RISC-V Patches for 4.2-rc2

This contains a pair of patches that add OpenSBI support to QEMU on
 RISC-V targets.  The patches have been floating around for a bit, but
 everything seems solid now.  These pass my standard test of booting
 OpenEmbedded, and also works when I swap around the various command-line
 arguments to use the new boot method.
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Merge remote-tracking branch 'remotes/palmer/tags/riscv-for-master-4.1-rc2' into staging

RISC-V Patches for 4.2-rc2

This contains a pair of patches that add OpenSBI support to QEMU on
RISC-V targets.  The patches have been floating around for a bit, but
everything seems solid now.  These pass my standard test of booting
OpenEmbedded, and also works when I swap around the various command-line
arguments to use the new boot method.

# gpg: Signature made Fri 19 Jul 2019 00:54:27 BST
# gpg:                using RSA key 00CE76D1834960DFCE886DF8EF4CA1502CCBAB41
# gpg:                issuer "palmer@dabbelt.com"
# gpg: Good signature from "Palmer Dabbelt <palmer@dabbelt.com>" [unknown]
# gpg:                 aka "Palmer Dabbelt <palmer@sifive.com>" [unknown]
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 00CE 76D1 8349 60DF CE88  6DF8 EF4C A150 2CCB AB41

* remotes/palmer/tags/riscv-for-master-4.1-rc2:
  hw/riscv: Load OpenSBI as the default firmware
  roms: Add OpenSBI version 0.4

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

.gitmodules

@@ -55,3 +55,6 @@
 [submodule "slirp"]
 	path = slirp
 	url = https://git.qemu.org/git/libslirp.git
+[submodule "roms/opensbi"]
+	path = roms/opensbi
+	url = 	https://git.qemu.org/git/opensbi.git

LICENSE

@@ -1,13 +1,18 @@
-The following points clarify the QEMU license:
+The QEMU distribution includes both the QEMU emulator and
+various firmware files.  These are separate programs that are
+distributed together for our users' convenience, and they have
+separate licenses.
 
-1) QEMU as a whole is released under the GNU General Public License,
-version 2.
+The following points clarify the license of the QEMU emulator:
 
-2) Parts of QEMU have specific licenses which are compatible with the
-GNU General Public License, version 2. Hence each source file contains
-its own licensing information.  Source files with no licensing information
-are released under the GNU General Public License, version 2 or (at your
-option) any later version.
+1) The QEMU emulator as a whole is released under the GNU General
+Public License, version 2.
+
+2) Parts of the QEMU emulator have specific licenses which are compatible
+with the GNU General Public License, version 2. Hence each source file
+contains its own licensing information.  Source files with no licensing
+information are released under the GNU General Public License, version
+2 or (at your option) any later version.
 
 As of July 2013, contributions under version 2 of the GNU General Public
 License (and no later version) are only accepted for the following files

Makefile

@@ -770,7 +770,10 @@ palcode-clipper \
 u-boot.e500 u-boot-sam460-20100605.bin \
 qemu_vga.ndrv \
 edk2-licenses.txt \
-hppa-firmware.img
+hppa-firmware.img \
+opensbi-riscv32-virt-fw_jump.bin \
+opensbi-riscv64-sifive_u-fw_jump.bin opensbi-riscv64-virt-fw_jump.bin
+
 
 DESCS=50-edk2-i386-secure.json 50-edk2-x86_64-secure.json \
 60-edk2-aarch64.json 60-edk2-arm.json 60-edk2-i386.json 60-edk2-x86_64.json

hw/riscv/boot.c

@@ -18,6 +18,7 @@
  */
 
 #include "qemu/osdep.h"
+#include "qemu-common.h"
 #include "qemu/units.h"
 #include "qemu/error-report.h"
 #include "exec/cpu-defs.h"
@@ -32,6 +33,59 @@
 # define KERNEL_BOOT_ADDRESS 0x80200000
 #endif
 
+void riscv_find_and_load_firmware(MachineState *machine,
+                                  const char *default_machine_firmware,
+                                  hwaddr firmware_load_addr)
+{
+    char *firmware_filename;
+
+    if (!machine->firmware) {
+        /*
+         * The user didn't specify -bios.
+         * At the moment we default to loading nothing when this hapens.
+         * In the future this defaul will change to loading the prebuilt
+         * OpenSBI firmware. Let's warn the user and then continue.
+        */
+        warn_report("No -bios option specified. Not loading a firmware.");
+        warn_report("This default will change in QEMU 4.3. Please use the " \
+                    "-bios option to aviod breakages when this happens.");
+        warn_report("See QEMU's deprecation documentation for details");
+        return;
+    }
+
+    if (!strcmp(machine->firmware, "default")) {
+        /*
+         * The user has specified "-bios default". That means we are going to
+         * load the OpenSBI binary included in the QEMU source.
+         *
+         * We can't load the binary by default as it will break existing users
+         * as users are already loading their own firmware.
+         *
+         * Let's try to get everyone to specify the -bios option at all times,
+         * so then in the future we can make "-bios default" the default option
+         * if no -bios option is set without breaking anything.
+         */
+        firmware_filename = qemu_find_file(QEMU_FILE_TYPE_BIOS,
+                                           default_machine_firmware);
+        if (firmware_filename == NULL) {
+            error_report("Unable to load the default RISC-V firmware \"%s\"",
+                         default_machine_firmware);
+            exit(1);
+        }
+    } else {
+        firmware_filename = machine->firmware;
+    }
+
+    if (strcmp(firmware_filename, "none")) {
+        /* If not "none" load the firmware */
+        riscv_load_firmware(firmware_filename, firmware_load_addr);
+    }
+
+    if (!strcmp(machine->firmware, "default")) {
+        g_free(firmware_filename);
+    }
+}
+
 target_ulong riscv_load_firmware(const char *firmware_filename,
                                  hwaddr firmware_load_addr)
 {

