind_vcpu *vcpu)
{
XenEvtchnState *s = xen_evtchn_singleton;
XenEvtchnPort *p;
int ret = -EINVAL;
if (!s) {
return -ENOTSUP;
}
if (!valid_port(vcpu->port)) {
return -EINVAL;
}
if (!valid_vcpu(vcpu->vcpu)) {
return -ENOENT;
}
qemu_mutex_lock(&s->port_lock);
p = &s->port_table[vcpu->port];
if (p->type == EVTCHNSTAT_interdomain ||
p->type == EVTCHNSTAT_unbound ||
p->type == EVTCHNSTAT_pirq ||
(p->type == EVTCHNSTAT_virq && virq_is_global(p->type_val))) {
/*
* unmask_port() with do_unmask==false will just raise the event
* on the new vCPU if the port was already pending.
*/
p->vcpu = vcpu->vcpu;
unmask_port(s, vcpu->port, false);
ret = 0;
}
qemu_mutex_unlock(&s->port_lock);
return ret;
}
int xen_evtchn_bind_virq_op(struct evtchn_bind_virq *virq)
{
XenEvtchnState *s = xen_evtchn_singleton;
int ret;
if (!s) {
return -ENOTSUP;
}
if (virq->virq >= NR_VIRQS) {
return -EINVAL;
}
/* Global VIRQ must be allocated on vCPU0 first */
if (virq_is_global(virq->virq) && virq->vcpu != 0) {
return -EINVAL;
}
if (!valid_vcpu(virq->vcpu)) {
return -ENOENT;
}
qemu_mutex_lock(&s->port_lock);
ret = allocate_port(s, virq->vcpu, EVTCHNSTAT_virq, virq->virq,
&virq->port);
if (!ret) {
ret = kvm_xen_set_vcpu_virq(virq->vcpu, virq->virq, virq->port);
if (ret) {
free_port(s, virq->port);
}
}
qemu_mutex_unlock(&s->port_lock);
return ret;
}
int xen_evtchn_bind_pirq_op(struct evtchn_bind_pirq *pirq)
{
XenEvtchnState *s = xen_evtchn_singleton;
int ret;
if (!s) {
return -ENOTSUP;
}
if (pirq->pirq >= s->nr_pirqs) {
return -EINVAL;
}
QEMU_IOTHREAD_LOCK_GUARD();
if (s->pirq[pirq->pirq].port) {
return -EBUSY;
}
qemu_mutex_lock(&s->port_lock);
ret = allocate_port(s, 0, EVTCHNSTAT_pirq, pirq->pirq,
&pirq->port);
if (ret) {
qemu_mutex_unlock(&s->port_lock);
return ret;
}
s->pirq[pirq->pirq].port = pirq->port;
trace_kvm_xen_bind_pirq(pirq->pirq, pirq->port);
qemu_mutex_unlock(&s->port_lock);
/*
* Need to do the unmask outside port_lock because it may call
* back into the MSI translate function.
*/
if (s->pirq[pirq->pirq].gsi == IRQ_MSI_EMU) {
if (s->pirq[pirq->pirq].is_masked) {
PCIDevice *dev = s->pirq[pirq->pirq].dev;
int vector = s->pirq[pirq->pirq].vector;
char *dev_path = qdev_get_dev_path(DEVICE(dev));
trace_kvm_xen_unmask_pirq(pirq->pirq, dev_path, vector);
g_free(dev_path);
if (s->pirq[pirq->pirq].is_msix) {
msix_set_mask(dev, vector, false);
} else {
msi_set_mask(dev, vector, false, NULL);
}
} else if (s->pirq[pirq->pirq].is_translated) {
/*
* If KVM had attempted to translate this one before, make it try
* again. If we unmasked, then the notifier on the MSI(-X) vector
* will already have had the same effect.
