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[Xen-devel] Re: [PATCH V2 08/10] Introduce Xen PCI Passthrough, qdevice (1/3)



On Wed, 19 Oct 2011, Anthony PERARD wrote:
> From: Allen Kay <allen.m.kay@xxxxxxxxx>
> 
> Signed-off-by: Allen Kay <allen.m.kay@xxxxxxxxx>
> Signed-off-by: Guy Zana <guy@xxxxxxxxxxxx>
> Signed-off-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>
> ---
>  Makefile.target                  |    2 +
>  hw/xen_pci_passthrough.c         |  861 
> ++++++++++++++++++++++++++++++++++++++
>  hw/xen_pci_passthrough.h         |  258 ++++++++++++
>  hw/xen_pci_passthrough_helpers.c |   46 ++
>  4 files changed, 1167 insertions(+), 0 deletions(-)
>  create mode 100644 hw/xen_pci_passthrough.c
>  create mode 100644 hw/xen_pci_passthrough.h
>  create mode 100644 hw/xen_pci_passthrough_helpers.c
> 
> diff --git a/Makefile.target b/Makefile.target
> index ca3420d..0673b51 100644
> --- a/Makefile.target
> +++ b/Makefile.target
> @@ -210,6 +210,8 @@ obj-i386-$(CONFIG_XEN) += xen_platform.o
> 
>  # Xen PCI Passthrough
>  obj-i386-$(CONFIG_XEN_PCI_PASSTHROUGH) += host-pci-device.o
> +obj-i386-$(CONFIG_XEN_PCI_PASSTHROUGH) += xen_pci_passthrough.o
> +obj-i386-$(CONFIG_XEN_PCI_PASSTHROUGH) += xen_pci_passthrough_helpers.o
> 
>  # Inter-VM PCI shared memory
>  CONFIG_IVSHMEM =
> diff --git a/hw/xen_pci_passthrough.c b/hw/xen_pci_passthrough.c
> new file mode 100644
> index 0000000..0b631f7
> --- /dev/null
> +++ b/hw/xen_pci_passthrough.c
> @@ -0,0 +1,861 @@
> +/*
> + * Copyright (c) 2007, Neocleus Corporation.
> + * Copyright (c) 2007, Intel Corporation.
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2.  See
> + * the COPYING file in the top-level directory.
> + *
> + * Alex Novik <alex@xxxxxxxxxxxx>
> + * Allen Kay <allen.m.kay@xxxxxxxxx>
> + * Guy Zana <guy@xxxxxxxxxxxx>
> + *
> + * This file implements direct PCI assignment to a HVM guest
> + */
> +
> +/*
> + * Interrupt Disable policy:
> + *
> + * INTx interrupt:
> + *   Initialize(register_real_device)
> + *     Map INTx(xc_physdev_map_pirq):
> + *       <fail>
> + *         - Set real Interrupt Disable bit to '1'.
> + *         - Set machine_irq and assigned_device->machine_irq to '0'.
> + *         * Don't bind INTx.
> + *
> + *     Bind INTx(xc_domain_bind_pt_pci_irq):
> + *       <fail>
> + *         - Set real Interrupt Disable bit to '1'.
> + *         - Unmap INTx.
> + *         - Decrement mapped_machine_irq[machine_irq]
> + *         - Set assigned_device->machine_irq to '0'.
> + *
> + *   Write to Interrupt Disable bit by guest software(pt_cmd_reg_write)
> + *     Write '0'
> + *       <ptdev->msi_trans_en is false>
> + *         - Set real bit to '0' if assigned_device->machine_irq isn't '0'.
> + *
> + *     Write '1'
> + *       <ptdev->msi_trans_en is false>
> + *         - Set real bit to '1'.
> + *
> + * MSI-INTx translation.
> + *   Initialize(xc_physdev_map_pirq_msi/pt_msi_setup)
> + *     Bind MSI-INTx(xc_domain_bind_pt_irq)
> + *       <fail>
> + *         - Unmap MSI.
> + *           <success>
> + *             - Set dev->msi->pirq to '-1'.
> + *           <fail>
> + *             - Do nothing.
> + *
> + *   Write to Interrupt Disable bit by guest software(pt_cmd_reg_write)
> + *     Write '0'
> + *       <ptdev->msi_trans_en is true>
> + *         - Set MSI Enable bit to '1'.
> + *
> + *     Write '1'
> + *       <ptdev->msi_trans_en is true>
> + *         - Set MSI Enable bit to '0'.
> + *
> + * MSI interrupt:
> + *   Initialize MSI register(pt_msi_setup, pt_msi_update)
> + *     Bind MSI(xc_domain_update_msi_irq)
> + *       <fail>
> + *         - Unmap MSI.
> + *         - Set dev->msi->pirq to '-1'.
> + *
> + * MSI-X interrupt:
> + *   Initialize MSI-X register(pt_msix_update_one)
> + *     Bind MSI-X(xc_domain_update_msi_irq)
> + *       <fail>
> + *         - Unmap MSI-X.
> + *         - Set entry->pirq to '-1'.
> + */
> +
> +#include <sys/ioctl.h>
> +
> +#include "pci.h"
> +#include "xen.h"
> +#include "xen_backend.h"
> +#include "xen_pci_passthrough.h"
> +
> +#define PCI_BAR_ENTRIES (6)
> +
> +#define PT_NR_IRQS          (256)
> +char mapped_machine_irq[PT_NR_IRQS] = {0};
> +
> +/* Config Space */
> +static int pt_pci_config_access_check(PCIDevice *d, uint32_t address, int 
> len)
> +{
> +    /* check offset range */
> +    if (address >= 0xFF) {
> +        PT_LOG("Error: Failed to access register with offset exceeding FFh. "
> +               "[%02x:%02x.%x][Offset:%02xh][Length:%d]\n",
> +               pci_bus_num(d->bus), PCI_SLOT(d->devfn), PCI_FUNC(d->devfn),
> +               address, len);
> +        return -1;
> +    }
> +    /* check read size */
> +    if ((len != 1) && (len != 2) && (len != 4)) {
> +        PT_LOG("Error: Failed to access register with invalid access length. 
