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> Reviewed-by: Atish Patra <atishp@xxxxxxxxxxxx> 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