diff --git a/Makefile b/Makefile
index d6d24d6..e4a3403 100644
--- a/Makefile
+++ b/Makefile
@@ -18,7 +18,7 @@ else
     VECHO = @printf
 endif
 
-OBJS := vm.o serial.o main.o
+OBJS := vm.o serial.o main.o pci.o
 OBJS := $(addprefix $(OUT)/,$(OBJS))
 deps := $(OBJS:%.o=%.o.d)
 
diff --git a/configs/linux.config b/configs/linux.config
index dfb6be6..712abf5 100644
--- a/configs/linux.config
+++ b/configs/linux.config
@@ -1,6 +1,6 @@
-CONFIG_CC_VERSION_TEXT="gcc (Ubuntu 9.3.0-17ubuntu1~20.04) 9.3.0"
+CONFIG_CC_VERSION_TEXT="gcc (Ubuntu 9.4.0-1ubuntu1~20.04.1) 9.4.0"
 CONFIG_CC_IS_GCC=y
-CONFIG_GCC_VERSION=90300
+CONFIG_GCC_VERSION=90400
 CONFIG_CLANG_VERSION=0
 CONFIG_AS_IS_GNU=y
 CONFIG_AS_VERSION=23400
@@ -235,6 +235,7 @@ CONFIG_X86_MPPARSE=y
 # CONFIG_RETPOLINE is not set
 # CONFIG_X86_CPU_RESCTRL is not set
 # CONFIG_X86_EXTENDED_PLATFORM is not set
+# CONFIG_IOSF_MBI is not set
 # CONFIG_SCHED_OMIT_FRAME_POINTER is not set
 # CONFIG_HYPERVISOR_GUEST is not set
 # CONFIG_MK8 is not set
@@ -259,6 +260,7 @@ CONFIG_CPU_SUP_CENTAUR=y
 CONFIG_CPU_SUP_ZHAOXIN=y
 CONFIG_HPET_TIMER=y
 # CONFIG_DMI is not set
+# CONFIG_GART_IOMMU is not set
 CONFIG_NR_CPUS_RANGE_BEGIN=1
 CONFIG_NR_CPUS_RANGE_END=1
 CONFIG_NR_CPUS_DEFAULT=1
@@ -272,6 +274,9 @@ CONFIG_X86_IO_APIC=y
 #
 # Performance monitoring
 #
+# CONFIG_PERF_EVENTS_INTEL_UNCORE is not set
+# CONFIG_PERF_EVENTS_INTEL_RAPL is not set
+# CONFIG_PERF_EVENTS_INTEL_CSTATE is not set
 # CONFIG_PERF_EVENTS_AMD_POWER is not set
 # CONFIG_PERF_EVENTS_AMD_UNCORE is not set
 # end of Performance monitoring
@@ -343,8 +348,11 @@ CONFIG_ARCH_SUPPORTS_ACPI=y
 #
 # Bus options (PCI etc.)
 #
+CONFIG_PCI_DIRECT=y
+# CONFIG_PCI_CNB20LE_QUIRK is not set
 # CONFIG_ISA_BUS is not set
 # CONFIG_ISA_DMA_API is not set
+CONFIG_AMD_NB=y
 # end of Bus options (PCI etc.)
 
