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hw/xen: Implement EVTCHNOP_bind_virq

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Add the array of virq ports to each vCPU so that we can deliver timers,
debug ports, etc. Global virqs are allocated against vCPU 0 initially,
but can be migrated to other vCPUs (when we implement that).

The kernel needs to know about VIRQ_TIMER in order to accelerate timers,
so tell it via KVM_XEN_VCPU_ATTR_TYPE_TIMER. Also save/restore the value
of the singleshot timer across migration, as the kernel will handle the
hypercalls automatically now.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
This commit is contained in:
David Woodhouse 2022-12-13 22:40:56 +00:00
parent 190cc3c0ed
commit c723d4c15e
6 changed files with 185 additions and 0 deletions
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85
hw/i386/kvm/xen_evtchn.c
View File

@ -244,6 +244,11 @@ static bool valid_port(evtchn_port_t port)
}
}
static bool valid_vcpu(uint32_t vcpu)
{
return !!qemu_get_cpu(vcpu);
}
int xen_evtchn_status_op(struct evtchn_status *status)
{
XenEvtchnState *s = xen_evtchn_singleton;
@ -496,6 +501,43 @@ static void free_port(XenEvtchnState *s, evtchn_port_t port)
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)
{
XenEvtchnPort *p = &s->port_table[port];
@ -504,6 +546,11 @@ static int close_port(XenEvtchnState *s, evtchn_port_t port)
case EVTCHNSTAT_closed:
return -ENOENT;
case EVTCHNSTAT_virq:
kvm_xen_set_vcpu_virq(virq_is_global(p->type_val) ? 0 : p->vcpu,
p->type_val, 0);
break;
default:
break;
}
@ -555,3 +602,41 @@ int xen_evtchn_unmask_op(struct evtchn_unmask *unmask)
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;
}

2
hw/i386/kvm/xen_evtchn.h
View File

@ -18,8 +18,10 @@ int xen_evtchn_set_callback_param(uint64_t param);
struct evtchn_status;
struct evtchn_close;
struct evtchn_unmask;
struct evtchn_bind_virq;
int xen_evtchn_status_op(struct evtchn_status *status);
int xen_evtchn_close_op(struct evtchn_close *close);
int xen_evtchn_unmask_op(struct evtchn_unmask *unmask);
int xen_evtchn_bind_virq_op(struct evtchn_bind_virq *virq);
#endif /* QEMU_XEN_EVTCHN_H */

1
include/sysemu/kvm_xen.h
View File

@ -23,6 +23,7 @@ int kvm_xen_soft_reset(void);
uint32_t kvm_xen_get_caps(void);
void *kvm_xen_get_vcpu_info_hva(uint32_t vcpu_id);
void kvm_xen_inject_vcpu_callback_vector(uint32_t vcpu_id, int type);
int kvm_xen_set_vcpu_virq(uint32_t vcpu_id, uint16_t virq, uint16_t port);
#define kvm_xen_has_cap(cap) (!!(kvm_xen_get_caps() & \
KVM_XEN_HVM_CONFIG_ ## cap))

4
target/i386/cpu.h
View File

@ -27,6 +27,8 @@
#include "qapi/qapi-types-common.h"
#include "qemu/cpu-float.h"
#define XEN_NR_VIRQS 24
/* The x86 has a strong memory model with some store-after-load re-ordering */
#define TCG_GUEST_DEFAULT_MO (TCG_MO_ALL & ~TCG_MO_ST_LD)
@ -1806,6 +1808,8 @@ typedef struct CPUArchState {
uint64_t xen_vcpu_time_info_gpa;
uint64_t xen_vcpu_runstate_gpa;
uint8_t xen_vcpu_callback_vector;
uint16_t xen_virq[XEN_NR_VIRQS];
uint64_t xen_singleshot_timer_ns;
#endif
#if defined(CONFIG_HVF)
HVFX86LazyFlags hvf_lflags;

