pcie: helper functions for pcie capability and extended capability

This patch implements helper functions for pci express capability
and pci express extended capability allocation.
NOTE: presence detection depends on pci_qdev_init() change.

Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

5 files changed, 654 insertions, 0 deletions

diff --git a/Makefile.objs b/Makefile.objs
index 5f5a4c5493..eeb5134600 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -186,6 +186,7 @@ hw-obj-$(CONFIG_PIIX4) += piix4.o
 # PCI watchdog devices
 hw-obj-y += wdt_i6300esb.o
 
+hw-obj-y += pcie.o
 hw-obj-y += msix.o msi.o
 
 # PCI network cards
diff --git a/hw/pci.h b/hw/pci.h
index 9e2f27d372..d6c522b8dd 100644
--- a/hw/pci.h
+++ b/hw/pci.h
@@ -9,6 +9,8 @@
 /* PCI includes legacy ISA access.  */
 #include "isa.h"
 
+#include "pcie.h"
+
 /* PCI bus */
 
 #define PCI_DEVFN(slot, func)   ((((slot) & 0x1f) << 3) | ((func) & 0x07))
@@ -175,6 +177,9 @@ struct PCIDevice {
     /* Offset of MSI capability in config space */
     uint8_t msi_cap;
 
+    /* PCI Express */
+    PCIExpressDevice exp;
+
     /* Location of option rom */
     char *romfile;
     ram_addr_t rom_offset;
diff --git a/hw/pcie.c b/hw/pcie.c
new file mode 100644
index 0000000000..53d1fce7c7
--- /dev/null
+++ b/hw/pcie.c
@@ -0,0 +1,540 @@
+/*
+ * pcie.c
+ *
+ * Copyright (c) 2010 Isaku Yamahata <yamahata at valinux co jp>
+ *                    VA Linux Systems Japan K.K.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "sysemu.h"
+#include "pci_bridge.h"
+#include "pcie.h"
+#include "msix.h"
+#include "msi.h"
+#include "pci_internals.h"
+#include "pcie_regs.h"
+
+//#define DEBUG_PCIE
+#ifdef DEBUG_PCIE
+# define PCIE_DPRINTF(fmt, ...)                                         \
+    fprintf(stderr, "%s:%d " fmt, __func__, __LINE__, ## __VA_ARGS__)
+#else
+# define PCIE_DPRINTF(fmt, ...) do {} while (0)
+#endif
+#define PCIE_DEV_PRINTF(dev, fmt, ...)                                  \
+    PCIE_DPRINTF("%s:%x "fmt, (dev)->name, (dev)->devfn, ## __VA_ARGS__)
+
+
+/***************************************************************************
+ * pci express capability helper functions
+ */
+int pcie_cap_init(PCIDevice *dev, uint8_t offset, uint8_t type, uint8_t port)
+{
+    int pos;
+    uint8_t *exp_cap;
+
+    assert(pci_is_express(dev));
+
+    pos = pci_add_capability(dev, PCI_CAP_ID_EXP, offset,
+                                 PCI_EXP_VER2_SIZEOF);
+    if (pos < 0) {
+        return pos;
+    }
+    dev->exp.exp_cap = pos;
+    exp_cap = dev->config + pos;
+
+    /* capability register
+       interrupt message number defaults to 0 */
+    pci_set_word(exp_cap + PCI_EXP_FLAGS,
+                 ((type << PCI_EXP_FLAGS_TYPE_SHIFT) & PCI_EXP_FLAGS_TYPE) |
+                 PCI_EXP_FLAGS_VER2);
+
+    /* device capability register
+     * table 7-12:
+     * roll based error reporting bit must be set by all
+     * Functions conforming to the ECN, PCI Express Base
+     * Specification, Revision 1.1., or subsequent PCI Express Base
+     * Specification revisions.