 #
@@ -546,8 +554,61 @@ CONFIG_ARCH_HAS_PTE_SPECIAL=y
 CONFIG_HAVE_EISA=y
 # CONFIG_EISA is not set
 CONFIG_HAVE_PCI=y
-# CONFIG_PCI is not set
+CONFIG_PCI=y
+CONFIG_PCI_DOMAINS=y
+# CONFIG_PCIEPORTBUS is not set
+# CONFIG_PCIEASPM is not set
+# CONFIG_PCIE_PTM is not set
+# CONFIG_PCI_MSI is not set
+# CONFIG_PCI_QUIRKS is not set
+# CONFIG_PCI_DEBUG is not set
+# CONFIG_PCI_STUB is not set
+CONFIG_PCI_LOCKLESS_CONFIG=y
+# CONFIG_PCI_IOV is not set
+# CONFIG_PCI_PRI is not set
+# CONFIG_PCI_PASID is not set
+# CONFIG_PCIE_BUS_TUNE_OFF is not set
+CONFIG_PCIE_BUS_DEFAULT=y
+# CONFIG_PCIE_BUS_SAFE is not set
+# CONFIG_PCIE_BUS_PERFORMANCE is not set
+# CONFIG_PCIE_BUS_PEER2PEER is not set
+# CONFIG_HOTPLUG_PCI is not set
+
+#
+# PCI controller drivers
+#
+
+#
+# DesignWare PCI Core Support
+#
+# end of DesignWare PCI Core Support
+
+#
+# Mobiveil PCIe Core Support
+#
+# end of Mobiveil PCIe Core Support
+
+#
+# Cadence PCIe controllers support
+#
+# end of Cadence PCIe controllers support
+# end of PCI controller drivers
+
+#
+# PCI Endpoint
+#
+# CONFIG_PCI_ENDPOINT is not set
+# end of PCI Endpoint
+
+#
+# PCI switch controller drivers
+#
+# CONFIG_PCI_SW_SWITCHTEC is not set
+# end of PCI switch controller drivers
+
+# CONFIG_CXL_BUS is not set
 # CONFIG_PCCARD is not set
+# CONFIG_RAPIDIO is not set
 
 #
 # Generic Driver Options
@@ -615,8 +676,14 @@ CONFIG_ARCH_MIGHT_HAVE_PC_PARPORT=y
 # Misc devices
 #
 # CONFIG_DUMMY_IRQ is not set
+# CONFIG_IBM_ASM is not set
+# CONFIG_PHANTOM is not set
+# CONFIG_TIFM_CORE is not set
 # CONFIG_ENCLOSURE_SERVICES is not set
+# CONFIG_HP_ILO is not set
 # CONFIG_SRAM is not set
+# CONFIG_DW_XDATA_PCIE is not set
+# CONFIG_PCI_ENDPOINT_TEST is not set
 # CONFIG_XILINX_SDFEC is not set
 # CONFIG_C2PORT is not set
 
@@ -626,6 +693,8 @@ CONFIG_ARCH_MIGHT_HAVE_PC_PARPORT=y
 # CONFIG_EEPROM_93CX6 is not set
 # end of EEPROM support
 
+# CONFIG_CB710_CORE is not set
+
 #
 # Texas Instruments shared transport line discipline
 #
@@ -634,7 +703,15 @@ CONFIG_ARCH_MIGHT_HAVE_PC_PARPORT=y
 #
 # Altera FPGA firmware download module (requires I2C)
 #
+# CONFIG_INTEL_MEI is not set
+# CONFIG_INTEL_MEI_ME is not set
+# CONFIG_INTEL_MEI_TXE is not set
+# CONFIG_VMWARE_VMCI is not set
+# CONFIG_GENWQE is not set
 # CONFIG_ECHO is not set
+# CONFIG_MISC_ALCOR_PCI is not set
+# CONFIG_MISC_RTSX_PCI is not set
+# CONFIG_HABANA_AI is not set
 # CONFIG_PVPANIC is not set
 # end of Misc devices
 
@@ -644,6 +721,15 @@ CONFIG_ARCH_MIGHT_HAVE_PC_PARPORT=y
 CONFIG_SCSI_MOD=y
 # end of SCSI device support
 
+# CONFIG_FUSION is not set
+
+#
+# IEEE 1394 (FireWire) support
+#
+# CONFIG_FIREWIRE is not set
+# CONFIG_FIREWIRE_NOSY is not set
+# end of IEEE 1394 (FireWire) support
+
 # CONFIG_MACINTOSH_DRIVERS is not set
 
