[PATCH v2 1/3] RISC-V: KVM: Add SBI extension validate callback

[Inochi Amaoto <inochiama@gmail.com>]

When user disable FWFT extension after setting any value of the
FWFT feature, the state of vCPU will be broken since the value
of disable FWFT feature is still functional.

Add the generic SBI extension validate callback so the FWFT
extension can fix its parameters before the first run.

Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
---
 arch/riscv/include/asm/kvm_vcpu_sbi.h |  4 ++++
 arch/riscv/kvm/vcpu_config.c          |  2 ++
 arch/riscv/kvm/vcpu_sbi.c             | 23 +++++++++++++++++++++++
 3 files changed, 29 insertions(+)

diff --git a/arch/riscv/include/asm/kvm_vcpu_sbi.h b/arch/riscv/include/asm/kvm_vcpu_sbi.h
index c1a7e3b40d9c..f01a2860c751 100644
--- a/arch/riscv/include/asm/kvm_vcpu_sbi.h
+++ b/arch/riscv/include/asm/kvm_vcpu_sbi.h
@@ -60,6 +60,9 @@ struct kvm_vcpu_sbi_extension {
 
 	void (*reset)(struct kvm_vcpu *vcpu);
 
+	/* Allow the extension to correct its parameters before the first run */
+	void (*validate)(struct kvm_vcpu *vcpu);
+
 	unsigned long state_reg_subtype;
 	unsigned long (*get_state_reg_count)(struct kvm_vcpu *vcpu);
 	int (*get_state_reg_id)(struct kvm_vcpu *vcpu, int index, u64 *reg_id);
@@ -93,6 +96,7 @@ 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);
 void kvm_riscv_vcpu_sbi_reset(struct kvm_vcpu *vcpu);
+void kvm_riscv_vcpu_sbi_validate(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_config.c b/arch/riscv/kvm/vcpu_config.c
index 238418fed2b9..b68aa830aaf5 100644
--- a/arch/riscv/kvm/vcpu_config.c
+++ b/arch/riscv/kvm/vcpu_config.c
@@ -69,6 +69,8 @@ void kvm_riscv_vcpu_config_ran_once(struct kvm_vcpu *vcpu)
 
 	if (vcpu->guest_debug)
 		cfg->hedeleg &= ~BIT(EXC_BREAKPOINT);
+
+	kvm_riscv_vcpu_sbi_validate(vcpu);
 }
 
 void kvm_riscv_vcpu_config_load(struct kvm_vcpu *vcpu)
diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c
index 46ab7b989432..b737e9a7a12a 100644
--- a/arch/riscv/kvm/vcpu_sbi.c
+++ b/arch/riscv/kvm/vcpu_sbi.c
@@ -723,3 +723,26 @@ void kvm_riscv_vcpu_sbi_reset(struct kvm_vcpu *vcpu)
 		ext->reset(vcpu);
 	}
 }
+
+void kvm_riscv_vcpu_sbi_validate(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_ENABLED ||
+		    !ext->validate)
+			continue;
+
+		ext->validate(vcpu);
+	}
+}
-- 
2.55.0