[Qemu-devel] [PATCH v4 3/7] fw-cfg: expose "file_slots" parameter in fw_cfg_init_io_dma()

[Laszlo Ersek]

Accordingly, generalize the "file_slots" minimum calculation in
fw_cfg_init_io_dma(), and move the constant FW_CFG_FILE_SLOTS_TRAD
argument to the callers of fw_cfg_init_io_dma().

Cc: "Gabriel L. Somlo" <address@hidden>
Cc: "Michael S. Tsirkin" <address@hidden>
Cc: Gerd Hoffmann <address@hidden>
Cc: Igor Mammedov <address@hidden>
Cc: Paolo Bonzini <address@hidden>
Signed-off-by: Laszlo Ersek <address@hidden>
---
 docs/specs/fw_cfg.txt     |  4 ++--
 include/hw/nvram/fw_cfg.h |  2 +-
 hw/i386/pc.c              |  3 ++-
 hw/nvram/fw_cfg.c         | 13 ++++++-------
 4 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/docs/specs/fw_cfg.txt b/docs/specs/fw_cfg.txt
index 84e2978706f5..4a6888b511f4 100644
--- a/docs/specs/fw_cfg.txt
+++ b/docs/specs/fw_cfg.txt
@@ -153,12 +153,12 @@ Selector Reg.    Range Usage
 0x4000 - 0x7fff  Generic (0x0000 - 0x3fff, RW, ignored in QEMU v2.4+)
 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 (FW_CFG_FILE_FIRST + FW_CFG_FILE_SLOTS_TRAD) (see fw_cfg.h).
+In practice, the number of allowed firmware configuration items depends on the
+machine type.
 
 = Guest-side DMA Interface =
 
 If bit 1 of the feature bitmap is set, the DMA interface is present. This does
 not replace the existing fw_cfg interface, it is an add-on. This interface
diff --git a/include/hw/nvram/fw_cfg.h b/include/hw/nvram/fw_cfg.h
index b980cbaebf43..e9a6b6aa968c 100644
--- a/include/hw/nvram/fw_cfg.h
+++ b/include/hw/nvram/fw_cfg.h
@@ -173,11 +173,11 @@ void fw_cfg_add_file_callback(FWCfgState *s, const char 
*filename,
  */
 void *fw_cfg_modify_file(FWCfgState *s, const char *filename, void *data,
                          size_t len);
 
 FWCfgState *fw_cfg_init_io_dma(uint32_t iobase, uint32_t dma_iobase,
-                                AddressSpace *dma_as);
+                                AddressSpace *dma_as, uint32_t file_slots);
 FWCfgState *fw_cfg_init_io(uint32_t iobase);
 FWCfgState *fw_cfg_init_mem(hwaddr ctl_addr, hwaddr data_addr);
 FWCfgState *fw_cfg_init_mem_wide(hwaddr ctl_addr,
                                  hwaddr data_addr, uint32_t data_width,
                                  hwaddr dma_addr, AddressSpace *dma_as);
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index a9e64a88e5e7..5d929d8fc887 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -741,11 +741,12 @@ static FWCfgState *bochs_bios_init(AddressSpace *as, 
PCMachineState *pcms)
 {
     FWCfgState *fw_cfg;
     uint64_t *numa_fw_cfg;
     int i, j;
 
-    fw_cfg = fw_cfg_init_io_dma(FW_CFG_IO_BASE, FW_CFG_IO_BASE + 4, as);
+    fw_cfg = fw_cfg_init_io_dma(FW_CFG_IO_BASE, FW_CFG_IO_BASE + 4, as,
+                                FW_CFG_FILE_SLOTS_TRAD);
     fw_cfg_add_i16(fw_cfg, FW_CFG_NB_CPUS, pcms->boot_cpus);
 
     /* FW_CFG_MAX_CPUS is a bit confusing/problematic on x86:
      *
      * For machine types prior to 1.8, SeaBIOS needs FW_CFG_MAX_CPUS for
diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c
index 2e1441c09750..c33c76ab93b1 100644
--- a/hw/nvram/fw_cfg.c
+++ b/hw/nvram/fw_cfg.c
@@ -926,11 +926,11 @@ static void fw_cfg_init1(DeviceState *dev)
     s->machine_ready.notify = fw_cfg_machine_ready;
     qemu_add_machine_init_done_notifier(&s->machine_ready);
 }
 
 FWCfgState *fw_cfg_init_io_dma(uint32_t iobase, uint32_t dma_iobase,
-                                AddressSpace *dma_as)
+                                AddressSpace *dma_as, uint32_t file_slots)
 {
     DeviceState *dev;
     FWCfgState *s;
     uint32_t version = FW_CFG_VERSION;
     bool dma_requested = dma_iobase && dma_as;
@@ -940,15 +940,14 @@ FWCfgState *fw_cfg_init_io_dma(uint32_t iobase, uint32_t 
dma_iobase,
     qdev_prop_set_uint32(dev, "dma_iobase", dma_iobase);
     if (!dma_requested) {
         qdev_prop_set_bit(dev, "dma_enabled", false);
     }
 
-    /* Once we expose the "file_slots" property to callers of
-     * fw_cfg_init_io_dma(), the following setting should become conditional on
-     * the input parameter being lower than the current value of the property.
-     */
-    qdev_prop_set_uint32(dev, "file_slots", FW_CFG_FILE_SLOTS_TRAD);
+    if (file_slots < object_property_get_int(OBJECT(dev), "file_slots",
+                                             &error_abort)) {
+        qdev_prop_set_uint32(dev, "file_slots", file_slots);
+    }
 
     fw_cfg_init1(dev);
     s = FW_CFG(dev);
 
     if (s->dma_enabled) {
@@ -964,11 +963,11 @@ FWCfgState *fw_cfg_init_io_dma(uint32_t iobase, uint32_t 
dma_iobase,
     return s;
 }
 
 FWCfgState *fw_cfg_init_io(uint32_t iobase)
 {
-    return fw_cfg_init_io_dma(iobase, 0, NULL);
+    return fw_cfg_init_io_dma(iobase, 0, NULL, FW_CFG_FILE_SLOTS_TRAD);
 }
 
 FWCfgState *fw_cfg_init_mem_wide(hwaddr ctl_addr,
                                  hwaddr data_addr, uint32_t data_width,
                                  hwaddr dma_addr, AddressSpace *dma_as)
-- 
2.9.2