[PATCH kvmtool 4/6] arm: Support firmware loading

[Julien Thierry <julien.thierry@arm.com>]

Implement firmware image loading for arm and set the boot start address
to the firmware address.

Add an option for the user to specify where to map the firmware.

Signed-off-by: Julien Thierry <julien.thierry@arm.com>
---
 arm/fdt.c                                | 14 +++++++-
 arm/include/arm-common/kvm-config-arch.h |  5 ++-
 arm/kvm.c                                | 58 +++++++++++++++++++++++++++++++-
 3 files changed, 74 insertions(+), 3 deletions(-)

diff --git a/arm/fdt.c b/arm/fdt.c
index 664bb62..2936986 100644
--- a/arm/fdt.c
+++ b/arm/fdt.c
@@ -131,7 +131,19 @@ static int setup_fdt(struct kvm *kvm)
 	/* /chosen */
 	_FDT(fdt_begin_node(fdt, "chosen"));
 	_FDT(fdt_property_cell(fdt, "linux,pci-probe-only", 1));
-	_FDT(fdt_property_string(fdt, "bootargs", kvm->cfg.real_cmdline));
+
+	if (kvm->cfg.firmware_filename) {
+		/*
+		 * When using a firmware, command line is not passed through DT,
+		 * or the firmware can add it itself
+		 */
+		if (kvm->cfg.kernel_cmdline)
+			pr_warning("Ignoring custom bootargs: %s\n",
+				   kvm->cfg.kernel_cmdline);
+	} else
+		_FDT(fdt_property_string(fdt, "bootargs",
+					 kvm->cfg.real_cmdline));
+
 	_FDT(fdt_property_u64(fdt, "kaslr-seed", kvm->cfg.arch.kaslr_seed));
 
 	/* Initrd */
diff --git a/arm/include/arm-common/kvm-config-arch.h b/arm/include/arm-common/kvm-config-arch.h
index 6a196f1..5734c46 100644
--- a/arm/include/arm-common/kvm-config-arch.h
+++ b/arm/include/arm-common/kvm-config-arch.h
@@ -11,6 +11,7 @@ struct kvm_config_arch {
 	bool		has_pmuv3;
 	u64		kaslr_seed;
 	enum irqchip_type irqchip;
+	u64		fw_addr;
 };
 
 int irqchip_parser(const struct option *opt, const char *arg, int unset);
@@ -30,6 +31,8 @@ int irqchip_parser(const struct option *opt, const char *arg, int unset);
         OPT_CALLBACK('\0', "irqchip", &(cfg)->irqchip,				\
 		     "[gicv2|gicv2m|gicv3|gicv3-its]",				\
 		     "Type of interrupt controller to emulate in the guest",	\
-		     irqchip_parser, NULL),
+		     irqchip_parser, NULL),					\
+	OPT_U64('\0', "firmware-address", &(cfg)->fw_addr,			\
+		"Address where firmware should be loaded"),
 
 #endif /* ARM_COMMON__KVM_CONFIG_ARCH_H */
diff --git a/arm/kvm.c b/arm/kvm.c
index c6843e5..d5bbbc3 100644
--- a/arm/kvm.c
+++ b/arm/kvm.c
@@ -169,9 +169,65 @@ bool kvm__arch_load_kernel_image(struct kvm *kvm, int fd_kernel, int fd_initrd,
 	return true;
 }
 
+static bool validate_fw_addr(struct kvm *kvm)
+{
+	u64 fw_addr = kvm->cfg.arch.fw_addr;
+	u64 ram_phys;
+
+	ram_phys = host_to_guest_flat(kvm, kvm->ram_start);
+
+	if (fw_addr < ram_phys || fw_addr >= ram_phys + kvm->ram_size) {
+		pr_err("Provide --firmware-address an address in RAM: "
+		       "0x%016llx - 0x%016llx",
+		       ram_phys, ram_phys + kvm->ram_size);
+
+		return false;
+	}
+
+	return true;
+}
+
 bool kvm__load_firmware(struct kvm *kvm, const char *firmware_filename)
 {
-	return false;
+	u64 fw_addr = kvm->cfg.arch.fw_addr;
+	void *host_pos;
+	void *limit;
+	ssize_t fw_sz;
+	int fd;
+
+	limit = kvm->ram_start + kvm->ram_size;
+
+	if (!validate_fw_addr(kvm))
+		die("Bad firmware destination: 0x%016llx", fw_addr);
+
+	fd = open(firmware_filename, O_RDONLY);
+	if (fd < 0)
+		return false;
+
+	host_pos = guest_flat_to_host(kvm, fw_addr);
+	if (!host_pos || host_pos < kvm->ram_start)
+		return false;
+
+	fw_sz = read_file(fd, host_pos, limit - host_pos);
+	if (fw_sz < 0)
+		die("failed to load firmware");
+	close(fd);
+
+	/* Kernel isn't loaded by kvm, point start address to firmware */
+	kvm->arch.kern_guest_start = fw_addr;
+
+	/* Load dtb just after the firmware image*/
+	host_pos += fw_sz;
+	if (host_pos + FDT_MAX_SIZE > limit)
+		die("not enough space to load fdt");
+
+	kvm->arch.dtb_guest_start = ALIGN(host_to_guest_flat(kvm, host_pos),
+					  FDT_ALIGN);
+	pr_info("Placing fdt at 0x%llx - 0x%llx",
+		kvm->arch.dtb_guest_start,
+		kvm->arch.dtb_guest_start + FDT_MAX_SIZE);
+
+	return true;
 }
 
 int kvm__arch_setup_firmware(struct kvm *kvm)
-- 
1.9.1