| Message ID | 20230116215805.1123514-27-dwmw2@infradead.org |
|---|---|
| State | New |
| Headers | show |
| Series | Xen support under KVM | expand |
On 16/01/2023 21:57, David Woodhouse wrote: > From: David Woodhouse <dwmw@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 <dwmw@amazon.co.uk> > --- > hw/i386/kvm/meson.build | 5 +- > hw/i386/kvm/xen_evtchn.c | 148 ++++++++++++++++++++++++++++++++++++++ > hw/i386/kvm/xen_evtchn.h | 18 +++++ > hw/i386/pc.c | 2 + > target/i386/kvm/xen-emu.c | 10 +++ > 5 files changed, 182 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..018f4ef4da > --- /dev/null > +++ b/hw/i386/kvm/xen_evtchn.c > @@ -0,0 +1,148 @@ > +/* > + * QEMU Xen emulation: Event channel support > + * > + * Copyright © 2022 Amazon.com, Inc. or its affiliates. All Rights Reserved. > + * > + * Authors: David Woodhouse <dwmw2@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; > + 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: { > + 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 && kvm_xen_has_cap(EVTCHN_SEND)) { > + in_kernel = true; > + } > + break; > + } > + default: > + ret = -ENOSYS; > + break; > + } > + > + if (!ret) { > + 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 <dwmw2@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 0ddae2f6ad..8f668a5138 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 3e05ef836d..b0e7620b16 100644 > --- a/target/i386/kvm/xen-emu.c > +++ b/target/i386/kvm/xen-emu.c > @@ -21,6 +21,7 @@ > #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" > @@ -507,6 +508,10 @@ 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; > } > @@ -712,6 +717,11 @@ static int kvm_xen_soft_reset(void) > CPUState *cpu; > int err; > > + err = xen_evtchn_set_callback_param(0); Doesn't this always result in -ENOSYS? > + if (err) { > + return err; > + } > + > CPU_FOREACH(cpu) { > async_run_on_cpu(cpu, do_vcpu_soft_reset, RUN_ON_CPU_NULL); > }
On Tue, 2023-01-17 at 10:00 +0000, Paul Durrant wrote: > > > @@ -712,6 +717,11 @@ static int kvm_xen_soft_reset(void) > > CPUState *cpu; > > int err; > > > > + err = xen_evtchn_set_callback_param(0); > > Doesn't this always result in -ENOSYS? Hm? Even at this point in the series, HVM_PARAM_CALLBACK_TYPE_VECTOR works and doesn't result in -ENOSYS. But even if xen_evtchn_set_callback_param() *was* a stub that just returned -ENOSYS at this point, that would be OK, surely? We add the (other) HVM_PARAM_CALLBACK_TYPE_* support later, which warrants separate review because of the GSI and iothread lock fun.
On 17/01/2023 10:23, David Woodhouse wrote: > On Tue, 2023-01-17 at 10:00 +0000, Paul Durrant wrote: >> >>> @@ -712,6 +717,11 @@ static int kvm_xen_soft_reset(void) >>> CPUState *cpu; >>> int err; >>> >>> + err = xen_evtchn_set_callback_param(0); >> >> Doesn't this always result in -ENOSYS? > > Hm? > > Even at this point in the series, HVM_PARAM_CALLBACK_TYPE_VECTOR works > and doesn't result in -ENOSYS. > > But even if xen_evtchn_set_callback_param() *was* a stub that just > returned -ENOSYS at this point, that would be OK, surely? We add the > (other) HVM_PARAM_CALLBACK_TYPE_* support later, which warrants > separate review because of the GSI and iothread lock fun. I'm just having a hard time seeing why passing 0 to xen_evtchn_set_callback_param() does anything useful... + switch (param >> CALLBACK_VIA_TYPE_SHIFT) { + case HVM_PARAM_CALLBACK_TYPE_VECTOR: { + struct kvm_xen_hvm_attr xa = { + .type = KVM_XEN_ATTR_TYPE_UPCALL_VECTOR, + .u.vector = (uint8_t)param, + }; HVM_PARAM_CALLBACK_TYPE_VECTOR is 2 AFAICT, so it won't hit that case. Also, you appear to be passing the unshifted param to kernel anyway. What is the call trying to achieve? Paul
On Tue, 2023-01-17 at 10:56 +0000, Paul Durrant wrote: > > I'm just having a hard time seeing why passing 0 to > xen_evtchn_set_callback_param() does anything useful... > > + switch (param >> CALLBACK_VIA_TYPE_SHIFT) { > + case HVM_PARAM_CALLBACK_TYPE_VECTOR: { > + struct kvm_xen_hvm_attr xa = { > + .type = KVM_XEN_ATTR_TYPE_UPCALL_VECTOR, > + .u.vector = (uint8_t)param, > + }; > > HVM_PARAM_CALLBACK_TYPE_VECTOR is 2 AFAICT, so it won't hit that case. > Also, you appear to be passing the unshifted param to kernel anyway. > > What is the call trying to achieve? Zero is HVM_PARAM_CALLBACK_TYPE_GSI, with GSI==0. It's basically disabling event channel delivery for the new kernel.