hw/riscv/sifive_u.c

@@ -49,6 +49,8 @@
 
 #include <libfdt.h>
 
+#define BIOS_FILENAME "opensbi-riscv64-sifive_u-fw_jump.bin"
+
 static const struct MemmapEntry {
     hwaddr base;
     hwaddr size;
@@ -269,9 +271,8 @@ static void riscv_sifive_u_init(MachineState *machine)
     /* create device tree */
     create_fdt(s, memmap, machine->ram_size, machine->kernel_cmdline);
 
-    if (machine->firmware) {
-        riscv_load_firmware(machine->firmware, memmap[SIFIVE_U_DRAM].base);
-    }
+    riscv_find_and_load_firmware(machine, BIOS_FILENAME,
+                                 memmap[SIFIVE_U_DRAM].base);
 
     if (machine->kernel_filename) {
         riscv_load_kernel(machine->kernel_filename);

hw/riscv/virt.c

@@ -44,6 +44,12 @@
 
 #include <libfdt.h>
 
+#if defined(TARGET_RISCV32)
+# define BIOS_FILENAME "opensbi-riscv32-virt-fw_jump.bin"
+#else
+# define BIOS_FILENAME "opensbi-riscv64-virt-fw_jump.bin"
+#endif
+
 static const struct MemmapEntry {
     hwaddr base;
     hwaddr size;
@@ -399,9 +405,8 @@ static void riscv_virt_board_init(MachineState *machine)
     memory_region_add_subregion(system_memory, memmap[VIRT_MROM].base,
                                 mask_rom);
 
-    if (machine->firmware) {
-        riscv_load_firmware(machine->firmware, memmap[VIRT_DRAM].base);
-    }
+    riscv_find_and_load_firmware(machine, BIOS_FILENAME,
+                                 memmap[VIRT_DRAM].base);
 
     if (machine->kernel_filename) {
         uint64_t kernel_entry = riscv_load_kernel(machine->kernel_filename);

include/hw/riscv/boot.h

@@ -20,6 +20,9 @@
 #ifndef RISCV_BOOT_H
 #define RISCV_BOOT_H
 
+void riscv_find_and_load_firmware(MachineState *machine,
+                                  const char *default_machine_firmware,
+                                  hwaddr firmware_load_addr);
 target_ulong riscv_load_firmware(const char *firmware_filename,
                                  hwaddr firmware_load_addr);
 target_ulong riscv_load_kernel(const char *kernel_filename);

pc-bios/README

@@ -63,3 +63,14 @@
   ARM. Licensing information is given in "edk2-licenses.txt". The image files
   are described by the JSON documents in the "pc-bios/descriptors" directory,
   which conform to the "docs/interop/firmware.json" schema.
+
+- OpenSBI (https://github.com/riscv/opensbi) aims to provide an open-source
+  reference implementation of the RISC-V Supervisor Binary Interface (SBI)
+  specifications for platform-specific firmwares executing in M-mode. For all
+  supported platforms, OpenSBI provides several runtime firmware examples.
+  These example firmwares can be used to replace the legacy riscv-pk bootloader
+  and enable the use of well-known bootloaders such as U-Boot.
+  OpenSBI is distributed under the terms of the BSD 2-clause license
+  ("Simplified BSD License" or "FreeBSD License", SPDX: BSD-2-Clause). OpenSBI
+  source code also contains code reused from other projects desribed here:
+  https://github.com/riscv/opensbi/blob/master/ThirdPartyNotices.md.

qemu-deprecated.texi

@@ -121,6 +121,26 @@ the backing storage specified with @option{-mem-path} can actually provide
 the guest RAM configured with @option{-m} and QEMU will fail to start up if
 RAM allocation is unsuccessful.
 