 #
@@ -670,6 +756,7 @@ CONFIG_KEYBOARD_ATKBD=y
 # CONFIG_KEYBOARD_LKKBD is not set
 # CONFIG_KEYBOARD_NEWTON is not set
 # CONFIG_KEYBOARD_OPENCORES is not set
+# CONFIG_KEYBOARD_SAMSUNG is not set
 # CONFIG_KEYBOARD_STOWAWAY is not set
 # CONFIG_KEYBOARD_SUNKBD is not set
 # CONFIG_KEYBOARD_XTKBD is not set
@@ -701,6 +788,7 @@ CONFIG_ARCH_MIGHT_HAVE_PC_SERIO=y
 CONFIG_SERIO_I8042=y
 CONFIG_SERIO_SERPORT=y
 # CONFIG_SERIO_CT82C710 is not set
+# CONFIG_SERIO_PCIPS2 is not set
 CONFIG_SERIO_LIBPS2=y
 # CONFIG_SERIO_RAW is not set
 # CONFIG_SERIO_ALTERA_PS2 is not set
@@ -734,11 +822,14 @@ CONFIG_SERIAL_8250_DEPRECATED_OPTIONS=y
 # CONFIG_SERIAL_8250_16550A_VARIANTS is not set
 # CONFIG_SERIAL_8250_FINTEK is not set
 CONFIG_SERIAL_8250_CONSOLE=y
+# CONFIG_SERIAL_8250_PCI is not set
 CONFIG_SERIAL_8250_NR_UARTS=4
 CONFIG_SERIAL_8250_RUNTIME_UARTS=4
 # CONFIG_SERIAL_8250_EXTENDED is not set
 # CONFIG_SERIAL_8250_DW is not set
 # CONFIG_SERIAL_8250_RT288X is not set
+# CONFIG_SERIAL_8250_LPSS is not set
+# CONFIG_SERIAL_8250_MID is not set
 
 #
 # Non-8250 serial port support
@@ -746,28 +837,36 @@ CONFIG_SERIAL_8250_RUNTIME_UARTS=4
 # CONFIG_SERIAL_UARTLITE is not set
 CONFIG_SERIAL_CORE=y
 CONFIG_SERIAL_CORE_CONSOLE=y
+# CONFIG_SERIAL_JSM is not set
 # CONFIG_SERIAL_LANTIQ is not set
 # CONFIG_SERIAL_SCCNXP is not set
+# CONFIG_SERIAL_BCM63XX is not set
 # CONFIG_SERIAL_ALTERA_JTAGUART is not set
 # CONFIG_SERIAL_ALTERA_UART is not set
 # CONFIG_SERIAL_ARC is not set
+# CONFIG_SERIAL_RP2 is not set
 # CONFIG_SERIAL_FSL_LPUART is not set
 # CONFIG_SERIAL_FSL_LINFLEXUART is not set
+# CONFIG_SERIAL_SPRD is not set
 # end of Serial drivers
 
 # CONFIG_SERIAL_NONSTANDARD is not set
+# CONFIG_NOZOMI is not set
 # CONFIG_NULL_TTY is not set
 # CONFIG_SERIAL_DEV_BUS is not set
 # CONFIG_TTY_PRINTK is not set
 # CONFIG_VIRTIO_CONSOLE is not set
 # CONFIG_IPMI_HANDLER is not set
 # CONFIG_HW_RANDOM is not set
+# CONFIG_APPLICOM is not set
 # CONFIG_MWAVE is not set
 # CONFIG_DEVMEM is not set
 # CONFIG_NVRAM is not set
+CONFIG_DEVPORT=y
 # CONFIG_HANGCHECK_TIMER is not set
 # CONFIG_TCG_TPM is not set
 # CONFIG_TELCLOCK is not set
+# CONFIG_XILLYBUS is not set
 # CONFIG_RANDOM_TRUST_BOOTLOADER is not set
 # end of Character devices
 
