接前一篇文章:
通过前文,SeaBIOS就把所有设备的BAR基址赋值好了。接下来解析与BAR地址设置相关的代码。pci_default_write_config函数在hw/pci/pci.c中,代码如下:
void pci_default_write_config(PCIDevice *d, uint32_t addr, uint32_t val_in, int l)
{
int i, was_irq_disabled = pci_irq_disabled(d);
uint32_t val = val_in;
assert(addr + l <= pci_config_size(d));
for (i = 0; i < l; val >>= 8, ++i) {
uint8_t wmask = d->wmask[addr + i];
uint8_t w1cmask = d->w1cmask[addr + i];
assert(!(wmask & w1cmask));
d->config[addr + i] = (d->config[addr + i] & ~wmask) | (val & wmask);
d->config[addr + i] &= ~(val & w1cmask); /* W1C: Write 1 to Clear */
}
if (ranges_overlap(addr, l, PCI_BASE_ADDRESS_0, 24