> "
> +               "[%02x:%02x.%x][Offset:%02xh][Length:%d]\n",
> +               pci_bus_num(d->bus), PCI_SLOT(d->devfn), PCI_FUNC(d->devfn),
> +               address, len);
> +        return -1;
> +    }
> +
> +    /* check offset alignment */
> +    if (address & (len - 1)) {
> +        PT_LOG("Error: Failed to access register with invalid access size "
> +            "alignment. [%02x:%02x.%x][Offset:%02xh][Length:%d]\n",
> +            pci_bus_num(d->bus), PCI_SLOT(d->devfn), PCI_FUNC(d->devfn),
> +            address, len);
> +        return -1;
> +    }
> +
> +    return 0;
> +}
> +
> +int pt_bar_offset_to_index(uint32_t offset)
> +{
> +    int index = 0;
> +
> +    /* check Exp ROM BAR */
> +    if (offset == PCI_ROM_ADDRESS) {
> +        return PCI_ROM_SLOT;
> +    }
> +
> +    /* calculate BAR index */
> +    index = (offset - PCI_BASE_ADDRESS_0) >> 2;
> +    if (index >= PCI_NUM_REGIONS) {
> +        return -1;
> +    }
> +
> +    return index;
> +}
> +
> +static uint32_t pt_pci_read_config(PCIDevice *d, uint32_t address, int len)
> +{
> +    XenPCIPassthroughState *s = DO_UPCAST(XenPCIPassthroughState, dev, d);
> +    uint32_t val = 0;
> +    XenPTRegGroup *reg_grp_entry = NULL;
> +    XenPTReg *reg_entry = NULL;
> +    int rc = 0;
> +    int emul_len = 0;
> +    uint32_t find_addr = address;
> +
> +    if (pt_pci_config_access_check(d, address, len)) {
> +        goto exit;
> +    }
> +
> +    /* check power state transition flags */
> +    if (s->pm_state != NULL && s->pm_state->flags & PT_FLAG_TRANSITING) {
> +        /* can't accept untill previous power state transition is completed.
> +         * so finished previous request here.
> +         */

until

> +        PT_LOG("Warning: guest want to write durring power state 
> transition\n");
> +        goto exit;
> +    }
> +
> +    /* find register group entry */
> +    reg_grp_entry = pt_find_reg_grp(s, address);
> +    if (reg_grp_entry) {
> +        /* check 0 Hardwired register group */
> +        if (reg_grp_entry->reg_grp->grp_type == GRP_TYPE_HARDWIRED) {
> +            /* no need to emulate, just return 0 */
> +            val = 0;
> +            goto exit;
> +        }
> +    }
> +
> +    /* read I/O device register value */
> +    rc = host_pci_get_block(s->real_device, address, (uint8_t *)&val, len);
> +    if (!rc) {
> +        PT_LOG("Error: pci_read_block failed. return value[%d].\n", rc);
> +        memset(&val, 0xff, len);
> +    }
> +
> +    /* just return the I/O device register value for
> +     * passthrough type register group */
> +    if (reg_grp_entry == NULL) {
> +        goto exit;
> +    }
> +
> +    /* adjust the read value to appropriate CFC-CFF window */
> +    val <<= (address & 3) << 3;
> +    emul_len = len;
> +
> +    /* loop Guest request size */
> +    while (emul_len > 0) {
> +        /* find register entry to be emulated */
> +        reg_entry = pt_find_reg(reg_grp_entry, find_addr);
> +        if (reg_entry) {
> +            XenPTRegInfo *reg = reg_entry->reg;
> +            uint32_t real_offset = reg_grp_entry->base_offset + reg->offset;
> +            uint32_t valid_mask = 0xFFFFFFFF >> ((4 - emul_len) << 3);
> +            uint8_t *ptr_val = NULL;
> +
> +            valid_mask <<= (find_addr - real_offset) << 3;
> +            ptr_val = (uint8_t *)&val + (real_offset & 3);
> +
> +            /* do emulation depend on register size */
> +            switch (reg->size) {
> +            case 1:
> +                if (reg->u.b.read) {
> +                    rc = reg->u.b.read(s, reg_entry, ptr_val, valid_mask);
> +                }
> +                break;
> +            case 2:
> +                if (reg->u.w.read) {
> +                    rc = reg->u.w.read(s, reg_entry,
> +                                       (uint16_t *)ptr_val, valid_mask);
> +                }
> +                break;
> +            case 4:
> +                if (reg->u.dw.read) {
> +                    rc = reg->u.dw.read(s, reg_entry,
> +                                        (uint32_t *)ptr_val, valid_mask);
> +                }
> +                break;
> +            }
> +
> +            if (rc < 0) {
> +                hw_error("Internal error: Invalid read emulation "
> +                         "return value[%d]. I/O emulator exit.\n", rc);
> +            }
> +
> +            /* calculate next address to find */
> +            emul_len -= reg->size;
> +            if (emul_len > 0) {
> +                find_addr = real_offset + reg->size;
> +            }
> +        } else {
> +            /* nothing to do with passthrough type register,
> +             * continue to find next byte */
> +            emul_len--;
> +            find_addr++;
> +        }
> +    }
> +
> +    /* need to shift back before returning them to pci bus emulator */
> +    val >>= ((address & 3) << 3);
> +
> +exit:
> +    PT_LOG_CONFIG("[%02x:%02x.%x]: address=%04x val=0x%08x len=%d\n",
> +                  pci_bus_num(d->bus), PCI_SLOT(d->devfn), 
> PCI_FUNC(d->devfn),
> +                  address, val, len);
> +    return val;
> +}
> +
> +static void pt_pci_write_config(PCIDevice *d, uint32_t address,
> +                                uint32_t val, int len)
> +{
> +    XenPCIPassthroughState *s = DO_UPCAST(XenPCIPassthroughState, dev, d);
> +    int index = 0;
> +    XenPTRegGroup *reg_grp_entry = NULL;
> +    int rc = 0;
> +    uint32_t read_val = 0;
> +    int emul_len = 0;
> +    XenPTReg *reg_entry = NULL;
> +    uint32_t find_addr = address;
> +    XenPTRegInfo *reg = NULL;
> +
> +    if (pt_pci_config_access_check(d, address, len)) {
> +        return;
> +    }
> +
> +    PT_LOG_CONFIG("[%02x:%02x.%x]: address=%04x val=0x%08x len=%d\n",
> +                  pci_bus_num(d->bus), PCI_SLOT(d->devfn), 
> PCI_FUNC(d->devfn),
> +                  address, val, len);
> +
> +    /* check unused BAR register */
> +    index = pt_bar_offset_to_index(address);
> +    if ((index >= 0) && (val > 0 && val < PT_BAR_ALLF) &&
> +        (s->bases[index].bar_flag == PT_BAR_FLAG_UNUSED)) {
> +        PT_LOG("Warning: Guest attempt to set address to unused Base Address 
> "
> +               "Register. [%02x:%02x.%x][Offset:%02xh][Length:%d]\n",
> +               pci_bus_num(d->bus), PCI_SLOT(d->devfn), PCI_FUNC(d->devfn),
> +               address, len);
> +    }
> +
> +    /* check power state transition flags */
> +    if (s->pm_state != NULL && s->pm_state->flags & PT_FLAG_TRANSITING) {
> +        /* can't accept untill previous power state transition is completed.