*/
kvm_update_msi_routes_all(NULL, true, 0, 0);
}
}
return ret;
}
int xen_evtchn_bind_ipi_op(struct evtchn_bind_ipi *ipi)
{
XenEvtchnState *s = xen_evtchn_singleton;
int ret;
if (!s) {
return -ENOTSUP;
}
if (!valid_vcpu(ipi->vcpu)) {
return -ENOENT;
}
qemu_mutex_lock(&s->port_lock);
ret = allocate_port(s, ipi->vcpu, EVTCHNSTAT_ipi, 0, &ipi->port);
if (!ret && s->evtchn_in_kernel) {
assign_kernel_port(EVTCHNSTAT_ipi, ipi->port, ipi->vcpu);
}
qemu_mutex_unlock(&s->port_lock);
return ret;
}
int xen_evtchn_bind_interdomain_op(struct evtchn_bind_interdomain *interdomain)
{
XenEvtchnState *s = xen_evtchn_singleton;
uint16_t type_val;
int ret;
if (!s) {
return -ENOTSUP;
}
if (interdomain->remote_dom == DOMID_QEMU) {
type_val = PORT_INFO_TYPEVAL_REMOTE_QEMU;
} else if (interdomain->remote_dom == DOMID_SELF ||
interdomain->remote_dom == xen_domid) {
type_val = 0;
} else {
return -ESRCH;
}
if (!valid_port(interdomain->remote_port)) {
return -EINVAL;
}
qemu_mutex_lock(&s->port_lock);
/* The newly allocated port starts out as unbound */
ret = allocate_port(s, 0, EVTCHNSTAT_unbound, type_val,
&interdomain->local_port);
if (ret) {
goto out;
}
if (interdomain->remote_dom == DOMID_QEMU) {
struct xenevtchn_handle *xc = s->be_handles[interdomain->remote_port];
XenEvtchnPort *lp = &s->port_table[interdomain->local_port];
if (!xc) {
ret = -ENOENT;
goto out_free_port;
}
if (xc->guest_port) {
ret = -EBUSY;
goto out_free_port;
}
assert(xc->be_port == interdomain->remote_port);
xc->guest_port = interdomain->local_port;
if (kvm_xen_has_cap(EVTCHN_SEND)) {
assign_kernel_eventfd(lp->type, xc->guest_port, xc->fd);
}
lp->type = EVTCHNSTAT_interdomain;
lp->type_val = PORT_INFO_TYPEVAL_REMOTE_QEMU | interdomain->remote_port;
ret = 0;
} else {
/* Loopback */
XenEvtchnPort *rp = &s->port_table[interdomain->remote_port];
XenEvtchnPort *lp = &s->port_table[interdomain->local_port];
if (rp->type == EVTCHNSTAT_unbound && rp->type_val == 0) {
/* It's a match! */
rp->type = EVTCHNSTAT_interdomain;
rp->type_val = interdomain->local_port;
lp->type = EVTCHNSTAT_interdomain;
lp->type_val = interdomain->remote_port;
} else {
ret = -EINVAL;
}
}
out_free_port:
if (ret) {
free_port(s, interdomain->local_port);
}
out:
qemu_mutex_unlock(&s->port_lock);
return ret;
}
int xen_evtchn_alloc_unbound_op(struct evtchn_alloc_unbound *alloc)
{
XenEvtchnState *s = xen_evtchn_singleton;
uint16_t type_val;
int ret;
if (!s) {
return -ENOTSUP;
}
if (alloc->dom != DOMID_SELF && alloc->dom != xen_domid) {
return -ESRCH;
}
if (alloc->remote_dom == DOMID_QEMU) {
type_val = PORT_INFO_TYPEVAL_REMOTE_QEMU;
} else if (alloc->remote_dom == DOMID_SELF ||
alloc->remote_dom == xen_domid) {
type_val = 0;
} else {
return -EPERM;
}
qemu_mutex_lock(&s->port_lock);
ret = allocate_port(s, 0, EVTCHNSTAT_unbound, type_val, &alloc->port);
qemu_mutex_unlock(&s->port_lock);
return ret;
}
int xen_evtchn_send_op(struct evtchn_send *send)
{
XenEvtchnState *s = xen_evtchn_singleton;
XenEvtchnPort *p;
int ret = 0;
if (!s) {
return -ENOTSUP;
}
if (!valid_port(send->port)) {
return -EINVAL;
}
qemu_mutex_lock(&s->port_lock);
p = &s->port_table[send->port];
switch (p->type) {
case EVTCHNSTAT_interdomain:
if (p->type_val & PORT_INFO_TYPEVAL_REMOTE_QEMU) {
/*
* This is an event from the guest to qemu itself, which is
* serving as the driver domain.
