On Sun, Dec 17, 2023 at 12:40 PM Andrew Jones <ajones@xxxxxxxxxxxxxxxx> wrote: > > Add a select SCHED_INFO to the KVM config in order to get run_delay > info. Then implement SBI STA's set-steal-time-shmem function and > kvm_riscv_vcpu_record_steal_time() to provide the steal-time info > to guests. > > Reviewed-by: Anup Patel <anup@xxxxxxxxxxxxxx> > Signed-off-by: Andrew Jones <ajones@xxxxxxxxxxxxxxxx> > --- > arch/riscv/kvm/Kconfig | 1 + > arch/riscv/kvm/vcpu_sbi_sta.c | 96 ++++++++++++++++++++++++++++++++++- > 2 files changed, 95 insertions(+), 2 deletions(-) > > diff --git a/arch/riscv/kvm/Kconfig b/arch/riscv/kvm/Kconfig > index dfc237d7875b..148e52b516cf 100644 > --- a/arch/riscv/kvm/Kconfig > +++ b/arch/riscv/kvm/Kconfig > @@ -32,6 +32,7 @@ config KVM > select KVM_XFER_TO_GUEST_WORK > select MMU_NOTIFIER > select PREEMPT_NOTIFIERS > + select SCHED_INFO > help > Support hosting virtualized guest machines. > > diff --git a/arch/riscv/kvm/vcpu_sbi_sta.c b/arch/riscv/kvm/vcpu_sbi_sta.c > index 87bf1a5f05ce..01f09fe8c3b0 100644 > --- a/arch/riscv/kvm/vcpu_sbi_sta.c > +++ b/arch/riscv/kvm/vcpu_sbi_sta.c > @@ -6,9 +6,15 @@ > #include <linux/kconfig.h> > #include <linux/kernel.h> > #include <linux/kvm_host.h> > +#include <linux/mm.h> > +#include <linux/sizes.h> > > +#include <asm/bug.h> > +#include <asm/current.h> > #include <asm/kvm_vcpu_sbi.h> > +#include <asm/page.h> > #include <asm/sbi.h> > +#include <asm/uaccess.h> > > void kvm_riscv_vcpu_sbi_sta_reset(struct kvm_vcpu *vcpu) > { > @@ -19,14 +25,100 @@ void kvm_riscv_vcpu_sbi_sta_reset(struct kvm_vcpu *vcpu) > void kvm_riscv_vcpu_record_steal_time(struct kvm_vcpu *vcpu) > { > gpa_t shmem = vcpu->arch.sta.shmem; > + u64 last_steal = vcpu->arch.sta.last_steal; > + u32 *sequence_ptr, sequence; > + u64 *steal_ptr, steal; > + unsigned long hva; > + gfn_t gfn; > > if (shmem == INVALID_GPA) > return; > + > + /* > + * shmem is 64-byte aligned (see the enforcement in > + * kvm_sbi_sta_steal_time_set_shmem()) and the size of sbi_sta_struct > + * is 64 bytes, so we know all its offsets are in the same page. > + */ > + gfn = shmem >> PAGE_SHIFT; > + hva = kvm_vcpu_gfn_to_hva(vcpu, gfn); > + > + if (WARN_ON(kvm_is_error_hva(hva))) { > + vcpu->arch.sta.shmem = INVALID_GPA; > + return; > + } > + > + sequence_ptr = (u32 *)(hva + offset_in_page(shmem) + > + offsetof(struct sbi_sta_struct, sequence)); > + steal_ptr = (u64 *)(hva + offset_in_page(shmem) + > + offsetof(struct sbi_sta_struct, steal)); > + > + if (WARN_ON(get_user(sequence, sequence_ptr))) > + return; > + > + sequence = le32_to_cpu(sequence); > + sequence += 1; > + > + if (WARN_ON(put_user(cpu_to_le32(sequence), sequence_ptr))) > + return; > + > + if (!WARN_ON(get_user(steal, steal_ptr))) { > + steal = le64_to_cpu(steal); > + vcpu->arch.sta.last_steal = READ_ONCE(current->sched_info.run_delay); > + steal += vcpu->arch.sta.last_steal - last_steal; > + WARN_ON(put_user(cpu_to_le64(steal), steal_ptr)); > + } > + > + sequence += 1; > + WARN_ON(put_user(cpu_to_le32(sequence), sequence_ptr)); > + > + kvm_vcpu_mark_page_dirty(vcpu, gfn); > } > > static int kvm_sbi_sta_steal_time_set_shmem(struct kvm_vcpu *vcpu) > { > - return SBI_ERR_FAILURE; > + struct kvm_cpu_context *cp = &vcpu->arch.guest_context; > + unsigned long shmem_phys_lo = cp->a0; > + unsigned long shmem_phys_hi = cp->a1; > + u32 flags = cp->a2; > + struct sbi_sta_struct zero_sta = {0}; > + unsigned long hva; > + bool writable; > + gpa_t shmem; > + int ret; > + > + if (flags != 0) > + return SBI_ERR_INVALID_PARAM; > + > + if (shmem_phys_lo == SBI_STA_SHMEM_DISABLE && > + shmem_phys_hi == SBI_STA_SHMEM_DISABLE) { > + vcpu->arch.sta.shmem = INVALID_GPA; > + return 0; > + } > + > + if (shmem_phys_lo & (SZ_64 - 1)) > + return SBI_ERR_INVALID_PARAM; > + > + shmem = shmem_phys_lo; > + > + if (shmem_phys_hi != 0) { > + if (IS_ENABLED(CONFIG_32BIT)) > + shmem |= ((gpa_t)shmem_phys_hi << 32); > + else > + return SBI_ERR_INVALID_ADDRESS; > + } > + > + hva = kvm_vcpu_gfn_to_hva_prot(vcpu, shmem >> PAGE_SHIFT, &writable); > + if (kvm_is_error_hva(hva) || !writable) > + return SBI_ERR_INVALID_ADDRESS; > + > + ret = kvm_vcpu_write_guest(vcpu, shmem, &zero_sta, sizeof(zero_sta)); > + if (ret) > + return SBI_ERR_FAILURE; > + > + vcpu->arch.sta.shmem = shmem; > + vcpu->arch.sta.last_steal = current->sched_info.run_delay; > + > + return 0; > } > > static int kvm_sbi_ext_sta_handler(struct kvm_vcpu *vcpu, struct kvm_run *run, > @@ -52,7 +144,7 @@ static int kvm_sbi_ext_sta_handler(struct kvm_vcpu *vcpu, struct kvm_run *run, > > static unsigned long kvm_sbi_ext_sta_probe(struct kvm_vcpu *vcpu) > { > - return 0; > + return !!sched_info_on(); > } > > const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_sta = { > -- > 2.43.0 > Reviewed-by: Atish Patra <atishp@xxxxxxxxxxxx> -- Regards, Atish