[PATCH v5] target/riscv/kvm/kvm-cpu.c: kvm_riscv_handle_sbi() fail with vendor-specific sbi.

[Alexei Filippov]

kvm_riscv_handle_sbi() may return not supported return code to not
trigger qemu abort with vendor-specific sbi.

Add new error path to provide proper error in case of
qemu_chr_fe_read_all() may not return sizeof(ch).

Added SBI related return code's defines.

Signed-off-by: Alexei Filippov <alexei.filip...@syntacore.com>
---
 target/riscv/kvm/kvm-cpu.c         | 9 +++++----
 target/riscv/sbi_ecall_interface.h | 1 +
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/target/riscv/kvm/kvm-cpu.c b/target/riscv/kvm/kvm-cpu.c
index aeca1e3e83..5bb7b74d03 100644
--- a/target/riscv/kvm/kvm-cpu.c
+++ b/target/riscv/kvm/kvm-cpu.c
@@ -1173,17 +1173,18 @@ static int kvm_riscv_handle_sbi(CPUState *cs, struct 
kvm_run *run)
         ret = qemu_chr_fe_read_all(serial_hd(0)->be, &ch, sizeof(ch));
         if (ret == sizeof(ch)) {
             run->riscv_sbi.ret[0] = ch;
-        } else {
+            ret = 0;
+        } else if (ret == 0) {
             run->riscv_sbi.ret[0] = SBI_ERR_FAILURE;
+        } else {
+            ret = -1;
         }
-        ret = 0;
         break;
     default:
         qemu_log_mask(LOG_UNIMP,
-                      "%s: un-handled SBI EXIT, specific reasons is %lu\n",
+                      "%s: Unhandled SBI exit with extension-id %lu\n"
                       __func__, run->riscv_sbi.extension_id);
         run->riscv_sbi.ret[0] = SBI_ERR_NOT_SUPPORTED;
-        ret = 0;
         break;
     }
     return ret;
diff --git a/target/riscv/sbi_ecall_interface.h 
b/target/riscv/sbi_ecall_interface.h
index 0279e92a36..a2e21d9b8c 100644
--- a/target/riscv/sbi_ecall_interface.h
+++ b/target/riscv/sbi_ecall_interface.h
@@ -79,5 +79,6 @@
 #define SBI_ERR_ALREADY_AVAILABLE   -6
 #define SBI_ERR_ALREADY_STARTED     -7
 #define SBI_ERR_ALREADY_STOPPED     -8
+#define SBI_ERR_NO_SHMEM            -9
 
 #endif
-- 
2.34.1