*/
uint16_t be_port = p->type_val & ~PORT_INFO_TYPEVAL_REMOTE_QEMU;
struct xenevtchn_handle *xc = s->be_handles[be_port];
if (xc) {
eventfd_write(xc->fd, 1);
ret = 0;
} else {
ret = -ENOENT;
}
} else {
/* Loopback interdomain ports; just a complex IPI */
set_port_pending(s, p->type_val);
}
break;
case EVTCHNSTAT_ipi:
set_port_pending(s, send->port);
break;
case EVTCHNSTAT_unbound:
/* Xen will silently drop these */
break;
default:
ret = -EINVAL;
break;
}
qemu_mutex_unlock(&s->port_lock);
return ret;
}
int xen_evtchn_set_port(uint16_t port)
{
XenEvtchnState *s = xen_evtchn_singleton;
XenEvtchnPort *p;
int ret = -EINVAL;
if (!s) {
return -ENOTSUP;
}
if (!valid_port(port)) {
return -EINVAL;
}
qemu_mutex_lock(&s->port_lock);
p = &s->port_table[port];
/* QEMU has no business sending to anything but these */
if (p->type == EVTCHNSTAT_virq ||
(p->type == EVTCHNSTAT_interdomain &&
(p->type_val & PORT_INFO_TYPEVAL_REMOTE_QEMU))) {
set_port_pending(s, port);
ret = 0;
}
qemu_mutex_unlock(&s->port_lock);
return ret;
}
static int allocate_pirq(XenEvtchnState *s, int type, int gsi)
{
uint16_t pirq;
/*
* Preserve the allocation strategy that Xen has. It looks like
* we *never* give out PIRQ 0-15, we give out 16-nr_irqs_gsi only
* to GSIs (counting up from 16), and then we count backwards from
* the top for MSIs or when the GSI space is exhausted.
*/
if (type == MAP_PIRQ_TYPE_GSI) {
for (pirq = 16 ; pirq < IOAPIC_NUM_PINS; pirq++) {
if (pirq_inuse(s, pirq)) {
continue;
}
/* Found it */
goto found;
}
}
for (pirq = s->nr_pirqs - 1; pirq >= IOAPIC_NUM_PINS; pirq--) {
/* Skip whole words at a time when they're full */
if (pirq_inuse_word(s, pirq) == UINT64_MAX) {
pirq &= ~63ULL;
continue;
}
if (pirq_inuse(s, pirq)) {
continue;
}
goto found;
}
return -ENOSPC;
found:
pirq_inuse_word(s, pirq) |= pirq_inuse_bit(pirq);
if (gsi >= 0) {
assert(gsi <= IOAPIC_NUM_PINS);
s->gsi_pirq[gsi] = pirq;
}
s->pirq[pirq].gsi = gsi;
return pirq;
}
bool xen_evtchn_set_gsi(int gsi, int level)
{
XenEvtchnState *s = xen_evtchn_singleton;
int pirq;
assert(qemu_mutex_iothread_locked());
if (!s || gsi < 0 || gsi > IOAPIC_NUM_PINS) {
return false;
}
/*
* Check that that it *isn't* the event channel GSI, and thus
* that we are not recursing and it's safe to take s->port_lock.
*
* Locking aside, it's perfectly sane to bail out early for that
* special case, as it would make no sense for the event channel
* GSI to be routed back to event channels, when the delivery
* method is to raise the GSI... that recursion wouldn't *just*
* be a locking issue.