> +         * so finished previous request here.
> +         */
> +        PT_LOG("Warning: guest want to write durring power state 
> transition\n");
> +        return;
> +    }
> +
> +    /* find register group entry */
> +    reg_grp_entry = pt_find_reg_grp(s, address);
> +    if (reg_grp_entry) {
> +        /* check 0 Hardwired register group */
> +        if (reg_grp_entry->reg_grp->grp_type == GRP_TYPE_HARDWIRED) {
> +            /* ignore silently */
> +            PT_LOG("Warning: Access to 0 Hardwired register. "
> +                   "[%02x:%02x.%x][Offset:%02xh][Length:%d]\n",
> +                   pci_bus_num(d->bus), PCI_SLOT(d->devfn), 
> PCI_FUNC(d->devfn),
> +                   address, len);
> +            return;
> +        }
> +    }
> +
> +    /* read I/O device register value */
> +    rc = host_pci_get_block(s->real_device, address,
> +                             (uint8_t *)&read_val, len);
> +    if (!rc) {
> +        PT_LOG("Error: pci_read_block failed. return value[%d].\n", rc);
> +        memset(&read_val, 0xff, len);
> +    }
> +
> +    /* pass directly to libpci for passthrough type register group */
> +    if (reg_grp_entry == NULL) {
> +        goto out;
> +    }
> +
> +    /* adjust the read and write value to appropriate CFC-CFF window */
> +    read_val <<= (address & 3) << 3;
> +    val <<= (address & 3) << 3;
> +    emul_len = len;
> +
> +    /* loop Guest request size */
> +    while (emul_len > 0) {
> +        /* find register entry to be emulated */
> +        reg_entry = pt_find_reg(reg_grp_entry, find_addr);
> +        if (reg_entry) {
> +            reg = reg_entry->reg;
> +            uint32_t real_offset = reg_grp_entry->base_offset + reg->offset;
> +            uint32_t valid_mask = 0xFFFFFFFF >> ((4 - emul_len) << 3);
> +            uint8_t *ptr_val = NULL;
> +
> +            valid_mask <<= (find_addr - real_offset) << 3;
> +            ptr_val = (uint8_t *)&val + (real_offset & 3);
> +
> +            /* do emulation depend on register size */
> +            switch (reg->size) {
> +            case 1:
> +                if (reg->u.b.write) {
> +                    rc = reg->u.b.write(s, reg_entry, ptr_val,
> +                                        read_val >> ((real_offset & 3) << 3),
> +                                        valid_mask);
> +                }
> +                break;
> +            case 2:
> +                if (reg->u.w.write) {
> +                    rc = reg->u.w.write(s, reg_entry, (uint16_t *)ptr_val,
> +                                        (read_val >> ((real_offset & 3) << 
> 3)),
> +                                        valid_mask);
> +                }
> +                break;
> +            case 4:
> +                if (reg->u.dw.write) {
> +                    rc = reg->u.dw.write(s, reg_entry, (uint32_t *)ptr_val,
> +                                         (read_val >> ((real_offset & 3) << 
> 3)),
> +                                         valid_mask);
> +                }
> +                break;
> +            }
> +
> +            if (rc < 0) {
> +                hw_error("Internal error: Invalid write emulation "
> +                         "return value[%d]. I/O emulator exit.\n", rc);
> +            }
> +
> +            /* calculate next address to find */
> +            emul_len -= reg->size;
> +            if (emul_len > 0) {
> +                find_addr = real_offset + reg->size;
> +            }
> +        } else {
> +            /* nothing to do with passthrough type register,
> +             * continue to find next byte */
> +            emul_len--;
> +            find_addr++;
> +        }
> +    }
> +
> +    /* need to shift back before passing them to libpci */
> +    val >>= (address & 3) << 3;
> +
> +out:
> +    if (!(reg && reg->no_wb)) {
> +        /* unknown regs are passed through */
> +        rc = host_pci_set_block(s->real_device, address, (uint8_t *)&val, 
> len);
> +
> +        if (!rc) {
> +            PT_LOG("Error: pci_write_block failed. return value[%d].\n", rc);
> +        }
> +    }
> +
> +    if (s->pm_state != NULL && s->pm_state->flags & PT_FLAG_TRANSITING) {
> +        qemu_mod_timer(s->pm_state->pm_timer,
> +                       qemu_get_clock_ms(rt_clock) + s->pm_state->pm_delay);
> +    }

where is this allocated?


