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From: Julien Thierry <julien.thierry@arm.com>
To: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu
Cc: will.deacon@arm.com, Sami.Mujawar@arm.com, Mark.Rutland@arm.com,
        andre.przywara@arm.com, Julien Thierry <julien.thierry@arm.com>
Subject: [PATCH kvmtool v2 6/6] arm: Support non-volatile memory
Date: Thu, 10 Jan 2019 14:20:46 +0000
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Add an option to let user load files as non-volatile memory.

An additional range of addresses is reserved for nv memory.
Loaded files must be a multiple of the system page size.

Users can chose whether the data written by the guest modifies the original
file.

Signed-off-by: Julien Thierry <julien.thierry@arm.com>
---
 arm/fdt.c                                |  34 ++++++++
 arm/include/arm-common/kvm-arch.h        |   5 +-
 arm/include/arm-common/kvm-config-arch.h |  18 ++++-
 arm/kvm.c                                | 134 +++++++++++++++++++++++++++++++
 4 files changed, 189 insertions(+), 2 deletions(-)

diff --git a/arm/fdt.c b/arm/fdt.c
index 2936986..e3a7a64 100644
--- a/arm/fdt.c
+++ b/arm/fdt.c
@@ -72,6 +72,37 @@ static void generate_irq_prop(void *fdt, u8 irq, enum irq_type irq_type)
 	_FDT(fdt_property(fdt, "interrupts", irq_prop, sizeof(irq_prop)));
 }
 
+static void generate_nvmem_node(void *fdt, struct kvm_nv_mem *nvmem)
+{
+	char buf[22]; // 22 >= len("flash@" + 16 hex char + '\0')
+	const u64 reg_prop[] = {
+		cpu_to_fdt64(nvmem->map_addr),
+		cpu_to_fdt64(nvmem->size)
+	};
+
+	snprintf(buf, sizeof(buf), "flash@%llx", nvmem->map_addr);
+	_FDT(fdt_begin_node(fdt, buf));
+
+	_FDT(fdt_property_string(fdt, "compatible", "kvmtool,flash"));
+
+	_FDT(fdt_property(fdt, "reg", reg_prop, sizeof(reg_prop)));
+
+	_FDT(fdt_property_string(fdt, "label", nvmem->name));
+
+	_FDT(fdt_end_node(fdt));
+}
+
+static void generate_nvmem_nodes(void *fdt, struct kvm *kvm)
+{
+	struct list_head *nvmem_node;
+
+	list_for_each(nvmem_node, &kvm->cfg.arch.nvmem_list)
+		generate_nvmem_node(fdt,
+				    container_of(nvmem_node,
+					         struct kvm_nv_mem,
+					         node));
+}
+
 struct psci_fns {
 	u32 cpu_suspend;
 	u32 cpu_off;
@@ -210,6 +241,9 @@ static int setup_fdt(struct kvm *kvm)
 	_FDT(fdt_property_cell(fdt, "migrate", fns->migrate));
 	_FDT(fdt_end_node(fdt));
 
+	/* Non volatile memories */
+	generate_nvmem_nodes(fdt, kvm);
+
 	/* Finalise. */
 	_FDT(fdt_end_node(fdt));
 	_FDT(fdt_finish(fdt));
diff --git a/arm/include/arm-common/kvm-arch.h b/arm/include/arm-common/kvm-arch.h
index b9d486d..f425d86 100644
--- a/arm/include/arm-common/kvm-arch.h
+++ b/arm/include/arm-common/kvm-arch.h
@@ -10,6 +10,7 @@
 #define ARM_IOPORT_AREA		_AC(0x0000000000000000, UL)
 #define ARM_MMIO_AREA		_AC(0x0000000000010000, UL)
 #define ARM_AXI_AREA		_AC(0x0000000040000000, UL)
+#define ARM_NVRAM_AREA		_AC(0x000000007f000000, UL)
 #define ARM_MEMORY_AREA		_AC(0x0000000080000000, UL)
 