*/
if (gsi && gsi == s->callback_gsi) {
return false;
}
QEMU_LOCK_GUARD(&s->port_lock);
pirq = s->gsi_pirq[gsi];
if (!pirq) {
return false;
}
if (level) {
int port = s->pirq[pirq].port;
s->pirq_gsi_set |= (1U << gsi);
if (port) {
set_port_pending(s, port);
}
} else {
s->pirq_gsi_set &= ~(1U << gsi);
}
return true;
}
static uint32_t msi_pirq_target(uint64_t addr, uint32_t data)
{
/* The vector (in low 8 bits of data) must be zero */
if (data & 0xff) {
return 0;
}
uint32_t pirq = (addr & 0xff000) >> 12;
pirq |= (addr >> 32) & 0xffffff00;
return pirq;
}
static void do_remove_pci_vector(XenEvtchnState *s, PCIDevice *dev, int vector,
int except_pirq)
{
uint32_t pirq;
for (pirq = 0; pirq < s->nr_pirqs; pirq++) {
/*
* We could be cleverer here, but it isn't really a fast path, and
* this trivial optimisation is enough to let us skip the big gap
* in the middle a bit quicker (in terms of both loop iterations,
* and cache lines).
*/
if (!(pirq & 63) && !(pirq_inuse_word(s, pirq))) {
pirq += 64;
continue;
}
if (except_pirq && pirq == except_pirq) {
continue;
}
if (s->pirq[pirq].dev != dev) {
continue;
}
if (vector != -1 && s->pirq[pirq].vector != vector) {
continue;
}
/* It could theoretically be bound to a port already, but that is OK. */
s->pirq[pirq].dev = dev;
s->pirq[pirq].gsi = IRQ_UNBOUND;
s->pirq[pirq].is_msix = false;
s->pirq[pirq].vector = 0;
s->pirq[pirq].is_masked = false;
s->pirq[pirq].is_translated = false;
}
}
void xen_evtchn_remove_pci_device(PCIDevice *dev)
{
XenEvtchnState *s = xen_evtchn_singleton;
if (!s) {
return;
}
QEMU_LOCK_GUARD(&s->port_lock);
do_remove_pci_vector(s, dev, -1, 0);
}
void xen_evtchn_snoop_msi(PCIDevice *dev, bool is_msix, unsigned int vector,
uint64_t addr, uint32_t data, bool is_masked)
{
XenEvtchnState *s = xen_evtchn_singleton;
uint32_t pirq;
if (!s) {
return;
}
assert(qemu_mutex_iothread_locked());
pirq = msi_pirq_target(addr, data);
/*
* The PIRQ# must be sane, and there must be an allocated PIRQ in
* IRQ_UNBOUND or IRQ_MSI_EMU state to match it.
*/
if (!pirq || pirq >= s->nr_pirqs || !pirq_inuse(s, pirq) ||
(s->pirq[pirq].gsi != IRQ_UNBOUND &&
s->pirq[pirq].gsi != IRQ_MSI_EMU)) {
pirq = 0;
}
if (pirq) {
s->pirq[pirq].dev = dev;
s->pirq[pirq].gsi = IRQ_MSI_EMU;
s->pirq[pirq].is_msix = is_msix;
s->pirq[pirq].vector = vector;
s->pirq[pirq].is_masked = is_masked;
}
/* Remove any (other) entries for this {device, vector} */
do_remove_pci_vector(s, dev, vector, pirq);
}
int xen_evtchn_translate_pirq_msi(struct kvm_irq_routing_entry *route,
uint64_t address, uint32_t data)
{
XenEvtchnState *s = xen_evtchn_singleton;
uint32_t pirq, port;
CPUState *cpu;
if (!s) {
