From: David Woodhouse <d...@amazon.co.uk>
Include basic support for setting HVM_PARAM_CALLBACK_IRQ to the global
vector method HVM_PARAM_CALLBACK_TYPE_VECTOR, which is handled in-kernel
by raising the vector whenever the vCPU's vcpu_info->evtchn_upcall_pending
flag is set.
Signed-off-by: David Woodhouse <d...@amazon.co.uk>
---
hw/i386/kvm/meson.build | 5 +-
hw/i386/kvm/xen_evtchn.c | 155 ++++++++++++++++++++++++++++++++++++++
hw/i386/kvm/xen_evtchn.h | 18 +++++
hw/i386/pc.c | 2 +
target/i386/kvm/xen-emu.c | 15 ++++
5 files changed, 194 insertions(+), 1 deletion(-)
create mode 100644 hw/i386/kvm/xen_evtchn.c
create mode 100644 hw/i386/kvm/xen_evtchn.h
diff --git a/hw/i386/kvm/meson.build b/hw/i386/kvm/meson.build
index 6165cbf019..cab64df339 100644
--- a/hw/i386/kvm/meson.build
+++ b/hw/i386/kvm/meson.build
@@ -4,6 +4,9 @@ i386_kvm_ss.add(when: 'CONFIG_APIC', if_true: files('apic.c'))
i386_kvm_ss.add(when: 'CONFIG_I8254', if_true: files('i8254.c'))
i386_kvm_ss.add(when: 'CONFIG_I8259', if_true: files('i8259.c'))
i386_kvm_ss.add(when: 'CONFIG_IOAPIC', if_true: files('ioapic.c'))
-i386_kvm_ss.add(when: 'CONFIG_XEN_EMU', if_true: files('xen_overlay.c'))
+i386_kvm_ss.add(when: 'CONFIG_XEN_EMU', if_true: files(
+ 'xen_overlay.c',
+ 'xen_evtchn.c',
+ ))
i386_ss.add_all(when: 'CONFIG_KVM', if_true: i386_kvm_ss)
diff --git a/hw/i386/kvm/xen_evtchn.c b/hw/i386/kvm/xen_evtchn.c
new file mode 100644
index 0000000000..99d9d84716
--- /dev/null
+++ b/hw/i386/kvm/xen_evtchn.c
@@ -0,0 +1,155 @@
+/*
+ * QEMU Xen emulation: Event channel support
+ *
+ * Copyright © 2022 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Authors: David Woodhouse <dw...@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/main-loop.h"
+#include "qapi/error.h"
+#include "qom/object.h"
+#include "exec/target_page.h"
+#include "exec/address-spaces.h"
+#include "migration/vmstate.h"
+
+#include "hw/sysbus.h"
+#include "hw/xen/xen.h"
+#include "xen_evtchn.h"
+
+#include "sysemu/kvm.h"
+#include "sysemu/kvm_xen.h"
+#include <linux/kvm.h>
+
+#include "standard-headers/xen/memory.h"
+#include "standard-headers/xen/hvm/params.h"
+
+#define TYPE_XEN_EVTCHN "xen-evtchn"
+OBJECT_DECLARE_SIMPLE_TYPE(XenEvtchnState, XEN_EVTCHN)
+
+struct XenEvtchnState {
+ /*< private >*/
+ SysBusDevice busdev;
+ /*< public >*/
+
+ uint64_t callback_param;
+ bool evtchn_in_kernel;
+
+ QemuMutex port_lock;
+};
+
+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 int xen_evtchn_post_load(void *opaque, int version_id)
+{
+ XenEvtchnState *s = opaque;
+
+ if (s->callback_param) {
+ xen_evtchn_set_callback_param(s->callback_param);
+ }
+
+ return 0;
+}
+
+static bool xen_evtchn_is_needed(void *opaque)
+{
+ return xen_mode == XEN_EMULATE;
+}
+
+static const VMStateDescription xen_evtchn_vmstate = {
+ .name = "xen_evtchn",
+ .version_id = 1,
+ .minimum_version_id = 1,
+ .needed = xen_evtchn_is_needed,
+ .post_load = xen_evtchn_post_load,
+ .fields = (VMStateField[]) {
+ VMSTATE_UINT64(callback_param, 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,
