| Message ID | 20230509204801.2824351-24-quic_eberman@quicinc.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Drivers for Gunyah hypervisor | expand |
On 5/9/23 3:48 PM, Elliot Berman wrote: > Allow userspace to attach an ioeventfd to an mmio address within the guest. > > Co-developed-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com> > Signed-off-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com> > Signed-off-by: Elliot Berman <quic_eberman@quicinc.com> Looks good. One question below. Reviewed-by: Alex Elder <elder@linaro.org> > --- > Documentation/virt/gunyah/vm-manager.rst | 2 +- > drivers/virt/gunyah/Kconfig | 9 ++ > drivers/virt/gunyah/Makefile | 1 + > drivers/virt/gunyah/gunyah_ioeventfd.c | 130 +++++++++++++++++++++++ > include/uapi/linux/gunyah.h | 37 +++++++ > 5 files changed, 178 insertions(+), 1 deletion(-) > create mode 100644 drivers/virt/gunyah/gunyah_ioeventfd.c > > diff --git a/Documentation/virt/gunyah/vm-manager.rst b/Documentation/virt/gunyah/vm-manager.rst > index c4960948c779..87838c5b5945 100644 > --- a/Documentation/virt/gunyah/vm-manager.rst > +++ b/Documentation/virt/gunyah/vm-manager.rst > @@ -115,7 +115,7 @@ the VM *before* the VM starts. > The argument types are documented below: > > .. kernel-doc:: include/uapi/linux/gunyah.h > - :identifiers: gh_fn_vcpu_arg gh_fn_irqfd_arg gh_irqfd_flags > + :identifiers: gh_fn_vcpu_arg gh_fn_irqfd_arg gh_irqfd_flags gh_fn_ioeventfd_arg gh_ioeventfd_flags > > Gunyah VCPU API Descriptions > ---------------------------- > diff --git a/drivers/virt/gunyah/Kconfig b/drivers/virt/gunyah/Kconfig > index bc2c46d9df94..63bebc5b9f82 100644 > --- a/drivers/virt/gunyah/Kconfig > +++ b/drivers/virt/gunyah/Kconfig > @@ -48,3 +48,12 @@ config GUNYAH_IRQFD > on Gunyah virtual machine. > > Say Y/M here if unsure and you want to support Gunyah VMMs. > + > +config GUNYAH_IOEVENTFD > + tristate "Gunyah ioeventfd interface" > + depends on GUNYAH > + help > + Enable kernel support for creating ioeventfds which can alert userspace > + when a Gunyah virtual machine accesses a memory address. > + > + Say Y/M here if unsure and you want to support Gunyah VMMs. > diff --git a/drivers/virt/gunyah/Makefile b/drivers/virt/gunyah/Makefile > index ad212a1cf967..63ca11e74796 100644 > --- a/drivers/virt/gunyah/Makefile > +++ b/drivers/virt/gunyah/Makefile > @@ -8,3 +8,4 @@ obj-$(CONFIG_GUNYAH) += gunyah.o > > obj-$(CONFIG_GUNYAH_VCPU) += gunyah_vcpu.o > obj-$(CONFIG_GUNYAH_IRQFD) += gunyah_irqfd.o > +obj-$(CONFIG_GUNYAH_IOEVENTFD) += gunyah_ioeventfd.o > diff --git a/drivers/virt/gunyah/gunyah_ioeventfd.c b/drivers/virt/gunyah/gunyah_ioeventfd.c > new file mode 100644 > index 000000000000..5b1b9fd9ac3a > --- /dev/null > +++ b/drivers/virt/gunyah/gunyah_ioeventfd.c > @@ -0,0 +1,130 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved. > + */ > + > +#include <linux/eventfd.h> > +#include <linux/file.h> > +#include <linux/fs.h> > +#include <linux/gunyah.h> > +#include <linux/gunyah_vm_mgr.h> > +#include <linux/module.h> > +#include <linux/printk.h> > + > +#include <uapi/linux/gunyah.h> > + > +struct gh_ioeventfd { > + struct gh_vm_function_instance *f; > + struct gh_vm_io_handler io_handler; > + > + struct eventfd_ctx *ctx; > +}; > + > +static int gh_write_ioeventfd(struct gh_vm_io_handler *io_dev, u64 addr, u32 len, u64 data) > +{ > + struct gh_ioeventfd *iofd = container_of(io_dev, struct gh_ioeventfd, io_handler); Does a write of 0 bytes still signal an event? > + > + eventfd_signal(iofd->ctx, 1); > + return 0; > +} > + > +static struct gh_vm_io_handler_ops io_ops = { > + .write = gh_write_ioeventfd, > +}; > + > +static long gh_ioeventfd_bind(struct gh_vm_function_instance *f) > +{ > + const struct gh_fn_ioeventfd_arg *args = f->argp; > + struct gh_ioeventfd *iofd; > + struct eventfd_ctx *ctx; > + int ret; > + > + if (f->arg_size != sizeof(*args)) > + return -EINVAL; > + > + /* All other flag bits are reserved for future use */ > + if (args->flags & ~GH_IOEVENTFD_FLAGS_DATAMATCH) > + return -EINVAL; > + > + /* must be natural-word sized, or 0 to ignore length */ > + switch (args->len) { > + case 0: > + case 1: > + case 2: > + case 4: > + case 8: > + break; > + default: > + return -EINVAL; > + } > + > + /* check for range overflow */ > + if (overflows_type(args->addr + args->len, u64)) > + return -EINVAL; > + > + /* ioeventfd with no length can't be combined with DATAMATCH */ > + if (!args->len && (args->flags & GH_IOEVENTFD_FLAGS_DATAMATCH)) > + return -EINVAL; > + > + ctx = eventfd_ctx_fdget(args->fd); > + if (IS_ERR(ctx)) > + return PTR_ERR(ctx); > + > + iofd = kzalloc(sizeof(*iofd), GFP_KERNEL); > + if (!iofd) { > + ret = -ENOMEM; > + goto err_eventfd; > + } > + > + f->data = iofd; > + iofd->f = f; > + > + iofd->ctx = ctx; > + > + if (args->flags & GH_IOEVENTFD_FLAGS_DATAMATCH) { > + iofd->io_handler.datamatch = true; > + iofd->io_handler.len = args->len; > + iofd->io_handler.data = args->datamatch; > + } > + iofd->io_handler.addr = args->addr; > + iofd->io_handler.ops = &io_ops; > + > + ret = gh_vm_add_io_handler(f->ghvm, &iofd->io_handler); > + if (ret) > + goto err_io_dev_add; > + > + return 0; > + > +err_io_dev_add: > + kfree(iofd); > +err_eventfd: > + eventfd_ctx_put(ctx); > + return ret; > +} > + > +static void gh_ioevent_unbind(struct gh_vm_function_instance *f) > +{ > + struct gh_ioeventfd *iofd = f->data; > + > + eventfd_ctx_put(iofd->ctx); > + gh_vm_remove_io_handler(iofd->f->ghvm, &iofd->io_handler); > + kfree(iofd); > +} > + > +static bool gh_ioevent_compare(const struct gh_vm_function_instance *f, > + const void *arg, size_t size) > +{ > + const struct gh_fn_ioeventfd_arg *instance = f->argp, > + *other = arg; > + > + if (sizeof(*other) != size) > + return false; > + > + return instance->addr == other->addr; > +} > + > +DECLARE_GH_VM_FUNCTION_INIT(ioeventfd, GH_FN_IOEVENTFD, 3, > + gh_ioeventfd_bind, gh_ioevent_unbind, > + gh_ioevent_compare); > +MODULE_DESCRIPTION("Gunyah ioeventfd VM