 #define ARM_LOMAP_MAX_MEMORY	((1ULL << 32) - ARM_MEMORY_AREA)
@@ -24,9 +25,11 @@
 #define ARM_IOPORT_SIZE		(ARM_MMIO_AREA - ARM_IOPORT_AREA)
 #define ARM_VIRTIO_MMIO_SIZE	(ARM_AXI_AREA - (ARM_MMIO_AREA + ARM_GIC_SIZE))
 #define ARM_PCI_CFG_SIZE	(1ULL << 24)
-#define ARM_PCI_MMIO_SIZE	(ARM_MEMORY_AREA - \
+#define ARM_PCI_MMIO_SIZE	(ARM_NVRAM_AREA - \
 				(ARM_AXI_AREA + ARM_PCI_CFG_SIZE))
 
+#define ARM_NVRAM_SIZE		(ARM_MEMORY_AREA - ARM_NVRAM_AREA)
+
 #define KVM_IOPORT_AREA		ARM_IOPORT_AREA
 #define KVM_PCI_CFG_AREA	ARM_AXI_AREA
 #define KVM_PCI_MMIO_AREA	(KVM_PCI_CFG_AREA + ARM_PCI_CFG_SIZE)
diff --git a/arm/include/arm-common/kvm-config-arch.h b/arm/include/arm-common/kvm-config-arch.h
index 5734c46..0f1fa11 100644
--- a/arm/include/arm-common/kvm-config-arch.h
+++ b/arm/include/arm-common/kvm-config-arch.h
@@ -1,8 +1,18 @@
 #ifndef ARM_COMMON__KVM_CONFIG_ARCH_H
 #define ARM_COMMON__KVM_CONFIG_ARCH_H
 
+#include <linux/list.h>
 #include "kvm/parse-options.h"
 
+struct kvm_nv_mem {
+	char			*data_file;
+	char			*name;
+	ssize_t			size;
+	u64			map_addr;
+	bool			write_back;
+	struct list_head	node;
+};
+
 struct kvm_config_arch {
 	const char	*dump_dtb_filename;
 	unsigned int	force_cntfrq;
@@ -12,9 +22,11 @@ struct kvm_config_arch {
 	u64		kaslr_seed;
 	enum irqchip_type irqchip;
 	u64		fw_addr;
+	struct list_head nvmem_list;
 };
 
 int irqchip_parser(const struct option *opt, const char *arg, int unset);
+int nvmem_parser(const struct option *opt, const char *arg, int unset);
 
 #define OPT_ARCH_RUN(pfx, cfg)							\
 	pfx,									\
@@ -33,6 +45,10 @@ int irqchip_parser(const struct option *opt, const char *arg, int unset);
 		     "Type of interrupt controller to emulate in the guest",	\
 		     irqchip_parser, NULL),					\
 	OPT_U64('\0', "firmware-address", &(cfg)->fw_addr,			\
-		"Address where firmware should be loaded"),
+		"Address where firmware should be loaded"),			\
+	OPT_CALLBACK('\0', "nvmem", NULL,					\
+		     "<file>,<label>[,wb]",					\
+		     "Load <file> as non-volatile memory",			\
+		     nvmem_parser, kvm),
 
 #endif /* ARM_COMMON__KVM_CONFIG_ARCH_H */
diff --git a/arm/kvm.c b/arm/kvm.c
index 50faab5..eaa7005 100644
--- a/arm/kvm.c
+++ b/arm/kvm.c
@@ -18,6 +18,53 @@ struct kvm_ext kvm_req_ext[] = {
 	{ 0, 0 },
 };
 
