[PATCH v5 10/13] RISC-V: KVM: add SBI extension init()/deinit() functions

Clément Léger
2025-04-17T12:36:23Z

The FWFT SBI extension will need to dynamically allocate memory and do
init time specific initialization. Add an init/deinit callbacks that
allows to do so.

Signed-off-by: Clément Léger <cleger@rivosinc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
---
arch/riscv/include/asm/kvm_vcpu_sbi.h | 9 +++++++++
arch/riscv/kvm/vcpu.c | 2 ++
arch/riscv/kvm/vcpu_sbi.c | 26 ++++++++++++++++++++++++++
3 files changed, 37 insertions(+)

diff --git a/arch/riscv/include/asm/kvm_vcpu_sbi.h b/arch/riscv/include/asm/kvm_vcpu_sbi.h
index 4ed6203cdd30..bcb90757b149 100644
--- a/arch/riscv/include/asm/kvm_vcpu_sbi.h
+++ b/arch/riscv/include/asm/kvm_vcpu_sbi.h
@@ -49,6 +49,14 @@ struct kvm_vcpu_sbi_extension {

/* Extension specific probe function */
unsigned long (*probe)(struct kvm_vcpu *vcpu);
+
+ /*
+ * Init/deinit function called once during VCPU init/destroy. These
+ * might be use if the SBI extensions need to allocate or do specific
+ * init time only configuration.
+ */
+ int (*init)(struct kvm_vcpu *vcpu);
+ void (*deinit)(struct kvm_vcpu *vcpu);
};

void kvm_riscv_vcpu_sbi_forward(struct kvm_vcpu *vcpu, struct kvm_run *run);
@@ -69,6 +77,7 @@ const struct kvm_vcpu_sbi_extension *kvm_vcpu_sbi_find_ext(
bool riscv_vcpu_supports_sbi_ext(struct kvm_vcpu *vcpu, int idx);
int kvm_riscv_vcpu_sbi_ecall(struct kvm_vcpu *vcpu, struct kvm_run *run);
void kvm_riscv_vcpu_sbi_init(struct kvm_vcpu *vcpu);
+void kvm_riscv_vcpu_sbi_deinit(struct kvm_vcpu *vcpu);

int kvm_riscv_vcpu_get_reg_sbi_sta(struct kvm_vcpu *vcpu, unsigned long reg_num,
unsigned long *reg_val);
diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
index 60d684c76c58..877bcc85c067 100644
--- a/arch/riscv/kvm/vcpu.c
+++ b/arch/riscv/kvm/vcpu.c
@@ -185,6 +185,8 @@ void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu)

void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
{
+ kvm_riscv_vcpu_sbi_deinit(vcpu);
+
/* Cleanup VCPU AIA context */
kvm_riscv_vcpu_aia_deinit(vcpu);

diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c
index d1c83a77735e..3139f171c20f 100644
--- a/arch/riscv/kvm/vcpu_sbi.c
+++ b/arch/riscv/kvm/vcpu_sbi.c
@@ -508,5 +508,31 @@ void kvm_riscv_vcpu_sbi_init(struct kvm_vcpu *vcpu)
scontext->ext_status[idx] = ext->default_disabled ?
KVM_RISCV_SBI_EXT_STATUS_DISABLED :
KVM_RISCV_SBI_EXT_STATUS_ENABLED;
+
+ if (ext->init && ext->init(vcpu) != 0)
+ scontext->ext_status[idx] = KVM_RISCV_SBI_EXT_STATUS_UNAVAILABLE;
+ }
+}
+
+void kvm_riscv_vcpu_sbi_deinit(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 idx, i;
+
+ for (i = 0; i < ARRAY_SIZE(sbi_ext); i++) {
+ entry = &sbi_ext[i];
+ ext = entry->ext_ptr;
+ idx = entry->ext_idx;
+
+ if (idx < 0 || idx >= ARRAY_SIZE(scontext->ext_status))
+ continue;
+
+ if (scontext->ext_status[idx] == KVM_RISCV_SBI_EXT_STATUS_UNAVAILABLE ||
+ !ext->deinit)
+ continue;
+
+ ext->deinit(vcpu);
}
}