Function"); > +MODULE_LICENSE("GPL"); > diff --git a/include/uapi/linux/gunyah.h b/include/uapi/linux/gunyah.h > index 0c480c622686..fa1cae7419d2 100644 > --- a/include/uapi/linux/gunyah.h > +++ b/include/uapi/linux/gunyah.h > @@ -79,10 +79,13 @@ struct gh_vm_dtb_config { > * Return: file descriptor to manipulate the vcpu. > * @GH_FN_IRQFD: register eventfd to assert a Gunyah doorbell > * &struct gh_fn_desc.arg is a pointer to &struct gh_fn_irqfd_arg > + * @GH_FN_IOEVENTFD: register ioeventfd to trigger when VM faults on parameter > + * &struct gh_fn_desc.arg is a pointer to &struct gh_fn_ioeventfd_arg > */ > enum gh_fn_type { > GH_FN_VCPU = 1, > GH_FN_IRQFD, > + GH_FN_IOEVENTFD, > }; > > #define GH_FN_MAX_ARG_SIZE 256 > @@ -134,6 +137,40 @@ struct gh_fn_irqfd_arg { > __u32 padding; > }; > > +/** > + * enum gh_ioeventfd_flags - flags for use in gh_fn_ioeventfd_arg > + * @GH_IOEVENTFD_FLAGS_DATAMATCH: the event will be signaled only if the > + * written value to the registered address is > + * equal to &struct gh_fn_ioeventfd_arg.datamatch > + */ > +enum gh_ioeventfd_flags { > + GH_IOEVENTFD_FLAGS_DATAMATCH = 1UL << 0, > +}; > + > +/** > + * struct gh_fn_ioeventfd_arg - Arguments to create an ioeventfd function > + * @datamatch: data used when GH_IOEVENTFD_DATAMATCH is set > + * @addr: Address in guest memory > + * @len: Length of access > + * @fd: When ioeventfd is matched, this eventfd is written > + * @flags: See &enum gh_ioeventfd_flags > + * @padding: padding bytes > + * > + * Create this function with &GH_VM_ADD_FUNCTION using type &GH_FN_IOEVENTFD. > + * > + * Attaches an ioeventfd to a legal mmio address within the guest. A guest write > + * in the registered address will signal the provided event instead of triggering > + * an exit on the GH_VCPU_RUN ioctl. > + */ > +struct gh_fn_ioeventfd_arg { > + __u64 datamatch; > + __u64 addr; /* legal mmio address */ > + __u32 len; /* 1, 2, 4, or 8 bytes; or 0 to ignore length */ > + __s32 fd; > + __u32 flags; > + __u32 padding; > +}; > + > /** > * struct gh_fn_desc - Arguments to create a VM function > * @type: Type of the function. See &enum gh_fn_type.
On 6/5/2023 12:50 PM, Alex Elder wrote: > On 5/9/23 3:48 PM, Elliot Berman wrote: >> Allow userspace to attach an ioeventfd to an mmio address within the >> guest. >> >> Co-developed-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com> >> Signed-off-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com> >> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com> > > Looks good. One question below. > > Reviewed-by: Alex Elder <elder@linaro.org> > Thanks! >> --- >> Documentation/virt/gunyah/vm-manager.rst | 2 +- >> drivers/virt/gunyah/Kconfig | 9 ++ >> drivers/virt/gunyah/Makefile | 1 + >> drivers/virt/gunyah/gunyah_ioeventfd.c | 130 +++++++++++++++++++++++ >> include/uapi/linux/gunyah.h | 37 +++++++ >> 5 files changed, 178 insertions(+), 1 deletion(-) >> create mode 100644 drivers/virt/gunyah/gunyah_ioeventfd.c >> >> diff --git