+     */
+    pci_set_long(exp_cap + PCI_EXP_DEVCAP, PCI_EXP_DEVCAP_RBER);
+
+    pci_set_long(exp_cap + PCI_EXP_LNKCAP,
+                 (port << PCI_EXP_LNKCAP_PN_SHIFT) |
+                 PCI_EXP_LNKCAP_ASPMS_0S |
+                 PCI_EXP_LNK_MLW_1 |
+                 PCI_EXP_LNK_LS_25);
+
+    pci_set_word(exp_cap + PCI_EXP_LNKSTA,
+                 PCI_EXP_LNK_MLW_1 | PCI_EXP_LNK_LS_25);
+
+    pci_set_long(exp_cap + PCI_EXP_DEVCAP2,
+                 PCI_EXP_DEVCAP2_EFF | PCI_EXP_DEVCAP2_EETLPP);
+
+    pci_set_word(dev->wmask + pos, PCI_EXP_DEVCTL2_EETLPPB);
+    return pos;
+}
+
+void pcie_cap_exit(PCIDevice *dev)
+{
+    pci_del_capability(dev, PCI_CAP_ID_EXP, PCI_EXP_VER2_SIZEOF);
+}
+
+uint8_t pcie_cap_get_type(const PCIDevice *dev)
+{
+    uint32_t pos = dev->exp.exp_cap;
+    assert(pos > 0);
+    return (pci_get_word(dev->config + pos + PCI_EXP_FLAGS) &
+            PCI_EXP_FLAGS_TYPE) >> PCI_EXP_FLAGS_TYPE_SHIFT;
+}
+
+/* MSI/MSI-X */
+/* pci express interrupt message number */
+/* 7.8.2 PCI Express Capabilities Register: Interrupt Message Number */
+void pcie_cap_flags_set_vector(PCIDevice *dev, uint8_t vector)
+{
+    uint8_t *exp_cap = dev->config + dev->exp.exp_cap;
+    assert(vector < 32);
+    pci_word_test_and_clear_mask(exp_cap + PCI_EXP_FLAGS, PCI_EXP_FLAGS_IRQ);
+    pci_word_test_and_set_mask(exp_cap + PCI_EXP_FLAGS,
+                               vector << PCI_EXP_FLAGS_IRQ_SHIFT);
+}
+
+uint8_t pcie_cap_flags_get_vector(PCIDevice *dev)
+{
+    return (pci_get_word(dev->config + dev->exp.exp_cap + PCI_EXP_FLAGS) &
+            PCI_EXP_FLAGS_IRQ) >> PCI_EXP_FLAGS_IRQ_SHIFT;
+}
+
+void pcie_cap_deverr_init(PCIDevice *dev)
+{
+    uint32_t pos = dev->exp.exp_cap;
+    pci_long_test_and_set_mask(dev->config + pos + PCI_EXP_DEVCAP,
+                               PCI_EXP_DEVCAP_RBER);
+    pci_long_test_and_set_mask(dev->wmask + pos + PCI_EXP_DEVCTL,
+                               PCI_EXP_DEVCTL_CERE | PCI_EXP_DEVCTL_NFERE |
+                               PCI_EXP_DEVCTL_FERE | PCI_EXP_DEVCTL_URRE);
+    pci_long_test_and_set_mask(dev->w1cmask + pos + PCI_EXP_DEVSTA,
+                               PCI_EXP_DEVSTA_CED | PCI_EXP_DEVSTA_NFED |
+                               PCI_EXP_DEVSTA_URD | PCI_EXP_DEVSTA_URD);
+}
+
+void pcie_cap_deverr_reset(PCIDevice *dev)
+{
+    uint8_t *devctl = dev->config + dev->exp.exp_cap + PCI_EXP_DEVCTL;
+    pci_long_test_and_clear_mask(devctl,
+                                 PCI_EXP_DEVCTL_CERE | PCI_EXP_DEVCTL_NFERE |
+                                 PCI_EXP_DEVCTL_FERE | PCI_EXP_DEVCTL_URRE);
+}
+
+/*
+ * A PCI Express Hot-Plug Event has occured, so update slot status register
+ * and notify OS of the event if necessary.