return 1; /* Not a PIRQ */
}
assert(qemu_mutex_iothread_locked());
pirq = msi_pirq_target(address, data);
if (!pirq || pirq >= s->nr_pirqs) {
return 1; /* Not a PIRQ */
}
if (!kvm_xen_has_cap(EVTCHN_2LEVEL)) {
return -ENOTSUP;
}
if (s->pirq[pirq].gsi != IRQ_MSI_EMU) {
return -EINVAL;
}
/* Remember that KVM tried to translate this. It might need to try again. */
s->pirq[pirq].is_translated = true;
QEMU_LOCK_GUARD(&s->port_lock);
port = s->pirq[pirq].port;
if (!valid_port(port)) {
return -EINVAL;
}
cpu = qemu_get_cpu(s->port_table[port].vcpu);
if (!cpu) {
return -EINVAL;
}
route->type = KVM_IRQ_ROUTING_XEN_EVTCHN;
route->u.xen_evtchn.port = port;
route->u.xen_evtchn.vcpu = kvm_arch_vcpu_id(cpu);
route->u.xen_evtchn.priority = KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL;
return 0; /* Handled */
}
bool xen_evtchn_deliver_pirq_msi(uint64_t address, uint32_t data)
{
XenEvtchnState *s = xen_evtchn_singleton;
uint32_t pirq, port;
if (!s) {
return false;
}
assert(qemu_mutex_iothread_locked());
pirq = msi_pirq_target(address, data);
if (!pirq || pirq >= s->nr_pirqs) {
return false;
}
QEMU_LOCK_GUARD(&s->port_lock);
port = s->pirq[pirq].port;
if (!valid_port(port)) {
return false;
}
set_port_pending(s, port);
return true;
}
int xen_physdev_map_pirq(struct physdev_map_pirq *map)
{
XenEvtchnState *s = xen_evtchn_singleton;
int pirq = map->pirq;
int gsi = map->index;
if (!s) {
return -ENOTSUP;
}
QEMU_IOTHREAD_LOCK_GUARD();
QEMU_LOCK_GUARD(&s->port_lock);
if (map->domid != DOMID_SELF && map->domid != xen_domid) {
return -EPERM;
}
if (map->type != MAP_PIRQ_TYPE_GSI) {
return -EINVAL;
}
if (gsi < 0 || gsi >= IOAPIC_NUM_PINS) {
return -EINVAL;
}
if (pirq < 0) {
pirq = allocate_pirq(s, map->type, gsi);
if (pirq < 0) {
return pirq;
}
map->pirq = pirq;
} else if (pirq > s->nr_pirqs) {
return -EINVAL;
} else {
/*
* User specified a valid-looking PIRQ#. Allow it if it is
* allocated and not yet bound, or if it is unallocated
*/
if (pirq_inuse(s, pirq)) {
if (s->pirq[pirq].gsi != IRQ_UNBOUND) {
return -EBUSY;
}
} else {
/* If it was unused, mark it used now. */
pirq_inuse_word(s, pirq) |= pirq_inuse_bit(pirq);
}
/* Set the mapping in both directions. */
s->pirq[pirq].gsi = gsi;
s->gsi_pirq[gsi] = pirq;
}
trace_kvm_xen_map_pirq(pirq, gsi);
return 0;
}
int xen_physdev_unmap_pirq(struct physdev_unmap_pirq *unmap)
{
XenEvtchnState *s = xen_evtchn_singleton;
int pirq = unmap->pirq;
int gsi;
if (!s) {
return -ENOTSUP;
}
if (unmap->domid != DOMID_SELF && unmap->domid != xen_domid) {
return -EPERM;
}
if (pirq < 0 || pirq >= s->nr_pirqs) {
return -EINVAL;
}
QEMU_IOTHREAD_LOCK_GUARD();
qemu_mutex_lock(&s->port_lock);