a/Documentation/virt/gunyah/vm-manager.rst >> b/Documentation/virt/gunyah/vm-manager.rst >> index c4960948c779..87838c5b5945 100644 >> --- a/Documentation/virt/gunyah/vm-manager.rst >> +++ b/Documentation/virt/gunyah/vm-manager.rst >> @@ -115,7 +115,7 @@ the VM *before* the VM starts. >> The argument types are documented below: >> .. kernel-doc:: include/uapi/linux/gunyah.h >> - :identifiers: gh_fn_vcpu_arg gh_fn_irqfd_arg gh_irqfd_flags >> + :identifiers: gh_fn_vcpu_arg gh_fn_irqfd_arg gh_irqfd_flags >> gh_fn_ioeventfd_arg gh_ioeventfd_flags >> Gunyah VCPU API Descriptions >> ---------------------------- >> diff --git a/drivers/virt/gunyah/Kconfig b/drivers/virt/gunyah/Kconfig >> index bc2c46d9df94..63bebc5b9f82 100644 >> --- a/drivers/virt/gunyah/Kconfig >> +++ b/drivers/virt/gunyah/Kconfig >> @@ -48,3 +48,12 @@ config GUNYAH_IRQFD >> on Gunyah virtual machine. >> Say Y/M here if unsure and you want to support Gunyah VMMs. >> + >> +config GUNYAH_IOEVENTFD >> + tristate "Gunyah ioeventfd interface" >> + depends on GUNYAH >> + help >> + Enable kernel support for creating ioeventfds which can alert >> userspace >> + when a Gunyah virtual machine accesses a memory address. >> + >> + Say Y/M here if unsure and you want to support Gunyah VMMs. >> diff --git a/drivers/virt/gunyah/Makefile b/drivers/virt/gunyah/Makefile >> index ad212a1cf967..63ca11e74796 100644 >> --- a/drivers/virt/gunyah/Makefile >> +++ b/drivers/virt/gunyah/Makefile >> @@ -8,3 +8,4 @@ obj-$(CONFIG_GUNYAH) += gunyah.o >> obj-$(CONFIG_GUNYAH_VCPU) += gunyah_vcpu.o >> obj-$(CONFIG_GUNYAH_IRQFD) += gunyah_irqfd.o >> +obj-$(CONFIG_GUNYAH_IOEVENTFD) += gunyah_ioeventfd.o >> diff --git a/drivers/virt/gunyah/gunyah_ioeventfd.c >> b/drivers/virt/gunyah/gunyah_ioeventfd.c >> new file mode 100644 >> index 000000000000..5b1b9fd9ac3a >> --- /dev/null >> +++ b/drivers/virt/gunyah/gunyah_ioeventfd.c >> @@ -0,0 +1,130 @@ >> +// SPDX-License-Identifier: GPL-2.0-only >> +/* >> + * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All >> rights reserved. >> + */ >> + >> +#include <linux/eventfd.h> >> +#include <linux/file.h> >> +#include <linux/fs.h> >> +#include <linux/gunyah.h> >> +#include <linux/gunyah_vm_mgr.h> >> +#include <linux/module.h> >> +#include <linux/printk.h> >> + >> +#include <uapi/linux/gunyah.h> >> + >> +struct gh_ioeventfd { >> + struct gh_vm_function_instance *f; >> + struct gh_vm_io_handler io_handler; >> + >> + struct eventfd_ctx *ctx; >> +}; >> + >> +static int gh_write_ioeventfd(struct gh_vm_io_handler *io_dev, u64 >> addr, u32 len, u64 data) >> +{ >> + struct gh_ioeventfd *iofd = container_of(io_dev, struct >> gh_ioeventfd, io_handler); > > Does a write of 0 bytes still signal an event? > From gunyah_ioeventfd perspective, yes. I don't think a write of 0 bytes is possible, but maybe you are thinking of scenario I'm not? >> + >> + eventfd_signal(iofd->ctx, 1); >> + return 0; >> +} >> + >> +static struct gh_vm_io_handler_ops io_ops = { >> + .write = gh_write_ioeventfd, >> +}; >> + >> +static