@@ -811,12 +910,20 @@ CONFIG_BCMA_POSSIBLE=y
 #
 # CONFIG_MFD_MADERA is not set
 # CONFIG_HTC_PASIC3 is not set
+# CONFIG_MFD_INTEL_QUARK_I2C_GPIO is not set
+# CONFIG_LPC_ICH is not set
+# CONFIG_LPC_SCH is not set
+# CONFIG_MFD_INTEL_LPSS_PCI is not set
+# CONFIG_MFD_INTEL_PMT is not set
+# CONFIG_MFD_JANZ_CMODIO is not set
 # CONFIG_MFD_KEMPLD is not set
 # CONFIG_MFD_MT6397 is not set
+# CONFIG_MFD_RDC321X is not set
 # CONFIG_MFD_SM501 is not set
 # CONFIG_MFD_SYSCON is not set
 # CONFIG_MFD_TI_AM335X_TSCADC is not set
 # CONFIG_MFD_TQMX86 is not set
+# CONFIG_MFD_VX855 is not set
 # end of Multifunction device drivers
 
 # CONFIG_REGULATOR is not set
@@ -833,6 +940,8 @@ CONFIG_BCMA_POSSIBLE=y
 #
 # Graphics support
 #
+# CONFIG_AGP is not set
+# CONFIG_VGA_ARB is not set
 # CONFIG_DRM is not set
 # CONFIG_DRM_DEBUG_MODESET_LOCK is not set
 
@@ -941,6 +1050,18 @@ CONFIG_HID_GENERIC=y
 # CONFIG_HID_SENSOR_HUB is not set
 # CONFIG_HID_ALPS is not set
 # end of Special HID drivers
+
+#
+# Intel ISH HID support
+#
+# CONFIG_INTEL_ISH_HID is not set
+# end of Intel ISH HID support
+
+#
+# AMD SFH HID Support
+#
+# CONFIG_AMD_SFH_HID is not set
+# end of AMD SFH HID Support
 # end of HID support
 
 CONFIG_USB_OHCI_LITTLE_ENDIAN=y
@@ -979,9 +1100,13 @@ CONFIG_RTC_MC146818_LIB=y
 # CONFIG_COMEDI is not set
 # CONFIG_STAGING is not set
 # CONFIG_X86_PLATFORM_DEVICES is not set
+CONFIG_PMC_ATOM=y
 # CONFIG_CHROME_PLATFORMS is not set
 # CONFIG_MELLANOX_PLATFORM is not set
-# CONFIG_COMMON_CLK is not set
+CONFIG_HAVE_CLK=y
+CONFIG_HAVE_CLK_PREPARE=y
+CONFIG_COMMON_CLK=y
+# CONFIG_XILINX_VCU is not set
 # CONFIG_HWSPINLOCK is not set
 
 #
@@ -1052,6 +1177,8 @@ CONFIG_CLKBLD_I8253=y
 # CONFIG_EXTCON is not set
 # CONFIG_MEMORY is not set
 # CONFIG_IIO is not set
+# CONFIG_NTB is not set
+# CONFIG_VME_BUS is not set
 # CONFIG_PWM is not set
 
