[PATCH V4 3/3] hw/riscv: virt: Enable booting S-mode firmware from pflash

[Sunil V L]

To boot S-mode firmware payload like EDK2 from persistent
flash storage, qemu needs to pass the flash address as the
next_addr in fw_dynamic_info to the opensbi.

When both -kernel and -pflash options are provided in command line,
the kernel (and initrd if -initrd) will be copied to fw_cfg table.
The S-mode FW will load the kernel/initrd from fw_cfg table.

If only pflash is given but not -kernel, then it is the job of
of the S-mode firmware to locate and load the kernel.

In either case, update the kernel_entry with the flash address
so that the opensbi can jump to the entry point of the S-mode
firmware.

Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
---
 hw/riscv/boot.c         | 29 +++++++++++++++++++++++++++++
 hw/riscv/virt.c         | 18 +++++++++++++++++-
 include/hw/riscv/boot.h |  1 +
 3 files changed, 47 insertions(+), 1 deletion(-)

diff --git a/hw/riscv/boot.c b/hw/riscv/boot.c
index 1ae7596873..fa8ad27da2 100644
--- a/hw/riscv/boot.c
+++ b/hw/riscv/boot.c
@@ -338,3 +338,32 @@ void riscv_setup_direct_kernel(hwaddr kernel_addr, hwaddr 
fdt_addr)
         riscv_cpu->env.fdt_addr = fdt_addr;
     }
 }
+
+void riscv_setup_firmware_boot(MachineState *machine)
+{
+    if (machine->kernel_filename) {
+        FWCfgState *fw_cfg;
+        fw_cfg = fw_cfg_find();
+
+        assert(fw_cfg);
+        /*
+         * Expose the kernel, the command line, and the initrd in fw_cfg.
+         * We don't process them here at all, it's all left to the
+         * firmware.
+         */
+        load_image_to_fw_cfg(fw_cfg,
+                             FW_CFG_KERNEL_SIZE, FW_CFG_KERNEL_DATA,
+                             machine->kernel_filename,
+                             true);
+        load_image_to_fw_cfg(fw_cfg,
+                             FW_CFG_INITRD_SIZE, FW_CFG_INITRD_DATA,
+                             machine->initrd_filename, false);
+
+        if (machine->kernel_cmdline) {
+            fw_cfg_add_i32(fw_cfg, FW_CFG_CMDLINE_SIZE,
+                           strlen(machine->kernel_cmdline) + 1);
+            fw_cfg_add_string(fw_cfg, FW_CFG_CMDLINE_DATA,
+                              machine->kernel_cmdline);
+        }
+    }
+}
diff --git a/hw/riscv/virt.c b/hw/riscv/virt.c
index b6bbf03f61..40515a793d 100644
--- a/hw/riscv/virt.c
+++ b/hw/riscv/virt.c
@@ -1258,7 +1258,23 @@ static void virt_machine_done(Notifier *notifier, void 
*data)
     s->fw_cfg = create_fw_cfg(machine);
     rom_set_fw(s->fw_cfg);
 
-    if (machine->kernel_filename) {
+    if (drive_get(IF_PFLASH, 0, 1)) {
+        /*
+         * S-mode FW like EDK2 will be kept in second plash (unit 1).
+         * When both kernel, initrd and pflash options are provided in the
+         * command line, the kernel and initrd will be copied to the fw_cfg
+         * table and opensbi will jump to the flash address which is the
+         * entry point of S-mode FW. It is the job of the S-mode FW to load
+         * the kernel and initrd using fw_cfg table.
+         *
+         * If only pflash is given but not -kernel, then it is the job of
+         * of the S-mode firmware to locate and load the kernel.
+         * In either case, the next_addr for opensbi will be the flash address.
+         */
+        riscv_setup_firmware_boot(machine);
+        kernel_entry = virt_memmap[VIRT_FLASH].base +
+                       virt_memmap[VIRT_FLASH].size / 2;
+    } else if (machine->kernel_filename) {
         kernel_start_addr = riscv_calc_kernel_start_addr(&s->soc[0],
                                                          firmware_end_addr);
 
diff --git a/include/hw/riscv/boot.h b/include/hw/riscv/boot.h
index a36f7618f5..93e5f8760d 100644
--- a/include/hw/riscv/boot.h
+++ b/include/hw/riscv/boot.h
@@ -57,5 +57,6 @@ void riscv_rom_copy_firmware_info(MachineState *machine, 
hwaddr rom_base,
                                   uint32_t reset_vec_size,
                                   uint64_t kernel_entry);
 void riscv_setup_direct_kernel(hwaddr kernel_addr, hwaddr fdt_addr);
+void riscv_setup_firmware_boot(MachineState *machine);
 
 #endif /* RISCV_BOOT_H */
-- 
2.25.1