target/riscv: Handle KVM_EXIT_RISCV_SBI exit

Use char-fe to handle console sbi call, which implement early
console io while apply 'earlycon=sbi' into kernel parameters.

Signed-off-by: Yifei Jiang <jiangyifei@huawei.com>
Signed-off-by: Mingwang Li <limingwang@huawei.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: 20220112081329.1835-9-jiangyifei@huawei.com
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

2 files changed, 113 insertions, 1 deletions

diff --git a/target/riscv/kvm.c b/target/riscv/kvm.c
index 0ba6479..e90e2a6 100644
--- a/target/riscv/kvm.c
+++ b/target/riscv/kvm.c
@@ -38,6 +38,8 @@
 #include "qemu/log.h"
 #include "hw/loader.h"
 #include "kvm_riscv.h"
+#include "sbi_ecall_interface.h"
+#include "chardev/char-fe.h"
 
 static uint64_t kvm_riscv_reg_id(CPURISCVState *env, uint64_t type,
                                  uint64_t idx)
@@ -367,9 +369,47 @@ bool kvm_arch_stop_on_emulation_error(CPUState *cs)
     return true;
 }
 
+static int kvm_riscv_handle_sbi(CPUState *cs, struct kvm_run *run)
+{
+    int ret = 0;
+    unsigned char ch;
+    switch (run->riscv_sbi.extension_id) {
+    case SBI_EXT_0_1_CONSOLE_PUTCHAR:
+        ch = run->riscv_sbi.args[0];
+        qemu_chr_fe_write(serial_hd(0)->be, &ch, sizeof(ch));
+        break;
+    case SBI_EXT_0_1_CONSOLE_GETCHAR:
+        ret = qemu_chr_fe_read_all(serial_hd(0)->be, &ch, sizeof(ch));
+        if (ret == sizeof(ch)) {
+            run->riscv_sbi.args[0] = ch;
+        } else {
+            run->riscv_sbi.args[0] = -1;
+        }
+        break;
+    default:
+        qemu_log_mask(LOG_UNIMP,
+                      "%s: un-handled SBI EXIT, specific reasons is %lu\n",
+                      __func__, run->riscv_sbi.extension_id);
+        ret = -1;
+        break;
+    }
+    return ret;
+}
+
 int kvm_arch_handle_exit(CPUState *cs, struct kvm_run *run)
 {
-    return 0;
+    int ret = 0;
+    switch (run->exit_reason) {
+    case KVM_EXIT_RISCV_SBI:
+        ret = kvm_riscv_handle_sbi(cs, run);
+        break;
+    default:
+        qemu_log_mask(LOG_UNIMP, "%s: un-handled exit reason %d\n",
+                      __func__, run->exit_reason);
+        ret = -1;
+        break;
+    }
+    return ret;
 }
 
 void kvm_riscv_reset_vcpu(RISCVCPU *cpu)
diff --git a/target/riscv/sbi_ecall_interface.h b/target/riscv/sbi_ecall_interface.h
new file mode 100644
index 0000000..fb1a3fa
--- /dev/null
+++ b/target/riscv/sbi_ecall_interface.h
@@ -0,0 +1,72 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2019 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ *   Anup Patel <anup.patel@wdc.com>
+ */
+
+#ifndef __SBI_ECALL_INTERFACE_H__
+#define __SBI_ECALL_INTERFACE_H__
+
+/* clang-format off */
+
+/* SBI Extension IDs */
+#define SBI_EXT_0_1_SET_TIMER           0x0
+#define SBI_EXT_0_1_CONSOLE_PUTCHAR     0x1
+#define SBI_EXT_0_1_CONSOLE_GETCHAR     0x2
+#define SBI_EXT_0_1_CLEAR_IPI           0x3
+#define SBI_EXT_0_1_SEND_IPI            0x4
+#define SBI_EXT_0_1_REMOTE_FENCE_I      0x5
+#define SBI_EXT_0_1_REMOTE_SFENCE_VMA   0x6
+#define SBI_EXT_0_1_REMOTE_SFENCE_VMA_ASID 0x7
+#define SBI_EXT_0_1_SHUTDOWN            0x8
+#define SBI_EXT_BASE                    0x10
+#define SBI_EXT_TIME                    0x54494D45
+#define SBI_EXT_IPI                     0x735049
+#define SBI_EXT_RFENCE                  0x52464E43
+#define SBI_EXT_HSM                     0x48534D
+
+/* SBI function IDs for BASE extension*/
+#define SBI_EXT_BASE_GET_SPEC_VERSION   0x0
+#define SBI_EXT_BASE_GET_IMP_ID         0x1
+#define SBI_EXT_BASE_GET_IMP_VERSION    0x2
+#define SBI_EXT_BASE_PROBE_EXT          0x3
+#define SBI_EXT_BASE_GET_MVENDORID      0x4
+#define SBI_EXT_BASE_GET_MARCHID        0x5
+#define SBI_EXT_BASE_GET_MIMPID         0x6
+
+/* SBI function IDs for TIME extension*/
+#define SBI_EXT_TIME_SET_TIMER          0x0
+
+/* SBI function IDs for IPI extension*/
+#define SBI_EXT_IPI_SEND_IPI            0x0
+
+/* SBI function IDs for RFENCE extension*/
+#define SBI_EXT_RFENCE_REMOTE_FENCE_I       0x0
+#define SBI_EXT_RFENCE_REMOTE_SFENCE_VMA    0x1
+#define SBI_EXT_RFENCE_REMOTE_SFENCE_VMA_ASID  0x2
+#define SBI_EXT_RFENCE_REMOTE_HFENCE_GVMA   0x3
+#define SBI_EXT_RFENCE_REMOTE_HFENCE_GVMA_VMID 0x4
+#define SBI_EXT_RFENCE_REMOTE_HFENCE_VVMA   0x5
+#define SBI_EXT_RFENCE_REMOTE_HFENCE_VVMA_ASID 0x6
+
+/* SBI function IDs for HSM extension */
+#define SBI_EXT_HSM_HART_START          0x0
+#define SBI_EXT_HSM_HART_STOP           0x1
+#define SBI_EXT_HSM_HART_GET_STATUS     0x2
+
+#define SBI_HSM_HART_STATUS_STARTED     0x0
+#define SBI_HSM_HART_STATUS_STOPPED     0x1
+#define SBI_HSM_HART_STATUS_START_PENDING   0x2
+#define SBI_HSM_HART_STATUS_STOP_PENDING    0x3
+
+#define SBI_SPEC_VERSION_MAJOR_OFFSET   24
+#define SBI_SPEC_VERSION_MAJOR_MASK     0x7f
+#define SBI_SPEC_VERSION_MINOR_MASK     0xffffff
+#define SBI_EXT_VENDOR_START            0x09000000
+#define SBI_EXT_VENDOR_END              0x09FFFFFF
+/* clang-format on */
+
+#endif