On 09/12/2022 09:56, David Woodhouse wrote:
From: Ankur Arora <ankur.a.ar...@oracle.com>
The HVM_PARAM_CALLBACK_IRQ parameter controls the system-wide event
channel upcall method. The vector support is handled by KVM internally,
when the evtchn_upcall_pending field in the vcpu_info is set.
The GSI and PCI_INTX delivery methods are not supported. yet; those
need to simulate a level-triggered event on the I/OAPIC.
That's gonna be somewhat limiting if anyone runs a Windows guest with
upcall vector support turned off... which is an option at:
https://xenbits.xen.org/gitweb/?p=pvdrivers/win/xenbus.git;a=blob;f=src/xenbus/evtchn.c;;hb=HEAD#l1928
Add a 'xen_evtchn' device to host the migration state, as we'll shortly
be adding a full event channel table there too.
Signed-off-by: Ankur Arora <ankur.a.ar...@oracle.com>
Signed-off-by: Joao Martins <joao.m.mart...@oracle.com>
[dwmw2: Rework for upstream kernel changes, split from per-VCPU vector]
Signed-off-by: David Woodhouse <d...@amazon.co.uk>
---
hw/i386/kvm/meson.build | 5 +-
hw/i386/kvm/xen_evtchn.c | 117 +++++++++++++++++++++++++++++++++++++++
hw/i386/kvm/xen_evtchn.h | 13 +++++
hw/i386/pc_piix.c | 2 +
target/i386/xen.c | 44 +++++++++++++--
5 files changed, 174 insertions(+), 7 deletions(-)
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..1ca0c034e7
--- /dev/null
+++ b/hw/i386/kvm/xen_evtchn.c
@@ -0,0 +1,117 @@
+/*
+ * QEMU Xen emulation: Shared/overlay pages 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 <linux/kvm.h>
+
+#include "standard-headers/xen/memory.h"
+#include "standard-headers/xen/hvm/params.h"
+
+#define TYPE_XEN_EVTCHN "xenevtchn"
+OBJECT_DECLARE_SIMPLE_TYPE(XenEvtchnState, XEN_EVTCHN)
+
+struct XenEvtchnState {
+ /*< private >*/
+ SysBusDevice busdev;
+ /*< public >*/
+
+ uint64_t callback_param;
+};
+
+struct XenEvtchnState *xen_evtchn_singleton;
+
+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)
+{
+ xen_evtchn_singleton = XEN_EVTCHN(sysbus_create_simple(TYPE_XEN_EVTCHN,
-1, NULL));
+}
+
+static void xen_evtchn_register_types(void)
+{
+ type_register_static(&xen_evtchn_info);
+}
+
+type_init(xen_evtchn_register_types)
+
+
+#define CALLBACK_VIA_TYPE_SHIFT 56
+
+int xen_evtchn_set_callback_param(uint64_t param)
+{
+ int ret = -ENOSYS;
+
+ if (param >> CALLBACK_VIA_TYPE_SHIFT == HVM_PARAM_CALLBACK_TYPE_VECTOR) {
+ struct kvm_xen_hvm_attr xa = {
+ .type = KVM_XEN_ATTR_TYPE_UPCALL_VECTOR,
+ .u.vector = (uint8_t)param,
+ };
+
+ ret = kvm_vm_ioctl(kvm_state, KVM_XEN_HVM_SET_ATTR, &xa);
+ if (!ret && xen_evtchn_singleton)
+ xen_evtchn_singleton->callback_param = param;
+ }
+ return ret;
+}
diff --git a/hw/i386/kvm/xen_evtchn.h b/hw/i386/kvm/xen_evtchn.h
new file mode 100644
index 0000000000..11c6ed22a0
--- /dev/null
+++ b/hw/i386/kvm/xen_evtchn.h
@@ -0,0 +1,13 @@
+/*
+ * 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.
+ */
+
+void xen_evtchn_create(void);
+int xen_evtchn_set_callback_param(uint64_t param);
diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index c3c61eedde..18540084a0 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -60,6 +60,7 @@
#endif
#ifdef CONFIG_XEN_EMU
#include "hw/i386/kvm/xen_overlay.h"
+#include "hw/i386/kvm/xen_evtchn.h"
#endif
#include "migration/global_state.h"
#include "migration/misc.h"
@@ -417,6 +418,7 @@ static void pc_xen_hvm_init(MachineState *machine)
#ifdef CONFIG_XEN_EMU
if (xen_mode == XEN_EMULATE) {
xen_overlay_create();
+ xen_evtchn_create();
}
#endif
}
diff --git a/target/i386/xen.c b/target/i386/xen.c
index 2583c00a6b..1af336d9e5 100644
--- a/target/i386/xen.c
+++ b/target/i386/xen.c
@@ -16,6 +16,8 @@
#include "xen.h"
#include "trace.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/memory.h"
#include "standard-headers/xen/hvm/hvm_op.h"
@@ -287,24 +289,53 @@ static bool kvm_xen_hcall_memory_op(struct kvm_xen_exit
*exit,
return true;
}
+static int handle_set_param(struct kvm_xen_exit *exit, X86CPU *cpu,
+ uint64_t arg)
+{
+ CPUState *cs = CPU(cpu);
+ struct xen_hvm_param hp;
+ int err = 0;
+
+ if (kvm_copy_from_gva(cs, arg, &hp, sizeof(hp))) {
+ err = -EFAULT;
+ goto out;
+ }
+
+ if (hp.domid != DOMID_SELF) {
Xen actually allows the domain's own id to be specified as well as the
magic DOMID_SELF.
+ err = -EINVAL;
And this should be -ESRCH.
+ goto out;
+ }
+
+ switch (hp.index) {
+ case HVM_PARAM_CALLBACK_IRQ:
+ err = xen_evtchn_set_callback_param(hp.value);
+ break;
+ default:
+ return false;
+ }
+
+out:
+ exit->u.hcall.result = err;
This is a bit on the ugly side isn't it? Why not return the err and have
kvm_xen_hcall_hvm_op() deal with passing it back?
+ return true;
+}
+
static int kvm_xen_hcall_evtchn_upcall_vector(struct kvm_xen_exit *exit,
X86CPU *cpu, uint64_t arg)
{
- struct xen_hvm_evtchn_upcall_vector *up;
+ struct xen_hvm_evtchn_upcall_vector up;
CPUState *target_cs;
int vector;
- up = gva_to_hva(CPU(cpu), arg);
- if (!up) {
+ if (kvm_copy_from_gva(CPU(cpu), arg, &up, sizeof(up))) {
return -EFAULT;
}
- vector = up->vector;
+ vector = up.vector;
if (vector < 0x10) {
return -EINVAL;
}
- target_cs = qemu_get_cpu(up->vcpu);
+ target_cs = qemu_get_cpu(up.vcpu);
if (!target_cs) {
return -EINVAL;
}
These changes to kvm_xen_hcall_evtchn_upcall_vector() seem to have
nothing to do with the rest of the patch. Am I missing something?
Paul
@@ -325,7 +356,8 @@ static bool kvm_xen_hcall_hvm_op(struct kvm_xen_exit *exit,
X86CPU *cpu,
case HVMOP_pagetable_dying:
ret = -ENOSYS;
break;
-
+ case HVMOP_set_param:
+ return handle_set_param(exit, cpu, arg);
default:
return false;
}
