Currently, all SBI extensions are enabled by default which is problematic for SBI extensions (such as DBCN) which are forwarded to the KVM user-space because we might have an older KVM user-space which is not aware/ready to handle newer SBI extensions. Ideally, the SBI extensions forwarded to the KVM user-space must be disabled by default. To address above, we allow certain SBI extensions to be disabled by default so that KVM user-space must explicitly enable such SBI extensions to receive forwarded calls from Guest VCPU. Signed-off-by: Anup Patel <apatel@xxxxxxxxxxxxxxxx> --- arch/riscv/include/asm/kvm_vcpu_sbi.h | 4 ++ arch/riscv/kvm/vcpu.c | 6 +++ arch/riscv/kvm/vcpu_sbi.c | 57 +++++++++++++-------------- 3 files changed, 38 insertions(+), 29 deletions(-) diff --git a/arch/riscv/include/asm/kvm_vcpu_sbi.h b/arch/riscv/include/asm/kvm_vcpu_sbi.h index 8d6d4dce8a5e..c02bda5559d7 100644 --- a/arch/riscv/include/asm/kvm_vcpu_sbi.h +++ b/arch/riscv/include/asm/kvm_vcpu_sbi.h @@ -35,6 +35,9 @@ struct kvm_vcpu_sbi_return { struct kvm_vcpu_sbi_extension { unsigned long extid_start; unsigned long extid_end; + + bool default_unavail; + /** * SBI extension handler. It can be defined for a given extension or group of * extension. But it should always return linux error codes rather than SBI @@ -59,6 +62,7 @@ int kvm_riscv_vcpu_get_reg_sbi_ext(struct kvm_vcpu *vcpu, const struct kvm_vcpu_sbi_extension *kvm_vcpu_sbi_find_ext( struct kvm_vcpu *vcpu, unsigned long extid); int kvm_riscv_vcpu_sbi_ecall(struct kvm_vcpu *vcpu, struct kvm_run *run); +void kvm_riscv_vcpu_sbi_init(struct kvm_vcpu *vcpu); #ifdef CONFIG_RISCV_SBI_V01 extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_v01; diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c index c061a1c5fe98..e087c809073c 100644 --- a/arch/riscv/kvm/vcpu.c +++ b/arch/riscv/kvm/vcpu.c @@ -141,6 +141,12 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu) if (rc) return rc; + /* + * Setup SBI extensions + * NOTE: This must be the last thing to be initialized. + */ + kvm_riscv_vcpu_sbi_init(vcpu); + /* Reset VCPU */ kvm_riscv_reset_vcpu(vcpu); diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c index 9cd97091c723..bda8b0b33343 100644 --- a/arch/riscv/kvm/vcpu_sbi.c +++ b/arch/riscv/kvm/vcpu_sbi.c @@ -155,14 +155,8 @@ static int riscv_vcpu_set_sbi_ext_single(struct kvm_vcpu *vcpu, if (!sext) return -ENOENT; - /* - * We can't set the extension status to available here, since it may - * have a probe() function which needs to confirm availability first, - * but it may be too early to call that here. We can set the status to - * unavailable, though. - */ - if (!reg_val) - scontext->ext_status[sext->ext_idx] = + scontext->ext_status[sext->ext_idx] = (reg_val) ? + KVM_RISCV_SBI_EXT_AVAILABLE : KVM_RISCV_SBI_EXT_UNAVAILABLE; return 0; @@ -188,16 +182,8 @@ static int riscv_vcpu_get_sbi_ext_single(struct kvm_vcpu *vcpu, if (!sext) return -ENOENT; - /* - * If the extension status is still uninitialized, then we should probe - * to determine if it's available, but it may be too early to do that - * here. The best we can do is report that the extension has not been - * disabled, i.e. we return 1 when the extension is available and also - * when it only may be available. - */ - *reg_val = scontext->ext_status[sext->ext_idx] != - KVM_RISCV_SBI_EXT_UNAVAILABLE; - + *reg_val = scontext->ext_status[sext->ext_idx] == + KVM_RISCV_SBI_EXT_AVAILABLE; return 0; } @@ -337,18 +323,8 @@ const struct kvm_vcpu_sbi_extension *kvm_vcpu_sbi_find_ext( scontext->ext_status[entry->ext_idx] == KVM_RISCV_SBI_EXT_AVAILABLE) return ext; - if (scontext->ext_status[entry->ext_idx] == - KVM_RISCV_SBI_EXT_UNAVAILABLE) - return NULL; - if (ext->probe && !ext->probe(vcpu)) { - scontext->ext_status[entry->ext_idx] = - KVM_RISCV_SBI_EXT_UNAVAILABLE; - return NULL; - } - scontext->ext_status[entry->ext_idx] = - KVM_RISCV_SBI_EXT_AVAILABLE; - return ext; + return NULL; } } @@ -419,3 +395,26 @@ int kvm_riscv_vcpu_sbi_ecall(struct kvm_vcpu *vcpu, struct kvm_run *run) return ret; } + +void kvm_riscv_vcpu_sbi_init(struct kvm_vcpu *vcpu) +{ + struct kvm_vcpu_sbi_context *scontext = &vcpu->arch.sbi_context; + const struct kvm_riscv_sbi_extension_entry *entry; + const struct kvm_vcpu_sbi_extension *ext; + int i; + + for (i = 0; i < ARRAY_SIZE(sbi_ext); i++) { + entry = &sbi_ext[i]; + ext = entry->ext_ptr; + + if (ext->probe && !ext->probe(vcpu)) { + scontext->ext_status[entry->ext_idx] = + KVM_RISCV_SBI_EXT_UNAVAILABLE; + continue; + } + + scontext->ext_status[entry->ext_idx] = ext->default_unavail ? + KVM_RISCV_SBI_EXT_UNAVAILABLE : + KVM_RISCV_SBI_EXT_AVAILABLE; + } +} -- 2.34.1