if (!pirq_inuse(s, pirq)) {
qemu_mutex_unlock(&s->port_lock);
return -ENOENT;
}
gsi = s->pirq[pirq].gsi;
/* We can only unmap GSI PIRQs */
if (gsi < 0) {
qemu_mutex_unlock(&s->port_lock);
return -EINVAL;
}
s->gsi_pirq[gsi] = 0;
s->pirq[pirq].gsi = IRQ_UNBOUND; /* Doesn't actually matter because: */
pirq_inuse_word(s, pirq) &= ~pirq_inuse_bit(pirq);
trace_kvm_xen_unmap_pirq(pirq, gsi);
qemu_mutex_unlock(&s->port_lock);
if (gsi == IRQ_MSI_EMU) {
kvm_update_msi_routes_all(NULL, true, 0, 0);
}
return 0;
}
int xen_physdev_eoi_pirq(struct physdev_eoi *eoi)
{
XenEvtchnState *s = xen_evtchn_singleton;
int pirq = eoi->irq;
int gsi;
if (!s) {
return -ENOTSUP;
}
QEMU_IOTHREAD_LOCK_GUARD();
QEMU_LOCK_GUARD(&s->port_lock);
if (!pirq_inuse(s, pirq)) {
return -ENOENT;
}
gsi = s->pirq[pirq].gsi;
if (gsi < 0) {
return -EINVAL;
}
/* Reassert a level IRQ if needed */
if (s->pirq_gsi_set & (1U << gsi)) {
int port = s->pirq[pirq].port;
if (port) {
set_port_pending(s, port);
}
}
return 0;
}
int xen_physdev_query_pirq(struct physdev_irq_status_query *query)
{
XenEvtchnState *s = xen_evtchn_singleton;
int pirq = query->irq;
if (!s) {
return -ENOTSUP;
}
QEMU_IOTHREAD_LOCK_GUARD();
QEMU_LOCK_GUARD(&s->port_lock);
if (!pirq_inuse(s, pirq)) {
return -ENOENT;
}
if (s->pirq[pirq].gsi >= 0) {
query->flags = XENIRQSTAT_needs_eoi;
} else {
query->flags = 0;
}
return 0;
}
int xen_physdev_get_free_pirq(struct physdev_get_free_pirq *get)
{
XenEvtchnState *s = xen_evtchn_singleton;
int pirq;
if (!s) {
return -ENOTSUP;
}
QEMU_LOCK_GUARD(&s->port_lock);
pirq = allocate_pirq(s, get->type, IRQ_UNBOUND);
if (pirq < 0) {
return pirq;
}
get->pirq = pirq;
trace_kvm_xen_get_free_pirq(pirq, get->type);
return 0;
}
struct xenevtchn_handle *xen_be_evtchn_open(void)
{
struct xenevtchn_handle *xc = g_new0(struct xenevtchn_handle, 1);
xc->fd = eventfd(0, EFD_CLOEXEC);
if (xc->fd < 0) {
free(xc);
return NULL;
}
return xc;
}
static int find_be_port(XenEvtchnState *s, struct xenevtchn_handle *xc)
{
int i;
for (i = 1; i < EVTCHN_2L_NR_CHANNELS; i++) {
if (!s->be_handles[i]) {
s->be_handles[i] = xc;
xc->be_port = i;
return i;
}
}
return 0;
}
int xen_be_evtchn_bind_interdomain(struct xenevtchn_handle *xc, uint32_t domid,
evtchn_port_t guest_port)
{
XenEvtchnState *s = xen_evtchn_singleton;
XenEvtchnPort *gp;
uint16_t be_port = 0;
int ret;
if (!s) {
return -ENOTSUP;
}
if (!xc) {
return -EFAULT;
}
if (domid != xen_domid) {
return -ESRCH;
}
if (!valid_port(guest_port)) {
return -EINVAL;
}
qemu_mutex_lock(&s->port_lock);
/* The guest has to have an unbound port waiting for us to bind */
gp = &s->port_table[guest_port];
switch (gp->type) {