> +}
> +
> +/* ioport/iomem space*/
> +static void pt_iomem_map(XenPCIPassthroughState *s, int i,
> +                         pcibus_t e_phys, pcibus_t e_size, int type)
> +{
> +    uint32_t old_ebase = s->bases[i].e_physbase;
> +    bool first_map = s->bases[i].e_size == 0;
> +    int ret = 0;
> +
> +    s->bases[i].e_physbase = e_phys;
> +    s->bases[i].e_size = e_size;
> +
> +    PT_LOG("e_phys=%#"PRIx64" maddr=%#"PRIx64" type=%%d"
> +           " len=%#"PRIx64" index=%d first_map=%d\n",
> +           e_phys, s->bases[i].access.maddr, /*type,*/
> +           e_size, i, first_map);
> +
> +    if (e_size == 0) {
> +        return;
> +    }
> +
> +    if (!first_map && old_ebase != -1) {
> +        pt_add_msix_mapping(s, i);
> +        /* Remove old mapping */
> +        ret = xc_domain_memory_mapping(xen_xc, xen_domid,
> +                               old_ebase >> XC_PAGE_SHIFT,
> +                               s->bases[i].access.maddr >> XC_PAGE_SHIFT,
> +                               (e_size + XC_PAGE_SIZE - 1) >> XC_PAGE_SHIFT,
> +                               DPCI_REMOVE_MAPPING);
> +        if (ret != 0) {
> +            PT_LOG("Error: remove old mapping failed!\n");
> +            return;
> +        }
> +    }
> +
> +    /* map only valid guest address */
> +    if (e_phys != -1) {
> +        /* Create new mapping */
> +        ret = xc_domain_memory_mapping(xen_xc, xen_domid,
> +                                   s->bases[i].e_physbase >> XC_PAGE_SHIFT,
> +                                   s->bases[i].access.maddr >> XC_PAGE_SHIFT,
> +                                   (e_size+XC_PAGE_SIZE-1) >> XC_PAGE_SHIFT,
> +                                   DPCI_ADD_MAPPING);
> +
> +        if (ret != 0) {
> +            PT_LOG("Error: create new mapping failed!\n");
> +        }
> +
> +        ret = pt_remove_msix_mapping(s, i);
> +        if (ret != 0) {
> +            PT_LOG("Error: remove MSI-X mmio mapping failed!\n");
> +        }
> +
> +        if (old_ebase != e_phys && old_ebase != -1) {
> +            pt_msix_update_remap(s, i);
> +        }
> +    }
> +}
> +
> +static void pt_ioport_map(XenPCIPassthroughState *s, int i,
> +                          pcibus_t e_phys, pcibus_t e_size, int type)
> +{
> +    uint32_t old_ebase = s->bases[i].e_physbase;
> +    bool first_map = s->bases[i].e_size == 0;
> +    int ret = 0;
> +
> +    s->bases[i].e_physbase = e_phys;
> +    s->bases[i].e_size = e_size;
> +
> +    PT_LOG("e_phys=%#04"PRIx64" pio_base=%#04"PRIx64" len=%"PRId64" index=%d"
> +           " first_map=%d\n",
> +           e_phys, s->bases[i].access.pio_base, e_size, i, first_map);
> +
> +    if (e_size == 0) {
> +        return;
> +    }
> +
> +    if (!first_map && old_ebase != -1) {
> +        /* Remove old mapping */
> +        ret = xc_domain_ioport_mapping(xen_xc, xen_domid, old_ebase,
> +                                       s->bases[i].access.pio_base, e_size,
> +                                       DPCI_REMOVE_MAPPING);
> +        if (ret != 0) {
> +            PT_LOG("Error: remove old mapping failed!\n");
> +            return;
> +        }
> +    }
> +
> +    /* map only valid guest address (include 0) */
> +    if (e_phys != -1) {
> +        /* Create new mapping */
> +        ret = xc_domain_ioport_mapping(xen_xc, xen_domid, e_phys,
> +                                       s->bases[i].access.pio_base, e_size,
> +                                       DPCI_ADD_MAPPING);
> +        if (ret != 0) {
> +            PT_LOG("Error: create new mapping failed!\n");
> +        }
> +    }
> +
> +}
> +
> +
> +/* mapping BAR */
> +
> +void pt_bar_mapping_one(XenPCIPassthroughState *s, int bar,
> +                        int io_enable, int mem_enable)
> +{
> +    PCIDevice *dev = &s->dev;
> +    PCIIORegion *r;
> +    XenPTRegGroup *reg_grp_entry = NULL;
> +    XenPTReg *reg_entry = NULL;
> +    XenPTRegion *base = NULL;
> +    pcibus_t r_size = 0, r_addr = -1;
> +    int rc = 0;
> +
> +    r = &dev->io_regions[bar];
> +
> +    /* check valid region */
> +    if (!r->size) {
> +        return;
> +    }
> +
> +    base = &s->bases[bar];
> +    /* skip unused BAR or upper 64bit BAR */
> +    if ((base->bar_flag == PT_BAR_FLAG_UNUSED)
> +        || (base->bar_flag == PT_BAR_FLAG_UPPER)) {
> +           return;
> +    }
> +
> +    /* copy region address to temporary */
> +    r_addr = r->addr;
> +
> +    /* need unmapping in case I/O Space or Memory Space disable */
> +    if (((base->bar_flag == PT_BAR_FLAG_IO) && !io_enable) ||
> +        ((base->bar_flag == PT_BAR_FLAG_MEM) && !mem_enable)) {
> +        r_addr = -1;
> +    }
> +    if ((bar == PCI_ROM_SLOT) && (r_addr != -1)) {
> +        reg_grp_entry = pt_find_reg_grp(s, PCI_ROM_ADDRESS);
> +        if (reg_grp_entry) {
> +            reg_entry = pt_find_reg(reg_grp_entry, PCI_ROM_ADDRESS);
> +            if (reg_entry && !(reg_entry->data & PCI_ROM_ADDRESS_ENABLE)) {
> +                r_addr = -1;
> +            }
> +        }
> +    }
> +
> +    /* prevent guest software mapping memory resource to 00000000h */
> +    if ((base->bar_flag == PT_BAR_FLAG_MEM) && (r_addr == 0)) {
> +        r_addr = -1;
> +    }
> +
> +    r_size = pt_get_emul_size(base->bar_flag, r->size);
> +
> +    rc = pci_check_bar_overlap(dev, r_addr, r_size, r->type);
> +    if (rc > 0) {
> +        PT_LOG("Warning: s[%02x:%02x.%x][Region:%d][Address:%"FMT_PCIBUS"h]"
> +               "[Size:%"FMT_PCIBUS"h] is overlapped.\n", 
> pci_bus_num(dev->bus),
> +               PCI_SLOT(dev->devfn), PCI_FUNC(dev->devfn), bar,
> +               r_addr, r_size);
> +    }
> +
> +    /* check whether we need to update the mapping or not */