+@subsection RISC-V -bios (since 4.1)
+
+QEMU 4.1 introduced support for the -bios option in QEMU for RISC-V for the
+RISC-V virt machine and sifive_u machine.
+
+QEMU 4.1 has no changes to the default behaviour to avoid breakages. This
+default will change in a future QEMU release, so please prepare now. All users
+of the virt or sifive_u machine must change their command line usage.
+
+QEMU 4.1 has three options, please migrate to one of these three:
+ 1. ``-bios none`` - This is the current default behavior if no -bios option
+      is included. QEMU will not automatically load any firmware. It is up
+      to the user to load all the images they need.
+ 2. ``-bios default`` - In a future QEMU release this will become the default
+      behaviour if no -bios option is specified. This option will load the
+      default OpenSBI firmware automatically. The firmware is included with
+      the QEMU release and no user interaction is required. All a user needs
+      to do is specify the kernel they want to boot with the -kernel option
+ 3. ``-bios <file>`` - Tells QEMU to load the specified file as the firmwrae.
+
 @section QEMU Machine Protocol (QMP) commands
 
 @subsection block-dirty-bitmap-add "autoload" parameter (since 2.12.0)

roms/Makefile

@@ -37,6 +37,8 @@ find-cross-prefix = $(subst gcc,,$(notdir $(call find-cross-gcc,$(1))))
 powerpc64_cross_prefix := $(call find-cross-prefix,powerpc64)
 powerpc_cross_prefix := $(call find-cross-prefix,powerpc)
 x86_64_cross_prefix := $(call find-cross-prefix,x86_64)
+riscv32_cross_prefix := $(call find-cross-prefix,riscv32)
+riscv64_cross_prefix := $(call find-cross-prefix,riscv64)
 
 # tag our seabios builds
 SEABIOS_EXTRAVERSION="-prebuilt.qemu.org"
@@ -52,18 +54,21 @@ EDK2_EFIROM = edk2/BaseTools/Source/C/bin/EfiRom
 default:
 	@echo "nothing is build by default"
 	@echo "available build targets:"
-	@echo "  bios           -- update bios.bin (seabios)"
-	@echo "  vgabios        -- update vgabios binaries (seabios)"
-	@echo "  sgabios        -- update sgabios binaries"
-	@echo "  pxerom         -- update nic roms (bios only)"
-	@echo "  efirom         -- update nic roms (bios+efi)"
-	@echo "  slof           -- update slof.bin"
-	@echo "  skiboot        -- update skiboot.lid"
-	@echo "  u-boot.e500    -- update u-boot.e500"
-	@echo "  u-boot.sam460  -- update u-boot.sam460"
-	@echo "  efi            -- update UEFI (edk2) platform firmware"
-	@echo "  clean          -- delete the files generated by the previous" \
-	                          "build targets"
+	@echo "  bios               -- update bios.bin (seabios)"
+	@echo "  vgabios            -- update vgabios binaries (seabios)"
+	@echo "  sgabios            -- update sgabios binaries"
+	@echo "  pxerom             -- update nic roms (bios only)"
+	@echo "  efirom             -- update nic roms (bios+efi)"
+	@echo "  slof               -- update slof.bin"
+	@echo "  skiboot            -- update skiboot.lid"
+	@echo "  u-boot.e500        -- update u-boot.e500"
+	@echo "  u-boot.sam460      -- update u-boot.sam460"
+	@echo "  efi                -- update UEFI (edk2) platform firmware"
+	@echo "  opensbi32-virt     -- update OpenSBI for 32-bit virt machine"
+	@echo "  opensbi64-virt     -- update OpenSBI for 64-bit virt machine"
+	@echo "  opensbi64-sifive_u -- update OpenSBI for 64-bit sifive_u machine"
+	@echo "  clean              -- delete the files generated by the previous" \
+	                              "build targets"
 
 bios: build-seabios-config-seabios-128k build-seabios-config-seabios-256k
 	cp seabios/builds/seabios-128k/bios.bin ../pc-bios/bios.bin
@@ -162,6 +167,24 @@ skiboot:
 efi: edk2-basetools
 	$(MAKE) -f Makefile.edk2
 
+opensbi32-virt:
+	$(MAKE) -C opensbi \
+		CROSS_COMPILE=$(riscv32_cross_prefix) \
+		PLATFORM="qemu/virt"
+	cp opensbi/build/platform/qemu/virt/firmware/fw_jump.bin ../pc-bios/opensbi-riscv32-virt-fw_jump.bin
+
+opensbi64-virt:
+	$(MAKE) -C opensbi \
+		CROSS_COMPILE=$(riscv64_cross_prefix) \
+		PLATFORM="qemu/virt"
+	cp opensbi/build/platform/qemu/virt/firmware/fw_jump.bin ../pc-bios/opensbi-riscv64-virt-fw_jump.bin
+
+opensbi64-sifive_u:
+	$(MAKE) -C opensbi \
+		CROSS_COMPILE=$(riscv64_cross_prefix) \
+		PLATFORM="qemu/sifive_u"
+	cp opensbi/build/platform/qemu/virt/firmware/fw_jump.bin ../pc-bios/opensbi-riscv64-sifive_u-fw_jump.bin
+
 clean:
 	rm -rf seabios/.config seabios/out seabios/builds
 	$(MAKE) -C sgabios clean
@@ -173,3 +196,4 @@ clean:
 	$(MAKE) -C u-boot-sam460ex distclean
 	$(MAKE) -C skiboot clean
 	$(MAKE) -f Makefile.edk2 clean
+	$(MAKE) -C opensbi clean

roms/opensbi

@@ -0,0 +1 @@
+Subproject commit ce228ee0919deb9957192d723eecc8aaae2697c6