+ *
+ * 6.7.3 PCI Express Hot-Plug Events
+ * 6.7.3.4 Software Notification of Hot-Plug Events
+ */
+static void pcie_cap_slot_event(PCIDevice *dev, PCIExpressHotPlugEvent event)
+{
+    uint8_t *exp_cap = dev->config + dev->exp.exp_cap;
+    uint16_t sltctl = pci_get_word(exp_cap + PCI_EXP_SLTCTL);
+    uint16_t sltsta = pci_get_word(exp_cap + PCI_EXP_SLTSTA);
+
+    PCIE_DEV_PRINTF(dev,
+                    "sltctl: 0x%02"PRIx16" sltsta: 0x%02"PRIx16" event: %x\n",
+                    sltctl, sltsta, event);
+
+    if (pci_word_test_and_set_mask(exp_cap + PCI_EXP_SLTSTA, event)) {
+        return;
+    }
+    sltsta = pci_get_word(exp_cap + PCI_EXP_SLTSTA);
+    PCIE_DEV_PRINTF(dev, "sltsta -> %02"PRIx16"\n", sltsta);
+
+    if ((sltctl & PCI_EXP_SLTCTL_HPIE) &&
+        (sltctl & event & PCI_EXP_HP_EV_SUPPORTED)) {
+        if (pci_msi_enabled(dev)) {
+            pci_msi_notify(dev, pcie_cap_flags_get_vector(dev));
+        } else {
+            qemu_set_irq(dev->irq[dev->exp.hpev_intx], 1);
+        }
+    }
+}
+
+static int pcie_cap_slot_hotplug(DeviceState *qdev,
+                                 PCIDevice *pci_dev, int state)
+{
+    PCIDevice *d = DO_UPCAST(PCIDevice, qdev, qdev);
+    uint8_t *exp_cap = d->config + d->exp.exp_cap;
+    uint16_t sltsta = pci_get_word(exp_cap + PCI_EXP_SLTSTA);
+
+    if (!pci_dev->qdev.hotplugged) {
+        assert(state); /* this case only happens at machine creation. */
+        pci_word_test_and_set_mask(exp_cap + PCI_EXP_SLTSTA,
+                                   PCI_EXP_SLTSTA_PDS);
+        return 0;
+    }
+
+    PCIE_DEV_PRINTF(pci_dev, "hotplug state: %d\n", state);
+    if (sltsta & PCI_EXP_SLTSTA_EIS) {
+        /* the slot is electromechanically locked.
+         * This error is propagated up to qdev and then to HMP/QMP.
+         */
+        return -EBUSY;
+    }
+
+    /* TODO: multifunction hot-plug.
+     * Right now, only a device of function = 0 is allowed to be
+     * hot plugged/unplugged.
+     */
+    assert(PCI_FUNC(pci_dev->devfn) == 0);
+
+    if (state) {
+        pci_word_test_and_set_mask(exp_cap + PCI_EXP_SLTSTA,
+                                   PCI_EXP_SLTSTA_PDS);
+        pcie_cap_slot_event(d, PCI_EXP_HP_EV_PDC);
+    } else {
+        qdev_free(&pci_dev->qdev);
+        pci_word_test_and_clear_mask(exp_cap + PCI_EXP_SLTSTA,
+                                     PCI_EXP_SLTSTA_PDS);
+        pcie_cap_slot_event(d, PCI_EXP_HP_EV_PDC);
+    }
+    return 0;
+}
+
+/* pci express slot for pci express root/downstream port
+   PCI express capability slot registers */
+void pcie_cap_slot_init(PCIDevice *dev, uint16_t slot)
+{
+    uint32_t pos = dev->exp.exp_cap;
+
+    pci_word_test_and_set_mask(dev->config + pos + PCI_EXP_FLAGS,
+                               PCI_EXP_FLAGS_SLOT);
+
+    pci_long_test_and_clear_mask(dev->config + pos + PCI_EXP_SLTCAP,
+                                 ~PCI_EXP_SLTCAP_PSN);
+    pci_long_test_and_set_mask(dev->config + pos + PCI_EXP_SLTCAP,
+                               (slot << PCI_EXP_SLTCAP_PSN_SHIFT) |
+                               PCI_EXP_SLTCAP_EIP |
+                               PCI_EXP_SLTCAP_HPS |