> +    if (r_addr != s->bases[bar].e_physbase) {
> +        /* mapping BAR */
> +        if (base->bar_flag == PT_BAR_FLAG_IO) {
> +            pt_ioport_map(s, bar, r_addr, r_size, r->type);
> +        } else {
> +            pt_iomem_map(s, bar, r_addr, r_size, r->type);
> +        }
> +    }
> +}
> +
> +void pt_bar_mapping(XenPCIPassthroughState *s, int io_enable, int mem_enable)
> +{
> +    int i;
> +
> +    for (i = 0; i < PCI_NUM_REGIONS; i++) {
> +        pt_bar_mapping_one(s, i, io_enable, mem_enable);
> +    }
> +}
> +
> +/* register regions */
> +static int pt_register_regions(XenPCIPassthroughState *s)
> +{
> +    int i = 0;
> +    uint32_t bar_data = 0;
> +    HostPCIDevice *d = s->real_device;
> +
> +    /* Register PIO/MMIO BARs */
> +    for (i = 0; i < PCI_BAR_ENTRIES; i++) {
> +        HostPCIIORegion *r = &d->io_regions[i];
> +
> +        if (r->base_addr) {
> +            s->bases[i].e_physbase = r->base_addr;
> +            s->bases[i].access.u = r->base_addr;
> +
> +            /* Register current region */
> +            if (r->flags & IORESOURCE_IO) {
> +                memory_region_init_io(&s->bar[i], NULL, NULL,
> +                                      "xen-pci-pt-bar", r->size);
> +                pci_register_bar(&s->dev, i, PCI_BASE_ADDRESS_SPACE_IO,
> +                                 &s->bar[i]);
> +            } else if (r->flags & IORESOURCE_PREFETCH) {
> +                memory_region_init_io(&s->bar[i], NULL, NULL,
> +                                      "xen-pci-pt-bar", r->size);
> +                pci_register_bar(&s->dev, i, PCI_BASE_ADDRESS_MEM_PREFETCH,
> +                                 &s->bar[i]);
> +            } else {
> +                memory_region_init_io(&s->bar[i], NULL, NULL,
> +                                      "xen-pci-pt-bar", r->size);
> +                pci_register_bar(&s->dev, i, PCI_BASE_ADDRESS_SPACE_MEMORY,
> +                                 &s->bar[i]);
> +            }
> +
> +            PT_LOG("IO region registered (size=0x%08"PRIx64
> +                   " base_addr=0x%08"PRIx64")\n",
> +                   r->size, r->base_addr);
> +        }
> +    }
> +
> +    /* Register expansion ROM address */
> +    if (d->rom.base_addr && d->rom.size) {
> +        /* Re-set BAR reported by OS, otherwise ROM can't be read. */
> +        bar_data = host_pci_get_long(d, PCI_ROM_ADDRESS);
> +        if ((bar_data & PCI_ROM_ADDRESS_MASK) == 0) {
> +            bar_data |= d->rom.base_addr & PCI_ROM_ADDRESS_MASK;
> +            host_pci_set_long(d, PCI_ROM_ADDRESS, bar_data);
> +        }
> +
> +        s->bases[PCI_ROM_SLOT].e_physbase = d->rom.base_addr;
> +        s->bases[PCI_ROM_SLOT].access.maddr = d->rom.base_addr;
> +
> +        memory_region_init_rom_device(&s->rom, NULL, NULL, &s->dev.qdev,
> +                                      "xen-pci-pt-rom", d->rom.size);
> +        pci_register_bar(&s->dev, PCI_ROM_SLOT, 
> PCI_BASE_ADDRESS_MEM_PREFETCH,
> +                         &s->rom);
> +
> +        PT_LOG("Expansion ROM registered (size=0x%08"PRIx64
> +               " base_addr=0x%08"PRIx64")\n",
> +               d->rom.size, d->rom.base_addr);
> +    }
> +
> +    return 0;
> +}
> +
> +static void pt_unregister_regions(XenPCIPassthroughState *s)
> +{
> +    int i, type, rc;
> +    uint32_t e_size;
> +    PCIDevice *d = &s->dev;
> +
> +    for (i = 0; i < PCI_NUM_REGIONS; i++) {
> +        e_size = s->bases[i].e_size;
> +        if ((e_size == 0) || (s->bases[i].e_physbase == -1)) {
> +            continue;
> +        }
> +
> +        type = d->io_regions[i].type;
> +
> +        if (type == PCI_BASE_ADDRESS_SPACE_MEMORY
> +            || type == PCI_BASE_ADDRESS_MEM_PREFETCH) {
> +            rc = xc_domain_memory_mapping(xen_xc, xen_domid,
> +                    s->bases[i].e_physbase >> XC_PAGE_SHIFT,
> +                    s->bases[i].access.maddr >> XC_PAGE_SHIFT,
> +                    (e_size+XC_PAGE_SIZE-1) >> XC_PAGE_SHIFT,
> +                    DPCI_REMOVE_MAPPING);
> +            if (rc != 0) {
> +                PT_LOG("Error: remove old mem mapping failed!\n");
> +                continue;
> +            }
> +
> +        } else if (type == PCI_BASE_ADDRESS_SPACE_IO) {
> +            rc = xc_domain_ioport_mapping(xen_xc, xen_domid,
> +                        s->bases[i].e_physbase,
> +                        s->bases[i].access.pio_base,
> +                        e_size,
> +                        DPCI_REMOVE_MAPPING);
> +            if (rc != 0) {
> +                PT_LOG("Error: remove old io mapping failed!\n");
> +                continue;
> +            }
> +        }
> +    }
> +}
> +
> +static int pt_initfn(PCIDevice *pcidev)
> +{
> +    XenPCIPassthroughState *s = DO_UPCAST(XenPCIPassthroughState, dev, 
> pcidev);
> +    int dom, bus;
> +    unsigned slot, func;
> +    int rc = 0;
> +    uint32_t machine_irq;
> +    int pirq = -1;
> +
> +    if (pci_parse_devaddr(s->hostaddr, &dom, &bus, &slot, &func) < 0) {
> +        fprintf(stderr, "error parse bdf: %s\n", s->hostaddr);
> +        return -1;
> +    }
> +
> +    /* register real device */
> +    PT_LOG("Assigning real physical device %02x:%02x.%x to devfn %i ...\n",
> +           bus, slot, func, s->dev.devfn);
> +
> +    s->real_device = host_pci_device_get(bus, slot, func);
> +    if (!s->real_device) {
> +        return -1;
> +    }
> +
> +    s->is_virtfn = s->real_device->is_virtfn;
> +    if (s->is_virtfn) {
> +        PT_LOG("%04x:%02x:%02x.%x is a SR-IOV Virtual Function\n",
> +               s->real_device->domain, bus, slot, func);
> +    }
> +