case EVTCHNSTAT_interdomain:
/* Allow rebinding after migration, preserve port # if possible */
be_port = gp->type_val & ~PORT_INFO_TYPEVAL_REMOTE_QEMU;
assert(be_port != 0);
if (!s->be_handles[be_port]) {
s->be_handles[be_port] = xc;
xc->guest_port = guest_port;
ret = xc->be_port = be_port;
if (kvm_xen_has_cap(EVTCHN_SEND)) {
assign_kernel_eventfd(gp->type, guest_port, xc->fd);
}
break;
}
/* fall through */
case EVTCHNSTAT_unbound:
be_port = find_be_port(s, xc);
if (!be_port) {
ret = -ENOSPC;
goto out;
}
gp->type = EVTCHNSTAT_interdomain;
gp->type_val = be_port | PORT_INFO_TYPEVAL_REMOTE_QEMU;
xc->guest_port = guest_port;
if (kvm_xen_has_cap(EVTCHN_SEND)) {
assign_kernel_eventfd(gp->type, guest_port, xc->fd);
}
ret = be_port;
break;
default:
ret = -EINVAL;
break;
}
out:
qemu_mutex_unlock(&s->port_lock);
return ret;
}
int xen_be_evtchn_unbind(struct xenevtchn_handle *xc, evtchn_port_t port)
{
XenEvtchnState *s = xen_evtchn_singleton;
int ret;
if (!s) {
return -ENOTSUP;
}
if (!xc) {
return -EFAULT;
}
qemu_mutex_lock(&s->port_lock);
if (port && port != xc->be_port) {
ret = -EINVAL;
goto out;
}
if (xc->guest_port) {
XenEvtchnPort *gp = &s->port_table[xc->guest_port];
/* This should never *not* be true */
if (gp->type == EVTCHNSTAT_interdomain) {
gp->type = EVTCHNSTAT_unbound;
gp->type_val = PORT_INFO_TYPEVAL_REMOTE_QEMU;
}
if (kvm_xen_has_cap(EVTCHN_SEND)) {
deassign_kernel_port(xc->guest_port);
}
xc->guest_port = 0;
}
s->be_handles[xc->be_port] = NULL;
xc->be_port = 0;
ret = 0;
out:
qemu_mutex_unlock(&s->port_lock);
return ret;
}
int xen_be_evtchn_close(struct xenevtchn_handle *xc)
{
if (!xc) {
return -EFAULT;
}
xen_be_evtchn_unbind(xc, 0);
close(xc->fd);
free(xc);
return 0;
}
int xen_be_evtchn_fd(struct xenevtchn_handle *xc)
{
if (!xc) {
return -1;
}
return xc->fd;
}
int xen_be_evtchn_notify(struct xenevtchn_handle *xc, evtchn_port_t port)
{
XenEvtchnState *s = xen_evtchn_singleton;
int ret;
if (!s) {
return -ENOTSUP;
}
if (!xc) {
return -EFAULT;
}
qemu_mutex_lock(&s->port_lock);
if (xc->guest_port) {
set_port_pending(s, xc->guest_port);
ret = 0;
} else {
ret = -ENOTCONN;
}
qemu_mutex_unlock(&s->port_lock);
return ret;
}
int xen_be_evtchn_pending(struct xenevtchn_handle *xc)
{
uint64_t val;
if (!xc) {
return -EFAULT;
}
if (!xc->be_port) {
return 0;
}
if (eventfd_read(xc->fd, &val)) {
return -errno;
}
return val ? xc->be_port : 0;
}
int xen_be_evtchn_unmask(struct xenevtchn_handle *xc, evtchn_port_t port)
{
if (!xc) {
return -EFAULT;
}
if (xc->be_port != port) {
return -EINVAL;
}
/*
* We don't actually do anything to unmask it; the event was already
* consumed in xen_be_evtchn_pending().
