From: Joao Martins <joao.m.mart...@oracle.com>
Introduce support for one shot and periodic mode of Xen PV timers,
whereby timer interrupts come through a special virq event channel
with deadlines being set through:
1) set_timer_op hypercall (only oneshot)
2) vcpu_op hypercall for {set,stop}_{singleshot,periodic}_timer
hypercalls
Signed-off-by: Joao Martins <joao.m.mart...@oracle.com>
Signed-off-by: David Woodhouse <d...@amazon.co.uk>
---
hw/i386/kvm/xen_evtchn.c | 31 +++++
hw/i386/kvm/xen_evtchn.h | 2 +
target/i386/cpu.h | 5 +
target/i386/kvm/xen-emu.c | 245 +++++++++++++++++++++++++++++++++++++-
target/i386/machine.c | 1 +
5 files changed, 282 insertions(+), 2 deletions(-)
diff --git a/hw/i386/kvm/xen_evtchn.c b/hw/i386/kvm/xen_evtchn.c
index 301a28264f..272f51e64a 100644
--- a/hw/i386/kvm/xen_evtchn.c
+++ b/hw/i386/kvm/xen_evtchn.c
@@ -1219,6 +1219,37 @@ int xen_evtchn_send_op(struct evtchn_send *send)
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;
+}
+
EvtchnInfoList *qmp_xen_event_list(Error **errp)
{
XenEvtchnState *s = xen_evtchn_singleton;
diff --git a/hw/i386/kvm/xen_evtchn.h b/hw/i386/kvm/xen_evtchn.h
index b03c3108bc..24611478b8 100644
--- a/hw/i386/kvm/xen_evtchn.h
+++ b/hw/i386/kvm/xen_evtchn.h
@@ -20,6 +20,8 @@ int xen_evtchn_set_callback_param(uint64_t param);
void xen_evtchn_connect_gsis(qemu_irq *system_gsis);
void xen_evtchn_set_callback_level(int level);
+int xen_evtchn_set_port(uint16_t port);
+
struct evtchn_status;
struct evtchn_close;
struct evtchn_unmask;
diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index e8718c31e5..b579f0f0f8 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -26,6 +26,7 @@
#include "exec/cpu-defs.h"
#include "qapi/qapi-types-common.h"
#include "qemu/cpu-float.h"
+#include "qemu/timer.h"
#define XEN_NR_VIRQS 24
@@ -1800,6 +1801,10 @@ typedef struct CPUArchState {
bool xen_callback_asserted;
uint16_t xen_virq[XEN_NR_VIRQS];
uint64_t xen_singleshot_timer_ns;
+ QEMUTimer *xen_singleshot_timer;
+ uint64_t xen_periodic_timer_period;
+ QEMUTimer *xen_periodic_timer;
+ QemuMutex xen_timers_lock;
#endif
#if defined(CONFIG_HVF)
HVFX86LazyFlags hvf_lflags;
diff --git a/target/i386/kvm/xen-emu.c b/target/i386/kvm/xen-emu.c
index f0909e088a..edc732b690 100644
--- a/target/i386/kvm/xen-emu.c
+++ b/target/i386/kvm/xen-emu.c
@@ -38,6 +38,9 @@
#include "xen-compat.h"
+static void xen_vcpu_singleshot_timer_event(void *opaque);
+static void xen_vcpu_periodic_timer_event(void *opaque);
+
#ifdef TARGET_X86_64
#define hypercall_compat32(longmode) (!(longmode))
#else
@@ -201,6 +204,23 @@ int kvm_xen_init_vcpu(CPUState *cs)
env->xen_vcpu_time_info_gpa = INVALID_GPA;
env->xen_vcpu_runstate_gpa = INVALID_GPA;
+ qemu_mutex_init(&env->xen_timers_lock);
+ env->xen_singleshot_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,
+ xen_vcpu_singleshot_timer_event,
+ cpu);
+ if (!env->xen_singleshot_timer) {
+ return -ENOMEM;
+ }
+ env->xen_singleshot_timer->opaque = cs;
+
+ env->xen_periodic_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,
+ xen_vcpu_periodic_timer_event,
+ cpu);
+ if (!env->xen_periodic_timer) {
+ return -ENOMEM;
+ }
+ env->xen_periodic_timer->opaque = cs;
+
return 0;
}
@@ -232,7 +252,8 @@ static bool kvm_xen_hcall_xen_version(struct kvm_xen_exit
*exit, X86CPU *cpu,
1 << XENFEAT_writable_descriptor_tables |
1 << XENFEAT_auto_translated_physmap |
1 << XENFEAT_supervisor_mode_kernel |
- 1 << XENFEAT_hvm_callback_vector;
+ 1 << XENFEAT_hvm_callback_vector |
+ 1 << XENFEAT_hvm_safe_pvclock;
}
err = kvm_copy_to_gva(CPU(cpu), arg, &fi, sizeof(fi));
