kvm: Initial PCI probe emulation

This patch adds simple PCI Configuration Mechanism 1 probing emulation. It
doesn't expose any actual PCI devices yet.

Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>

Makefile

@@ -16,6 +16,7 @@ OBJS	+= ioport.o
 OBJS	+= kvm.o
 OBJS	+= main.o
 OBJS	+= mmio.o
+OBJS	+= pci.o
 OBJS	+= util.o
 
 DEPS	:= $(patsubst %.o,%.d,$(OBJS))

include/kvm/pci.h

@@ -0,0 +1,6 @@
+#ifndef KVM__PCI_H
+#define KVM__PCI_H
+
+void pci__init(void);
+
+#endif /* KVM__PCI_H */

main.c

@@ -2,6 +2,7 @@
 
 #include "kvm/early_printk.h"
 #include "kvm/util.h"
+#include "kvm/pci.h"
 
 #include <inttypes.h>
 #include <signal.h>
@@ -110,6 +111,7 @@ int main(int argc, char *argv[])
 		kvm__enable_singlestep(kvm);
 
 	early_printk__init();
+	pci__init();
 
 	for (;;) {
 		kvm__run(kvm);

pci.c

@@ -0,0 +1,51 @@
+#include "kvm/pci.h"
+
+#include "kvm/ioport.h"
+
+#include <stdint.h>
+
+static uint32_t pci_cse;	/* PCI configuration space enable */
+
+static bool pci_cse_out(struct kvm *self, uint16_t port, void *data, int size, uint32_t count)
+{
+	uint32_t *p = data;
+
+	pci_cse		= *p;
+
+	return true;
+}
+
+static bool pci_cse_in(struct kvm *self, uint16_t port, void *data, int size, uint32_t count)
+{
+	uint32_t *p = data;
+
+	*p		= pci_cse;
+
+	return true;
+}
+
+static struct ioport_operations pci_cse_ops = {
+	.io_in		= pci_cse_in,
+	.io_out		= pci_cse_out,
+};
+
+static bool pci_mechanism_out(struct kvm *self, uint16_t port, void *data, int size, uint32_t count)
+{
+	return true;
+}
+
+static bool pci_mechanism_in(struct kvm *self, uint16_t port, void *data, int size, uint32_t count)
+{
+	return true;
+}
+
+static struct ioport_operations pci_mechanism_ops = {
+	.io_in		= pci_mechanism_in,
+	.io_out		= pci_mechanism_out,
+};
+
+void pci__init(void)
+{
+	ioport__register(0xcfb, &pci_mechanism_ops);
+	ioport__register(0xcf8, &pci_cse_ops);
+}