implement PCIBIOS specification

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 73 insertions, 0 deletions

diff --git a/code32seg.c b/code32seg.c
new file mode 100644
index 0000000..213bf44
--- /dev/null
+++ b/code32seg.c
@@ -0,0 +1,73 @@
+#include <stddef.h>
+#include "bios.h"
+#include "pci.h"
+#include "processor-flags.h"
+
+#define PCI_FUNC_NOT_SUPPORTED 0x81
+#define PCI_BAD_VENDOR_ID      0x83
+#define PCI_DEVICE_NOT_FOUND   0x86
+#define PCI_BUFFER_TOO_SMALL   0x89
+
+/*
+ * The PCIBIOS handler must be position independent.  To read a flat pointer,
+ * we use the instruction pointer to retrieve the address corresponding to
+ * physical address 0 (i.e., what Linux calls PAGE_OFFSET).
+ */
+
+static inline void *from_flat_ptr(void *p)
+{
+	return p + pic_base();
+}
+
+#define FLAT_VAR(x)  (*(typeof(&(x))) from_flat_ptr(&(x)))
+
+bioscall void pcibios_handler(struct bios32regs *args)
+{
+	switch (args->eax) {
+		/* discovery */
+	case 0xb101:
+		args->eax = 0x01;
+		args->ebx = 0x210;
+		args->ecx = FLAT_VAR(max_bus);
+		args->edx = 0x20494350;
+		goto success;
+
+		/* config space access */
+	case 0xb108:
+		args->ecx = pci_config_readb(args->ebx, args->edi);
+		goto success;
+	case 0xb109:
+		args->ecx = pci_config_readw(args->ebx, args->edi);
+		goto success;
+	case 0xb10a:
+		args->ecx = pci_config_readl(args->ebx, args->edi);
+		goto success;
+	case 0xb10b:
+		pci_config_writeb(args->ebx, args->edi, args->ecx);
+		goto success;
+	case 0xb10c:
+		pci_config_writew(args->ebx, args->edi, args->ecx);
+		goto success;
+	case 0xb10d:
+		pci_config_writel(args->ebx, args->edi, args->ecx);
+		goto success;
+
+		/* find device id, find class code */
+	case 0xb102:
+	case 0xb103:
+		args->eax &= ~0xff00;
+		args->eax |= PCI_DEVICE_NOT_FOUND << 8;
+		break;
+
+	default:
+		args->eax &= ~0xff00;
+		args->eax |= PCI_FUNC_NOT_SUPPORTED << 8;
+		break;
+	}
+	args->eflags |= X86_EFLAGS_CF;
+	return;
+
+success:
+	/* On entry, CF=0 */
+	args->eax &= ~0xff00; /* clear ah */
+}