+                               PCI_EXP_SLTCAP_HPC |
+                               PCI_EXP_SLTCAP_PIP |
+                               PCI_EXP_SLTCAP_AIP |
+                               PCI_EXP_SLTCAP_ABP);
+
+    pci_word_test_and_clear_mask(dev->config + pos + PCI_EXP_SLTCTL,
+                                 PCI_EXP_SLTCTL_PIC |
+                                 PCI_EXP_SLTCTL_AIC);
+    pci_word_test_and_set_mask(dev->config + pos + PCI_EXP_SLTCTL,
+                               PCI_EXP_SLTCTL_PIC_OFF |
+                               PCI_EXP_SLTCTL_AIC_OFF);
+    pci_word_test_and_set_mask(dev->wmask + pos + PCI_EXP_SLTCTL,
+                               PCI_EXP_SLTCTL_PIC |
+                               PCI_EXP_SLTCTL_AIC |
+                               PCI_EXP_SLTCTL_HPIE |
+                               PCI_EXP_SLTCTL_CCIE |
+                               PCI_EXP_SLTCTL_PDCE |
+                               PCI_EXP_SLTCTL_ABPE);
+    /* Although reading PCI_EXP_SLTCTL_EIC returns always 0,
+     * make the bit writable here in order to detect 1b is written.
+     * pcie_cap_slot_write_config() test-and-clear the bit, so
+     * this bit always returns 0 to the guest.
+     */
+    pci_word_test_and_set_mask(dev->wmask + pos + PCI_EXP_SLTCTL,
+                               PCI_EXP_SLTCTL_EIC);
+
+    pci_word_test_and_set_mask(dev->w1cmask + pos + PCI_EXP_SLTSTA,
+                               PCI_EXP_HP_EV_SUPPORTED);
+
+    pci_bus_hotplug(pci_bridge_get_sec_bus(DO_UPCAST(PCIBridge, dev, dev)),
+                    pcie_cap_slot_hotplug, &dev->qdev);
+}
+
+void pcie_cap_slot_reset(PCIDevice *dev)
+{
+    uint8_t *exp_cap = dev->config + dev->exp.exp_cap;
+
+    PCIE_DEV_PRINTF(dev, "reset\n");
+
+    pci_word_test_and_clear_mask(exp_cap + PCI_EXP_SLTCTL,
+                                 PCI_EXP_SLTCTL_EIC |
+                                 PCI_EXP_SLTCTL_PIC |
+                                 PCI_EXP_SLTCTL_AIC |
+                                 PCI_EXP_SLTCTL_HPIE |
+                                 PCI_EXP_SLTCTL_CCIE |
+                                 PCI_EXP_SLTCTL_PDCE |
+                                 PCI_EXP_SLTCTL_ABPE);
+    pci_word_test_and_set_mask(exp_cap + PCI_EXP_SLTCTL,
+                               PCI_EXP_SLTCTL_PIC_OFF |
+                               PCI_EXP_SLTCTL_AIC_OFF);
+
+    pci_word_test_and_clear_mask(exp_cap + PCI_EXP_SLTSTA,
+                                 PCI_EXP_SLTSTA_EIS |/* on reset,
+                                                        the lock is released */
+                                 PCI_EXP_SLTSTA_CC |
+                                 PCI_EXP_SLTSTA_PDC |
+                                 PCI_EXP_SLTSTA_ABP);
+}
+
+void pcie_cap_slot_write_config(PCIDevice *dev,
+                                uint32_t addr, uint32_t val, int len,
+                                uint16_t sltctl_prev)
+{
+    uint32_t pos = dev->exp.exp_cap;
+    uint8_t *exp_cap = dev->config + pos;
+    uint16_t sltctl = pci_get_word(exp_cap + PCI_EXP_SLTCTL);
+    uint16_t sltsta = pci_get_word(exp_cap + PCI_EXP_SLTSTA);
+
+    PCIE_DEV_PRINTF(dev,
