diff options
Diffstat (limited to 'arch/riscv/kvm/vcpu_sbi_sta.c')
| -rw-r--r-- | arch/riscv/kvm/vcpu_sbi_sta.c | 208 |
1 files changed, 208 insertions, 0 deletions
diff --git a/arch/riscv/kvm/vcpu_sbi_sta.c b/arch/riscv/kvm/vcpu_sbi_sta.c new file mode 100644 index 000000000000..01f09fe8c3b0 --- /dev/null +++ b/arch/riscv/kvm/vcpu_sbi_sta.c @@ -0,0 +1,208 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2023 Ventana Micro Systems Inc. + */ + +#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) +{ + vcpu->arch.sta.shmem = INVALID_GPA; + vcpu->arch.sta.last_steal = 0; +} + +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) +{ + 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, + struct kvm_vcpu_sbi_return *retdata) +{ + struct kvm_cpu_context *cp = &vcpu->arch.guest_context; + unsigned long funcid = cp->a6; + int ret; + + switch (funcid) { + case SBI_EXT_STA_STEAL_TIME_SET_SHMEM: + ret = kvm_sbi_sta_steal_time_set_shmem(vcpu); + break; + default: + ret = SBI_ERR_NOT_SUPPORTED; + break; + } + + retdata->err_val = ret; + + return 0; +} + +static unsigned long kvm_sbi_ext_sta_probe(struct kvm_vcpu *vcpu) +{ + return !!sched_info_on(); +} + +const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_sta = { + .extid_start = SBI_EXT_STA, + .extid_end = SBI_EXT_STA, + .handler = kvm_sbi_ext_sta_handler, + .probe = kvm_sbi_ext_sta_probe, +}; + +int kvm_riscv_vcpu_get_reg_sbi_sta(struct kvm_vcpu *vcpu, + unsigned long reg_num, + unsigned long *reg_val) +{ + switch (reg_num) { + case KVM_REG_RISCV_SBI_STA_REG(shmem_lo): + *reg_val = (unsigned long)vcpu->arch.sta.shmem; + break; + case KVM_REG_RISCV_SBI_STA_REG(shmem_hi): + if (IS_ENABLED(CONFIG_32BIT)) + *reg_val = upper_32_bits(vcpu->arch.sta.shmem); + else + *reg_val = 0; + break; + default: + return -EINVAL; + } + + return 0; +} + +int kvm_riscv_vcpu_set_reg_sbi_sta(struct kvm_vcpu *vcpu, + unsigned long reg_num, + unsigned long reg_val) +{ + switch (reg_num) { + case KVM_REG_RISCV_SBI_STA_REG(shmem_lo): + if (IS_ENABLED(CONFIG_32BIT)) { + gpa_t hi = upper_32_bits(vcpu->arch.sta.shmem); + + vcpu->arch.sta.shmem = reg_val; + vcpu->arch.sta.shmem |= hi << 32; + } else { + vcpu->arch.sta.shmem = reg_val; + } + break; + case KVM_REG_RISCV_SBI_STA_REG(shmem_hi): + if (IS_ENABLED(CONFIG_32BIT)) { + gpa_t lo = lower_32_bits(vcpu->arch.sta.shmem); + + vcpu->arch.sta.shmem = ((gpa_t)reg_val << 32); + vcpu->arch.sta.shmem |= lo; + } else if (reg_val != 0) { + return -EINVAL; + } + break; + default: + return -EINVAL; + } + + return 0; +} |