RISC-V: KVM: Modify SBI extension handler to return SBI error code

Currently, the SBI extension handle is expected to return Linux error code.
The top SBI layer converts the Linux error code to SBI specific error code
that can be returned to guest invoking the SBI calls. This model works
as long as SBI error codes have 1-to-1 mappings between them.
However, that may not be true always. This patch attempts to disassociate
both these error codes by allowing the SBI extension implementation to
return SBI specific error codes as well.

The extension will continue to return the Linux error specific code which
will indicate any problem *with* the extension emulation while the
SBI specific error will indicate the problem *of* the emulation.

Reviewed-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Suggested-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Signed-off-by: Anup Patel <anup@brainfault.org>

1 files changed, 8 insertions, 2 deletions

diff --git a/arch/riscv/include/asm/kvm_vcpu_sbi.h b/arch/riscv/include/asm/kvm_vcpu_sbi.h
index 45ba341e887a..8425556af7d1 100644
--- a/arch/riscv/include/asm/kvm_vcpu_sbi.h
+++ b/arch/riscv/include/asm/kvm_vcpu_sbi.h
@@ -18,6 +18,13 @@ struct kvm_vcpu_sbi_context {
 	int return_handled;
 };
 
+struct kvm_vcpu_sbi_return {
+	unsigned long out_val;
+	unsigned long err_val;
+	struct kvm_cpu_trap *utrap;
+	bool uexit;
+};
+
 struct kvm_vcpu_sbi_extension {
 	unsigned long extid_start;
 	unsigned long extid_end;
@@ -27,8 +34,7 @@ struct kvm_vcpu_sbi_extension {
 	 * specific error codes.
 	 */
 	int (*handler)(struct kvm_vcpu *vcpu, struct kvm_run *run,
-		       unsigned long *out_val, struct kvm_cpu_trap *utrap,
-		       bool *exit);
+		       struct kvm_vcpu_sbi_return *retdata);
 
 	/* Extension specific probe function */
 	unsigned long (*probe)(struct kvm_vcpu *vcpu);