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author | Laszlo Ersek <lersek@redhat.com> | 2017-01-12 19:24:15 +0100 |
---|---|---|
committer | Michael S. Tsirkin <mst@redhat.com> | 2017-01-18 22:59:53 +0200 |
commit | e12f3a13e2e134fe9b8d3d1a160a8e54de1e8fa7 (patch) | |
tree | b4caa2a8ecd7ed28ee9302a934db45935701de24 /hw/nvram/fw_cfg.c | |
parent | baf2d5bfbac015b27f4db74feab235e167df0c84 (diff) | |
download | qemu-e12f3a13e2e134fe9b8d3d1a160a8e54de1e8fa7.zip qemu-e12f3a13e2e134fe9b8d3d1a160a8e54de1e8fa7.tar.gz qemu-e12f3a13e2e134fe9b8d3d1a160a8e54de1e8fa7.tar.bz2 |
fw-cfg: turn FW_CFG_FILE_SLOTS into a device property
We'd like to raise the value of FW_CFG_FILE_SLOTS. Doing it naively could
lead to problems with backward migration: a more recent QEMU (running an
older machine type) would allow the guest, in fw_cfg_select(), to select a
high key value that is unavailable in the same machine type implemented by
the older (target) QEMU. On the target host, fw_cfg_data_read() for
example could dereference nonexistent entries.
As first step, size the FWCfgState.entries[*] and FWCfgState.entry_order
arrays dynamically. All three array sizes will be influenced by the new
field FWCfgState.file_slots (and matching device property).
Make the following changes:
- Replace the FW_CFG_FILE_SLOTS macro with FW_CFG_FILE_SLOTS_MIN (minimum
count of fw_cfg file slots) in the header file. The value remains 0x10.
- Replace all uses of FW_CFG_FILE_SLOTS with a helper function called
fw_cfg_file_slots(), returning the new property.
- Eliminate the macro FW_CFG_MAX_ENTRY, and replace all its uses with a
helper function called fw_cfg_max_entry().
- In the MMIO- and IO-mapped realize functions both, allocate all three
arrays dynamically, based on the new property.
- The new property defaults to FW_CFG_FILE_SLOTS_MIN. This is going to be
customized in the following patches.
Cc: "Gabriel L. Somlo" <somlo@cmu.edu>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Acked-by: Gabriel Somlo <somlo@cmu.edu>
Tested-by: Gabriel Somlo <somlo@cmu.edu>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Diffstat (limited to 'hw/nvram/fw_cfg.c')
-rw-r--r-- | hw/nvram/fw_cfg.c | 71 |
1 files changed, 63 insertions, 8 deletions
diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c index e0145c1..bf75ef7 100644 --- a/hw/nvram/fw_cfg.c +++ b/hw/nvram/fw_cfg.c @@ -33,6 +33,7 @@ #include "qemu/error-report.h" #include "qemu/config-file.h" #include "qemu/cutils.h" +#include "qapi/error.h" #define FW_CFG_NAME "fw_cfg" #define FW_CFG_PATH "/machine/" FW_CFG_NAME @@ -71,8 +72,9 @@ struct FWCfgState { SysBusDevice parent_obj; /*< public >*/ - FWCfgEntry entries[2][FW_CFG_MAX_ENTRY]; - int entry_order[FW_CFG_MAX_ENTRY]; + uint16_t file_slots; + FWCfgEntry *entries[2]; + int *entry_order; FWCfgFiles *files; uint16_t cur_entry; uint32_t cur_offset; @@ -257,13 +259,24 @@ static void fw_cfg_write(FWCfgState *s, uint8_t value) /* nothing, write support removed in QEMU v2.4+ */ } +static inline uint16_t fw_cfg_file_slots(const FWCfgState *s) +{ + return s->file_slots; +} + +/* Note: this function returns an exclusive limit. */ +static inline uint32_t fw_cfg_max_entry(const FWCfgState *s) +{ + return FW_CFG_FILE_FIRST + fw_cfg_file_slots(s); +} + static int fw_cfg_select(FWCfgState *s, uint16_t key) { int arch, ret; FWCfgEntry *e; s->cur_offset = 0; - if ((key & FW_CFG_ENTRY_MASK) >= FW_CFG_MAX_ENTRY) { + if ((key & FW_CFG_ENTRY_MASK) >= fw_cfg_max_entry(s)) { s->cur_entry = FW_CFG_INVALID; ret = 0; } else { @@ -610,7 +623,7 @@ static void fw_cfg_add_bytes_read_callback(FWCfgState *s, uint16_t key, key &= FW_CFG_ENTRY_MASK; - assert(key < FW_CFG_MAX_ENTRY && len < UINT32_MAX); + assert(key < fw_cfg_max_entry(s) && len < UINT32_MAX); assert(s->entries[arch][key].data == NULL); /* avoid