+                    "addr: 0x%"PRIx32" val: 0x%"PRIx32" len: %d\n"
+                    "\tsltctl_prev: 0x%02"PRIx16" sltctl: 0x%02"PRIx16
+                    " sltsta: 0x%02"PRIx16"\n",
+                    addr, val, len, sltctl_prev, sltctl, sltsta);
+
+    /* SLTCTL */
+    if (ranges_overlap(addr, len, pos + PCI_EXP_SLTCTL, 2)) {
+        PCIE_DEV_PRINTF(dev, "sltctl: 0x%02"PRIx16" -> 0x%02"PRIx16"\n",
+                        sltctl_prev, sltctl);
+        if (pci_word_test_and_clear_mask(exp_cap + PCI_EXP_SLTCTL,
+                                         PCI_EXP_SLTCTL_EIC)) {
+            sltsta ^= PCI_EXP_SLTSTA_EIS; /* toggle PCI_EXP_SLTSTA_EIS bit */
+            pci_set_word(exp_cap + PCI_EXP_SLTSTA, sltsta);
+            PCIE_DEV_PRINTF(dev, "PCI_EXP_SLTCTL_EIC: "
+                            "sltsta -> 0x%02"PRIx16"\n",
+                            sltsta);
+        }
+
+        /*
+         * The events control bits might be enabled or disabled,
+         * Check if the software notificastion condition is satisfied
+         * or disatisfied.
+         *
+         * 6.7.3.4 Software Notification of Hot-plug events
+         */
+        if (pci_msi_enabled(dev)) {
+            bool msi_trigger =
+                (sltctl & PCI_EXP_SLTCTL_HPIE) &&
+                ((sltctl_prev ^ sltctl) & sltctl & /* stlctl: 0 -> 1 */
+                 sltsta & PCI_EXP_HP_EV_SUPPORTED);
+            if (msi_trigger) {
+                pci_msi_notify(dev, pcie_cap_flags_get_vector(dev));
+            }
+        } else {
+            int int_level =
+                (sltctl & PCI_EXP_SLTCTL_HPIE) &&
+                (sltctl & sltsta & PCI_EXP_HP_EV_SUPPORTED);
+            qemu_set_irq(dev->irq[dev->exp.hpev_intx], int_level);
+        }
+
+        if (!((sltctl_prev ^ sltctl) & PCI_EXP_SLTCTL_SUPPORTED)) {
+            PCIE_DEV_PRINTF(dev,
+                            "sprious command completion slctl "
+                            "0x%"PRIx16" -> 0x%"PRIx16"\n",
+                            sltctl_prev, sltctl);
+        }
+
+        /* command completion.
+         * Real hardware might take a while to complete
+         * requested command because physical movement would be involved
+         * like locking the electromechanical lock.
+         * However in our case, command is completed instantaneously above,
+         * so send a command completion event right now.
+         *
+         * 6.7.3.2 Command Completed Events
+         */
+        /* set command completed bit */
+        pcie_cap_slot_event(dev, PCI_EXP_HP_EV_CCI);
+    }
+}
+
+void pcie_cap_slot_push_attention_button(PCIDevice *dev)
+{
+    pcie_cap_slot_event(dev, PCI_EXP_HP_EV_ABP);
+}
+
+/* root control/capabilities/status. PME isn't emulated for now */
+void pcie_cap_root_init(PCIDevice *dev)
+{
+    pci_set_word(dev->wmask + dev->exp.exp_cap + PCI_EXP_RTCTL,
+                 PCI_EXP_RTCTL_SECEE | PCI_EXP_RTCTL_SENFEE |
+                 PCI_EXP_RTCTL_SEFEE);
+}
+
+void pcie_cap_root_reset(PCIDevice *dev)
+{
+    pci_set_word(dev->config + dev->exp.exp_cap + PCI_EXP_RTCTL, 0);
+}
+
+/*
+ * TODO: implement FLR:
+ * Right now sets the bit which indicates FLR is supported.