 #
@@ -1088,6 +1215,7 @@ CONFIG_CLKBLD_I8253=y
 # end of Performance monitor support
 
 # CONFIG_RAS is not set
+# CONFIG_USB4 is not set
 
 #
 # Android
@@ -1195,6 +1323,7 @@ CONFIG_GENERIC_STRNLEN_USER=y
 CONFIG_GENERIC_FIND_FIRST_BIT=y
 # CONFIG_CORDIC is not set
 # CONFIG_PRIME_NUMBERS is not set
+CONFIG_RATIONAL=y
 CONFIG_GENERIC_PCI_IOMAP=y
 CONFIG_GENERIC_IOMAP=y
 CONFIG_ARCH_USE_CMPXCHG_LOCKREF=y
@@ -1396,6 +1525,7 @@ CONFIG_HAVE_OBJTOOL_MCOUNT=y
 CONFIG_HAVE_C_RECORDMCOUNT=y
 CONFIG_TRACING_SUPPORT=y
 # CONFIG_FTRACE is not set
+# CONFIG_PROVIDE_OHCI1394_DMA_INIT is not set
 # CONFIG_SAMPLES is not set
 CONFIG_HAVE_SAMPLE_FTRACE_DIRECT=y
 CONFIG_HAVE_SAMPLE_FTRACE_DIRECT_MULTI=y
@@ -1418,6 +1548,7 @@ CONFIG_IO_DELAY_0X80=y
 # CONFIG_DEBUG_ENTRY is not set
 # CONFIG_DEBUG_NMI_SELFTEST is not set
 # CONFIG_X86_DEBUG_FPU is not set
+# CONFIG_PUNIT_ATOM_DEBUG is not set
 # CONFIG_UNWINDER_ORC is not set
 # CONFIG_UNWINDER_FRAME_POINTER is not set
 CONFIG_UNWINDER_GUESS=y
diff --git a/src/pci.c b/src/pci.c
new file mode 100644
index 0000000..0022743
--- /dev/null
+++ b/src/pci.c
@@ -0,0 +1,244 @@
+#include <stdlib.h>
+#include <string.h>
+
+#include "pci.h"
+#include "utils.h"
+
+static inline struct dev *bus_find_dev(struct bus *bus, uint64_t addr)
+{
+    struct dev **p = &bus->head;
+
+    while (*p) {
+        uint64_t start = (*p)->base;
+        uint64_t end = start + (*p)->len - 1;
+        if (addr >= start && addr <= end)
+            return *p;
+        p = &(*p)->next;
+    }
+    return NULL;
+}
+
+void bus_handle_io(struct bus *bus,
+                   void *data,
+                   uint8_t is_write,
+                   uint64_t addr,
+                   uint8_t size)
+{
+    struct dev *dev = bus_find_dev(bus, addr);
+
+    if (dev && addr + size - 1 <= dev->base + dev->len - 1) {
+        dev->do_io(dev->owner, data, is_write, addr - dev->base, size);
+    }
+}
+
+void bus_register_dev(struct bus *bus, struct dev *dev)
+{
+    dev->next = bus->head;
+    bus->head = dev;
+    bus->dev_num++;
+}
+
+void bus_deregister_dev(struct bus *bus, struct dev *dev)
+{
+    struct dev **p = &bus->head;
+
+    while (*p != dev && *p) {
+        p = &(*p)->next;
+    }
+
+    if (*p)
+        *p = (*p)->next;
+}
+
+void bus_init(struct bus *bus)
+{
+    bus->dev_num = 0;
+    bus->head = NULL;
+}
+
+static inline void dev_init(struct dev *dev,
+                            uint64_t base,
+                            uint64_t len,
+                            void *owner,
+                            dev_io_fn do_io)
+{
+    dev->base = base;
+    dev->len = len;
+    dev->owner = owner;
+    dev->do_io = do_io;
+    dev->next = NULL;
+}
+
+static void pci_address_io(void *owner,
+                           void *data,
+                           uint8_t is_write,
+                           uint64_t offset,
+                           uint8_t size)
+{
+    struct pci *pci = (struct pci *) owner;
+    void *p = (void *) &pci->pci_addr + offset;
+    /* The data in port 0xCF8 is as an address when Guest Linux accesses the configuration space */
+    if (is_write)
+        memcpy(p, data, size);
+    else
+        memcpy(data, p, size);
+    pci->pci_addr.reg_offset = 0;
+}
+
+static inline void pci_activate_bar(struct pci_dev *dev,
+                                    uint8_t bar,
+                                    struct bus *bus)
+{
+    uint32_t mask = ~(dev->bar_size[bar] - 1);
+    if (!dev->bar_active[bar] && dev->space_dev[bar].base & mask)
+        bus_register_dev(bus, &dev->space_dev[bar]);
+    dev->bar_active[bar] = true;
+}
+
+static inline void pci_deactivate_bar(struct pci_dev *dev,
+                                      uint8_t bar,
