From: David Woodhouse <d...@amazon.co.uk>
This finally comes with a mechanism for actually injecting events into
the guest vCPU, with all the atomic-test-and-set that's involved in
setting the bit in the shinfo, then the index in the vcpu_info, and
injecting either the lapic vector as MSI, or letting KVM inject the
bare vector.
Signed-off-by: David Woodhouse <d...@amazon.co.uk>
Reviewed-by: Paul Durrant <p...@xen.org>
---
hw/i386/kvm/xen_evtchn.c | 175 ++++++++++++++++++++++++++++++++++++++
hw/i386/kvm/xen_evtchn.h | 2 +
target/i386/kvm/xen-emu.c | 12 +++
3 files changed, 189 insertions(+)
diff --git a/hw/i386/kvm/xen_evtchn.c b/hw/i386/kvm/xen_evtchn.c
index 08c6fac357..deea7de027 100644
--- a/hw/i386/kvm/xen_evtchn.c
+++ b/hw/i386/kvm/xen_evtchn.c
@@ -224,6 +224,13 @@ int xen_evtchn_set_callback_param(uint64_t param)
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 bool valid_port(evtchn_port_t port)
{
if (!port) {
@@ -294,6 +301,152 @@ int xen_evtchn_status_op(struct evtchn_status *status)
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 clear_port_pending(XenEvtchnState *s, evtchn_port_t port)
{
void *p = xen_overlay_get_shinfo_ptr();
@@ -378,3 +531,25 @@ int xen_evtchn_close_op(struct evtchn_close *close)
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;
+}
diff --git a/hw/i386/kvm/xen_evtchn.h b/hw/i386/kvm/xen_evtchn.h
index cb3924941a..69c6b0d743 100644
--- a/hw/i386/kvm/xen_evtchn.h
+++ b/hw/i386/kvm/xen_evtchn.h
@@ -17,7 +17,9 @@ int xen_evtchn_set_callback_param(uint64_t param);
struct evtchn_status;
struct evtchn_close;
+struct evtchn_unmask;
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);
#endif /* QEMU_XEN_EVTCHN_H */
diff --git a/target/i386/kvm/xen-emu.c b/target/i386/kvm/xen-emu.c
index c54372700a..418028b04f 100644
--- a/target/i386/kvm/xen-emu.c
+++ b/target/i386/kvm/xen-emu.c
@@ -814,6 +814,18 @@ static bool kvm_xen_hcall_evtchn_op(struct kvm_xen_exit
*exit, X86CPU *cpu,
err = xen_evtchn_close_op(&close);
break;
}
+ case EVTCHNOP_unmask: {
+ struct evtchn_unmask unmask;
+
+ qemu_build_assert(sizeof(unmask) == 4);
+ if (kvm_copy_from_gva(cs, arg, &unmask, sizeof(unmask))) {
+ err = -EFAULT;
+ break;
+ }
+
+ err = xen_evtchn_unmask_op(&unmask);
+ break;
+ }
default:
return false;
}
--
2.39.0
