On 12/20/16 16:58, Marcel Apfelbaum wrote: > On 12/01/2016 07:06 PM, Laszlo Ersek wrote: >> 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) >> { >> > > Hi Laszlo, > The 'write' documentation is very helpful, thanks. > I would add that QEMU will 'use' the written values > when the guest selects another file (for reading), > that being protocol specific, of course. > But maybe is not connected directly.
I think it's not connected; it's a general characteristic that callbacks are invoked at item selection. Also, the data that a given callback consumes to produce the selected item's new contents may or may not include any fw_cfg data written previously (for example, with the ACPI linker/loader, the regenerated contents are independent of any fw_cfg writes). > > Reviewed-by: Marcel Apfelbaum <mar...@redhat.com> Thanks! I'm about to rebase / rework this series; if this patch applies with at most minor updates, I'll keep your R-b. Cheers, Laszlo > Thanks, > Marcel >