+                                      struct bus *bus)
+{
+    uint32_t mask = ~(dev->bar_size[bar] - 1);
+    if (dev->bar_active[bar] && dev->space_dev[bar].base & mask)
+        bus_deregister_dev(bus, &dev->space_dev[bar]);
+    dev->bar_active[bar] = false;
+}
+
+static void pci_command_bar(struct pci_dev *dev)
+{
+    bool enable_io = PCI_HDR_READ(dev->hdr, PCI_COMMAND, 16) & PCI_COMMAND_IO;
+    bool enable_mem =
+        PCI_HDR_READ(dev->hdr, PCI_COMMAND, 16) & PCI_COMMAND_MEMORY;
+    for (int i = 0; i < PCI_STD_NUM_BARS; i++) {
+        struct bus *bus = dev->bar_is_io_space[i] ? dev->io_bus : dev->mmio_bus;
+        bool enable = dev->bar_is_io_space[i] ? enable_io : enable_mem;
+
+        if (enable)
+            pci_activate_bar(dev, i, bus);
+        else
+            pci_deactivate_bar(dev, i, bus);
+    }
+}
+
+static void pci_config_command(struct pci_dev *dev)
+{
+    pci_command_bar(dev);
+}
+
+static void pci_config_bar(struct pci_dev *dev, uint8_t bar)
+{
+    uint32_t mask = ~(dev->bar_size[bar] - 1);
+    uint32_t old_bar = PCI_HDR_READ(dev->hdr, PCI_BAR_OFFSET(bar), 32);
+    uint32_t new_bar = (old_bar & mask) | dev->bar_is_io_space[bar];
+    PCI_HDR_WRITE(dev->hdr, PCI_BAR_OFFSET(bar), new_bar, 32);
+    dev->space_dev[bar].base = new_bar;
+}
+
+static void pci_config_write(struct pci_dev *dev,
+                             void *data,
+                             uint64_t offset,
+                             uint8_t size)
+{
+    void *p = dev->hdr + offset;
+
+    memcpy(p, data, size);
+    if (offset == PCI_COMMAND) {
+        pci_config_command(dev);
+    } else if (offset >= PCI_BASE_ADDRESS_0 && offset <= PCI_BASE_ADDRESS_5) {
+        uint8_t bar = (offset - PCI_BASE_ADDRESS_0) >> 2;
+        pci_config_bar(dev, bar);
+    } else if (offset == PCI_ROM_ADDRESS) {
+        PCI_HDR_WRITE(dev->hdr, PCI_ROM_ADDRESS, 0, 32);
+    }
+    /* TODO: write to capability */
+}
+
+static void pci_config_read(struct pci_dev *dev,
+                            void *data,
+                            uint64_t offset,
+                            uint8_t size)
+{
+    void *p = dev->hdr + offset;
+    memcpy(data, p, size);
+}
+
+static void pci_config_do_io(void *owner,
+                             void *data,
+                             uint8_t is_write,
+                             uint64_t offset,
+                             uint8_t size)
+{
+    struct pci_dev *dev = (struct pci_dev *) owner;
+    if (is_write)
+        pci_config_write(dev, data, offset, size);
+    else
+        pci_config_read(dev, data, offset, size);
+}
+
+static void pci_data_io(void *owner,
+                        void *data,
+                        uint8_t is_write,
+                        uint64_t offset,
+                        uint8_t size)
+{
+    struct pci *pci = (struct pci *) owner;
+    uint64_t addr = pci->pci_addr.value | offset;
+    bus_handle_io(&pci->pci_bus, data, is_write, addr, size);
+}
+
+void pci_set_bar(struct pci_dev *dev,
+                 uint8_t bar,
+                 uint32_t bar_size,
+                 bool is_io_space,
+                 dev_io_fn do_io)
+{
+    /* TODO: mem type, prefetch */
+    /* FIXME: bar_size must be power of 2 */
+    PCI_HDR_WRITE(dev->hdr, PCI_BAR_OFFSET(bar), is_io_space, 32);
+    dev->bar_size[bar] = bar_size;
+    dev->bar_is_io_space[bar] = is_io_space;
+    dev_init(&dev->space_dev[bar], 0, bar_size, dev, do_io);
+}
+
+void pci_set_status(struct pci_dev *dev, uint16_t status)
+{
+    PCI_HDR_WRITE(dev->hdr, PCI_STATUS, status, 16);
+}
+
+void pci_dev_init(struct pci_dev *dev,
+                  struct pci *pci,
+                  struct bus *io_bus,
+                  struct bus *mmio_bus)
