On 8/6/26 11:12, Peter Maydell wrote:
On Wed, 3 Jun 2026 at 08:08, Philippe Mathieu-Daudé <[email protected]> wrote:
On 29/5/26 19:46, Peter Maydell wrote:
The fw_cfg_init_io_dma() function allows the caller to specify the
base port number of the selector/data register and the base port
number of the DMA address register separately. No caller actually
uses this: they all pass in base + 4 for the dma_iobase.
To reduce the risk of unnecessary variation in what different x86
machine types use as their fw_cfg register layout, remove the
dma_iobase argument from fw_cfg_init_io_dma(), and have the function
always use the same "DMA port is base port + 4" layout.
Signed-off-by: Peter Maydell <[email protected]>
---
hw/i386/fw_cfg.c | 3 +--
hw/i386/microvm.c | 3 +--
hw/i386/pc.c | 3 +--
hw/nvram/fw_cfg.c | 8 ++++----
include/hw/nvram/fw_cfg.h | 17 +++++++++++++++--
5 files changed, 22 insertions(+), 12 deletions(-)
diff --git a/include/hw/nvram/fw_cfg.h b/include/hw/nvram/fw_cfg.h
index 45a3747908..be3fb5f8aa 100644
--- a/include/hw/nvram/fw_cfg.h
+++ b/include/hw/nvram/fw_cfg.h
@@ -305,8 +305,21 @@ bool fw_cfg_add_file_from_generator(FWCfgState *s,
Object *parent, const char *part,
const char *filename, Error **errp);
-FWCfgState *fw_cfg_init_io_dma(uint32_t iobase, uint32_t dma_iobase,
- AddressSpace *dma_as);
+/**
+ * fw_cfg_init_io_dma:
+ * @iobase: x86 port number which is the base of the fw_cfg port range
s/x86/ISA/?
This is specifically x86, because we use this where we're
wiring fw_cfg up to the x86 in/out port instructions. There's
no ISA-bus version of fw_cfg. Anything other than x86 should
be using the memory-mapped fw_cfg.
But this "x86 port number" is really a address on the ISA I/O bus.
Maybe make explicit we want this method restricted to x86 instead?
"ISA port number which is the base of the fw_cfg port range (restricted
to x86 targets)."
Regards,
Phil.