+ */
+/* function level reset(FLR) */
+void pcie_cap_flr_init(PCIDevice *dev)
+{
+    pci_long_test_and_set_mask(dev->config + dev->exp.exp_cap + PCI_EXP_DEVCAP,
+                               PCI_EXP_DEVCAP_FLR);
+
+    /* Although reading BCR_FLR returns always 0,
+     * the bit is made writable here in order to detect the 1b is written
+     * pcie_cap_flr_write_config() test-and-clear the bit, so
+     * this bit always returns 0 to the guest.
+     */
+    pci_word_test_and_set_mask(dev->wmask + dev->exp.exp_cap + PCI_EXP_DEVCTL,
+                               PCI_EXP_DEVCTL_BCR_FLR);
+}
+
+void pcie_cap_flr_write_config(PCIDevice *dev,
+                               uint32_t addr, uint32_t val, int len)
+{
+    uint8_t *devctl = dev->config + dev->exp.exp_cap + PCI_EXP_DEVCTL;
+    if (pci_word_test_and_clear_mask(devctl, PCI_EXP_DEVCTL_BCR_FLR)) {
+        /* TODO: implement FLR */
+    }
+}
+
+/* Alternative Routing-ID Interpretation (ARI) */
+/* ari forwarding support for down stream port */
+void pcie_cap_ari_init(PCIDevice *dev)
+{
+    uint32_t pos = dev->exp.exp_cap;
+    pci_long_test_and_set_mask(dev->config + pos + PCI_EXP_DEVCAP2,
+                               PCI_EXP_DEVCAP2_ARI);
+    pci_long_test_and_set_mask(dev->wmask + pos + PCI_EXP_DEVCTL2,
+                               PCI_EXP_DEVCTL2_ARI);
+}
+
+void pcie_cap_ari_reset(PCIDevice *dev)
+{
+    uint8_t *devctl2 = dev->config + dev->exp.exp_cap + PCI_EXP_DEVCTL2;
+    pci_long_test_and_clear_mask(devctl2, PCI_EXP_DEVCTL2_ARI);
+}
+
+bool pcie_cap_is_ari_enabled(const PCIDevice *dev)
+{
+    if (!pci_is_express(dev)) {
+        return false;
+    }
+    if (!dev->exp.exp_cap) {
+        return false;
+    }
+
+    return pci_get_long(dev->config + dev->exp.exp_cap + PCI_EXP_DEVCTL2) &
+        PCI_EXP_DEVCTL2_ARI;
+}
+
+/**************************************************************************
+ * pci express extended capability allocation functions
+ * uint16_t ext_cap_id (16 bit)
+ * uint8_t cap_ver (4 bit)
+ * uint16_t cap_offset (12 bit)
+ * uint16_t ext_cap_size
+ */
+
+static uint16_t pcie_find_capability_list(PCIDevice *dev, uint16_t cap_id,
+                                          uint16_t *prev_p)
+{
+    uint16_t prev = 0;
+    uint16_t next;
+    uint32_t header = pci_get_long(dev->config + PCI_CONFIG_SPACE_SIZE);
+
+    if (!header) {
+        /* no extended capability */
+        next = 0;
+        goto out;
+    }
+    for (next = PCI_CONFIG_SPACE_SIZE; next;
+         prev = next, next = PCI_EXT_CAP_NEXT(header)) {
+
+        assert(next >= PCI_CONFIG_SPACE_SIZE);
+        assert(next <= PCIE_CONFIG_SPACE_SIZE - 8);
+
+        header = pci_get_long(dev->config + next);
+        if (PCI_EXT_CAP_ID(header) == cap_id) {
+            break;
+        }
+    }
+
+out:
+    if (prev_p) {
+        *prev_p = prev;
+    }
+    return next;
+}
+
+uint16_t pcie_find_capability(PCIDevice *dev, uint16_t cap_id)
+{
+    return pcie_find_capability_list(dev, cap_id, NULL);
+}
+
+static void pcie_ext_cap_set_next(PCIDevice *dev, uint16_t pos, uint16_t next)
+{
+    uint16_t header = pci_get_long(dev->config + pos);
+    assert(!(next & (PCI_EXT_CAP_ALIGN - 1)));
+    header = (header & ~PCI_EXT_CAP_NEXT_MASK) |
+        ((next << PCI_EXT_CAP_NEXT_SHIFT) & PCI_EXT_CAP_NEXT_MASK);
+    pci_set_long(dev->config + pos, header);
+}
+
+/*
+ * caller must supply valid (offset, size) * such that the range shouldn't
+ * overlap with other capability or other registers.