+{
+    memset(dev, 0x00, sizeof(struct pci_dev));
+    dev->hdr = dev->cfg_space;
+    dev->pci_bus = &pci->pci_bus;
+    dev->io_bus = io_bus;
+    dev->mmio_bus = mmio_bus;
+}
+
+void pci_register_dev(struct pci_dev *dev)
+{
+    /* FIXEME: it just simply register on pci bus 0 */
+    /* FIXEME: dev_num might exceed 32 */
+    union pci_config_address addr = {.enable_bit = 1,
+                                     .dev_num = dev->pci_bus->dev_num};
+    dev_init(&dev->config_dev, addr.value, PCI_CFG_SPACE_SIZE, dev,
+             pci_config_do_io);
+    bus_register_dev(dev->pci_bus, &dev->config_dev);
+}
+
+#define PCI_CONFIG_ADDR 0xCF8
+#define PCI_CONFIG_DATA 0xCFC
+
+void pci_init(struct pci *pci, struct bus *io_bus)
+{
+    dev_init(&pci->pci_addr_dev, PCI_CONFIG_ADDR, sizeof(uint32_t), pci,
+             pci_address_io);
+    dev_init(&pci->pci_bus_dev, PCI_CONFIG_DATA, sizeof(uint32_t), pci,
+             pci_data_io);
+    bus_init(&pci->pci_bus);
+    bus_register_dev(io_bus, &pci->pci_addr_dev);
+    bus_register_dev(io_bus, &pci->pci_bus_dev);
+}
\ No newline at end of file
diff --git a/src/pci.h b/src/pci.h
new file mode 100644
index 0000000..c0ce355
--- /dev/null
+++ b/src/pci.h
@@ -0,0 +1,87 @@
+#pragma once
+
+#include <linux/kvm.h>
+#include <linux/pci_regs.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+struct dev;
+
+typedef void (*dev_io_fn)(void *owner,
+                          void *data,
+                          uint8_t is_write,
+                          uint64_t offset,
+                          uint8_t size);
+
+struct dev {
+    uint64_t base;
+    uint64_t len;
+    void *owner;
+    dev_io_fn do_io;
+    struct dev *next;
+};
+
+struct bus {
+    uint64_t dev_num;
+    struct dev *head;
+};
+
+void bus_register_dev(struct bus *bus, struct dev *dev);
+void bus_deregister_dev(struct bus *bus, struct dev *dev);
+void bus_handle_io(struct bus *bus,
+                   void *data,
+                   uint8_t is_write,
+                   uint64_t addr,
+                   uint8_t size);
+void bus_init(struct bus *bus);
+
+union pci_config_address {
+    struct {
+        unsigned reg_offset : 2;
+        unsigned reg_num : 6;
+        unsigned func_num : 3;
+        unsigned dev_num : 5;
+        unsigned bus_num : 8;
+        unsigned reserved : 7;
+        unsigned enable_bit : 1;
+    };
+    uint32_t value;
+};
+
+#define PCI_HDR_READ(hdr, offset, width) (*((uint##width##_t *) (hdr + offset)))
+#define PCI_HDR_WRITE(hdr, offset, value, width) \
+    ((uint##width##_t *) (hdr + offset))[0] = value
+#define PCI_BAR_OFFSET(bar) (PCI_BASE_ADDRESS_0 + ((bar) << 2))
+
+struct pci_dev {
+    uint8_t cfg_space[PCI_CFG_SPACE_SIZE];
+    void *hdr;
+    uint32_t bar_size[6];
+    bool bar_active[6];
+    bool bar_is_io_space[6];
+    struct dev space_dev[6];
+    struct dev config_dev;
+    struct bus *io_bus;
+    struct bus *mmio_bus;
+    struct bus *pci_bus;
+};
+
+struct pci {
+    union pci_config_address pci_addr;
+    struct bus pci_bus;
+    struct dev pci_bus_dev;
+    struct dev pci_addr_dev;
+};
+
+void pci_set_bar(struct pci_dev *dev,
+                 uint8_t bar,
+                 uint32_t bar_size,
+                 bool is_io_space,
+                 dev_io_fn do_io);
+void pci_set_status(struct pci_dev *dev, uint16_t status);
+void pci_register_dev(struct pci_dev *dev);
+void pci_dev_init(struct pci_dev *dev,
+                  struct pci *pci,
+                  struct bus *io_bus,
+                  struct bus *mmio_bus);
+void pci_init();
\ No newline at end of file
diff --git a/src/vm.c b/src/vm.c
index 8639040..d1ff12c 100644
--- a/src/vm.c
+++ b/src/vm.c
@@ -17,7 +17,9 @@
 #include <unistd.h>
 
