| Message ID | 1434386038-9246-7-git-send-email-eric.auger@linaro.org |
|---|---|
| State | New |
| Headers | show |
On 15 June 2015 at 17:33, Eric Auger <eric.auger@linaro.org> wrote: > This patch aims at optimizing IRQ handling using irqfd framework. > > Instead of handling the eventfds on user-side they are handled on > kernel side using > - the KVM irqfd framework, > - the VFIO driver virqfd framework. > > the virtual IRQ completion is trapped at interrupt controller > This removes the need for fast/slow path swap. > > Overall this brings significant performance improvements. > > Signed-off-by: Alvise Rigo <a.rigo@virtualopensystems.com> > Signed-off-by: Eric Auger <eric.auger@linaro.org> > Reviewed-by: Alex Bennée <alex.bennee@linaro.org> > Tested-by: Vikram Sethi <vikrams@codeaurora.org> > > --- > v15 -> v16: > - add Vikram's T-b > > v13 -> v14: > - use connect_irq_notifier > - remove trace_vfio_platform_start_eventfd > > v12 -> v13: > - setup the new mechanism for starting irqfd, based on > LinkPropertySetter override > - use kvm_irqchip_[add,remove]_irqfd_notifier new functions: no need > to bother about gsi (hence virtualID could be removed with small > change in trace-events) > > v10 -> v11: > - Add Alex' Reviewed-by > - introduce kvm_accel in this patch and initialize it > > v5 -> v6 > - rely on kvm_irqfds_enabled() and kvm_resamplefds_enabled() > - guard KVM code with #ifdef CONFIG_KVM > > v3 -> v4: > [Alvise Rigo] > Use of VFIO Platform driver v6 unmask/virqfd feature and removal > of resamplefd handler. Physical IRQ unmasking is now done in > VFIO driver. > > v3: > [Eric Auger] > initial support with resamplefd handled on QEMU side since the > unmask was not supported on VFIO platform driver v5. > --- > hw/vfio/platform.c | 107 ++++++++++++++++++++++++++++++++++++++++ > include/hw/vfio/vfio-platform.h | 2 + > trace-events | 1 + > 3 files changed, 110 insertions(+) > > diff --git a/hw/vfio/platform.c b/hw/vfio/platform.c > index 9382bb7..1d44085 100644 > --- a/hw/vfio/platform.c > +++ b/hw/vfio/platform.c > @@ -26,6 +26,7 @@ > #include "hw/sysbus.h" > #include "trace.h" > #include "hw/platform-bus.h" > +#include "sysemu/kvm.h" > > /* > * Functions used whatever the injection method > @@ -51,6 +52,7 @@ static VFIOINTp *vfio_init_intp(VFIODevice *vbasedev, > intp->pin = info.index; > intp->flags = info.flags; > intp->state = VFIO_IRQ_INACTIVE; > + intp->kvm_accel = false; > > sysbus_init_irq(sbdev, &intp->qemuirq); > > @@ -61,6 +63,13 @@ static VFIOINTp *vfio_init_intp(VFIODevice *vbasedev, > error_report("vfio: Error: trigger event_notifier_init failed "); > return NULL; > } > + /* Get an eventfd for resample/unmask */ > + ret = event_notifier_init(&intp->unmask, 0); > + if (ret) { > + g_free(intp); > + error_report("vfio: Error: resample event_notifier_init failed eoi"); This error message seems rather cryptic; what is it trying to tell the user? > + return NULL; > + } > > QLIST_INSERT_HEAD(&vdev->intp_list, intp, next); > return intp; > @@ -315,6 +324,95 @@ static int vfio_start_eventfd_injection(VFIOINTp *intp) > return ret; > } > > +/* > + * Functions used for irqfd > + */ > + > +#ifdef CONFIG_KVM > + > +/** > + * vfio_set_resample_eventfd - sets the resamplefd for an IRQ > + * @intp: the IRQ struct handle > + * programs the VFIO driver to unmask this IRQ when the > + * intp->unmask eventfd is triggered > + */ > +static int vfio_set_resample_eventfd(VFIOINTp *intp) > +{ > + VFIODevice *vbasedev = &intp->vdev->vbasedev; > + struct vfio_irq_set *irq_set; > + int argsz, ret; > + int32_t *pfd; > + > + argsz = sizeof(*irq_set) + sizeof(*pfd); > + irq_set = g_malloc0(argsz); > + irq_set->argsz = argsz; > + irq_set->flags = VFIO_IRQ_SET_DATA_EVENTFD | VFIO_IRQ_SET_ACTION_UNMASK; > + irq_set->index = intp->pin; > + irq_set->start = 0; > + irq_set->count = 1; > + pfd = (int32_t *)&irq_set->data; > + *pfd = event_notifier_get_fd(&intp->unmask); > + qemu_set_fd_handler(*pfd, NULL, NULL, NULL); > + ret = ioctl(vbasedev->fd, VFIO_DEVICE_SET_IRQS, irq_set); > + g_free(irq_set); > + if (ret < 0) { > + error_report("vfio: Failed to set resample eventfd: %m"); > + } > + return ret; > +} > + > +static void vfio_start_irqfd_injection(SysBusDevice *sbdev, qemu_irq irq) > +{ > + VFIOPlatformDevice *vdev = VFIO_PLATFORM_DEVICE(sbdev); > + VFIOINTp *intp; > + bool found = false; > + > + QLIST_FOREACH(intp, &vdev->intp_list, next) { > + if (intp->qemuirq == irq) { > + found = true; Stray double-space. > + break; > + } > + } > + assert(found); > + > + /* Get to a known interrupt state */ > + qemu_set_fd_handler(event_notifier_get_fd(&intp->interrupt), > + NULL, NULL, vdev); > + > + vfio_mask_single_irqindex(&vdev->vbasedev, intp->pin); > + qemu_set_irq(intp->qemuirq, 0); > + > + if (kvm_irqchip_add_irqfd_notifier(kvm_state, &intp->interrupt, > + &intp->unmask, irq) < 0) { > + goto fail_irqfd; > + } > + > + if (vfio_set_trigger_eventfd(intp, NULL) < 0) { > + goto fail_vfio; > + } > + if (vfio_set_resample_eventfd(intp) < 0) { > + goto fail_vfio; > + } > + > + /* Let'em rip */ This comment could probably be phrased more informatively :-) > + vfio_unmask_single_irqindex(&vdev->vbasedev, intp->pin); > + > + intp->kvm_accel = true; > + > + trace_vfio_platform_start_irqfd_injection(intp->pin, > + event_notifier_get_fd(&intp->interrupt), > + event_notifier_get_fd(&intp->unmask)); > + return; > +fail_vfio: > + kvm_irqchip_remove_irqfd_notifier(kvm_state, &intp->interrupt, irq); > +fail_irqfd: > + vfio_start_eventfd_injection(intp); > + vfio_unmask_single_irqindex(&vdev->vbasedev, intp->pin); > + return; > +} > + > +#endif /* CONFIG_KVM */ > + > /* VFIO skeleton */ > > static void vfio_platform_compute_needs_reset(VFIODevice *vbasedev) > @@ -548,6 +646,7 @@ static void vfio_platform_realize(DeviceState *dev, Error **errp) > { > VFIOPlatformDevice *vdev = VFIO_PLATFORM_DEVICE(dev); > SysBusDevice *sbdev = SYS_BUS_DEVICE(dev); > + SysBusDeviceClass *sbc = SYS_BUS_DEVICE_GET_CLASS(dev); > VFIODevice *vbasedev = &vdev->vbasedev; > VFIOINTp *intp; > int i, ret; > @@ -555,6 +654,13 @@ static void vfio_platform_realize(DeviceState *dev, Error **errp) > vbasedev->type = VFIO_DEVICE_TYPE_PLATFORM; > vbasedev->ops = &vfio_platform_ops; > > +#ifdef CONFIG_KVM > + if (kvm_irqfds_enabled() && kvm_resamplefds_enabled() && > + vdev->irqfd_allowed) { > + sbc->connect_irq_notifier = vfio_start_irqfd_injection; > + } > +#endif You shouldn't need this CONFIG_KVM ifdef -- we deliberately provide "always false" versions of functions like kvm_irqfds_enabled() in sysemu/kvm.h so that we can avoid littering code with ifdefs. It looks like your commit f41389ae3c54b failed to provide the non-KVM version of kvm_resamplefds_enabled(), but the correct fix is to provide it... This implies removing the ifdefs earlier around vfio_start_irqfd_injection, but that should be OK -- we provide stub versions of functions like kvm_irqchip_add_irqfd_notifier() so the non-KVM code can still compile. > + > trace_vfio_platform_realize(vbasedev->name, vdev->compat); > > ret = vfio_base_device_init(vbasedev); > @@ -584,6 +690,7 @@ static Property vfio_platform_dev_properties[] = { > DEFINE_PROP_BOOL("x-mmap", VFIOPlatformDevice, vbasedev.allow_mmap, true), > DEFINE_PROP_UINT32("mmap-timeout-ms", VFIOPlatformDevice, > mmap_timeout, 1100), > + DEFINE_PROP_BOOL("x-irqfd", VFIOPlatformDevice, irqfd_allowed, true), > DEFINE_PROP_END_OF_LIST(), > }; > > diff --git a/include/hw/vfio/vfio-platform.h b/include/hw/vfio/vfio-platform.h > index 26b2ad6..c5cf1d7 100644 > --- a/include/hw/vfio/vfio-platform.h > +++ b/include/hw/vfio/vfio-platform.h > @@ -41,6 +41,7 @@ typedef struct VFIOINTp { > int state; /* inactive, pending, active */ > uint8_t pin; /* index */ > uint32_t flags; /* IRQ info flags */ > + bool kvm_accel; /* set when QEMU bypass through KVM enabled */ > } VFIOINTp; > > /* function type for user side eventfd handler */ > @@ -57,6 +58,7 @@ typedef struct VFIOPlatformDevice { > uint32_t mmap_timeout; /* delay to re-enable mmaps after interrupt */ > QEMUTimer *mmap_timer; /* allows fast-path resume after IRQ hit */ > QemuMutex intp_mutex; /* protect the intp_list IRQ state */ > + bool irqfd_allowed; /* debug option to force irqfd on/off */ > } VFIOPlatformDevice; > > typedef struct VFIOPlatformDeviceClass { > diff --git a/trace-events b/trace-events > index 6060d36..4390381 100644 > --- a/trace-events > +++ b/trace-events > @@ -1594,6 +1594,7 @@ vfio_platform_intp_interrupt(int pin, int fd) "Inject IRQ #%d (fd = %d)" > vfio_platform_intp_inject_pending_lockheld(int pin, int fd) "Inject pending IRQ #%d (fd = %d)" > vfio_platform_populate_interrupts(int pin, int count, int flags) "- IRQ index %d: count %d, flags=0x%x" > vfio_intp_interrupt_set_pending(int index) "irq %d is set PENDING" > +vfio_platform_start_irqfd_injection(int index, int fd, int resamplefd) "IRQ index=%d, fd = %d, resamplefd = %d" > > #hw/acpi/memory_hotplug.c > mhp_acpi_invalid_slot_selected(uint32_t slot) "0x%"PRIx32 > -- > 1.8.3.2 > thanks -- PMM
On 06/26/2015 01:57 PM, Peter Maydell wrote: > On 15 June 2015 at 17:33, Eric Auger <eric.auger@linaro.org> wrote: >> This patch aims at optimizing IRQ handling using irqfd framework. >> >> Instead of handling the eventfds on user-side they are handled on >> kernel side using >> - the KVM irqfd framework, >> - the VFIO driver virqfd framework. >> >> the virtual IRQ completion is trapped at interrupt controller >> This removes the need for fast/slow path swap. >> >> Overall this brings significant performance improvements. >> >> Signed-off-by: Alvise Rigo <a.rigo@virtualopensystems.com> >> Signed-off-by: Eric Auger <eric.auger@linaro.org> >> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> >> Tested-by: Vikram Sethi <vikrams@codeaurora.org> >> >> --- >> v15 -> v16: >> - add Vikram's T-b >> >> v13 -> v14: >> - use connect_irq_notifier >> - remove trace_vfio_platform_start_eventfd >> >> v12 -> v13: >> - setup the new mechanism for starting irqfd, based on >> LinkPropertySetter override >> - use kvm_irqchip_[add,remove]_irqfd_notifier new functions: no need >> to bother about gsi (hence virtualID could be removed with small >> change in trace-events) >> >> v10 -> v11: >> - Add Alex' Reviewed-by >> - introduce kvm_accel in this patch and initialize it >> >> v5 -> v6 >> - rely on kvm_irqfds_enabled() and kvm_resamplefds_enabled() >> - guard KVM code with #ifdef CONFIG_KVM >> >> v3 -> v4: >> [Alvise Rigo] >> Use of VFIO Platform driver v6 unmask/virqfd feature and removal >> of resamplefd handler. Physical IRQ unmasking is now done in >> VFIO driver. >> >> v3: >> [Eric Auger] >> initial support with resamplefd handled on QEMU side since the >> unmask was not supported on VFIO platform driver v5. >> --- >> hw/vfio/platform.c | 107 ++++++++++++++++++++++++++++++++++++++++ >> include/hw/vfio/vfio-platform.h | 2 + >> trace-events | 1 + >> 3 files changed, 110 insertions(+) >> >> diff --git a/hw/vfio/platform.c b/hw/vfio/platform.c >> index 9382bb7..1d44085 100644 >> --- a/hw/vfio/platform.c >> +++ b/hw/vfio/platform.c >> @@ -26,6 +26,7 @@ >> #include "hw/sysbus.h" >> #include "trace.h" >> #include "hw/platform-bus.h" >> +#include "sysemu/kvm.h" >> >> /* >> * Functions used whatever the injection method >> @@ -51,6 +52,7 @@ static VFIOINTp *vfio_init_intp(VFIODevice *vbasedev, >> intp->pin = info.index; >> intp->flags = info.flags; >> intp->state = VFIO_IRQ_INACTIVE; >> + intp->kvm_accel = false; >> >> sysbus_init_irq(sbdev, &intp->qemuirq); >> >> @@ -61,6 +63,13 @@ static VFIOINTp *vfio_init_intp(VFIODevice *vbasedev, >> error_report("vfio: Error: trigger event_notifier_init failed "); >> return NULL; >> } >> + /* Get an eventfd for resample/unmask */ >> + ret = event_notifier_init(&intp->unmask, 0); >> + if (ret) { >> + g_free(intp); >> + error_report("vfio: Error: resample event_notifier_init failed eoi"); > > This error message seems rather cryptic; what is it trying to tell the user? I acknowledge ;-) I will replace by "vfio: Unable to init event notifier for resampling" > >> + return NULL; >> + } >> >> QLIST_INSERT_HEAD(&vdev->intp_list, intp, next); >> return intp; >> @@ -315,6 +324,95 @@ static int vfio_start_eventfd_injection(VFIOINTp *intp) >> return ret; >> } >> >> +/* >> + * Functions used for irqfd >> + */ >> + >> +#ifdef CONFIG_KVM >> + >> +/** >> + * vfio_set_resample_eventfd - sets the resamplefd for an IRQ >> + * @intp: the IRQ struct handle >> + * programs the VFIO driver to unmask this IRQ when the >> + * intp->unmask eventfd is triggered >> + */ >> +static int vfio_set_resample_eventfd(VFIOINTp *intp) >> +{ >> + VFIODevice *vbasedev = &intp->vdev->vbasedev; >> + struct vfio_irq_set *irq_set; >> + int argsz, ret; >> + int32_t *pfd; >> + >> + argsz = sizeof(*irq_set) + sizeof(*pfd); >> + irq_set = g_malloc0(argsz); >> + irq_set->argsz = argsz; >> + irq_set->flags = VFIO_IRQ_SET_DATA_EVENTFD | VFIO_IRQ_SET_ACTION_UNMASK; >> + irq_set->index = intp->pin; >> + irq_set->start = 0; >> + irq_set->count = 1; >> + pfd = (int32_t *)&irq_set->data; >> + *pfd = event_notifier_get_fd(&intp->unmask); >> + qemu_set_fd_handler(*pfd, NULL, NULL, NULL); >> + ret = ioctl(vbasedev->fd, VFIO_DEVICE_SET_IRQS, irq_set); >> + g_free(irq_set); >> + if (ret < 0) { >> + error_report("vfio: Failed to set resample eventfd: %m"); >> + } >> + return ret; >> +} >> + >> +static void vfio_start_irqfd_injection(SysBusDevice *sbdev, qemu_irq irq) >> +{ >> + VFIOPlatformDevice *vdev = VFIO_PLATFORM_DEVICE(sbdev); >> + VFIOINTp *intp; >> + bool found = false; >> + >> + QLIST_FOREACH(intp, &vdev->intp_list, next) { >> + if (intp->qemuirq == irq) { >> + found = true; > > Stray double-space. ok > >> + break; >> + } >> + } >> + assert(found); >> + >> + /* Get to a known interrupt state */ >> + qemu_set_fd_handler(event_notifier_get_fd(&intp->interrupt), >> + NULL, NULL, vdev); >> + >> + vfio_mask_single_irqindex(&vdev->vbasedev, intp->pin); >> + qemu_set_irq(intp->qemuirq, 0); >> + >> + if (kvm_irqchip_add_irqfd_notifier(kvm_state, &intp->interrupt, >> + &intp->unmask, irq) < 0) { >> + goto fail_irqfd; >> + } >> + >> + if (vfio_set_trigger_eventfd(intp, NULL) < 0) { >> + goto fail_vfio; >> + } >> + if (vfio_set_resample_eventfd(intp) < 0) { >> + goto fail_vfio; >> + } >> + >> + /* Let'em rip */ > > This comment could probably be phrased more informatively :-) sure > >> + vfio_unmask_single_irqindex(&vdev->vbasedev, intp->pin); >> + >> + intp->kvm_accel = true; >> + >> + trace_vfio_platform_start_irqfd_injection(intp->pin, >> + event_notifier_get_fd(&intp->interrupt), >> + event_notifier_get_fd(&intp->unmask)); >> + return; >> +fail_vfio: >> + kvm_irqchip_remove_irqfd_notifier(kvm_state, &intp->interrupt, irq); >> +fail_irqfd: >> + vfio_start_eventfd_injection(intp); >> + vfio_unmask_single_irqindex(&vdev->vbasedev, intp->pin); >> + return; >> +} >> + >> +#endif /* CONFIG_KVM */ >> + >> /* VFIO skeleton */ >> >> static void vfio_platform_compute_needs_reset(VFIODevice *vbasedev) >> @@ -548,6 +646,7 @@ static void vfio_platform_realize(DeviceState *dev, Error **errp) >> { >> VFIOPlatformDevice *vdev = VFIO_PLATFORM_DEVICE(dev); >> SysBusDevice *sbdev = SYS_BUS_DEVICE(dev); >> + SysBusDeviceClass *sbc = SYS_BUS_DEVICE_GET_CLASS(dev); >> VFIODevice *vbasedev = &vdev->vbasedev; >> VFIOINTp *intp; >> int i, ret; >> @@ -555,6 +654,13 @@ static void vfio_platform_realize(DeviceState *dev, Error **errp) >> vbasedev->type = VFIO_DEVICE_TYPE_PLATFORM; >> vbasedev->ops = &vfio_platform_ops; >> >> +#ifdef CONFIG_KVM >> + if (kvm_irqfds_enabled() && kvm_resamplefds_enabled() && >> + vdev->irqfd_allowed) { >> + sbc->connect_irq_notifier = vfio_start_irqfd_injection; >> + } >> +#endif > > You shouldn't need this CONFIG_KVM ifdef -- we deliberately provide > "always false" versions of functions like kvm_irqfds_enabled() in > sysemu/kvm.h so that we can avoid littering code with ifdefs. > > It looks like your commit f41389ae3c54b failed to provide the > non-KVM