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 <[email protected]>
Reviewed-by: Andrew Jones <[email protected]>
Suggested-by: Andrew Jones <[email protected]>
Signed-off-by: Atish Patra <[email protected]>
Signed-off-by: Anup Patel <[email protected]>

1 files changed, 8 insertions, 11 deletions

diff --git a/arch/riscv/kvm/vcpu_sbi_base.c b/arch/riscv/kvm/vcpu_sbi_base.c
index 66398065a6a6..9945aff34c14 100644
--- a/arch/riscv/kvm/vcpu_sbi_base.c
+++ b/arch/riscv/kvm/vcpu_sbi_base.c
@@ -14,12 +14,11 @@
 #include <asm/kvm_vcpu_sbi.h>
 
 static int kvm_sbi_ext_base_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
-				    unsigned long *out_val,
-				    struct kvm_cpu_trap *trap, bool *exit)
+				    struct kvm_vcpu_sbi_return *retdata)
 {
-	int ret = 0;
 	struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
 	const struct kvm_vcpu_sbi_extension *sbi_ext;
+	unsigned long *out_val = &retdata->out_val;
 
 	switch (cp->a6) {
 	case SBI_EXT_BASE_GET_SPEC_VERSION:
@@ -43,7 +42,7 @@ static int kvm_sbi_ext_base_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
 			 * forward it to the userspace
 			 */
 			kvm_riscv_vcpu_sbi_forward(vcpu, run);
-			*exit = true;
+			retdata->uexit = true;
 		} else {
 			sbi_ext = kvm_vcpu_sbi_find_ext(cp->a0);
 			*out_val = sbi_ext && sbi_ext->probe ?
@@ -60,11 +59,11 @@ static int kvm_sbi_ext_base_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
 		*out_val = vcpu->arch.mimpid;
 		break;
 	default:
-		ret = -EOPNOTSUPP;
+		retdata->err_val = SBI_ERR_NOT_SUPPORTED;
 		break;
 	}
 
-	return ret;
+	return 0;
 }
 
 const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_base = {
@@ -74,17 +73,15 @@ const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_base = {
 };
 
 static int kvm_sbi_ext_forward_handler(struct kvm_vcpu *vcpu,
-					struct kvm_run *run,
-					unsigned long *out_val,
-					struct kvm_cpu_trap *utrap,
-					bool *exit)
+				       struct kvm_run *run,
+				       struct kvm_vcpu_sbi_return *retdata)
 {
 	/*
 	 * Both SBI experimental and vendor extensions are
 	 * unconditionally forwarded to userspace.
 	 */
 	kvm_riscv_vcpu_sbi_forward(vcpu, run);
-	*exit = true;
+	retdata->uexit = true;
 	return 0;
 }