From: "Michael S. Tsirkin" <m...@redhat.com> Useful to send guest data back to QEMU.
Changes from Laszlo Ersek <ler...@redhat.com>: - rebase the patch from Michael Tsirkin's original postings at [1] and [2] to the following patches: - loader: Allow a custom AddressSpace when loading ROMs - loader: Add AddressSpace loading support to uImages - loader: fix handling of custom address spaces when adding ROM blobs - reject such writes immediately that would exceed the end of the array, rather than performing a partial write before setting the error bit: see the (len != dma.length) condition - document the write interface [1] http://lists.nongnu.org/archive/html/qemu-devel/2016-02/msg04968.html [2] http://lists.nongnu.org/archive/html/qemu-devel/2016-03/msg02735.html Cc: "Gabriel L. Somlo" <so...@cmu.edu> Cc: "Michael S. Tsirkin" <m...@redhat.com> Cc: Gerd Hoffmann <kra...@redhat.com> Cc: Igor Mammedov <imamm...@redhat.com> Cc: Michael Walle <mich...@walle.cc> Cc: Paolo Bonzini <pbonz...@redhat.com> Cc: Peter Maydell <peter.mayd...@linaro.org> Cc: Shannon Zhao <zhaoshengl...@huawei.com> Cc: qemu-...@nongnu.org Signed-off-by: Michael S. Tsirkin <m...@redhat.com> Signed-off-by: Laszlo Ersek <ler...@redhat.com> --- docs/specs/fw_cfg.txt | 32 +++++++++++++++++++++++++------- hw/lm32/lm32_hwsetup.h | 2 +- include/hw/loader.h | 7 ++++--- include/hw/nvram/fw_cfg.h | 3 ++- hw/arm/virt-acpi-build.c | 2 +- hw/core/loader.c | 18 +++++++++++------- hw/i386/acpi-build.c | 4 ++-- hw/nvram/fw_cfg.c | 37 +++++++++++++++++++++++++++++-------- 8 files changed, 75 insertions(+), 30 deletions(-) diff --git a/docs/specs/fw_cfg.txt b/docs/specs/fw_cfg.txt index 7a5f8c7824ce..a19e2adbe1c6 100644 --- a/docs/specs/fw_cfg.txt +++ b/docs/specs/fw_cfg.txt @@ -31,21 +31,25 @@ register. In other words, configuration write mode is enabled when the selector value is between 0x4000-0x7fff or 0xc000-0xffff. NOTE: As of QEMU v2.4, writes to the fw_cfg data register are no longer supported, and will be ignored (treated as no-ops)! +NOTE: As of QEMU v2.9, writes are reinstated, but only through the DMA + interface (see below). Furthermore, writeability of any specific item is + governed independently of Bit14 in the selector key value. + Bit15 of the selector register indicates whether the configuration setting is architecture specific. A value of 0 means the item is a generic configuration item. A value of 1 means the item is specific to a particular architecture. In other words, generic configuration items are accessed with a selector value between 0x0000-0x7fff, and architecture specific configuration items are accessed with a selector value between 0x8000-0xffff. == Data Register == -* Read/Write (writes ignored as of QEMU v2.4) +* Read/Write (writes ignored as of QEMU v2.4, but see the DMA interface) * Location: platform dependent (IOport [*] or MMIO) * Width: 8-bit (if IOport), 8/16/32/64-bit (if MMIO) * Endianness: string-preserving [*] On platforms where the data register is exposed as an IOport, its @@ -132,23 +136,25 @@ struct FWCfgFile { /* an individual file entry, 64 bytes total */ char name[56]; /* fw_cfg item name, NUL-terminated ascii */ }; === All Other Data Items === -Please consult the QEMU source for the most up-to-date and authoritative -list of selector keys and their respective items' purpose and format. +Please consult the QEMU source for the most up-to-date and authoritative list +of selector keys and their respective items' purpose, format and writeability. === Ranges === Theoretically, there may be up to 0x4000 generic firmware configuration items, and up to 0x4000 architecturally specific ones. Selector Reg. Range Usage --------------- ----------- -0x0000 - 0x3fff Generic (0x0000 - 0x3fff, RO) +0x0000 - 0x3fff Generic (0x0000 - 0x3fff, generally RO, possibly RW through + the DMA interface in QEMU v2.9+) 0x4000 - 0x7fff Generic (0x0000 - 0x3fff, RW, ignored in QEMU v2.4+) -0x8000 - 0xbfff Arch. Specific (0x0000 - 0x3fff, RO) +0x8000 - 0xbfff Arch. Specific (0x0000 - 0x3fff, generally RO, possibly RW + through the DMA interface in QEMU v2.9+) 0xc000 - 0xffff Arch. Specific (0x0000 - 0x3fff, RW, ignored in v2.4+) In practice, the number of allowed firmware configuration items is given by the value of FW_CFG_MAX_ENTRY (see fw_cfg.h). @@ -180,21 +186,31 @@ address is the "control" field. The "control" field has the following bits: - Bit 0: Error - Bit 1: Read - Bit 2: Skip - Bit 3: Select. The upper 16 bits are the selected index. + - Bit 4: Write When an operation is triggered, if the "control" field has bit 3 set, the upper 16 bits are interpreted as an index of a firmware configuration item. This has the same effect as writing the selector register. If the "control" field has bit 1 set, a read operation will be performed. "length" bytes for the current selector and offset will be copied into the physical RAM address specified by the "address" field. -If the "control" field has bit 2 set (and not bit 1), a skip operation will be -performed. The offset for the current selector will be advanced "length" bytes. +If the "control" field has bit 4 set (and not bit 1), a write operation will be +performed. "length" bytes will be copied from the physical RAM address +specified by the "address" field to the current selector and offset. QEMU +prevents starting or finishing the write beyond the end of the item associated +with the current selector (i.e., the item cannot be resized). Truncated writes +are dropped entirely. Writes to read-only items are also rejected. All of these +write errors set bit 0 (the error bit) in the "control" field. + +If the "control" field has bit 2 set (and neither bit 1 nor bit 4), a skip +operation will be performed. The offset for the current selector will be +advanced "length" bytes. To check the result, read the "control" field: error bit set -> something went wrong. all bits cleared -> transfer finished successfully. otherwise -> transfer still in progress (doesn't happen @@ -232,5 +248,7 @@ For historical reasons, "opt/ovmf/" is reserved for OVMF firmware. Prefix "opt/org.qemu/" is reserved for QEMU itself. Use of names not beginning with "opt/" is potentially dangerous and entirely unsupported. QEMU will warn if you try. + +All externally provided fw_cfg items are read-only to the guest. diff --git a/hw/lm32/lm32_hwsetup.h b/hw/lm32/lm32_hwsetup.h index 