long gh_ioeventfd_bind(struct gh_vm_function_instance *f) >> +{ >> + const struct gh_fn_ioeventfd_arg *args = f->argp; >> + struct gh_ioeventfd *iofd; >> + struct eventfd_ctx *ctx; >> + int ret; >> + >> + if (f->arg_size != sizeof(*args)) >> + return -EINVAL; >> + >> + /* All other flag bits are reserved for future use */ >> + if (args->flags & ~GH_IOEVENTFD_FLAGS_DATAMATCH) >> + return -EINVAL; >> + >> + /* must be natural-word sized, or 0 to ignore length */ >> + switch (args->len) { >> + case 0: >> + case 1: >> + case 2: >> + case 4: >> + case 8: >> + break; >> + default: >> + return -EINVAL; >> + } >> + >> + /* check for range overflow */ >> + if (overflows_type(args->addr + args->len, u64)) >> + return -EINVAL; >> + >> + /* ioeventfd with no length can't be combined with DATAMATCH */ >> + if (!args->len && (args->flags & GH_IOEVENTFD_FLAGS_DATAMATCH)) >> + return -EINVAL; >> + >> + ctx = eventfd_ctx_fdget(args->fd); >> + if (IS_ERR(ctx)) >> + return PTR_ERR(ctx); >> + >> + iofd = kzalloc(sizeof(*iofd), GFP_KERNEL); >> + if (!iofd) { >> + ret = -ENOMEM; >> + goto err_eventfd; >> + } >> + >> + f->data = iofd; >> + iofd->f = f; >> + >> + iofd->ctx = ctx; >> + >> + if (args->flags & GH_IOEVENTFD_FLAGS_DATAMATCH) { >> + iofd->io_handler.datamatch = true; >> + iofd->io_handler.len = args->len; >> + iofd->io_handler.data = args->datamatch; >> + } >> + iofd->io_handler.addr = args->addr; >> + iofd->io_handler.ops = &io_ops; >> + >> + ret = gh_vm_add_io_handler(f->ghvm, &iofd->io_handler); >> + if (ret) >> + goto err_io_dev_add; >> + >> + return 0; >> + >> +err_io_dev_add: >> + kfree(iofd); >> +err_eventfd: >> + eventfd_ctx_put(ctx); >> + return ret; >> +} >> + >> +static void gh_ioevent_unbind(struct gh_vm_function_instance *f) >> +{ >> + struct gh_ioeventfd *iofd = f->data; >> + >> + eventfd_ctx_put(iofd->ctx); >> + gh_vm_remove_io_handler(iofd->f->ghvm, &iofd->io_handler); >> + kfree(iofd); >> +} >> + >> +static bool gh_ioevent_compare(const struct gh_vm_function_instance *f, >> + const void *arg, size_t size) >> +{ >> + const struct gh_fn_ioeventfd_arg *instance = f->argp, >> + *other = arg; >> + >> + if (sizeof(*other) != size) >> + return false; >> + >> + return instance->addr == other->addr; >> +} >> + >> +DECLARE_GH_VM_FUNCTION_INIT(ioeventfd, GH_FN_IOEVENTFD, 3, >> + gh_ioeventfd_bind, gh_ioevent_unbind, >> + gh_ioevent_compare); >> +MODULE_DESCRIPTION("Gunyah ioeventfd VM Function"); >> +MODULE_LICENSE("GPL"); >> diff --git a/include/uapi/linux/gunyah.h b/include/uapi/linux/gunyah.h >> index 0c480c622686..fa1cae7419d2 100644 >> --- a/include/uapi/linux/gunyah.h >> +++ b/include/uapi/linux/gunyah.h >> @@ -79,10 +79,13 @@ struct gh_vm_dtb_config { >> * Return: file descriptor to manipulate the vcpu. >> * @GH_FN_IRQFD: register eventfd to assert a Gunyah doorbell >> * &struct gh_fn_desc.arg is a pointer to &struct >> gh_fn_irqfd_arg >> + * @GH_FN_IOEVENTFD: register ioeventfd to trigger when VM faults on >> parameter >> + * &struct gh_fn_desc.arg is a pointer to &struct >> gh_fn_ioeventfd_arg >> */ >> enum gh_fn_type { >> GH_FN_VCPU = 1, >> GH_FN_IRQFD, >> + GH_FN_IOEVENTFD, >> }; >> #define GH_FN_MAX_ARG_SIZE 256 >> @@ -134,6 +137,40 @@ struct gh_fn_irqfd_arg { >> __u32 padding; >> }; >> +/** >> + * enum gh_ioeventfd_flags - flags for use in gh_fn_ioeventfd_arg >> + * @GH_IOEVENTFD_FLAGS_DATAMATCH: the event will be signaled only if the >> + * written value to the registered >> address is >> + * equal to &struct >> gh_fn_ioeventfd_arg.datamatch >> + */ >> +enum gh_ioeventfd_flags { >> + GH_IOEVENTFD_FLAGS_DATAMATCH = 1UL << 0, >> +}; >> + >> +/** >> + * struct gh_fn_ioeventfd_arg - Arguments to create an ioeventfd >> function >> + * @datamatch: data used when GH_IOEVENTFD_DATAMATCH is set >> + * @addr: Address in guest memory >> + * @len: Length of access >> + * @fd: When ioeventfd is matched, this eventfd is written >> + * @flags: See &enum gh_ioeventfd_flags >> + * @padding: padding bytes >> + * >> + * Create this function with &GH_VM_ADD_FUNCTION using type >> &GH_FN_IOEVENTFD. >> + * >> + * Attaches an ioeventfd to a legal mmio address within the guest. A >> guest write >> + * in the registered address will signal the provided event instead >> of triggering >> + * an exit on the GH_VCPU_RUN ioctl. >> + */ >> +struct gh_fn_ioeventfd_arg { >> + __u64 datamatch; >> + __u64 addr; /* legal mmio address */ >> + __u32 len; /* 1, 2, 4, or 8 bytes; or 0 to ignore length */ >> + __s32 fd; >> + __u32 flags; >> + __u32 padding; >> +}; >> + >> /** >> * struct gh_fn_desc - Arguments to create a VM function >> * @type: Type of the function. See &enum gh_fn_type. >
On 6/9/23 12:33 PM, Elliot Berman wrote: >>> +static int gh_write_ioeventfd(struct gh_vm_io_handler *io_dev, u64 >>> addr, u32 len, u64 data) >>> +{ >>> + struct gh_ioeventfd *iofd = container_of(io_dev, struct >>> gh_ioeventfd, io_handler); >> >> Does a write of 0 bytes still signal an event? >> > > From gunyah_ioeventfd perspective, yes. I don't think a write of 0 > bytes is possible, but maybe you are thinking of scenario I'm not? > >>> + >>> + eventfd_signal(iofd->ctx, 1); >>> + return 0; >>> +} No, I was just observing that eventfd_signal() is called regardless of the value of len. -Alex
diff --git a/Documentation/virt/gunyah/vm-manager.rst b/Documentation/virt/gunyah/vm-manager.rst index c4960948c779..87838c5b5945 100644 --- a/Documentation/virt/gunyah/vm-manager.rst +++ b/Documentation/virt/gunyah/vm-manager.rst @@ -115,7 +115,7 @@ the VM *before* the VM starts. The argument types are documented below: .. kernel-doc:: include/uapi/linux/gunyah.h - :identifiers: gh_fn_vcpu_arg gh_fn_irqfd_arg gh_irqfd_flags + :identifiers: gh_fn_vcpu_arg gh_fn_irqfd_arg gh_irqfd_flags gh_fn_ioeventfd_arg gh_ioeventfd_flags Gunyah VCPU API Descriptions ---------------------------- diff --git a/drivers/virt/gunyah/Kconfig b/drivers/virt/gunyah/Kconfig index bc2c46d9df94..63bebc5b9f82 100644 --- a/drivers/virt/gunyah/Kconfig +++ b/drivers/virt/gunyah/Kconfig @@ -48,3 +48,12 @@ config GUNYAH_IRQFD on Gunyah virtual machine. Say Y/M here if unsure and you want to support Gunyah VMMs. + +config GUNYAH_IOEVENTFD + tristate "Gunyah ioeventfd interface" + depends on GUNYAH + help + Enable kernel support for creating ioeventfds which can alert userspace + when a Gunyah virtual machine accesses a memory address. + + Say Y/M here if unsure and you want to support Gunyah VMMs. diff --git a/drivers/virt/gunyah/Makefile b/drivers/virt/gunyah/Makefile index ad212a1cf967..63ca11e74796 100644 --- a/drivers/virt/gunyah/Makefile +++ b/drivers/virt/gunyah/Makefile @@ -8,3 +8,4 @@ obj-$(CONFIG_GUNYAH) += gunyah.o obj-$(CONFIG_GUNYAH_VCPU) += gunyah_vcpu.o obj-$(CONFIG_GUNYAH_IRQFD) += gunyah_irqfd.o +obj-$(CONFIG_GUNYAH_IOEVENTFD) += gunyah_ioeventfd.o diff --git a/drivers/virt/gunyah/gunyah_ioeventfd.c b/drivers/virt/gunyah/gunyah_ioeventfd.c new file mode 100644 index 000000000000..5b1b9fd9ac3a --- /dev/null +++ b/drivers/virt/gunyah/gunyah_ioeventfd.c @@ -0,0 +1,130 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved. + */ + +#include <linux/eventfd.h> +#include <linux/file.h> +#include <linux/fs.h> +#include <linux/gunyah.h> +#include <linux/gunyah_vm_mgr.h> +#include <linux/module.h> +#include <linux/printk.h> + +#include <uapi/linux/gunyah.h> + +struct gh_ioeventfd { + struct gh_vm_function_instance *f; + struct gh_vm_io_handler io_handler; + + struct eventfd_ctx *ctx; +}; + +static int gh_write_ioeventfd(struct gh_vm_io_handler *io_dev, u64 addr, u32 len, u64 data) +{ + struct gh_ioeventfd *iofd = container_of(io_dev, struct gh_ioeventfd, io_handler); + + eventfd_signal(iofd->ctx, 1); + return 0; +} + +static struct gh_vm_io_handler_ops io_ops = { + .write = gh_write_ioeventfd, +}; + +static long gh_ioeventfd_bind(struct gh_vm_function_instance *f) +{ + const struct gh_fn_ioeventfd_arg *args = f->argp; + struct gh_ioeventfd *iofd; + struct eventfd_ctx *ctx; + int ret; + + if (f->arg_size != sizeof(*args)) + return -EINVAL; + + /* All other flag bits are reserved for future use */ + if (args->flags & ~GH_IOEVENTFD_FLAGS_DATAMATCH) + return -EINVAL; + + /* must be natural-word sized, or 0 to ignore length */ + switch (args->len) { + case 0: + case 1: + case 2: + case 4: + case 8: + break; + default: + return -EINVAL; + } + + /* check for range overflow */ + if (overflows_type(args->addr + args->len, u64)) + return -EINVAL; + + /* ioeventfd with no length can't be combined with DATAMATCH */ + if (!args->len && (args->flags & GH_IOEVENTFD_FLAGS_DATAMATCH)) + return -EINVAL; + + ctx = eventfd_ctx_fdget(args->fd); + if (IS_ERR(ctx)) + return PTR_ERR(ctx); + + iofd = kzalloc(sizeof(*iofd), GFP_KERNEL); + if (!iofd) { + ret = -ENOMEM; + goto err_eventfd; + } + + f->data = iofd; + iofd->f = f; + + iofd->ctx = ctx; + + if (args->flags & GH_IOEVENTFD_FLAGS_DATAMATCH) { + iofd->io_handler.datamatch = true; + iofd->io_handler.len = args->len; + iofd->io_handler.data = args->datamatch; + } + iofd->io_handler.addr = args->addr; + iofd->io_handler.ops = &io_ops; + + ret = gh_vm_add_io_handler(f->ghvm, &iofd->io_handler); + if (ret) + goto err_io_dev_add; + + return 0; + +err_io_dev_add: + kfree(iofd); +err_eventfd: + eventfd_ctx_put(ctx); + return ret; +} + +static void gh_ioevent_unbind(struct gh_vm_function_instance *f) +{ + struct gh_ioeventfd *iofd = f->data; + + eventfd_ctx_put(iofd->ctx); + gh_vm_remove_io_handler(iofd->f->ghvm, &iofd->io_handler); + kfree(iofd); +} + +static bool gh_ioevent_compare(const struct gh_vm_function_instance *f, + const void *arg, size_t size) +{ + const struct gh_fn_ioeventfd_arg *instance = f->argp, + *other = arg; + + if (sizeof(*other) != size) + return false; + + return instance->addr == other->addr; +} + +DECLARE_GH_VM_FUNCTION_INIT(ioeventfd, GH_FN_IOEVENTFD, 3, + gh_ioeventfd_bind, gh_ioevent_unbind, + gh_ioevent_compare); +MODULE_DESCRIPTION("Gunyah ioeventfd VM Function"); +MODULE_LICENSE("GPL"); diff --git a/include/uapi/linux/gunyah.h b/include/uapi/linux/gunyah.h index 0c480c622686..fa1cae7419d2 100644 --- a/include/uapi/linux/gunyah.h +++ b/include/uapi/linux/gunyah.h @@ -79,10 +79,13 @@ struct gh_vm_dtb_config { * Return: file descriptor to manipulate the vcpu. * @GH_FN_IRQFD: register eventfd to assert a Gunyah doorbell * &struct gh_fn_desc.arg is a pointer to &struct gh_fn_irqfd_arg + * @GH_FN_IOEVENTFD: register ioeventfd to trigger when VM faults on parameter + * &struct gh_fn_desc.arg is a pointer to &struct gh_fn_ioeventfd_arg */ enum gh_fn_type { GH_FN_VCPU = 1, GH_FN_IRQFD, + GH_FN_IOEVENTFD, }; #define GH_FN_MAX_ARG_SIZE 256 @@ -134,6 +137,40 @@ struct gh_fn_irqfd_arg { __u32 padding; }; +/** + * enum gh_ioeventfd_flags - flags for use in gh_fn_ioeventfd_arg + * @GH_IOEVENTFD_FLAGS_DATAMATCH: the event will be signaled only if the + * written value to the registered address is + * equal to &struct gh_fn_ioeventfd_arg.datamatch + */ +enum gh_ioeventfd_flags { + GH_IOEVENTFD_FLAGS_DATAMATCH = 1UL << 0, +}; + +/** + * struct gh_fn_ioeventfd_arg - Arguments to create an ioeventfd function + * @datamatch: data used when GH_IOEVENTFD_DATAMATCH is set + * @addr: Address in guest memory + * @len: Length of access + * @fd: When ioeventfd is matched, this eventfd is written + * @flags: See &enum gh_ioeventfd_flags + * @padding: padding bytes + * + * Create this function with &GH_VM_ADD_FUNCTION using type &GH_FN_IOEVENTFD. + * + * Attaches an ioeventfd to a legal mmio address within the guest. A guest write + * in the registered address will signal the provided event instead of triggering + * an exit on the GH_VCPU_RUN ioctl. + */ +struct gh_fn_ioeventfd_arg { + __u64 datamatch; + __u64 addr; /* legal mmio address */ + __u32 len; /* 1, 2, 4, or 8 bytes; or 0 to ignore length */ + __s32 fd; + __u32 flags; + __u32 padding; +}; + /** * struct gh_fn_desc - Arguments to create a VM function * @type: Type of the function. See &enum gh_fn_type.