From: Jesse Taube <Mr.Bossman075@gmail.com>
Date: Thu, 12 Jan 2023 04:52:48 +0000 (-0500)
Subject: works with less than base ISA qemu-system-riscv32 -M virt -bios none -kernel output... 
X-Git-Url: https://repo.jachan.dev/qemu.git/commitdiff_plain/228744bcba2620507e330ce7a30bf4f9f38d9c54

works with less than base ISA qemu-system-riscv32 -M virt -bios none -kernel output/images/Image -nographic -cpu rv32,mmu=off,m=off,d=off,f=off,s=off,u=off,h=off,pmp=off,Zawrs=off,c=off,a=off,Zifencei=off,Zicsr=off
---

diff --git a/hw/riscv/boot.c b/hw/riscv/boot.c
index ebd351c840..1aa6d7c17b 100644
--- a/hw/riscv/boot.c
+++ b/hw/riscv/boot.c
@@ -299,11 +299,12 @@ void riscv_setup_rom_reset_vec(MachineState *machine, RISCVHartArrayState *harts
         start_addr_hi32 = start_addr >> 32;
         fdt_load_addr_hi32 = fdt_load_addr >> 32;
     }
+
     /* reset vector */
     uint32_t reset_vec[10] = {
         0x00000297,                  /* 1:  auipc  t0, %pcrel_hi(fw_dyn) */
         0x02828613,                  /*     addi   a2, t0, %pcrel_lo(1b) */
-        0xf1402573,                  /*     csrr   a0, mhartid  */
+        0x00000513,                  /*     csrr   a0, mhartid  */
         0,
         0,
         0x00028067,                  /*     jr     t0 */
diff --git a/hw/riscv/virt.c b/hw/riscv/virt.c
index 94ff2a1584..5f1e808038 100644
--- a/hw/riscv/virt.c
+++ b/hw/riscv/virt.c
@@ -74,6 +74,7 @@
 
 static const MemMapEntry virt_memmap[] = {
     [VIRT_DEBUG] =        {        0x0,         0x100 },
+    [VIRT_CSR] =          {      0x400,         0xc00 },
     [VIRT_MROM] =         {     0x1000,        0xf000 },
     [VIRT_TEST] =         {   0x100000,        0x1000 },
     [VIRT_RTC] =          {   0x101000,        0x1000 },
@@ -1339,12 +1340,52 @@ static void virt_machine_done(Notifier *notifier, void *data)
     }
 }
 
+static void csr_mem_ops_wr(void *opaque, hwaddr addr,
+                            uint64_t value, unsigned size) {
+    riscv_csr_operations ops;
+    uint32_t csrnums[18] = {0x300, 0xC00, 0x340, 0x305, 0x304, 0x344,
+    0x341, 0x343, 0x342, 0xf11, 0x301,0xf14,0x3a0,0x3b0};
+    CPURISCVState* env = &RISCV_CPU(qemu_get_cpu(0))->env;
+    if(((addr&0xff)/4) > 18)
+        return;
+    int csrno = csrnums[((addr&0xff)/4)];
+    riscv_get_csr_ops(csrno,&ops);
+    if(ops.write){
+        ops.write(env,csrno,value);
+    } else if (ops.op) {
+        ops.op(env,csrno,NULL,value,UINT32_MAX);
+    }
+}
+static uint64_t csr_mem_ops_rd(void *opaque, hwaddr addr, unsigned size){
+    uint32_t value = 0;
+    riscv_csr_operations ops;
+    uint32_t csrnums[18] = {0x300, 0xC00, 0x340, 0x305, 0x304, 0x344,
+    0x341, 0x343, 0x342, 0xf11, 0x301,0xf14,0x3a0,0x3b0};
+    CPURISCVState* env = &RISCV_CPU(qemu_get_cpu(0))->env;
+
+    if(((addr&0xff)/4) > 18)
+        return 0;
+    int csrno = csrnums[((addr&0xff)/4)];
+    riscv_get_csr_ops(csrno,&ops);
+    if(ops.read){
+       ops.read(env,csrno,&value);
+    } else if (ops.op) {
+        ops.op(env,csrno,&value,0,0);
+    }
+    return value;
+}
+static const MemoryRegionOps csr_mem_ops = {
+    .read = csr_mem_ops_rd,
+    .write = csr_mem_ops_wr,
+};
+
 static void virt_machine_init(MachineState *machine)
 {
     const MemMapEntry *memmap = virt_memmap;
     RISCVVirtState *s = RISCV_VIRT_MACHINE(machine);
     MemoryRegion *system_memory = get_system_memory();
     MemoryRegion *mask_rom = g_new(MemoryRegion, 1);
+    MemoryRegion *csr_ram = g_new(MemoryRegion, 1);
     char *soc_name;
     DeviceState *mmio_irqchip, *virtio_irqchip, *pcie_irqchip;
     int i, base_hartid, hart_count;
@@ -1478,6 +1519,10 @@ static void virt_machine_init(MachineState *machine)
     /* boot rom */
     memory_region_init_rom(mask_rom, NULL, "riscv_virt_board.mrom",
                            memmap[VIRT_MROM].size, &error_fatal);
+    memory_region_init_io(csr_ram, NULL, &csr_mem_ops, NULL,"csr_ram",
+                           memmap[VIRT_CSR].size);
+    memory_region_add_subregion(system_memory, memmap[VIRT_CSR].base,
+                                csr_ram);
     memory_region_add_subregion(system_memory, memmap[VIRT_MROM].base,
                                 mask_rom);
 
diff --git a/include/hw/riscv/virt.h b/include/hw/riscv/virt.h
index b3d26135c0..10118200f8 100644
--- a/include/hw/riscv/virt.h
+++ b/include/hw/riscv/virt.h
@@ -60,6 +60,7 @@ struct RISCVVirtState {
 
 enum {
     VIRT_DEBUG,
+    VIRT_CSR,
     VIRT_MROM,
     VIRT_TEST,
     VIRT_RTC,