 #include "err.h"
+#include "pci.h"
 #include "serial.h"
+#include "virtio-pci.h"
 #include "vm.h"
 
 static int vm_init_regs(vm_t *v)
@@ -115,7 +117,8 @@ int vm_init(vm_t *v)
     vm_init_cpu_id(v);
     if (serial_init(&v->serial))
         return throw_err("Failed to init UART device");
-
+    bus_init(&v->io_bus);
+    bus_init(&v->mmio_bus);
     return 0;
 }
 
@@ -203,6 +206,28 @@ int vm_load_initrd(vm_t *v, const char *initrd_path)
     return 0;
 }
 
+void vm_handle_io(vm_t *v, struct kvm_run *run)
+{
+    uint64_t addr = run->io.port;
+    void *data = (void *) run + run->io.data_offset;
+    bool is_write = run->io.direction == KVM_EXIT_IO_OUT;
+
+    if (run->io.port >= COM1_PORT_BASE && run->io.port < COM1_PORT_END) {
+        serial_handle(&v->serial, run);
+    } else {
+        for (int i = 0; i < run->io.count; i++) {
+            bus_handle_io(&v->io_bus, data, is_write, addr, run->io.size);
+            addr += run->io.size;
+        }
+    }
+}
+
+void vm_handle_mmio(vm_t *v, struct kvm_run *run)
+{
+    bus_handle_io(&v->mmio_bus, run->mmio.data, run->mmio.is_write,
+                  run->mmio.phys_addr, run->mmio.len);
+}
+
 int vm_run(vm_t *v)
 {
     int run_size = ioctl(v->kvm_fd, KVM_GET_VCPU_MMAP_SIZE, 0);
@@ -217,8 +242,10 @@ int vm_run(vm_t *v)
         }
         switch (run->exit_reason) {
         case KVM_EXIT_IO:
-            if (run->io.port >= COM1_PORT_BASE && run->io.port < COM1_PORT_END)
-                serial_handle(&v->serial, run);
+            vm_handle_io(v, run);
+            break;
+        case KVM_EXIT_MMIO:
+            vm_handle_mmio(v, run);
             break;
         case KVM_EXIT_INTR:
             serial_console(&v->serial);
diff --git a/src/vm.h b/src/vm.h
index 3f5fd70..e6d2353 100644
--- a/src/vm.h
+++ b/src/vm.h
@@ -1,14 +1,18 @@
 #pragma once
 
 #define RAM_SIZE (1 << 30)
-#define KERNEL_OPTS "console=ttyS0"
+#define KERNEL_OPTS "console=ttyS0 pci=conf1"
 
+#include "pci.h"
 #include "serial.h"
 
 typedef struct {
     int kvm_fd, vm_fd, vcpu_fd;
     void *mem;
     serial_dev_t serial;
+    struct bus mmio_bus;
+    struct bus io_bus;
+    struct pci pci;
 } vm_t;
 
 int vm_init(vm_t *v);
@@ -16,4 +20,6 @@ int vm_load_image(vm_t *v, const char *image_path);
 int vm_load_initrd(vm_t *v, const char *initrd_path);
 int vm_run(vm_t *v);
 int vm_irq_line(vm_t *v, int irq, int level);
+void vm_handle_io(vm_t *v, struct kvm_run *run);
+void vm_handle_mmio(vm_t *v, struct kvm_run *run);
 void vm_exit(vm_t *v);