key conflict */ s->entries[arch][key].data = data; @@ -628,7 +641,7 @@ static void *fw_cfg_modify_bytes_read(FWCfgState *s, uint16_t key, key &= FW_CFG_ENTRY_MASK; - assert(key < FW_CFG_MAX_ENTRY && len < UINT32_MAX); + assert(key < fw_cfg_max_entry(s) && len < UINT32_MAX); /* return the old data to the function caller, avoid memory leak */ ptr = s->entries[arch][key].data; @@ -777,13 +790,13 @@ void fw_cfg_add_file_callback(FWCfgState *s, const char *filename, int order = 0; if (!s->files) { - dsize = sizeof(uint32_t) + sizeof(FWCfgFile) * FW_CFG_FILE_SLOTS; + dsize = sizeof(uint32_t) + sizeof(FWCfgFile) * fw_cfg_file_slots(s); s->files = g_malloc0(dsize); fw_cfg_add_bytes(s, FW_CFG_FILE_DIR, s->files, dsize); } count = be32_to_cpu(s->files->count); - assert(count < FW_CFG_FILE_SLOTS); + assert(count < fw_cfg_file_slots(s)); /* Find the insertion point. */ if (mc->legacy_fw_cfg_order) { @@ -857,7 +870,7 @@ void *fw_cfg_modify_file(FWCfgState *s, const char *filename, assert(s->files); index = be32_to_cpu(s->files->count); - assert(index < FW_CFG_FILE_SLOTS); + assert(index < fw_cfg_file_slots(s)); for (i = 0; i < index; i++) { if (strcmp(filename, s->files->f[i].name) == 0) { @@ -1014,12 +1027,38 @@ static const TypeInfo fw_cfg_info = { .class_init = fw_cfg_class_init, }; +static void fw_cfg_file_slots_allocate(FWCfgState *s, Error **errp) +{ + uint16_t file_slots_max; + + if (fw_cfg_file_slots(s) < FW_CFG_FILE_SLOTS_MIN) { + error_setg(errp, "\"file_slots\" must be at least 0x%x", + FW_CFG_FILE_SLOTS_MIN); + return; + } + + /* (UINT16_MAX & FW_CFG_ENTRY_MASK) is the highest inclusive selector value + * that we permit. The actual (exclusive) value coming from the + * configuration is (FW_CFG_FILE_FIRST + fw_cfg_file_slots(s)). */ + file_slots_max = (UINT16_MAX & FW_CFG_ENTRY_MASK) - FW_CFG_FILE_FIRST + 1; + if (fw_cfg_file_slots(s) > file_slots_max) { + error_setg(errp, "\"file_slots\" must not exceed 0x%" PRIx16, + file_slots_max); + return; + } + + s->entries[0] = g_new0(FWCfgEntry, fw_cfg_max_entry(s)); + s->entries[1] = g_new0(FWCfgEntry, fw_cfg_max_entry(s)); + s->entry_order = g_new0(int, fw_cfg_max_entry(s)); +} static Property fw_cfg_io_properties[] = { DEFINE_PROP_UINT32("iobase", FWCfgIoState, iobase, -1), DEFINE_PROP_UINT32("dma_iobase", FWCfgIoState, dma_iobase, -1), DEFINE_PROP_BOOL("dma_enabled", FWCfgIoState, parent_obj.dma_enabled, true), + DEFINE_PROP_UINT16("x-file-slots", FWCfgIoState, parent_obj.file_slots, + FW_CFG_FILE_SLOTS_MIN), DEFINE_PROP_END_OF_LIST(), }; @@ -1027,6 +1066,13 @@ static void fw_cfg_io_realize(DeviceState *dev, Error **errp) { FWCfgIoState *s = FW_CFG_IO(dev); SysBusDevice *sbd = SYS_BUS_DEVICE(dev); + Error *local_err = NULL; + + fw_cfg_file_slots_allocate(FW_CFG(s), &local_err); + if (local_err) { + error_propagate(errp, local_err); + return; + } /* when using port i/o, the 8-bit data register ALWAYS overlaps * with half of the 16-bit control register. Hence, the total size @@ -1063,6 +1109,8 @@ static Property fw_cfg_mem_properties[] = { DEFINE_PROP_UINT32("data_width", FWCfgMemState, data_width, -1), DEFINE_PROP_BOOL("dma_enabled", FWCfgMemState, parent_obj.dma_enabled, true), + DEFINE_PROP_UINT16("x-file-slots", FWCfgMemState, parent_obj.file_slots, + FW_CFG_FILE_SLOTS_MIN), DEFINE_PROP_END_OF_LIST(), }; @@ -1071,6 +1119,13 @@ static void fw_cfg_mem_realize(DeviceState *dev, Error **errp) FWCfgMemState *s = FW_CFG_MEM(dev); SysBusDevice *sbd = SYS_BUS_DEVICE(dev); const MemoryRegionOps *data_ops = &fw_cfg_data_mem_ops; + Error *local_err = NULL; + + fw_cfg_file_slots_allocate(FW_CFG(s), &local_err); + if (local_err) { + error_propagate(errp, local_err); + return; + } memory_region_init_io(&s->ctl_iomem, OBJECT(s), &fw_cfg_ctl_mem_ops, FW_CFG(s), "fwcfg.ctl", FW_CFG_CTL_SIZE); |