hw/char: riscv_htif: Move registers from CPUArchState to HTIFState

At present for some unknown reason the HTIF registers (fromhost &
tohost) are defined in the RISC-V CPUArchState. It should really
be put in the HTIFState struct as it is only meaningful to HTIF.

Signed-off-by: Bin Meng <bmeng@tinylab.org>
Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20221229091828.1945072-6-bmeng@tinylab.org>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

hw/char/riscv_htif.c

@@ -100,7 +100,7 @@ static void htif_recv(void *opaque, const uint8_t *buf, int size)
     uint64_t val_written = s->pending_read;
     uint64_t resp = 0x100 | *buf;
 
-    s->env->mfromhost = (val_written >> 48 << 48) | (resp << 16 >> 16);
+    s->fromhost = (val_written >> 48 << 48) | (resp << 16 >> 16);
 }
 
 /*
@@ -175,7 +175,7 @@ static void htif_handle_tohost_write(HTIFState *s, uint64_t val_written)
         if (cmd == HTIF_CONSOLE_CMD_GETC) {
             /* this should be a queue, but not yet implemented as such */
             s->pending_read = val_written;
-            s->env->mtohost = 0; /* clear to indicate we read */
+            s->tohost = 0; /* clear to indicate we read */
             return;
         } else if (cmd == HTIF_CONSOLE_CMD_PUTC) {
             qemu_chr_fe_write(&s->chr, (uint8_t *)&payload, 1);
@@ -195,11 +195,11 @@ static void htif_handle_tohost_write(HTIFState *s, uint64_t val_written)
      * HTIF needs protocol documentation and a more complete state machine.
      *
      *  while (!s->fromhost_inprogress &&
-     *      s->env->mfromhost != 0x0) {
+     *      s->fromhost != 0x0) {
      *  }
      */
-    s->env->mfromhost = (val_written >> 48 << 48) | (resp << 16 >> 16);
-    s->env->mtohost = 0; /* clear to indicate we read */
+    s->fromhost = (val_written >> 48 << 48) | (resp << 16 >> 16);
+    s->tohost = 0; /* clear to indicate we read */
 }
 
 #define TOHOST_OFFSET1      (s->tohost_offset)
@@ -212,13 +212,13 @@ static uint64_t htif_mm_read(void *opaque, hwaddr addr, unsigned size)
 {
     HTIFState *s = opaque;
     if (addr == TOHOST_OFFSET1) {
-        return s->env->mtohost & 0xFFFFFFFF;
+        return s->tohost & 0xFFFFFFFF;
     } else if (addr == TOHOST_OFFSET2) {
-        return (s->env->mtohost >> 32) & 0xFFFFFFFF;
+        return (s->tohost >> 32) & 0xFFFFFFFF;
     } else if (addr == FROMHOST_OFFSET1) {
-        return s->env->mfromhost & 0xFFFFFFFF;
+        return s->fromhost & 0xFFFFFFFF;
     } else if (addr == FROMHOST_OFFSET2) {
-        return (s->env->mfromhost >> 32) & 0xFFFFFFFF;
+        return (s->fromhost >> 32) & 0xFFFFFFFF;
     } else {
         qemu_log("Invalid htif read: address %016" PRIx64 "\n",
             (uint64_t)addr);
@@ -232,22 +232,22 @@ static void htif_mm_write(void *opaque, hwaddr addr,
 {
     HTIFState *s = opaque;
     if (addr == TOHOST_OFFSET1) {
-        if (s->env->mtohost == 0x0) {
+        if (s->tohost == 0x0) {
             s->allow_tohost = 1;
-            s->env->mtohost = value & 0xFFFFFFFF;
+            s->tohost = value & 0xFFFFFFFF;
         } else {
             s->allow_tohost = 0;
         }
     } else if (addr == TOHOST_OFFSET2) {
         if (s->allow_tohost) {
-            s->env->mtohost |= value << 32;
-            htif_handle_tohost_write(s, s->env->mtohost);
+            s->tohost |= value << 32;
+            htif_handle_tohost_write(s, s->tohost);
         }
     } else if (addr == FROMHOST_OFFSET1) {
         s->fromhost_inprogress = 1;
-        s->env->mfromhost = value & 0xFFFFFFFF;
+        s->fromhost = value & 0xFFFFFFFF;
     } else if (addr == FROMHOST_OFFSET2) {
-        s->env->mfromhost |= value << 32;
+        s->fromhost |= value << 32;
         s->fromhost_inprogress = 0;
     } else {
         qemu_log("Invalid htif write: address %016" PRIx64 "\n",
@@ -265,8 +265,8 @@ bool htif_uses_elf_symbols(void)
     return (address_symbol_set == 3) ? true : false;
 }
 