version of kvm_resamplefds_enabled(), but the correct > fix is to provide it... OK I ignored that. I will add kvm_resamplefds_allowed in kvm-stub.c then. > > This implies removing the ifdefs earlier around vfio_start_irqfd_injection, > but that should be OK -- we provide stub versions of functions like > kvm_irqchip_add_irqfd_notifier() so the non-KVM code can still compile. OK will try this out. So this answers my previous question. Will send a v17 Thanks Eric > >> + >> trace_vfio_platform_realize(vbasedev->name, vdev->compat); >> >> ret = vfio_base_device_init(vbasedev); >> @@ -584,6 +690,7 @@ static Property vfio_platform_dev_properties[] = { >> DEFINE_PROP_BOOL("x-mmap", VFIOPlatformDevice, vbasedev.allow_mmap, true), >> DEFINE_PROP_UINT32("mmap-timeout-ms", VFIOPlatformDevice, >> mmap_timeout, 1100), >> + DEFINE_PROP_BOOL("x-irqfd", VFIOPlatformDevice, irqfd_allowed, true), >> DEFINE_PROP_END_OF_LIST(), >> }; >> >> diff --git a/include/hw/vfio/vfio-platform.h b/include/hw/vfio/vfio-platform.h >> index 26b2ad6..c5cf1d7 100644 >> --- a/include/hw/vfio/vfio-platform.h >> +++ b/include/hw/vfio/vfio-platform.h >> @@ -41,6 +41,7 @@ typedef struct VFIOINTp { >> int state; /* inactive, pending, active */ >> uint8_t pin; /* index */ >> uint32_t flags; /* IRQ info flags */ >> + bool kvm_accel; /* set when QEMU bypass through KVM enabled */ >> } VFIOINTp; >> >> /* function type for user side eventfd handler */ >> @@ -57,6 +58,7 @@ typedef struct VFIOPlatformDevice { >> uint32_t mmap_timeout; /* delay to re-enable mmaps after interrupt */ >> QEMUTimer *mmap_timer; /* allows fast-path resume after IRQ hit */ >> QemuMutex intp_mutex; /* protect the intp_list IRQ state */ >> + bool irqfd_allowed; /* debug option to force irqfd on/off */ >> } VFIOPlatformDevice; >> >> typedef struct VFIOPlatformDeviceClass { >> diff --git a/trace-events b/trace-events >> index 6060d36..4390381 100644 >> --- a/trace-events >> +++ b/trace-events >> @@ -1594,6 +1594,7 @@ vfio_platform_intp_interrupt(int pin, int fd) "Inject IRQ #%d (fd = %d)" >> vfio_platform_intp_inject_pending_lockheld(int pin, int fd) "Inject pending IRQ #%d (fd = %d)" >> vfio_platform_populate_interrupts(int pin, int count, int flags) "- IRQ index %d: count %d, flags=0x%x" >> vfio_intp_interrupt_set_pending(int index) "irq %d is set PENDING" >> +vfio_platform_start_irqfd_injection(int index, int fd, int resamplefd) "IRQ index=%d, fd = %d, resamplefd = %d" >> >> #hw/acpi/memory_hotplug.c >> mhp_acpi_invalid_slot_selected(uint32_t slot) "0x%"PRIx32 >> -- >> 1.8.3.2 >> > > thanks > -- PMM >
On 06/26/2015 06:26 PM, Paolo Bonzini wrote: > > > On 26/06/2015 18:21, Alex Williamson wrote: >>>> +#ifdef CONFIG_KVM >>>> + if (kvm_irqfds_enabled() && kvm_resamplefds_enabled() && >>>> + vdev->irqfd_allowed) { >>>> + sbc->connect_irq_notifier = vfio_start_irqfd_injection; >> Should we be abstracting this to a >> sysbus_register_connect_irq_notifier()? It seems a littler personal to >> be reaching in and setting it ourselves and would avoid us needing to >> reference the class. > > It's your class, so it's not too bad to touch it from that point of > view; on the other hand it's ugly to do it here nevertheless. :) > > I think you should always set "sbc->connect_irq_notifier = > vfio_start_irqfd_injection" in the class_init function. The > vfio_start_irqfd_injection function can just exit if it finds > "!kvm_enabled() || !kvm_irqfds_enabled() || !kvm_resamplefds_enabled() > || !vdev->irqfd_allowed". OK thanks for the guidance. Alex, are you OK with that solution. It avoids touching the other patch Thanks Eric > > Paolo >