+};
+
+void xen_evtchn_create(void)
+{
+ XenEvtchnState *s = XEN_EVTCHN(sysbus_create_simple(TYPE_XEN_EVTCHN,
+ -1, NULL));
+ xen_evtchn_singleton = s;
+
+ qemu_mutex_init(&s->port_lock);
+}
+
+static void xen_evtchn_register_types(void)
+{
+ type_register_static(&xen_evtchn_info);
+}
+
+type_init(xen_evtchn_register_types)
+
+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;
+ int ret;
+
+ if (!s) {
+ return -ENOTSUP;
+ }
+
+ qemu_mutex_lock(&s->port_lock);
+
+ switch (param >> CALLBACK_VIA_TYPE_SHIFT) {
+ 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;
+ }
+ 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;
+ }
+
+ qemu_mutex_unlock(&s->port_lock);
+
+ return ret;
+}
diff --git a/hw/i386/kvm/xen_evtchn.h b/hw/i386/kvm/xen_evtchn.h
new file mode 100644
index 0000000000..c9b7f9d11f
--- /dev/null
+++ b/hw/i386/kvm/xen_evtchn.h
@@ -0,0 +1,18 @@
+/*
+ * QEMU Xen emulation: Event channel support
+ *
+ * Copyright © 2022 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Authors: David Woodhouse <dw...@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.
+ */
+
+#ifndef QEMU_XEN_EVTCHN_H
+#define QEMU_XEN_EVTCHN_H
+
+void xen_evtchn_create(void);
+int xen_evtchn_set_callback_param(uint64_t param);
+
+#endif /* QEMU_XEN_EVTCHN_H */
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 9169305f4f..3ea123b5bd 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -90,6 +90,7 @@
#include "hw/virtio/virtio-pmem-pci.h"
#include "hw/virtio/virtio-mem-pci.h"
#include "hw/i386/kvm/xen_overlay.h"
+#include "hw/i386/kvm/xen_evtchn.h"
#include "hw/mem/memory-device.h"
#include "sysemu/replay.h"
#include "target/i386/cpu.h"
@@ -1850,6 +1851,7 @@ int pc_machine_kvm_type(MachineState *machine, const char
*kvm_type)
#ifdef CONFIG_XEN_EMU
if (xen_mode == XEN_EMULATE) {
xen_overlay_create();
+ xen_evtchn_create();
}
#endif
return 0;
diff --git a/target/i386/kvm/xen-emu.c b/target/i386/kvm/xen-emu.c
index eba6e21a6c..25a0b6f1b0 100644
--- a/target/i386/kvm/xen-emu.c
+++ b/target/i386/kvm/xen-emu.c
@@ -22,6 +22,7 @@
#include "sysemu/runstate.h"
#include "hw/i386/kvm/xen_overlay.h"
+#include "hw/i386/kvm/xen_evtchn.h"
#include "standard-headers/xen/version.h"
#include "standard-headers/xen/sched.h"
@@ -510,6 +511,10 @@ static bool handle_set_param(struct kvm_xen_exit *exit,
X86CPU *cpu,
}
switch (hp.index) {
+ case HVM_PARAM_CALLBACK_IRQ:
+ err = xen_evtchn_set_callback_param(hp.value);
+ xen_set_long_mode(exit->u.hcall.longmode);
+ break;
default:
return false;
}
@@ -719,6 +724,16 @@ int kvm_xen_soft_reset(void)
trace_kvm_xen_soft_reset();
+ /*
+ * Zero is the reset/startup state for HVM_PARAM_CALLBACK_IRQ. Strictly,
+ * it maps to HVM_PARAM_CALLBACK_TYPE_GSI with GSI#0, but Xen refuses to
+ * to deliver to the timer interrupt and treats that as 'disabled'.
+ */
+ err = xen_evtchn_set_callback_param(0);
+ if (err) {
+ return err;
+ }
+
CPU_FOREACH(cpu) {
async_run_on_cpu(cpu, do_vcpu_soft_reset, RUN_ON_CPU_NULL);
}
--
2.39.0