@@ -868,13 +889,192 @@ static int vcpuop_register_runstate_info(CPUState *cs,
CPUState *target,
return 0;
}
+static uint64_t kvm_get_current_ns(void)
+{
+ struct kvm_clock_data data;
+ int ret;
+
+ ret = kvm_vm_ioctl(kvm_state, KVM_GET_CLOCK, &data);
+ if (ret < 0) {
+ fprintf(stderr, "KVM_GET_CLOCK failed: %s\n", strerror(ret));
+ abort();
+ }
+
+ return data.clock;
+}
+
+static void xen_vcpu_singleshot_timer_event(void *opaque)
+{
+ CPUState *cpu = opaque;
+ CPUX86State *env = &X86_CPU(cpu)->env;
+ uint16_t port = env->xen_virq[VIRQ_TIMER];
+
+ if (likely(port)) {
+ xen_evtchn_set_port(port);
+ }
+
+ qemu_mutex_lock(&env->xen_timers_lock);
+ env->xen_singleshot_timer_ns = 0;
+ qemu_mutex_unlock(&env->xen_timers_lock);
+}
+
+static void xen_vcpu_periodic_timer_event(void *opaque)
+{
+ CPUState *cpu = opaque;
+ CPUX86State *env = &X86_CPU(cpu)->env;
+ uint16_t port = env->xen_virq[VIRQ_TIMER];
+ int64_t qemu_now;
+
+ if (likely(port)) {
+ xen_evtchn_set_port(port);
+ }
+
+ qemu_mutex_lock(&env->xen_timers_lock);
+
+ qemu_now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
+ timer_mod_ns(env->xen_periodic_timer,
+ qemu_now + env->xen_periodic_timer_period);
+
+ qemu_mutex_unlock(&env->xen_timers_lock);
+}
+
+static int do_set_periodic_timer(CPUState *target, uint64_t period_ns)
+{
+ CPUX86State *tenv = &X86_CPU(target)->env;
+ int64_t qemu_now;
+
+ timer_del(tenv->xen_periodic_timer);
+
+ qemu_mutex_lock(&tenv->xen_timers_lock);
+
+ qemu_now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
+ timer_mod_ns(tenv->xen_periodic_timer, qemu_now + period_ns);
+ tenv->xen_periodic_timer_period = period_ns;
+
+ qemu_mutex_unlock(&tenv->xen_timers_lock);
+ return 0;
+}
+
+#define MILLISECS(_ms) ((int64_t)((_ms) * 1000000ULL))
+#define MICROSECS(_us) ((int64_t)((_us) * 1000ULL))
+#define STIME_MAX ((time_t)((int64_t)~0ull >> 1))
+/* Chosen so (NOW() + delta) wont overflow without an uptime of 200 years */
+#define STIME_DELTA_MAX ((int64_t)((uint64_t)~0ull >> 2))
+
+static int vcpuop_set_periodic_timer(CPUState *cs, CPUState *target,
+ uint64_t arg)
+{
+ struct vcpu_set_periodic_timer spt;
+
+ qemu_build_assert(sizeof(spt) == 8);
+ if (kvm_copy_from_gva(cs, arg, &spt, sizeof(spt))) {
+ return -EFAULT;
+ }
+
+ if (spt.period_ns < MILLISECS(1) || spt.period_ns > STIME_DELTA_MAX) {
+ return -EINVAL;
+ }
+
+ return do_set_periodic_timer(target, spt.period_ns);
+}
+
+static int vcpuop_stop_periodic_timer(CPUState *target)
+{
+ CPUX86State *tenv = &X86_CPU(target)->env;
+
+ qemu_mutex_lock(&tenv->xen_timers_lock);
+
+ timer_del(tenv->xen_periodic_timer);
+ tenv->xen_periodic_timer_period = 0;
+
+ qemu_mutex_unlock(&tenv->xen_timers_lock);
+ return 0;
+}
+
+static int do_set_singleshot_timer(CPUState *cs, uint64_t timeout_abs,
+ bool future, bool linux_wa)
+{
+ CPUX86State *env = &X86_CPU(cs)->env;
+ int64_t now = kvm_get_current_ns();
+ int64_t qemu_now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
+ int64_t delta = timeout_abs - now;
+
+ if (future && timeout_abs < now) {
+ return -ETIME;
+ }
+
+ if (linux_wa && unlikely((int64_t)timeout_abs < 0 ||
+ (delta > 0 && (uint32_t)(delta >> 50) != 0))) {
+ /*
+ * Xen has a 'Linux workaround' in do_set_timer_op() which checks
+ * for negative absolute timeout values (caused by integer
+ * overflow), and for values about 13 days in the future (2^50ns)
+ * which would be caused by jiffies overflow. For those cases, it
+ * sets the timeout 100ms in the future (not *too* soon, since if
+ * a guest really did set a long timeout on purpose we don't want
+ * to keep churning CPU time by waking it up).