diff --git a/hw/vfio/platform.c b/hw/vfio/platform.c index 9382bb7..1d44085 100644 --- a/hw/vfio/platform.c +++ b/hw/vfio/platform.c @@ -26,6 +26,7 @@ #include "hw/sysbus.h" #include "trace.h" #include "hw/platform-bus.h" +#include "sysemu/kvm.h" /* * Functions used whatever the injection method @@ -51,6 +52,7 @@ static VFIOINTp *vfio_init_intp(VFIODevice *vbasedev, intp->pin = info.index; intp->flags = info.flags; intp->state = VFIO_IRQ_INACTIVE; + intp->kvm_accel = false; sysbus_init_irq(sbdev, &intp->qemuirq); @@ -61,6 +63,13 @@ static VFIOINTp *vfio_init_intp(VFIODevice *vbasedev, error_report("vfio: Error: trigger event_notifier_init failed "); return NULL; } + /* Get an eventfd for resample/unmask */ + ret = event_notifier_init(&intp->unmask, 0); + if (ret) { + g_free(intp); + error_report("vfio: Error: resample event_notifier_init failed eoi"); + return NULL; + } QLIST_INSERT_HEAD(&vdev->intp_list, intp, next); return intp; @@ -315,6 +324,95 @@ static int vfio_start_eventfd_injection(VFIOINTp *intp) return ret; } +/* + * Functions used for irqfd + */ + +#ifdef CONFIG_KVM + +/** + * vfio_set_resample_eventfd - sets the resamplefd for an IRQ + * @intp: the IRQ struct handle + * programs the VFIO driver to unmask this IRQ when the + * intp->unmask eventfd is triggered + */ +static int vfio_set_resample_eventfd(VFIOINTp *intp) +{ + VFIODevice *vbasedev = &intp->vdev->vbasedev; + struct vfio_irq_set *irq_set; + int argsz, ret; + int32_t *pfd; + + argsz = sizeof(*irq_set) + sizeof(*pfd); + irq_set = g_malloc0(argsz); + irq_set->argsz = argsz; + irq_set->flags = VFIO_IRQ_SET_DATA_EVENTFD | VFIO_IRQ_SET_ACTION_UNMASK; + irq_set->index = intp->pin; + irq_set->start = 0; + irq_set->count = 1; + pfd = (int32_t *)&irq_set->data; + *pfd = event_notifier_get_fd(&intp->unmask); + qemu_set_fd_handler(*pfd, NULL, NULL, NULL); + ret = ioctl(vbasedev->fd, VFIO_DEVICE_SET_IRQS, irq_set); + g_free(irq_set); + if (ret < 0) { + error_report("vfio: Failed to set resample eventfd: %m"); + } + return ret; +} + +static void vfio_start_irqfd_injection(SysBusDevice *sbdev, qemu_irq irq) +{ + VFIOPlatformDevice *vdev = VFIO_PLATFORM_DEVICE(sbdev); + VFIOINTp *intp; + bool found = false; + + QLIST_FOREACH(intp, &vdev->intp_list, next) { + if (intp->qemuirq == irq) { + found = true; + break; + } + } + assert(found); + + /* Get to a known interrupt state */ + qemu_set_fd_handler(event_notifier_get_fd(&intp->interrupt), + NULL, NULL, vdev); + + vfio_mask_single_irqindex(&vdev->vbasedev, intp->pin); + qemu_set_irq(intp->qemuirq, 0); + + if (kvm_irqchip_add_irqfd_notifier(kvm_state, &intp->interrupt, + &intp->unmask, irq) < 0) { + goto fail_irqfd; + } + + if (vfio_set_trigger_eventfd(intp, NULL) < 0) { + goto fail_vfio; + } + if (vfio_set_resample_eventfd(intp) < 