-HTIFState *htif_mm_init(MemoryRegion *address_space, CPURISCVState *env,
-                        Chardev *chr, uint64_t nonelf_base)
+HTIFState *htif_mm_init(MemoryRegion *address_space, Chardev *chr,
+                        uint64_t nonelf_base)
 {
     uint64_t base, size, tohost_offset, fromhost_offset;
 
@@ -281,7 +281,6 @@ HTIFState *htif_mm_init(MemoryRegion *address_space, CPURISCVState *env,
     fromhost_offset = fromhost_addr - base;
 
     HTIFState *s = g_new0(HTIFState, 1);
-    s->env = env;
     s->tohost_offset = tohost_offset;
     s->fromhost_offset = fromhost_offset;
     s->pending_read = 0;

hw/riscv/spike.c

@@ -316,8 +316,7 @@ static void spike_board_init(MachineState *machine)
                               fdt_load_addr);
 
     /* initialize HTIF using symbols found in load_kernel */
-    htif_mm_init(system_memory, &s->soc[0].harts[0].env,
-                 serial_hd(0), memmap[SPIKE_HTIF].base);
+    htif_mm_init(system_memory, serial_hd(0), memmap[SPIKE_HTIF].base);
 }
 
 static void spike_machine_instance_init(Object *obj)

include/hw/char/riscv_htif.h

@@ -23,7 +23,6 @@
 #include "chardev/char.h"
 #include "chardev/char-fe.h"
 #include "exec/memory.h"
-#include "target/riscv/cpu.h"
 
 #define TYPE_HTIF_UART "riscv.htif.uart"
 
@@ -31,11 +30,12 @@ typedef struct HTIFState {
     int allow_tohost;
     int fromhost_inprogress;
 
+    uint64_t tohost;
+    uint64_t fromhost;
     hwaddr tohost_offset;
     hwaddr fromhost_offset;
     MemoryRegion mmio;
 
-    CPURISCVState *env;
     CharBackend chr;
     uint64_t pending_read;
 } HTIFState;
@@ -51,7 +51,7 @@ void htif_symbol_callback(const char *st_name, int st_info, uint64_t st_value,
 bool htif_uses_elf_symbols(void);
 
 /* legacy pre qom */
-HTIFState *htif_mm_init(MemoryRegion *address_space, CPURISCVState *env,
-                        Chardev *chr, uint64_t nonelf_base);
+HTIFState *htif_mm_init(MemoryRegion *address_space, Chardev *chr,
+                        uint64_t nonelf_base);
 
 #endif

target/riscv/cpu.h

@@ -309,10 +309,6 @@ struct CPUArchState {
     target_ulong sscratch;
     target_ulong mscratch;
 
-    /* temporary htif regs */
-    uint64_t mfromhost;
-    uint64_t mtohost;
-
     /* Sstc CSRs */
     uint64_t stimecmp;
 

target/riscv/machine.c

@@ -333,8 +333,8 @@ static const VMStateDescription vmstate_pmu_ctr_state = {
 
 const VMStateDescription vmstate_riscv_cpu = {
     .name = "cpu",
-    .version_id = 5,
-    .minimum_version_id = 5,
+    .version_id = 6,
+    .minimum_version_id = 6,
     .post_load = riscv_cpu_post_load,
     .fields = (VMStateField[]) {
         VMSTATE_UINTTL_ARRAY(env.gpr, RISCVCPU, 32),
@@ -384,8 +384,6 @@ const VMStateDescription vmstate_riscv_cpu = {
         VMSTATE_UINTTL_ARRAY(env.mhpmeventh_val, RISCVCPU, RV_MAX_MHPMEVENTS),
         VMSTATE_UINTTL(env.sscratch, RISCVCPU),
         VMSTATE_UINTTL(env.mscratch, RISCVCPU),
-        VMSTATE_UINT64(env.mfromhost, RISCVCPU),
-        VMSTATE_UINT64(env.mtohost, RISCVCPU),
         VMSTATE_UINT64(env.stimecmp, RISCVCPU),
 
         VMSTATE_END_OF_LIST()