| Message ID | 20240403140116.3002809-5-vineeth@bitbyteword.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Paravirt Scheduling (Dynamic vcpu priority management) | expand |
Adding sched_ext folks On Wed, Apr 3, 2024 at 10:01 AM Vineeth Pillai (Google) <vineeth@bitbyteword.org> wrote: > > Add support for implementing bpf pvsched drivers. bpf programs can use > the struct_ops to define the callbacks of pvsched drivers. > > This is only a skeleton of the bpf framework for pvsched. Some > verification details are not implemented yet. > > Signed-off-by: Vineeth Pillai (Google) <vineeth@bitbyteword.org> > Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> > --- > kernel/bpf/bpf_struct_ops_types.h | 4 + > virt/pvsched/Makefile | 2 +- > virt/pvsched/pvsched_bpf.c | 141 ++++++++++++++++++++++++++++++ > 3 files changed, 146 insertions(+), 1 deletion(-) > create mode 100644 virt/pvsched/pvsched_bpf.c > > diff --git a/kernel/bpf/bpf_struct_ops_types.h b/kernel/bpf/bpf_struct_ops_types.h > index 5678a9ddf817..9d5e4d1a331a 100644 > --- a/kernel/bpf/bpf_struct_ops_types.h > +++ b/kernel/bpf/bpf_struct_ops_types.h > @@ -9,4 +9,8 @@ BPF_STRUCT_OPS_TYPE(bpf_dummy_ops) > #include <net/tcp.h> > BPF_STRUCT_OPS_TYPE(tcp_congestion_ops) > #endif > +#ifdef CONFIG_PARAVIRT_SCHED_HOST > +#include <linux/pvsched.h> > +BPF_STRUCT_OPS_TYPE(pvsched_vcpu_ops) > +#endif > #endif > diff --git a/virt/pvsched/Makefile b/virt/pvsched/Makefile > index 4ca38e30479b..02bc072cd806 100644 > --- a/virt/pvsched/Makefile > +++ b/virt/pvsched/Makefile > @@ -1,2 +1,2 @@ > > -obj-$(CONFIG_PARAVIRT_SCHED_HOST) += pvsched.o > +obj-$(CONFIG_PARAVIRT_SCHED_HOST) += pvsched.o pvsched_bpf.o > diff --git a/virt/pvsched/pvsched_bpf.c b/virt/pvsched/pvsched_bpf.c > new file mode 100644 > index 000000000000..b125089abc3b > --- /dev/null > +++ b/virt/pvsched/pvsched_bpf.c > @@ -0,0 +1,141 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* Copyright (c) 2024 Google */ > + > +#include <linux/types.h> > +#include <linux/bpf_verifier.h> > +#include <linux/bpf.h> > +#include <linux/btf.h> > +#include <linux/filter.h> > +#include <linux/pvsched.h> > + > + > +/* "extern" is to avoid sparse warning. It is only used in bpf_struct_ops.c. */ > +extern struct bpf_struct_ops bpf_pvsched_vcpu_ops; > + > +static int bpf_pvsched_vcpu_init(struct btf *btf) > +{ > + return 0; > +} > + > +static bool bpf_pvsched_vcpu_is_valid_access(int off, int size, > + enum bpf_access_type type, > + const struct bpf_prog *prog, > + struct bpf_insn_access_aux *info) > +{ > + if (off < 0 || off >= sizeof(__u64) * MAX_BPF_FUNC_ARGS) > + return false; > + if (type != BPF_READ) > + return false; > + if (off % size != 0) > + return false; > + > + if (!btf_ctx_access(off, size, type, prog, info)) > + return false; > + > + return true; > +} > + > +static int bpf_pvsched_vcpu_btf_struct_access(struct bpf_verifier_log *log, > + const struct bpf_reg_state *reg, > + int off, int size) > +{ > + /* > + * TODO: Enable write access to Guest shared mem. > + */ > + return -EACCES; > +} > + > +static const struct bpf_func_proto * > +bpf_pvsched_vcpu_get_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) > +{ > + return bpf_base_func_proto(func_id); > +} > + > +static const struct bpf_verifier_ops bpf_pvsched_vcpu_verifier_ops = { > + .get_func_proto = bpf_pvsched_vcpu_get_func_proto, > + .is_valid_access = bpf_pvsched_vcpu_is_valid_access, > + .btf_struct_access = bpf_pvsched_vcpu_btf_struct_access, > +}; > + > +static