On 17/01/2023 11:02, David Woodhouse wrote: > On Tue, 2023-01-17 at 10:56 +0000, Paul Durrant wrote: >> >> I'm just having a hard time seeing why passing 0 to >> xen_evtchn_set_callback_param() does anything useful... >> >> + switch (param >> CALLBACK_VIA_TYPE_SHIFT) { >> + case HVM_PARAM_CALLBACK_TYPE_VECTOR: { >> + struct kvm_xen_hvm_attr xa = { >> + .type = KVM_XEN_ATTR_TYPE_UPCALL_VECTOR, >> + .u.vector = (uint8_t)param, >> + }; >> >> HVM_PARAM_CALLBACK_TYPE_VECTOR is 2 AFAICT, so it won't hit that case. >> Also, you appear to be passing the unshifted param to kernel anyway. >> >> What is the call trying to achieve? > > Zero is HVM_PARAM_CALLBACK_TYPE_GSI, with GSI==0. It's basically > disabling event channel delivery for the new kernel. > AFAICT it is doing nothing at this point. Unless I am going insane it results in this codepath: + default: + ret = -ENOSYS; + break; + } + + if (!ret) { + s->callback_param = param; + s->evtchn_in_kernel = in_kernel; + } So it doesn't result in any cleanup. What am I missing? Paul
On Tue, 2023-01-17 at 11:06 +0000, Paul Durrant wrote: > On 17/01/2023 11:02, David Woodhouse wrote: > > On Tue, 2023-01-17 at 10:56 +0000, Paul Durrant wrote: > > > > > > I'm just having a hard time seeing why passing 0 to > > > xen_evtchn_set_callback_param() does anything useful... > > > > > > + switch (param >> CALLBACK_VIA_TYPE_SHIFT) { > > > + case HVM_PARAM_CALLBACK_TYPE_VECTOR: { > > > + struct kvm_xen_hvm_attr xa = { > > > + .type = KVM_XEN_ATTR_TYPE_UPCALL_VECTOR, > > > + .u.vector = (uint8_t)param, > > > + }; > > > > > > HVM_PARAM_CALLBACK_TYPE_VECTOR is 2 AFAICT, so it won't hit that > > > case. > > > Also, you appear to be passing the unshifted param to kernel > > > anyway. > > > > > > What is the call trying to achieve? > > > > Zero is HVM_PARAM_CALLBACK_TYPE_GSI, with GSI==0. It's basically > > disabling event channel delivery for the new kernel. > > > > AFAICT it is doing nothing at this point. Unless I am going insane it > results in this codepath: > > + default: > + ret = -ENOSYS; > + break; > + } > + > + if (!ret) { > + s->callback_param = param; > + s->evtchn_in_kernel = in_kernel; > + } > > So it doesn't result in any cleanup. What am I missing? Indeed, it doesn't result in any cleanup at *this* point in the series because HVM_PARAM_CALLBACK_TYPE_GSI hasn't been implemented yet; it's in a later patch. The series is broken up into sensible individual patches for review, not so people can actually *run* with some partial subset of them. Otherwise I'd have to implement vmstate migration versioning for every change in the series, and that way lies madness :) I *will* add a comment in the code explaining what zero means though, and note in the commit message that it doesn't actually have any effect will, but will do in a few patches' time.