91
target/i386/kvm/xen-emu.c
View File

@ -355,6 +355,53 @@ void kvm_xen_inject_vcpu_callback_vector(uint32_t vcpu_id, int type)
}
}
static int kvm_xen_set_vcpu_timer(CPUState *cs)
{
X86CPU *cpu = X86_CPU(cs);
CPUX86State *env = &cpu->env;
struct kvm_xen_vcpu_attr va = {
.type = KVM_XEN_VCPU_ATTR_TYPE_TIMER,
.u.timer.port = env->xen_virq[VIRQ_TIMER],
.u.timer.priority = KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL,
.u.timer.expires_ns = env->xen_singleshot_timer_ns,
};
return kvm_vcpu_ioctl(cs, KVM_XEN_VCPU_SET_ATTR, &va);
}
static void do_set_vcpu_timer_virq(CPUState *cs, run_on_cpu_data data)
{
kvm_xen_set_vcpu_timer(cs);
}
int kvm_xen_set_vcpu_virq(uint32_t vcpu_id, uint16_t virq, uint16_t port)
{
CPUState *cs = qemu_get_cpu(vcpu_id);
if (!cs) {
return -ENOENT;
}
/* cpu.h doesn't include the actual Xen header. */
qemu_build_assert(NR_VIRQS == XEN_NR_VIRQS);
if (virq >= NR_VIRQS) {
return -EINVAL;
}
if (port && X86_CPU(cs)->env.xen_virq[virq]) {
return -EEXIST;
}
X86_CPU(cs)->env.xen_virq[virq] = port;
if (virq == VIRQ_TIMER && kvm_xen_has_cap(EVTCHN_SEND)) {
async_run_on_cpu(cs, do_set_vcpu_timer_virq,
RUN_ON_CPU_HOST_INT(port));
}
return 0;
}
static void do_set_vcpu_time_info_gpa(CPUState *cs, run_on_cpu_data data)
{
X86CPU *cpu = X86_CPU(cs);
@ -387,6 +434,8 @@ static void do_vcpu_soft_reset(CPUState *cs, run_on_cpu_data data)
env->xen_vcpu_time_info_gpa = INVALID_GPA;
env->xen_vcpu_runstate_gpa = INVALID_GPA;
env->xen_vcpu_callback_vector = 0;
env->xen_singleshot_timer_ns = 0;
memset(env->xen_virq, 0, sizeof(env->xen_virq));
set_vcpu_info(cs, INVALID_GPA);
kvm_xen_set_vcpu_attr(cs, KVM_XEN_VCPU_ATTR_TYPE_VCPU_TIME_INFO,
@ -395,6 +444,7 @@ static void do_vcpu_soft_reset(CPUState *cs, run_on_cpu_data data)
INVALID_GPA);
if (kvm_xen_has_cap(EVTCHN_SEND)) {
kvm_xen_set_vcpu_callback_vector(cs);
kvm_xen_set_vcpu_timer(cs);
}
}
@ -829,6 +879,21 @@ static bool kvm_xen_hcall_evtchn_op(struct kvm_xen_exit *exit, X86CPU *cpu,
err = xen_evtchn_unmask_op(&unmask);
break;
}
case EVTCHNOP_bind_virq: {
struct evtchn_bind_virq virq;
qemu_build_assert(sizeof(virq) == 12);
if (kvm_copy_from_gva(cs, arg, &virq, sizeof(virq))) {
err = -EFAULT;
break;
}
err = xen_evtchn_bind_virq_op(&virq);
if (!err && kvm_copy_to_gva(cs, arg, &virq, sizeof(virq))) {
err = -EFAULT;
}
break;
}
default:
return false;
}
@ -1060,6 +1125,12 @@ int kvm_put_xen_state(CPUState *cs)
}
}
if (env->xen_virq[VIRQ_TIMER]) {
ret = kvm_xen_set_vcpu_timer(cs);
if (ret < 0) {
return ret;
}
}
return 0;
}
@ -1068,6 +1139,7 @@ int kvm_get_xen_state(CPUState *cs)
X86CPU *cpu = X86_CPU(cs);
CPUX86State *env = &cpu->env;
uint64_t gpa;
int ret;
/*
* The kernel does not mark vcpu_info as dirty when it delivers interrupts
@ -1090,5 +1162,24 @@ int kvm_get_xen_state(CPUState *cs)
}
}
if (!kvm_xen_has_cap(EVTCHN_SEND)) {
return 0;
}
/*
* If the kernel is accelerating timers, read out the current value of the
* singleshot timer deadline.
*/
if (env->xen_virq[VIRQ_TIMER]) {
struct kvm_xen_vcpu_attr va = {
.type = KVM_XEN_VCPU_ATTR_TYPE_TIMER,
};
ret = kvm_vcpu_ioctl(cs, KVM_XEN_VCPU_GET_ATTR, &va);
if (ret < 0) {
return ret;
}
env->xen_singleshot_timer_ns = va.u.timer.expires_ns;
}
return 0;
}

2
target/i386/machine.c
View File

@ -1275,6 +1275,8 @@ static const VMStateDescription vmstate_xen_vcpu = {
VMSTATE_UINT64(env.xen_vcpu_time_info_gpa, X86CPU),
VMSTATE_UINT64(env.xen_vcpu_runstate_gpa, X86CPU),
VMSTATE_UINT8(env.xen_vcpu_callback_vector, X86CPU),
VMSTATE_UINT16_ARRAY(env.xen_virq, X86CPU, XEN_NR_VIRQS),
VMSTATE_UINT64(env.xen_singleshot_timer_ns, X86CPU),
VMSTATE_END_OF_LIST()
}
};