0) { + goto fail_vfio; + } + + /* Let'em rip */ + vfio_unmask_single_irqindex(&vdev->vbasedev, intp->pin); + + intp->kvm_accel = true; + + trace_vfio_platform_start_irqfd_injection(intp->pin, + event_notifier_get_fd(&intp->interrupt), + event_notifier_get_fd(&intp->unmask)); + return; +fail_vfio: + kvm_irqchip_remove_irqfd_notifier(kvm_state, &intp->interrupt, irq); +fail_irqfd: + vfio_start_eventfd_injection(intp); + vfio_unmask_single_irqindex(&vdev->vbasedev, intp->pin); + return; +} + +#endif /* CONFIG_KVM */ + /* VFIO skeleton */ static void vfio_platform_compute_needs_reset(VFIODevice *vbasedev) @@ -548,6 +646,7 @@ static void vfio_platform_realize(DeviceState *dev, Error **errp) { VFIOPlatformDevice *vdev = VFIO_PLATFORM_DEVICE(dev); SysBusDevice *sbdev = SYS_BUS_DEVICE(dev); + SysBusDeviceClass *sbc = SYS_BUS_DEVICE_GET_CLASS(dev); VFIODevice *vbasedev = &vdev->vbasedev; VFIOINTp *intp; int i, ret; @@ -555,6 +654,13 @@ static void vfio_platform_realize(DeviceState *dev, Error **errp) vbasedev->type = VFIO_DEVICE_TYPE_PLATFORM; vbasedev->ops = &vfio_platform_ops; +#ifdef CONFIG_KVM + if (kvm_irqfds_enabled() && kvm_resamplefds_enabled() && + vdev->irqfd_allowed) { + sbc->connect_irq_notifier = vfio_start_irqfd_injection; + } +#endif + trace_vfio_platform_realize(vbasedev->name, vdev->compat); ret = vfio_base_device_init(vbasedev); @@ -584,6 +690,7 @@ static Property vfio_platform_dev_properties[] = { DEFINE_PROP_BOOL("x-mmap", VFIOPlatformDevice, vbasedev.allow_mmap, true), DEFINE_PROP_UINT32("mmap-timeout-ms", VFIOPlatformDevice, mmap_timeout, 1100), + DEFINE_PROP_BOOL("x-irqfd", VFIOPlatformDevice, irqfd_allowed, true), DEFINE_PROP_END_OF_LIST(), }; diff --git a/include/hw/vfio/vfio-platform.h b/include/hw/vfio/vfio-platform.h index 26b2ad6..c5cf1d7 100644 --- a/include/hw/vfio/vfio-platform.h +++ b/include/hw/vfio/vfio-platform.h @@ -41,6 +41,7 @@ typedef struct VFIOINTp { int state; /* inactive, pending, active */ uint8_t pin; /* index */ uint32_t flags; /* IRQ info flags */ + bool kvm_accel; /* set when QEMU bypass through KVM enabled */ } VFIOINTp; /* function type for user side eventfd handler */ @@ -57,6 +58,7 @@ typedef struct VFIOPlatformDevice { uint32_t mmap_timeout; /* delay to re-enable mmaps after interrupt */ QEMUTimer *mmap_timer; /* allows fast-path resume after IRQ hit */ QemuMutex intp_mutex; /* protect the intp_list IRQ state */ + bool irqfd_allowed; /* debug option to force irqfd on/off */ } VFIOPlatformDevice; typedef struct VFIOPlatformDeviceClass { diff --git a/trace-events b/trace-events index 6060d36..4390381 100644 --- a/trace-events +++ b/trace-events @@ -1594,6 +1594,7 @@ vfio_platform_intp_interrupt(int pin, int fd) "Inject IRQ #%d (fd = %d)" vfio_platform_intp_inject_pending_lockheld(int pin, int fd) "Inject pending IRQ #%d (fd = %d)" vfio_platform_populate_interrupts(int pin, int count, int flags) "- IRQ index %d: count %d, flags=0x%x" vfio_intp_interrupt_set_pending(int index) "irq %d is set PENDING" +vfio_platform_start_irqfd_injection(int index, int fd, int resamplefd) "IRQ index=%d, fd = %d, resamplefd = %d" #hw/acpi/memory_hotplug.c mhp_acpi_invalid_slot_selected(uint32_t slot) "0x%"PRIx32