+int nvmem_parser(const struct option *opt, const char *arg, int unset)
+{
+	struct kvm *kvm = (struct kvm*) opt->ptr;
+	struct kvm_nv_mem *nvmem;
+	struct stat st;
+	const char *ptr;
+	uint32_t len;
+
+	nvmem = calloc(sizeof (*nvmem), 1);
+
+	if (!nvmem)
+		die("nvmem: cannot add non-volatile memory");
+
+	ptr = strstr(arg, ",");
+
+	if (!ptr)
+		die("nvmem: missing name for non-volatile memory");
+
+	len = ptr - arg + 1;
+	nvmem->data_file = malloc(len);
+	strncpy(nvmem->data_file, arg, len);
+	nvmem->data_file[len - 1] = '\0';
+
+	if (stat(nvmem->data_file, &st))
+		die("nvmem: failed to stat data file");
+	nvmem->size = st.st_size;
+
+	arg = arg + len;
+	for (ptr = arg; *ptr != '\0' && *ptr != ','; ++ptr)
+		;
+	len = ptr - arg + 1;
+	nvmem->name = malloc(len);
+	strncpy(nvmem->name, arg, len);
+	nvmem->name[len - 1] = '\0';
+
+	if (*ptr == ',') {
+		if (!strcmp(ptr + 1, "wb"))
+			nvmem->write_back = true;
+		else
+			die("firmware-data: invalid option %s", ptr + 1);
+	}
+
+	list_add(&nvmem->node, &kvm->cfg.arch.nvmem_list);
+
+	return 0;
+}
+
 bool kvm__arch_cpu_supports_vm(void)
 {
 	/* The KVM capability check is enough. */
@@ -59,6 +106,7 @@ void kvm__arch_set_cmdline(char *cmdline, bool video)
 
 void kvm__arch_reset(struct kvm *kvm)
 {
+	INIT_LIST_HEAD(&kvm->cfg.arch.nvmem_list);
 }
 
 void kvm__arch_init(struct kvm *kvm, const char *hugetlbfs_path, u64 ram_size)
@@ -241,3 +289,89 @@ int kvm__arch_setup_firmware(struct kvm *kvm)
 {
 	return 0;
 }
+
+static int setup_nvmem(struct kvm *kvm)
+{
+	u64 map_address = ARM_NVRAM_AREA;
+	const u64 limit = ARM_NVRAM_AREA + ARM_NVRAM_SIZE;
+	struct list_head *nvmem_node;
+	const int pagesize = getpagesize();
+
+	list_for_each(nvmem_node, &kvm->cfg.arch.nvmem_list) {
+		struct kvm_nv_mem *nvmem = container_of(nvmem_node,
+							struct kvm_nv_mem,
+							node);
+		void *user_addr;
+		int fd;
+
+		if (map_address + nvmem->size > limit)
+			die("cannot map file %s in non-volatile memory, no space left",
+			    nvmem->data_file);
+
+		if (nvmem->size & (pagesize - 1))
+			die("size of non-volatile memory files must be a multiple of system page size (= %d)",
+			    pagesize);
+
+		user_addr = mmap(NULL, nvmem->size, PROT_RW, MAP_ANON_NORESERVE, -1, 0);
+		if (user_addr == MAP_FAILED)
+			die("cannot create mapping for file %s",
+			     nvmem->data_file);
+
+		fd = open(nvmem->data_file, O_RDONLY);
+		if (fd < 0)
+			die("cannot read file %s", nvmem->data_file);
+		if (read_file(fd, user_addr, nvmem->size) < 0)
+			die("failed to map nv memory data %s",
+			    nvmem->data_file);
+		close(fd);
+
+		if (kvm__register_dev_mem(kvm, map_address, nvmem->size,
+					  user_addr))
+			die("failed to register nv memory mapping for guest");
+
+		nvmem->map_addr = map_address;
+		map_address += nvmem->size;
+	}
+
+	return 0;
+}
+firmware_init(setup_nvmem);
+
+static int flush_nv_mem(struct kvm *kvm)
+{
+	struct list_head *nvmem_node;
+	int err = 0;
+
+	list_for_each(nvmem_node, &kvm->cfg.arch.nvmem_list) {
+		struct kvm_nv_mem *nvmem = container_of(nvmem_node,
+							struct kvm_nv_mem,
+							node);
+		void *host_pos;
+
+		host_pos = guest_flat_to_host(kvm,
+					      nvmem->map_addr);
+
+		if (nvmem->write_back) {
+			int fd;
+
+			fd = open(nvmem->data_file, O_WRONLY);
+			if (fd < 0) {
+				pr_err("failed to open firmware data file for writting");
+				err = -1;
+				continue;
+			}
+
+			if (write_in_full(fd, host_pos, nvmem->size) < 0) {
+				pr_err("failed to flush firmware data to file");
+				err = -1;
+			}
+			close(fd);
+		}
+
+		if (munmap(host_pos, nvmem->size))
+			err = -1;
+	}
+
+	return err;
+}
+firmware_exit(flush_nv_mem);