> +    /* Initialize virtualized PCI configuration (Extended 256 Bytes) */
> +    if (host_pci_get_block(s->real_device, 0, pcidev->config,
> +                           PCI_CONFIG_SPACE_SIZE) == -1) {
> +        return -1;
> +    }
> +
> +    /* Handle real device's MMIO/PIO BARs */
> +    pt_register_regions(s);
> +
> +    /* reinitialize each config register to be emulated */
> +    pt_config_init(s);
> +
> +    /* Bind interrupt */
> +    if (!s->dev.config[PCI_INTERRUPT_PIN]) {
> +        PT_LOG("no pin interrupt\n");
> +        goto out;
> +    }
> +
> +    machine_irq = host_pci_get_byte(s->real_device, PCI_INTERRUPT_LINE);
> +    rc = xc_physdev_map_pirq(xen_xc, xen_domid, machine_irq, &pirq);
> +
> +    if (rc) {
> +        PT_LOG("Error: Mapping irq failed, rc = %d\n", rc);
> +
> +        /* Disable PCI intx assertion (turn on bit10 of devctl) */
> +        host_pci_set_word(s->real_device,
> +                          PCI_COMMAND,
> +                          pci_get_word(s->dev.config + PCI_COMMAND)
> +                          | PCI_COMMAND_INTX_DISABLE);
> +        machine_irq = 0;
> +        s->machine_irq = 0;
> +    } else {
> +        machine_irq = pirq;
> +        s->machine_irq = pirq;
> +        mapped_machine_irq[machine_irq]++;
> +    }
> +
> +    /* setup MSI-INTx translation if support */
> +    rc = pt_enable_msi_translate(s);
> +
> +    /* bind machine_irq to device */
> +    if (rc < 0 && machine_irq != 0) {
> +        uint8_t e_device = PCI_SLOT(s->dev.devfn);
> +        uint8_t e_intx = pci_intx(s);
> +
> +        rc = xc_domain_bind_pt_pci_irq(xen_xc, xen_domid, machine_irq, 0,
> +                                       e_device, e_intx);
> +        if (rc < 0) {
> +            PT_LOG("Error: Binding of interrupt failed! rc=%d\n", rc);
> +
> +            /* Disable PCI intx assertion (turn on bit10 of devctl) */
> +            host_pci_set_word(s->real_device, PCI_COMMAND,
> +                              *(uint16_t *)(&s->dev.config[PCI_COMMAND])
> +                              | PCI_COMMAND_INTX_DISABLE);
> +            mapped_machine_irq[machine_irq]--;
> +
> +            if (mapped_machine_irq[machine_irq] == 0) {
> +                if (xc_physdev_unmap_pirq(xen_xc, xen_domid, machine_irq)) {
> +                    PT_LOG("Error: Unmapping of interrupt failed! rc=%d\n",
> +                           rc);
> +                }
> +            }
> +            s->machine_irq = 0;
> +        }
> +    }
> +
> +out:
> +    PT_LOG("Real physical device %02x:%02x.%x registered successfuly!\n"
> +           "IRQ type = %s\n", bus, slot, func,
> +           s->msi_trans_en ? "MSI-INTx" : "INTx");
> +
> +    return 0;
> +}
> +
> +static int pt_unregister_device(PCIDevice *pcidev)
> +{
> +    XenPCIPassthroughState *s = DO_UPCAST(XenPCIPassthroughState, dev, 
> pcidev);
> +    uint8_t e_device, e_intx;
> +    uint32_t machine_irq;
> +    int rc;
> +
> +    /* Unbind interrupt */
> +    e_device = PCI_SLOT(s->dev.devfn);
> +    e_intx = pci_intx(s);
> +    machine_irq = s->machine_irq;
> +
> +    if (s->msi_trans_en == 0 && machine_irq) {
> +        rc = xc_domain_unbind_pt_irq(xen_xc, xen_domid, machine_irq,
> +                                     PT_IRQ_TYPE_PCI, 0, e_device, e_intx, 
> 0);
> +        if (rc < 0) {
> +            PT_LOG("Error: Unbinding of interrupt failed! rc=%d\n", rc);
> +        }
> +    }
> +
> +    if (s->msi) {
> +        pt_msi_disable(s);
> +    }
> +    if (s->msix) {
> +        pt_msix_disable(s);
> +    }
> +
> +    if (machine_irq) {
> +        mapped_machine_irq[machine_irq]--;
> +
> +        if (mapped_machine_irq[machine_irq] == 0) {
> +            rc = xc_physdev_unmap_pirq(xen_xc, xen_domid, machine_irq);
> +
> +            if (rc < 0) {
> +                PT_LOG("Error: Unmaping of interrupt failed! rc=%d\n", rc);
> +            }
> +        }
> +    }
> +
> +    /* delete all emulated config registers */
> +    pt_config_delete(s);
> +
> +    /* unregister real device's MMIO/PIO BARs */
> +    pt_unregister_regions(s);
> +
> +    host_pci_device_put(s->real_device);
> +
> +    return 0;
> +}
> +
> +static PCIDeviceInfo xen_pci_passthrough = {
> +    .init = pt_initfn,
> +    .exit = pt_unregister_device,
> +    .qdev.name = "xen-pci-passthrough",
> +    .qdev.desc = "Assign an host pci device with Xen",
> +    .qdev.size = sizeof(XenPCIPassthroughState),
> +    .config_read = pt_pci_read_config,
> +    .config_write = pt_pci_write_config,
> +    .is_express = 0,
> +    .qdev.props = (Property[]) {
> +        DEFINE_PROP_STRING("hostaddr", XenPCIPassthroughState, hostaddr),
> +        DEFINE_PROP_BIT("msitranslate", XenPCIPassthroughState, 
> msi_trans_cap,
> +                        0, true),
> +        DEFINE_PROP_BIT("power-mgmt", XenPCIPassthroughState, power_mgmt,
> +                        0, false),
> +        DEFINE_PROP_END_OF_LIST(),
> +    }
> +};
> +
> +static void xen_passthrough_register(void)
> +{
> +    pci_qdev_register(&xen_pci_passthrough);
> +}
> +
> +device_init(xen_passthrough_register);
> diff --git a/hw/xen_pci_passthrough.h b/hw/xen_pci_passthrough.h
> new file mode 100644
> index 0000000..2d43c18
> --- /dev/null
> +++ b/hw/xen_pci_passthrough.h
> @@ -0,0 +1,258 @@
> +#ifndef QEMU_HW_XEN_PCI_PASSTHROUGH_H
> +#  define QEMU_HW_XEN_PCI_PASSTHROUGH_H
> +
> +#include "qemu-common.h"
> +#include "xen_common.h"
> +#include "pci.h"
> +#include "host-pci-device.h"
> +
> +#define PT_LOGGING_ENABLED
> +#define PT_DEBUG_PCI_CONFIG_ACCESS
> +
> +#ifdef PT_LOGGING_ENABLED
> +#  define PT_LOG(_f, _a...)   fprintf(stderr, "%s: " _f, __func__, ##_a)
> +#else
> +#  define PT_LOG(_f, _a...)