int bpf_pvsched_vcpu_init_member(const struct btf_type *t, > + const struct btf_member *member, > + void *kdata, const void *udata) > +{ > + const struct pvsched_vcpu_ops *uvm_ops; > + struct pvsched_vcpu_ops *vm_ops; > + u32 moff; > + > + uvm_ops = (const struct pvsched_vcpu_ops *)udata; > + vm_ops = (struct pvsched_vcpu_ops *)kdata; > + > + moff = __btf_member_bit_offset(t, member) / 8; > + switch (moff) { > + case offsetof(struct pvsched_vcpu_ops, events): > + vm_ops->events = *(u32 *)(udata + moff); > + return 1; > + case offsetof(struct pvsched_vcpu_ops, name): > + if (bpf_obj_name_cpy(vm_ops->name, uvm_ops->name, > + sizeof(vm_ops->name)) <= 0) > + return -EINVAL; > + return 1; > + } > + > + return 0; > +} > + > +static int bpf_pvsched_vcpu_check_member(const struct btf_type *t, > + const struct btf_member *member, > + const struct bpf_prog *prog) > +{ > + return 0; > +} > + > +static int bpf_pvsched_vcpu_reg(void *kdata) > +{ > + return pvsched_register_vcpu_ops((struct pvsched_vcpu_ops *)kdata); > +} > + > +static void bpf_pvsched_vcpu_unreg(void *kdata) > +{ > + pvsched_unregister_vcpu_ops((struct pvsched_vcpu_ops *)kdata); > +} > + > +static int bpf_pvsched_vcpu_validate(void *kdata) > +{ > + return pvsched_validate_vcpu_ops((struct pvsched_vcpu_ops *)kdata); > +} > + > +static int bpf_pvsched_vcpu_update(void *kdata, void *old_kdata) > +{ > + return -EOPNOTSUPP; > +} > + > +static int __pvsched_vcpu_register(struct pid *pid) > +{ > + return 0; > +} > +static void __pvsched_vcpu_unregister(struct pid *pid) > +{ > +} > +static void __pvsched_notify_event(void *addr, struct pid *pid, u32 event) > +{ > +} > + > +static struct pvsched_vcpu_ops __bpf_ops_pvsched_vcpu_ops = { > + .pvsched_vcpu_register = __pvsched_vcpu_register, > + .pvsched_vcpu_unregister = __pvsched_vcpu_unregister, > + .pvsched_vcpu_notify_event = __pvsched_notify_event, > +}; > + > +struct bpf_struct_ops bpf_pvsched_vcpu_ops = { > + .init = &bpf_pvsched_vcpu_init, > + .validate = bpf_pvsched_vcpu_validate, > + .update = bpf_pvsched_vcpu_update, > + .verifier_ops = &bpf_pvsched_vcpu_verifier_ops, > + .reg = bpf_pvsched_vcpu_reg, > + .unreg = bpf_pvsched_vcpu_unreg, > + .check_member = bpf_pvsched_vcpu_check_member, > + .init_member = bpf_pvsched_vcpu_init_member, > + .name = "pvsched_vcpu_ops", > + .cfi_stubs = &__bpf_ops_pvsched_vcpu_ops, > +}; > -- > 2.40.1 >
diff --git a/kernel/bpf/bpf_struct_ops_types.h b/kernel/bpf/bpf_struct_ops_types.h index 5678a9ddf817..9d5e4d1a331a 100644 --- a/kernel/bpf/bpf_struct_ops_types.h +++ b/kernel/bpf/bpf_struct_ops_types.h @@ -9,4 +9,8 @@ BPF_STRUCT_OPS_TYPE(bpf_dummy_ops) #include <net/tcp.h> BPF_STRUCT_OPS_TYPE(tcp_congestion_ops) #endif +#ifdef CONFIG_PARAVIRT_SCHED_HOST +#include <linux/pvsched.h> +BPF_STRUCT_OPS_TYPE(pvsched_vcpu_ops) +#endif #endif diff --git a/virt/pvsched/Makefile b/virt/pvsched/Makefile index 4ca38e30479b..02bc072cd806 100644 --- a/virt/pvsched/Makefile +++ b/virt/pvsched/Makefile @@ -1,2 +1,2 @@ -obj-$(CONFIG_PARAVIRT_SCHED_HOST) += pvsched.o +obj-$(CONFIG_PARAVIRT_SCHED_HOST) += pvsched.o pvsched_bpf.o diff --git a/virt/pvsched/pvsched_bpf.c b/virt/pvsched/pvsched_bpf.c new file mode 100644 index 000000000000..b125089abc3b --- /dev/null +++ b/virt/pvsched/pvsched_bpf.c @@ -0,0 +1,141 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2024 Google */ + +#include <linux/types.h> +#include <linux/bpf_verifier.h> +#include <linux/bpf.h> +#include <linux/btf.h> +#include <linux/filter.h> +#include <linux/pvsched.h> + + +/* "extern" is to avoid sparse warning. It is only used in bpf_struct_ops.c. */ +extern struct bpf_struct_ops bpf_pvsched_vcpu_ops; + +static int bpf_pvsched_vcpu_init(struct btf *btf) +{ + return 0; +} + +static bool bpf_pvsched_vcpu_is_valid_access(int off, int size, + enum bpf_access_type type, + const struct bpf_prog *prog, + struct bpf_insn_access_aux *info) +{ + if (off < 0 || off >= sizeof(__u64) * MAX_BPF_FUNC_ARGS) + return false; + if (type != BPF_READ) + return false; + if (off % size != 0) + return false; + + if (!btf_ctx_access(off, size, type, prog, info)) + return false; + + return true; +} + +static int bpf_pvsched_vcpu_btf_struct_access(struct bpf_verifier_log *log, + const struct bpf_reg_state *reg, + int off, int size) +{ + /* + * TODO: Enable write access to Guest shared mem. + */ + return -EACCES; +} + +static const struct bpf_func_proto * +bpf_pvsched_vcpu_get_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) +{ + return bpf_base_func_proto(func_id); +} + +static const struct bpf_verifier_ops bpf_pvsched_vcpu_verifier_ops = { + .get_func_proto = bpf_pvsched_vcpu_get_func_proto, + .is_valid_access = bpf_pvsched_vcpu_is_valid_access, + .btf_struct_access = bpf_pvsched_vcpu_btf_struct_access, +}; + +static int bpf_pvsched_vcpu_init_member(const struct btf_type *t, + const struct btf_member *member, + void *kdata, const void *udata) +{ + const struct pvsched_vcpu_ops *uvm_ops; + struct pvsched_vcpu_ops *vm_ops; + u32 moff; + + uvm_ops = (const struct pvsched_vcpu_ops *)udata; + vm_ops = (struct pvsched_vcpu_ops *)kdata; + + moff = __btf_member_bit_offset(t, member) / 8; + switch (moff) { + case offsetof(struct pvsched_vcpu_ops, events): + vm_ops->events = *(u32 *)(udata + moff); + return 1; + case offsetof(struct pvsched_vcpu_ops, name): + if (bpf_obj_name_cpy(vm_ops->name, uvm_ops->name, + sizeof(vm_ops->name)) <= 0) + return -EINVAL; + return 1; + } + + return 0; +} + +static int bpf_pvsched_vcpu_check_member(const struct btf_type *t, + const struct btf_member *member, + const struct bpf_prog *prog) +{ + return 0; +} + +static int bpf_pvsched_vcpu_reg(void *kdata) +{ + return pvsched_register_vcpu_ops((struct pvsched_vcpu_ops *)kdata); +} + +static void bpf_pvsched_vcpu_unreg(void *kdata) +{ + pvsched_unregister_vcpu_ops((struct pvsched_vcpu_ops *)kdata); +} + +static int bpf_pvsched_vcpu_validate(void *kdata) +{ + return pvsched_validate_vcpu_ops((struct pvsched_vcpu_ops *)kdata); +} + +static int bpf_pvsched_vcpu_update(void *kdata, void *old_kdata) +{ + return -EOPNOTSUPP; +} + +static int __pvsched_vcpu_register(struct pid *pid) +{ + return 0; +} +static void __pvsched_vcpu_unregister(struct pid *pid) +{ +} +static void __pvsched_notify_event(void *addr, struct pid *pid, u32 event) +{ +} + +static struct pvsched_vcpu_ops __bpf_ops_pvsched_vcpu_ops = { + .pvsched_vcpu_register = __pvsched_vcpu_register, + .pvsched_vcpu_unregister = __pvsched_vcpu_unregister, + .pvsched_vcpu_notify_event = __pvsched_notify_event, +}; + +struct bpf_struct_ops bpf_pvsched_vcpu_ops = { + .init = &bpf_pvsched_vcpu_init, + .validate = bpf_pvsched_vcpu_validate, + .update = bpf_pvsched_vcpu_update, + .verifier_ops = &bpf_pvsched_vcpu_verifier_ops, + .reg = bpf_pvsched_vcpu_reg, + .unreg = bpf_pvsched_vcpu_unreg, + .check_member = bpf_pvsched_vcpu_check_member, + .init_member = bpf_pvsched_vcpu_init_member, + .name = "pvsched_vcpu_ops", + .cfi_stubs = &__bpf_ops_pvsched_vcpu_ops, +};