+ */
+ delta = (100 * SCALE_MS);
+ timeout_abs = now + delta;
+ }
+
+ qemu_mutex_lock(&env->xen_timers_lock);
+
+ timer_mod_ns(env->xen_singleshot_timer, qemu_now + delta);
+ env->xen_singleshot_timer_ns = now + delta;
+
+ qemu_mutex_unlock(&env->xen_timers_lock);
+ return 0;
+}
+
+static int vcpuop_set_singleshot_timer(CPUState *cs, uint64_t arg)
+{
+ struct vcpu_set_singleshot_timer sst;
+
+ qemu_build_assert(sizeof(sst) == 16);
+ if (kvm_copy_from_gva(cs, arg, &sst, sizeof(sst))) {
+ return -EFAULT;
+ }
+
+ return do_set_singleshot_timer(cs, sst.timeout_abs_ns,
+ !!(sst.flags & VCPU_SSHOTTMR_future),
+ false);
+}
+
+static int vcpuop_stop_singleshot_timer(CPUState *cs)
+{
+ CPUX86State *env = &X86_CPU(cs)->env;
+
+ qemu_mutex_lock(&env->xen_timers_lock);
+
+ timer_del(env->xen_singleshot_timer);
+ env->xen_singleshot_timer_ns = 0;
+
+ qemu_mutex_unlock(&env->xen_timers_lock);
+ return 0;
+}
+
+static int kvm_xen_hcall_set_timer_op(struct kvm_xen_exit *exit, X86CPU *cpu,
+ uint64_t timeout)
+{
+ if (unlikely(timeout == 0)) {
+ return vcpuop_stop_singleshot_timer(CPU(cpu));
+ } else {
+ return do_set_singleshot_timer(CPU(cpu), timeout, false, true);
+ }
+}
+
static bool kvm_xen_hcall_vcpu_op(struct kvm_xen_exit *exit, X86CPU *cpu,
int cmd, int vcpu_id, uint64_t arg)
{
- CPUState *dest = qemu_get_cpu(vcpu_id);
CPUState *cs = CPU(cpu);
+ CPUState *dest = cs->cpu_index == vcpu_id ? cs : qemu_get_cpu(vcpu_id);
int err;
+ if (!dest) {
+ return -ENOENT;
+ }
+
switch (cmd) {
case VCPUOP_register_runstate_memory_area:
err = vcpuop_register_runstate_info(cs, dest, arg);
@@ -885,6 +1085,26 @@ static bool kvm_xen_hcall_vcpu_op(struct kvm_xen_exit
*exit, X86CPU *cpu,
case VCPUOP_register_vcpu_info:
err = vcpuop_register_vcpu_info(cs, dest, arg);
break;
+ case VCPUOP_set_singleshot_timer: {
+ if (cs->cpu_index != vcpu_id) {
+ return -EINVAL;
+ }
+ err = vcpuop_set_singleshot_timer(dest, arg);
+ break;
+ }
+ case VCPUOP_stop_singleshot_timer:
+ if (cs->cpu_index != vcpu_id) {
+ return -EINVAL;
+ }
+ err = vcpuop_stop_singleshot_timer(dest);
+ break;
+ case VCPUOP_set_periodic_timer: {
+ err = vcpuop_set_periodic_timer(cs, dest, arg);
+ break;
+ }
+ case VCPUOP_stop_periodic_timer:
+ err = vcpuop_stop_periodic_timer(dest);
+ break;
default:
return false;
@@ -1239,6 +1459,9 @@ static bool do_kvm_xen_handle_exit(X86CPU *cpu, struct
kvm_xen_exit *exit)
}
switch (code) {
+ case __HYPERVISOR_set_timer_op:
+ return kvm_xen_hcall_set_timer_op(exit, cpu,
+ exit->u.hcall.params[0]);
case __HYPERVISOR_grant_table_op:
return kvm_xen_hcall_gnttab_op(exit, cpu, exit->u.hcall.params[0],
exit->u.hcall.params[1],
@@ -1348,7 +1571,25 @@ int kvm_put_xen_state(CPUState *cs)
}
}
+ if (env->xen_periodic_timer_period) {
+ ret = do_set_periodic_timer(cs, env->xen_periodic_timer_period);
+ if (ret < 0) {
+ return ret;
+ }
+ }
+
if (!kvm_xen_has_cap(EVTCHN_SEND)) {
+ /*
+ * If the kernel has EVTCHN_SEND support then it handles timers too,
+ * so the timer will be restored by kvm_xen_set_vcpu_timer() below.
+ */
+ if (env->xen_singleshot_timer_ns) {
+ ret = do_set_singleshot_timer(cs, env->xen_singleshot_timer_ns,
+ false, false);
+ if (ret < 0) {
+ return ret;
+ }
+ }
return 0;
}
diff --git a/target/i386/machine.c b/target/i386/machine.c
index 603a1077e3..c7ac8084b2 100644
--- a/target/i386/machine.c
+++ b/target/i386/machine.c
@@ -1277,6 +1277,7 @@ static const VMStateDescription vmstate_xen_vcpu = {
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_UINT64(env.xen_periodic_timer_period, X86CPU),
VMSTATE_END_OF_LIST()
}
};
--
2.39.0