> +#endif
> +
> +#ifdef PT_DEBUG_PCI_CONFIG_ACCESS
> +#  define PT_LOG_CONFIG(_f, _a...) PT_LOG(_f, ##_a)
> +#else
> +#  define PT_LOG_CONFIG(_f, _a...)
> +#endif
> +
> +
> +typedef struct XenPTRegInfo XenPTRegInfo;
> +typedef struct XenPTReg XenPTReg;
> +
> +typedef struct XenPCIPassthroughState XenPCIPassthroughState;
> +
> +/* function type for config reg */
> +typedef uint32_t (*conf_reg_init)
> +    (XenPCIPassthroughState *, XenPTRegInfo *, uint32_t real_offset);
> +typedef int (*conf_dword_write)
> +    (XenPCIPassthroughState *, XenPTReg *cfg_entry,
> +     uint32_t *val, uint32_t dev_value, uint32_t valid_mask);
> +typedef int (*conf_word_write)
> +    (XenPCIPassthroughState *, XenPTReg *cfg_entry,
> +     uint16_t *val, uint16_t dev_value, uint16_t valid_mask);
> +typedef int (*conf_byte_write)
> +    (XenPCIPassthroughState *, XenPTReg *cfg_entry,
> +     uint8_t *val, uint8_t dev_value, uint8_t valid_mask);
> +typedef int (*conf_dword_read)
> +    (XenPCIPassthroughState *, XenPTReg *cfg_entry,
> +     uint32_t *val, uint32_t valid_mask);
> +typedef int (*conf_word_read)
> +    (XenPCIPassthroughState *, XenPTReg *cfg_entry,
> +     uint16_t *val, uint16_t valid_mask);
> +typedef int (*conf_byte_read)
> +    (XenPCIPassthroughState *, XenPTReg *cfg_entry,
> +     uint8_t *val, uint8_t valid_mask);
> +typedef int (*conf_dword_restore)
> +    (XenPCIPassthroughState *, XenPTReg *cfg_entry, uint32_t real_offset,
> +     uint32_t dev_value, uint32_t *val);
> +typedef int (*conf_word_restore)
> +    (XenPCIPassthroughState *, XenPTReg *cfg_entry, uint32_t real_offset,
> +     uint16_t dev_value, uint16_t *val);
> +typedef int (*conf_byte_restore)
> +    (XenPCIPassthroughState *, XenPTReg *cfg_entry, uint32_t real_offset,
> +     uint8_t dev_value, uint8_t *val);
> +
> +/* power state transition */
> +#define PT_FLAG_TRANSITING 0x0001
> +
> +
> +typedef enum {
> +    GRP_TYPE_HARDWIRED = 0,                     /* 0 Hardwired reg group */
> +    GRP_TYPE_EMU,                               /* emul reg group */
> +} RegisterGroupType;
> +
> +typedef enum {
> +    PT_BAR_FLAG_MEM = 0,                        /* Memory type BAR */
> +    PT_BAR_FLAG_IO,                             /* I/O type BAR */
> +    PT_BAR_FLAG_UPPER,                          /* upper 64bit BAR */
> +    PT_BAR_FLAG_UNUSED,                         /* unused BAR */
> +} PTBarFlag;
> +
> +
> +typedef struct XenPTRegion {
> +    /* Virtual phys base & size */
> +    uint32_t e_physbase;
> +    uint32_t e_size;
> +    /* Index of region in qemu */
> +    uint32_t memory_index;
> +    /* BAR flag */
> +    PTBarFlag bar_flag;
> +    /* Translation of the emulated address */
> +    union {
> +        uint64_t maddr;
> +        uint64_t pio_base;
> +        uint64_t u;
> +    } access;
> +} XenPTRegion;
> +
> +/* XenPTRegInfo declaration
> + * - only for emulated register (either a part or whole bit).
> + * - for passthrough register that need special behavior (like interacting 
> with
> + *   other component), set emu_mask to all 0 and specify r/w func properly.
> + * - do NOT use ALL F for init_val, otherwise the tbl will not be registered.
> + */
> +
> +/* emulated register infomation */
> +struct XenPTRegInfo {
> +    uint32_t offset;
> +    uint32_t size;
> +    uint32_t init_val;
> +    /* reg read only field mask (ON:RO/ROS, OFF:other) */
> +    uint32_t ro_mask;
> +    /* reg emulate field mask (ON:emu, OFF:passthrough) */
> +    uint32_t emu_mask;
> +    /* no write back allowed */
> +    uint32_t no_wb;
> +    conf_reg_init init;
> +    /* read/write/restore function pointer
> +     * for double_word/word/byte size */
> +    union {
> +        struct {
> +            conf_dword_write write;
> +            conf_dword_read read;
> +            conf_dword_restore restore;
> +        } dw;
> +        struct {
> +            conf_word_write write;
> +            conf_word_read read;
> +            conf_word_restore restore;
> +        } w;
> +        struct {
> +            conf_byte_write write;
> +            conf_byte_read read;
> +            conf_byte_restore restore;
> +        } b;
> +    } u;
> +};
> +
> +/* emulated register management */
> +struct XenPTReg {
> +    QLIST_ENTRY(XenPTReg) entries;
> +    XenPTRegInfo *reg;
> +    uint32_t data;
> +};
> +
> +typedef struct XenPTRegGroupInfo XenPTRegGroupInfo;
> +
> +/* emul reg group size initialize method */
> +typedef uint8_t (*pt_reg_size_init_fn)
> +    (XenPCIPassthroughState *, const XenPTRegGroupInfo *,
> +     uint32_t base_offset);
> +
> +/* emulated register group infomation */
> +struct XenPTRegGroupInfo {
> +    uint8_t grp_id;
> +    RegisterGroupType grp_type;
> +    uint8_t grp_size;
> +    pt_reg_size_init_fn size_init;
> +    XenPTRegInfo *emu_reg_tbl;
> +};
> +
> +/* emul register group management table */
> +typedef struct XenPTRegGroup {
> +    QLIST_ENTRY(XenPTRegGroup) entries;
> +    const XenPTRegGroupInfo *reg_grp;
> +    uint32_t base_offset;
> +    uint8_t size;