*/
return 0;
}
int xen_be_evtchn_get_guest_port(struct xenevtchn_handle *xc)
{
return xc->guest_port;
}
EvtchnInfoList *qmp_xen_event_list(Error **errp)
{
XenEvtchnState *s = xen_evtchn_singleton;
EvtchnInfoList *head = NULL, **tail = &head;
void *shinfo, *pending, *mask;
int i;
if (!s) {
error_setg(errp, "Xen event channel emulation not enabled");
return NULL;
}
shinfo = xen_overlay_get_shinfo_ptr();
if (!shinfo) {
error_setg(errp, "Xen shared info page not allocated");
return NULL;
}
if (xen_is_long_mode()) {
pending = shinfo + offsetof(struct shared_info, evtchn_pending);
mask = shinfo + offsetof(struct shared_info, evtchn_mask);
} else {
pending = shinfo + offsetof(struct compat_shared_info, evtchn_pending);
mask = shinfo + offsetof(struct compat_shared_info, evtchn_mask);
}
QEMU_LOCK_GUARD(&s->port_lock);
for (i = 0; i < s->nr_ports; i++) {
XenEvtchnPort *p = &s->port_table[i];
EvtchnInfo *info;
if (p->type == EVTCHNSTAT_closed) {
continue;
}
info = g_new0(EvtchnInfo, 1);
info->port = i;
qemu_build_assert(EVTCHN_PORT_TYPE_CLOSED == EVTCHNSTAT_closed);
qemu_build_assert(EVTCHN_PORT_TYPE_UNBOUND == EVTCHNSTAT_unbound);
qemu_build_assert(EVTCHN_PORT_TYPE_INTERDOMAIN == EVTCHNSTAT_interdomain);
qemu_build_assert(EVTCHN_PORT_TYPE_PIRQ == EVTCHNSTAT_pirq);
qemu_build_assert(EVTCHN_PORT_TYPE_VIRQ == EVTCHNSTAT_virq);
qemu_build_assert(EVTCHN_PORT_TYPE_IPI == EVTCHNSTAT_ipi);
info->type = p->type;
if (p->type == EVTCHNSTAT_interdomain) {
info->remote_domain = g_strdup((p->type_val & PORT_INFO_TYPEVAL_REMOTE_QEMU) ?
"qemu" : "loopback");
info->target = p->type_val & PORT_INFO_TYPEVAL_REMOTE_PORT_MASK;
} else {
info->target = p->type_val;
}
info->vcpu = p->vcpu;
info->pending = test_bit(i, pending);
info->masked = test_bit(i, mask);
QAPI_LIST_APPEND(tail, info);
}
return head;
}
void qmp_xen_event_inject(uint32_t port, Error **errp)
{
XenEvtchnState *s = xen_evtchn_singleton;
if (!s) {
error_setg(errp, "Xen event channel emulation not enabled");
return;
}
if (!valid_port(port)) {
error_setg(errp, "Invalid port %u", port);
}
QEMU_LOCK_GUARD(&s->port_lock);
if (set_port_pending(s, port)) {
error_setg(errp, "Failed to set port %u", port);
return;
}
}
void hmp_xen_event_list(Monitor *mon, const QDict *qdict)
{
EvtchnInfoList *iter, *info_list;
Error *err = NULL;
info_list = qmp_xen_event_list(&err);
if (err) {
hmp_handle_error(mon, err);
return;
}
for (iter = info_list; iter; iter = iter->next) {
EvtchnInfo *info = iter->value;
monitor_printf(mon, "port %4u: vcpu: %d %s", info->port, info->vcpu,
EvtchnPortType_str(info->type));
if (info->type != EVTCHN_PORT_TYPE_IPI) {
monitor_printf(mon, "(");
if (info->remote_domain) {
monitor_printf(mon, "%s:", info->remote_domain);
}
monitor_printf(mon, "%d)", info->target);
}
if (info->pending) {
monitor_printf(mon, " PENDING");
}
if (info->masked) {
monitor_printf(mon, " MASKED");
}
monitor_printf(mon, "\n");
}
qapi_free_EvtchnInfoList(info_list);
}
void hmp_xen_event_inject(Monitor *mon, const QDict *qdict)
{
int port = qdict_get_int(qdict, "port");
Error *err = NULL;
qmp_xen_event_inject(port, &err);
if (err) {
hmp_handle_error(mon, err);
} else {
monitor_printf(mon, "Delivered port %d\n", port);
}
}
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