23e18784dffd..a01f6bc5dfeb 100644 --- a/hw/lm32/lm32_hwsetup.h +++ b/hw/lm32/lm32_hwsetup.h @@ -73,11 +73,11 @@ static inline void hwsetup_free(HWSetup *hw) static inline void hwsetup_create_rom(HWSetup *hw, hwaddr base) { rom_add_blob("hwsetup", hw->data, TARGET_PAGE_SIZE, - TARGET_PAGE_SIZE, base, NULL, NULL, NULL, NULL); + TARGET_PAGE_SIZE, base, NULL, NULL, NULL, NULL, true); } static inline void hwsetup_add_u8(HWSetup *hw, uint8_t u) { stb_p(hw->ptr, u); diff --git a/include/hw/loader.h b/include/hw/loader.h index 0c864cfd6046..0dbd8d6bf37a 100644 --- a/include/hw/loader.h +++ b/include/hw/loader.h @@ -178,11 +178,12 @@ int rom_add_file(const char *file, const char *fw_dir, bool option_rom, MemoryRegion *mr, AddressSpace *as); MemoryRegion *rom_add_blob(const char *name, const void *blob, size_t len, size_t max_len, hwaddr addr, const char *fw_file_name, FWCfgReadCallback fw_callback, - void *callback_opaque, AddressSpace *as); + void *callback_opaque, AddressSpace *as, + bool read_only); int rom_add_elf_program(const char *name, void *data, size_t datasize, size_t romsize, hwaddr addr, AddressSpace *as); int rom_check_and_register_reset(void); void rom_set_fw(FWCfgState *f); void rom_set_order_override(int order); @@ -192,19 +193,19 @@ void *rom_ptr(hwaddr addr); void hmp_info_roms(Monitor *mon, const QDict *qdict); #define rom_add_file_fixed(_f, _a, _i) \ rom_add_file(_f, NULL, _a, _i, false, NULL, NULL) #define rom_add_blob_fixed(_f, _b, _l, _a) \ - rom_add_blob(_f, _b, _l, _l, _a, NULL, NULL, NULL, NULL) + rom_add_blob(_f, _b, _l, _l, _a, NULL, NULL, NULL, NULL, true) #define rom_add_file_mr(_f, _mr, _i) \ rom_add_file(_f, NULL, 0, _i, false, _mr, NULL) #define rom_add_file_as(_f, _as, _i) \ rom_add_file(_f, NULL, 0, _i, false, NULL, _as) #define rom_add_file_fixed_as(_f, _a, _i, _as) \ rom_add_file(_f, NULL, _a, _i, false, NULL, _as) #define rom_add_blob_fixed_as(_f, _b, _l, _a, _as) \ - rom_add_blob(_f, _b, _l, _l, _a, NULL, NULL, NULL, _as) + rom_add_blob(_f, _b, _l, _l, _a, NULL, NULL, NULL, _as, true) #define PC_ROM_MIN_VGA 0xc0000 #define PC_ROM_MIN_OPTION 0xc8000 #define PC_ROM_MAX 0xe0000 #define PC_ROM_ALIGN 0x800 diff --git a/include/hw/nvram/fw_cfg.h b/include/hw/nvram/fw_cfg.h index 5c27a1f0d50b..b980cbaebf43 100644 --- a/include/hw/nvram/fw_cfg.h +++ b/include/hw/nvram/fw_cfg.h @@ -134,10 +134,11 @@ void fw_cfg_add_file(FWCfgState *s, const char *filename, void *data, * @filename: name of new fw_cfg file item * @callback: callback function * @callback_opaque: argument to be passed into callback function * @data: pointer to start of item data * @len: size of item data + * @read_only: is file read only * * Add a new NAMED fw_cfg item as a raw "blob" of the given size. The data * referenced by the starting pointer is only linked, NOT copied, into the * data structure of the fw_cfg device. * The next available (unused) selector key starting at FW_CFG_FILE_FIRST @@ -149,11 +150,11 @@ void fw_cfg_add_file(FWCfgState *s, const char *filename, void *data, * the fw_cfg control register, or passed to QEMU in FWCfgDmaAccess.control * with FW_CFG_DMA_CTL_SELECT). */ void fw_cfg_add_file_callback(FWCfgState *s, const char *filename, FWCfgReadCallback callback, void *callback_opaque, - void *data, size_t len); + void *data, size_t len, bool read_only); /** * fw_cfg_modify_file: * @s: fw_cfg device being modified * @filename: name of new fw_cfg file item diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c index d4160dfa7d34..542fb67239db 100644 --- a/hw/arm/virt-acpi-build.c +++ b/hw/arm/virt-acpi-build.c @@ -807,11 +807,11 @@ static void virt_acpi_build_reset(void *build_opaque) static MemoryRegion *acpi_add_rom_blob(AcpiBuildState *build_state, GArray *blob, const char *name, uint64_t max_size) { return rom_add_blob(name, blob->data, acpi_data_len(blob), max_size, -1, - name, virt_acpi_build_update, build_state, NULL); + name, virt_acpi_build_update, build_state, NULL, true); } static const VMStateDescription vmstate_virt_acpi_build = { .name = "virt_acpi_build", .version_id = 1, diff --git a/hw/core/loader.c b/hw/core/loader.c index 45742494e6fd..ee5abd6eb7f4 100644 --- a/hw/core/loader.c +++ b/hw/core/loader.c @@ -851,20 +851,20 @@ static void fw_cfg_resized(const char *id, uint64_t length, void *host) if (fw_cfg) { fw_cfg_modify_file(fw_cfg, id + strlen("/rom@"), host, length); } } -static void *rom_set_mr(Rom *rom, Object *owner, const char *name) +static void *rom_set_mr(Rom *rom, Object *owner, const char *name, bool ro) { void *data; rom->mr = g_malloc(sizeof(*rom->mr)); memory_region_init_resizeable_ram(rom->mr, owner, name, rom->datasize, rom->romsize, fw_cfg_resized, &error_fatal); - memory_region_set_readonly(rom->mr, true); + memory_region_set_readonly(rom->mr, ro); vmstate_register_ram_global(rom->mr); data = memory_region_get_ram_ptr(rom->mr); memcpy(data, rom->data, rom->datasize); @@ -940,11 +940,11 @@ int rom_add_file(const char *file, const char *fw_dir, snprintf(fw_file_name, sizeof(fw_file_name), "%s/%s", rom->fw_dir, basename); snprintf(devpath, sizeof(devpath), "/rom@%s", fw_file_name); if ((!option_rom || mc->option_rom_has_mr) && mc->rom_file_has_mr) { - data = rom_set_mr(rom, OBJECT(fw_cfg), devpath); + data = rom_set_mr(rom, OBJECT(fw_cfg), devpath, true); } else { data = rom->data; } fw_cfg_add_file(fw_cfg, fw_file_name, data, rom->romsize); @@ -977,11 +977,11 @@ err: } MemoryRegion *rom_add_blob(const char *name, const void *blob, size_t len, size_t max_len, hwaddr addr, const char *fw_file_name, FWCfgReadCallback fw_callback, void *callback_opaque, - AddressSpace *as) + AddressSpace *as, bool read_only) { MachineClass *mc = MACHINE_GET_CLASS(qdev_get_machine()); Rom *rom; MemoryRegion *mr = NULL; @@ -996,22 +996,26 @@ MemoryRegion *rom_add_blob(const char *name, const void *blob, size_t len, rom_insert(rom); if (fw_file_name && fw_cfg) { char devpath[100]; void *data; - snprintf(devpath, sizeof(devpath), "/rom@%s", fw_file_name); + if (read_only) { + snprintf(devpath, sizeof(devpath), "/rom@%s", fw_file_name); + } else { + snprintf(devpath, sizeof(devpath), "/ram@%s", fw_file_name); + } if (mc->rom_file_has_mr) { - data = rom_set_mr(rom, OBJECT(fw_cfg), devpath); + data = rom_set_mr(rom, OBJECT(fw_cfg), devpath, read_only); mr = rom->mr; } else { data = rom->data; } fw_cfg_add_file_callback(fw_cfg, fw_file_name, fw_callback, callback_opaque, - data, rom->datasize); + data, rom->datasize, read_only); } return