> +    QLIST_HEAD(, XenPTReg) reg_tbl_list;
> +} XenPTRegGroup;
> +
> +
> +typedef struct XenPTMSI {
> +    uint32_t flags;
> +    uint32_t ctrl_offset; /* saved control offset */
> +    int pirq;          /* guest pirq corresponding */
> +    uint32_t addr_lo;  /* guest message address */
> +    uint32_t addr_hi;  /* guest message upper address */
> +    uint16_t data;     /* guest message data */
> +} XenPTMSI;
> +
> +typedef struct XenMSIXEntry {
> +    int pirq;        /* -1 means unmapped */
> +    int flags;       /* flags indicting whether MSI ADDR or DATA is updated 
> */
> +    uint32_t io_mem[4];
> +} XenMSIXEntry;
> +typedef struct XenPTMSIX {
> +    uint32_t ctrl_offset;
> +    int enabled;
> +    int total_entries;
> +    int bar_index;
> +    uint64_t table_base;
> +    uint32_t table_off;
> +    uint32_t table_offset_adjust; /* page align mmap */
> +    uint64_t mmio_base_addr;
> +    int mmio_index;
> +    void *phys_iomem_base;
> +    XenMSIXEntry msix_entry[0];
> +} XenPTMSIX;
> +
> +typedef struct XenPTPM {
> +    QEMUTimer *pm_timer;  /* QEMUTimer struct */
> +    int no_soft_reset;    /* No Soft Reset flags */
> +    uint16_t flags;       /* power state transition flags */
> +    uint16_t pmc_field;   /* Power Management Capabilities field */
> +    int pm_delay;         /* power state transition delay */
> +    uint16_t cur_state;   /* current power state */
> +    uint16_t req_state;   /* requested power state */
> +    uint32_t pm_base;     /* Power Management Capability reg base offset */
> +    uint32_t aer_base;    /* AER Capability reg base offset */
> +} XenPTPM;
> +
> +struct XenPCIPassthroughState {
> +    PCIDevice dev;
> +
> +    char *hostaddr;
> +    bool is_virtfn;
> +    HostPCIDevice *real_device;
> +    XenPTRegion bases[PCI_NUM_REGIONS]; /* Access regions */
> +    QLIST_HEAD(, XenPTRegGroup) reg_grp_tbl;
> +
> +    uint32_t machine_irq;
> +
> +    XenPTMSI *msi;
> +    XenPTMSIX *msix;
> +
> +    /* Physical MSI to guest INTx translation when possible */
> +    uint32_t msi_trans_cap;
> +    bool msi_trans_en;
> +
> +    uint32_t power_mgmt;
> +    XenPTPM *pm_state;
> +
> +    MemoryRegion bar[PCI_NUM_REGIONS - 1];
> +    MemoryRegion rom;
> +};
> +
> +void pt_config_init(XenPCIPassthroughState *s);
> +void pt_config_delete(XenPCIPassthroughState *s);
> +void pt_bar_mapping(XenPCIPassthroughState *s, int io_enable, int 
> mem_enable);
> +void pt_bar_mapping_one(XenPCIPassthroughState *s, int bar,
> +                        int io_enable, int mem_enable);
> +XenPTRegGroup *pt_find_reg_grp(XenPCIPassthroughState *s, uint32_t address);
> +XenPTReg *pt_find_reg(XenPTRegGroup *reg_grp, uint32_t address);
> +int pt_bar_offset_to_index(uint32_t offset);
> +
> +static inline pcibus_t pt_get_emul_size(PTBarFlag flag, pcibus_t r_size)
> +{
> +    /* align resource size (memory type only) */
> +    if (flag == PT_BAR_FLAG_MEM) {
> +        return (r_size + XC_PAGE_SIZE - 1) & XC_PAGE_MASK;
> +    } else {
> +        return r_size;
> +    }
> +}
> +
> +/* INTx */
> +static inline uint8_t pci_read_intx(XenPCIPassthroughState *s)
> +{
> +    return host_pci_get_byte(s->real_device, PCI_INTERRUPT_PIN);
> +}
> +uint8_t pci_intx(XenPCIPassthroughState *ptdev);
> +
> +#endif /* !QEMU_HW_XEN_PCI_PASSTHROUGH_H */
> diff --git a/hw/xen_pci_passthrough_helpers.c 
> b/hw/xen_pci_passthrough_helpers.c
> new file mode 100644
> index 0000000..192e918
> --- /dev/null
> +++ b/hw/xen_pci_passthrough_helpers.c
> @@ -0,0 +1,46 @@
> +#include "xen_pci_passthrough.h"
> +
> +/* The PCI Local Bus Specification, Rev. 3.0, {
> + * Section 6.2.4 Miscellaneous Registers, pp 223
> + * outlines 5 valid values for the intertupt pin (intx).
> + *  0: For devices (or device functions) that don't use an interrupt in
> + *  1: INTA#
> + *  2: INTB#
> + *  3: INTC#
> + *  4: INTD#
> + *
> + * Xen uses the following 4 values for intx
> + *  0: INTA#
> + *  1: INTB#
> + *  2: INTC#
> + *  3: INTD#
> + *
> + * Observing that these list of values are not the same, pci_read_intx()
> + * uses the following mapping from hw to xen values.
> + * This seems to reflect the current usage within Xen.
> + *
> + * PCI hardware    | Xen | Notes
> + * 
> ----------------+-----+----------------------------------------------------
> + * 0               | 0   | No interrupt
> + * 1               | 0   | INTA#
> + * 2               | 1   | INTB#
> + * 3               | 2   | INTC#
> + * 4               | 3   | INTD#
> + * any other value | 0   | This should never happen, log error message
> +}
> + */
> +uint8_t pci_intx(XenPCIPassthroughState *ptdev)
> +{
> +    uint8_t r_val = pci_read_intx(ptdev);
> +
> +    PT_LOG("intx=%i\n", r_val);
> +    if (r_val < 1 || r_val > 4) {
> +        PT_LOG("Interrupt pin read from hardware is out of range: "
> +               "value=%i, acceptable range is 1 - 4\n", r_val);
> +        r_val = 0;
> +    } else {
> +        r_val -= 1;
> +    }
> +
> +    return r_val;
> +}
> --
> Anthony PERARD
> 

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