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fw_cfg: Define a static signature to be returned on DMA port reads

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Return a static signature ("QEMU CFG") if the guest does a read to the
DMA address io register.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
This commit is contained in:
Kevin O'Connor 2015-10-08 17:02:58 +02:00 • committed by Gerd Hoffmann
parent c886fc4c20
commit 2cc06a8843
2 changed files with 15 additions and 2 deletions
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14
hw/nvram/fw_cfg.c
View file

@ -53,6 +53,8 @@
#define FW_CFG_DMA_CTL_SKIP 0x04
#define FW_CFG_DMA_CTL_SELECT 0x08
#define FW_CFG_DMA_SIGNATURE 0x51454d5520434647ULL /* "QEMU CFG" */
typedef struct FWCfgEntry {
uint32_t len;
uint8_t *data;
@ -397,6 +399,13 @@ static void fw_cfg_dma_transfer(FWCfgState *s)
trace_fw_cfg_read(s, 0);
}
static uint64_t fw_cfg_dma_mem_read(void *opaque, hwaddr addr,
unsigned size)
{
/* Return a signature value (and handle various read sizes) */
return extract64(FW_CFG_DMA_SIGNATURE, (8 - addr - size) * 8, size * 8);
}
static void fw_cfg_dma_mem_write(void *opaque, hwaddr addr,
uint64_t value, unsigned size)
{
@ -420,8 +429,8 @@ static void fw_cfg_dma_mem_write(void *opaque, hwaddr addr,
static bool fw_cfg_dma_mem_valid(void *opaque, hwaddr addr,
unsigned size, bool is_write)
{
return is_write && ((size == 4 && (addr == 0 || addr == 4)) ||
(size == 8 && addr == 0));
return !is_write || ((size == 4 && (addr == 0 || addr == 4)) ||
(size == 8 && addr == 0));
}
static bool fw_cfg_data_mem_valid(void *opaque, hwaddr addr,
@ -492,6 +501,7 @@ static const MemoryRegionOps fw_cfg_comb_mem_ops = {
};
static const MemoryRegionOps fw_cfg_dma_mem_ops = {
.read = fw_cfg_dma_mem_read,
.write = fw_cfg_dma_mem_write,
.endianness = DEVICE_BIG_ENDIAN,
.valid.accepts = fw_cfg_dma_mem_valid,