+ * This function doesn't check it.
+ */
+void pcie_add_capability(PCIDevice *dev,
+                         uint16_t cap_id, uint8_t cap_ver,
+                         uint16_t offset, uint16_t size)
+{
+    uint32_t header;
+    uint16_t next;
+
+    assert(offset >= PCI_CONFIG_SPACE_SIZE);
+    assert(offset < offset + size);
+    assert(offset + size < PCIE_CONFIG_SPACE_SIZE);
+    assert(size >= 8);
+    assert(pci_is_express(dev));
+
+    if (offset == PCI_CONFIG_SPACE_SIZE) {
+        header = pci_get_long(dev->config + offset);
+        next = PCI_EXT_CAP_NEXT(header);
+    } else {
+        uint16_t prev;
+
+        /* 0 is reserved cap id. use internally to find the last capability
+           in the linked list */
+        next = pcie_find_capability_list(dev, 0, &prev);
+
+        assert(prev >= PCI_CONFIG_SPACE_SIZE);
+        assert(next == 0);
+        pcie_ext_cap_set_next(dev, prev, offset);
+    }
+    pci_set_long(dev->config + offset, PCI_EXT_CAP(cap_id, cap_ver, next));
+
+    /* Make capability read-only by default */
+    memset(dev->wmask + offset, 0, size);
+    memset(dev->w1cmask + offset, 0, size);
+    /* Check capability by default */
+    memset(dev->cmask + offset, 0xFF, size);
+}
+
+/**************************************************************************
+ * pci express extended capability helper functions
+ */
+
+/* ARI */
+void pcie_ari_init(PCIDevice *dev, uint16_t offset, uint16_t nextfn)
+{
+    pcie_add_capability(dev, PCI_EXT_CAP_ID_ARI, PCI_ARI_VER,
+                        offset, PCI_ARI_SIZEOF);
+    pci_set_long(dev->config + offset + PCI_ARI_CAP, PCI_ARI_CAP_NFN(nextfn));
+}
diff --git a/hw/pcie.h b/hw/pcie.h
new file mode 100644
index 0000000000..68327d8d0d
--- /dev/null
+++ b/hw/pcie.h
@@ -0,0 +1,107 @@
+/*
+ * pcie.h
+ *
+ * Copyright (c) 2010 Isaku Yamahata <yamahata at valinux co jp>
+ *                    VA Linux Systems Japan K.K.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef QEMU_PCIE_H
+#define QEMU_PCIE_H
+
+#include "hw.h"
+#include "pci_regs.h"
+#include "pcie_regs.h"
+
+typedef enum {
+    /* for attention and power indicator */
+    PCI_EXP_HP_IND_RESERVED     = PCI_EXP_SLTCTL_IND_RESERVED,
+    PCI_EXP_HP_IND_ON           = PCI_EXP_SLTCTL_IND_ON,
+    PCI_EXP_HP_IND_BLINK        = PCI_EXP_SLTCTL_IND_BLINK,
+    PCI_EXP_HP_IND_OFF          = PCI_EXP_SLTCTL_IND_OFF,
+} PCIExpressIndicator;
+
+typedef enum {
+    /* these bits must match the bits in Slot Control/Status registers.