mr; } /* This function is specific for elf program because we don't need to allocate diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c index 9708cdc463df..965cb4cd4c51 100644 --- a/hw/i386/acpi-build.c +++ b/hw/i386/acpi-build.c @@ -2934,11 +2934,11 @@ static void acpi_build_reset(void *build_opaque) static MemoryRegion *acpi_add_rom_blob(AcpiBuildState *build_state, GArray *blob, const char *name, uint64_t max_size) { return rom_add_blob(name, blob->data, acpi_data_len(blob), max_size, -1, - name, acpi_build_update, build_state, NULL); + name, acpi_build_update, build_state, NULL, true); } static const VMStateDescription vmstate_acpi_build = { .name = "acpi_build", .version_id = 1, @@ -3000,11 +3000,11 @@ void acpi_setup(void) uint32_t rsdp_size = acpi_data_len(tables.rsdp); build_state->rsdp = g_memdup(tables.rsdp->data, rsdp_size); fw_cfg_add_file_callback(pcms->fw_cfg, ACPI_BUILD_RSDP_FILE, acpi_build_update, build_state, - build_state->rsdp, rsdp_size); + build_state->rsdp, rsdp_size, true); build_state->rsdp_mr = NULL; } else { build_state->rsdp = NULL; build_state->rsdp_mr = acpi_add_rom_blob(build_state, tables.rsdp, ACPI_BUILD_RSDP_FILE, 0); diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c index 3ebecb22606a..e0145c11a19b 100644 --- a/hw/nvram/fw_cfg.c +++ b/hw/nvram/fw_cfg.c @@ -52,15 +52,17 @@ /* FW_CFG_DMA_CONTROL bits */ #define FW_CFG_DMA_CTL_ERROR 0x01 #define FW_CFG_DMA_CTL_READ 0x02 #define FW_CFG_DMA_CTL_SKIP 0x04 #define FW_CFG_DMA_CTL_SELECT 0x08 +#define FW_CFG_DMA_CTL_WRITE 0x10 #define FW_CFG_DMA_SIGNATURE 0x51454d5520434647ULL /* "QEMU CFG" */ typedef struct FWCfgEntry { uint32_t len; + bool allow_write; uint8_t *data; void *callback_opaque; FWCfgReadCallback read_callback; } FWCfgEntry; @@ -324,11 +326,11 @@ static void fw_cfg_dma_transfer(FWCfgState *s) { dma_addr_t len; FWCfgDmaAccess dma; int arch; FWCfgEntry *e; - int read; + int read = 0, write = 0; dma_addr_t dma_addr; /* Reset the address before the next access */ dma_addr = s->dma_addr; s->dma_addr = 0; @@ -351,12 +353,17 @@ static void fw_cfg_dma_transfer(FWCfgState *s) e = (s->cur_entry == FW_CFG_INVALID) ? NULL : &s->entries[arch][s->cur_entry & FW_CFG_ENTRY_MASK]; if (dma.control & FW_CFG_DMA_CTL_READ) { read = 1; + write = 0; + } else if (dma.control & FW_CFG_DMA_CTL_WRITE) { + read = 0; + write = 1; } else if (dma.control & FW_CFG_DMA_CTL_SKIP) { read = 0; + write = 0; } else { dma.length = 0; } dma.control = 0; @@ -372,11 +379,13 @@ static void fw_cfg_dma_transfer(FWCfgState *s) if (read) { if (dma_memory_set(s->dma_as, dma.address, 0, len)) { dma.control |= FW_CFG_DMA_CTL_ERROR; } } - + if (write) { + dma.control |= FW_CFG_DMA_CTL_ERROR; + } } else { if (dma.length <= (e->len - s->cur_offset)) { len = dma.length; } else { len = (e->len - s->cur_offset); @@ -389,10 +398,18 @@ static void fw_cfg_dma_transfer(FWCfgState *s) if (dma_memory_write(s->dma_as, dma.address, &e->data[s->cur_offset], len)) { dma.control |= FW_CFG_DMA_CTL_ERROR; } } + if (write) { + if (!e->allow_write || + len != dma.length || + dma_memory_read(s->dma_as, dma.address, + &e->data[s->cur_offset], len)) { + dma.control |= FW_CFG_DMA_CTL_ERROR; + } + } s->cur_offset += len; } dma.address += len; @@ -584,11 +601,12 @@ static const VMStateDescription vmstate_fw_cfg = { }; static void fw_cfg_add_bytes_read_callback(FWCfgState *s, uint16_t key, FWCfgReadCallback callback, void *callback_opaque, - void *data, size_t len) + void *data, size_t len, + bool read_only) { int arch = !!