[PATCH v2 3/3] RISC-V: KVM: Reset the SBI extension when disable it

[Inochi Amaoto <inochiama@gmail.com>]

The SBI extension validation callback can only fix the parameter if
the extension is enabled. However, if the extension is disabled after
modifty some parameters, the state of the extension is still broken.

Reset the extension when the extenion is disabled so it can have
a clear context.

Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
---
 arch/riscv/kvm/vcpu_sbi.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c
index b737e9a7a12a..3eb7b7c57059 100644
--- a/arch/riscv/kvm/vcpu_sbi.c
+++ b/arch/riscv/kvm/vcpu_sbi.c
@@ -221,6 +221,7 @@ static int riscv_vcpu_set_sbi_ext_single(struct kvm_vcpu *vcpu,
 {
 	struct kvm_vcpu_sbi_context *scontext = &vcpu->arch.sbi_context;
 	const struct kvm_riscv_sbi_extension_entry *sext;
+	const struct kvm_vcpu_sbi_extension *ext;
 
 	if (reg_val != 1 && reg_val != 0)
 		return -EINVAL;
@@ -229,6 +230,15 @@ static int riscv_vcpu_set_sbi_ext_single(struct kvm_vcpu *vcpu,
 	if (!sext || scontext->ext_status[sext->ext_idx] == KVM_RISCV_SBI_EXT_STATUS_UNAVAILABLE)
 		return -ENOENT;
 
+	ext = sext->ext_ptr;
+
+	if (!reg_val && scontext->ext_status[sext->ext_idx] == KVM_RISCV_SBI_EXT_STATUS_ENABLED) {
+		if (ext->reset) {
+			ext->reset(vcpu);
+			vcpu->arch.csr_dirty = true;
+		}
+	}
+
 	scontext->ext_status[sext->ext_idx] = (reg_val) ?
 			KVM_RISCV_SBI_EXT_STATUS_ENABLED :
 			KVM_RISCV_SBI_EXT_STATUS_DISABLED;
-- 
2.55.0