+     * PCI_EXP_HP_EV_xxx = PCI_EXP_SLTCTL_xxxE = PCI_EXP_SLTSTA_xxx
+     *
+     * Not all the bits of slot control register match with the ones of
+     * slot status. Not some bits of slot status register is used to
+     * show status, not to report event occurence.
+     * So such bits must be masked out when checking the software
+     * notification condition.
+     */
+    PCI_EXP_HP_EV_ABP           = PCI_EXP_SLTCTL_ABPE,
+                                        /* attention button pressed */
+    PCI_EXP_HP_EV_PDC           = PCI_EXP_SLTCTL_PDCE,
+                                        /* presence detect changed */
+    PCI_EXP_HP_EV_CCI           = PCI_EXP_SLTCTL_CCIE,
+                                        /* command completed */
+
+    PCI_EXP_HP_EV_SUPPORTED     = PCI_EXP_HP_EV_ABP |
+                                  PCI_EXP_HP_EV_PDC |
+                                  PCI_EXP_HP_EV_CCI,
+                                                /* supported event mask  */
+
+    /* events not listed aren't supported */
+} PCIExpressHotPlugEvent;
+
+struct PCIExpressDevice {
+    /* Offset of express capability in config space */
+    uint8_t exp_cap;
+
+    /* TODO FLR */
+
+    /* SLOT */
+    unsigned int hpev_intx;     /* INTx for hot plug event */
+};
+
+/* PCI express capability helper functions */
+int pcie_cap_init(PCIDevice *dev, uint8_t offset, uint8_t type, uint8_t port);
+void pcie_cap_exit(PCIDevice *dev);
+uint8_t pcie_cap_get_type(const PCIDevice *dev);
+void pcie_cap_flags_set_vector(PCIDevice *dev, uint8_t vector);
+uint8_t pcie_cap_flags_get_vector(PCIDevice *dev);
+
+void pcie_cap_deverr_init(PCIDevice *dev);
+void pcie_cap_deverr_reset(PCIDevice *dev);
+
+void pcie_cap_slot_init(PCIDevice *dev, uint16_t slot);
+void pcie_cap_slot_reset(PCIDevice *dev);
+void pcie_cap_slot_write_config(PCIDevice *dev,
+                                uint32_t addr, uint32_t val, int len,
+                                uint16_t sltctl_prev);
+void pcie_cap_slot_push_attention_button(PCIDevice *dev);
+
+void pcie_cap_root_init(PCIDevice *dev);
+void pcie_cap_root_reset(PCIDevice *dev);
+
+void pcie_cap_flr_init(PCIDevice *dev);
+void pcie_cap_flr_write_config(PCIDevice *dev,
+                           uint32_t addr, uint32_t val, int len);
+
+void pcie_cap_ari_init(PCIDevice *dev);
+void pcie_cap_ari_reset(PCIDevice *dev);
+bool pcie_cap_is_ari_enabled(const PCIDevice *dev);
+
+/* PCI express extended capability helper functions */
+uint16_t pcie_find_capability(PCIDevice *dev, uint16_t cap_id);
+void pcie_add_capability(PCIDevice *dev,
+                         uint16_t cap_id, uint8_t cap_ver,
+                         uint16_t offset, uint16_t size);
+
+void pcie_ari_init(PCIDevice *dev, uint16_t offset, uint16_t nextfn);
+
+#endif /* QEMU_PCIE_H */
diff --git a/qemu-common.h b/qemu-common.h
index d735235f84..6d9ee26df0 100644
--- a/qemu-common.h
+++ b/qemu-common.h
@@ -219,6 +219,7 @@ typedef struct PCIHostState PCIHostState;
 typedef struct PCIExpressHost PCIExpressHost;
 typedef struct PCIBus PCIBus;
 typedef struct PCIDevice PCIDevice;
+typedef struct PCIExpressDevice PCIExpressDevice;
 typedef struct PCIBridge PCIBridge;
 typedef struct SerialState SerialState;
 typedef struct IRQState *qemu_irq;