(key & FW_CFG_ARCH_LOCAL); key &= FW_CFG_ENTRY_MASK; @@ -597,10 +615,11 @@ static void fw_cfg_add_bytes_read_callback(FWCfgState *s, uint16_t key, s->entries[arch][key].data = data; s->entries[arch][key].len = (uint32_t)len; s->entries[arch][key].read_callback = callback; s->entries[arch][key].callback_opaque = callback_opaque; + s->entries[arch][key].allow_write = !read_only; } static void *fw_cfg_modify_bytes_read(FWCfgState *s, uint16_t key, void *data, size_t len) { @@ -614,17 +633,18 @@ static void *fw_cfg_modify_bytes_read(FWCfgState *s, uint16_t key, /* return the old data to the function caller, avoid memory leak */ ptr = s->entries[arch][key].data; s->entries[arch][key].data = data; s->entries[arch][key].len = len; s->entries[arch][key].callback_opaque = NULL; + s->entries[arch][key].allow_write = false; return ptr; } void fw_cfg_add_bytes(FWCfgState *s, uint16_t key, void *data, size_t len) { - fw_cfg_add_bytes_read_callback(s, key, NULL, NULL, data, len); + fw_cfg_add_bytes_read_callback(s, key, NULL, NULL, data, len, true); } void fw_cfg_add_string(FWCfgState *s, uint16_t key, const char *value) { size_t sz = strlen(value) + 1; @@ -747,11 +767,11 @@ static int get_fw_cfg_order(FWCfgState *s, const char *name) return FW_CFG_ORDER_OVERRIDE_LAST; } void fw_cfg_add_file_callback(FWCfgState *s, const char *filename, FWCfgReadCallback callback, void *callback_opaque, - void *data, size_t len) + void *data, size_t len, bool read_only) { int i, index, count; size_t dsize; MachineClass *mc = MACHINE_GET_CLASS(qdev_get_machine()); int order = 0; @@ -809,11 +829,12 @@ void fw_cfg_add_file_callback(FWCfgState *s, const char *filename, exit(1); } } fw_cfg_add_bytes_read_callback(s, FW_CFG_FILE_FIRST + index, - callback, callback_opaque, data, len); + callback, callback_opaque, data, len, + read_only); s->files->f[index].size = cpu_to_be32(len); s->files->f[index].select = cpu_to_be16(FW_CFG_FILE_FIRST + index); s->entry_order[index] = order; trace_fw_cfg_add_file(s, index, s->files->f[index].name, len); @@ -822,11 +843,11 @@ void fw_cfg_add_file_callback(FWCfgState *s, const char *filename, } void fw_cfg_add_file(FWCfgState *s, const char *filename, void *data, size_t len) { - fw_cfg_add_file_callback(s, filename, NULL, NULL, data, len); + fw_cfg_add_file_callback(s, filename, NULL, NULL, data, len, true); } void *fw_cfg_modify_file(FWCfgState *s, const char *filename, void *data, size_t len) { @@ -845,11 +866,11 @@ void *fw_cfg_modify_file(FWCfgState *s, const char *filename, s->files->f[i].size = cpu_to_be32(len); return ptr; } } /* add new one */ - fw_cfg_add_file_callback(s, filename, NULL, NULL, data, len); + fw_cfg_add_file_callback(s, filename, NULL, NULL, data, len, true); return NULL; } static void fw_cfg_machine_reset(void *opaque) { -- 2.9.2