On 17/01/2023 11:24, David Woodhouse wrote: > On Tue, 2023-01-17 at 11:06 +0000, Paul Durrant wrote: >> On 17/01/2023 11:02, David Woodhouse wrote: >>> On Tue, 2023-01-17 at 10:56 +0000, Paul Durrant wrote: >>>> >>>> I'm just having a hard time seeing why passing 0 to >>>> xen_evtchn_set_callback_param() does anything useful... >>>> >>>> + switch (param >> CALLBACK_VIA_TYPE_SHIFT) { >>>> + case HVM_PARAM_CALLBACK_TYPE_VECTOR: { >>>> + struct kvm_xen_hvm_attr xa = { >>>> + .type = KVM_XEN_ATTR_TYPE_UPCALL_VECTOR, >>>> + .u.vector = (uint8_t)param, >>>> + }; >>>> >>>> HVM_PARAM_CALLBACK_TYPE_VECTOR is 2 AFAICT, so it won't hit that >>>> case. >>>> Also, you appear to be passing the unshifted param to kernel >>>> anyway. >>>> >>>> What is the call trying to achieve? >>> >>> Zero is HVM_PARAM_CALLBACK_TYPE_GSI, with GSI==0. It's basically >>> disabling event channel delivery for the new kernel. >>> >> >> AFAICT it is doing nothing at this point. Unless I am going insane it >> results in this codepath: >> >> + default: >> + ret = -ENOSYS; >> + break; >> + } >> + >> + if (!ret) { >> + s->callback_param = param; >> + s->evtchn_in_kernel = in_kernel; >> + } >> >> So it doesn't result in any cleanup. What am I missing? > > Indeed, it doesn't result in any cleanup at *this* point in the series > because HVM_PARAM_CALLBACK_TYPE_GSI hasn't been implemented yet; it's > in a later patch. > > The series is broken up into sensible individual patches for review, > not so people can actually *run* with some partial subset of them. > That's fine. It's just confusing for a reviewer to know whether you are intentionally introducing code that has no effect, or whether that is a bug. > Otherwise I'd have to implement vmstate migration versioning for every > change in the series, and that way lies madness :) > > I *will* add a comment in the code explaining what zero means though, > and note in the commit message that it doesn't actually have any effect > will, but will do in a few patches' time. That would certainly help, thanks.
On Tue, 2023-01-17 at 11:53 +0000, Paul Durrant wrote: > On 17/01/2023 11:24, David Woodhouse wrote: > > On Tue, 2023-01-17 at 11:06 +0000, Paul Durrant wrote: > > > On 17/01/2023 11:02, David Woodhouse wrote: > > > > On Tue, 2023-01-17 at 10:56 +0000, Paul Durrant wrote: > > > > > > > > > > I'm just having a hard time seeing why passing 0 to > > > > > xen_evtchn_set_callback_param() does anything useful... > > > > > > > > > > + switch (param >> CALLBACK_VIA_TYPE_SHIFT) { > > > > > + case HVM_PARAM_CALLBACK_TYPE_VECTOR: { > > > > > + struct kvm_xen_hvm_attr xa = { > > > > > + .type = KVM_XEN_ATTR_TYPE_UPCALL_VECTOR, > > > > > + .u.vector = (uint8_t)param, > > > > > + }; > > > > > > > > > > HVM_PARAM_CALLBACK_TYPE_VECTOR is 2 AFAICT, so it won't hit that > > > > > case. > > > > > Also, you appear to be passing the unshifted param to kernel > > > > > anyway. > > > > > > > > > > What is the call trying to achieve? > > > > > > > > Zero is HVM_PARAM_CALLBACK_TYPE_GSI, with GSI==0. It's basically > > > > disabling event channel delivery for the new kernel. > > > > > > > > > > AFAICT it is doing nothing at this point. Unless I am going insane it > > > results in this codepath: > > > > > > + default: > > > + ret = -ENOSYS; > > > + break; > > > + } > > > + > > > + if (!ret) { > > > + s->callback_param = param; > > > + s->evtchn_in_kernel = in_kernel; > > > + } > > > > > > So it doesn't result in any cleanup. What am I missing? > > > > Indeed, it doesn't result in any cleanup at *this* point in the series > > because HVM_PARAM_CALLBACK_TYPE_GSI hasn't been implemented yet; it's > > in a later patch. > > > > The series is broken up into sensible individual patches for review, > > not so people can actually *run* with some partial subset of them. > > > > That's fine. It's just confusing for a reviewer to know whether you are > intentionally introducing code that has no effect, or whether that is a bug. Actually... it *is* a bug. Even when GSI support is added later, nothing ever tells the kernel to *stop* delivering via the upcall vector. I'll fix. Thanks for drawing attention to it.
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..018f4ef4da --- /dev/null +++ b/hw/i386/kvm/xen_evtchn.c @@ -0,0 +1,148 @@ +/* + * QEMU Xen emulation: Event channel support + * + * Copyright © 2022 Amazon.com, Inc. or its affiliates. All Rights Reserved. + * + * Authors: David Woodhouse <dwmw2@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; + 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: { + 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 && kvm_xen_has_cap(EVTCHN_SEND)) { + in_kernel = true; + } + break; + } + default: + ret = -ENOSYS; + break; + } + + if (!ret) { + 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 <dwmw2@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 0ddae2f6ad..8f668a5138 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 3e05ef836d..b0e7620b16 100644 --- a/target/i386/kvm/xen-emu.c +++ b/target/i386/kvm/xen-emu.c @@ -21,6 +21,7 @@ #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" @@ -507,6 +508,10 @@ 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; } @@ -712,6 +717,11 @@ static int kvm_xen_soft_reset(void) CPUState *cpu; int err; + 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); }