Re: [Qemu-devel] [PATCH V9 3/8] Introduce HostPCIDevice to access a pci device on the host.

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Mar 21, 2012 at 06:29:00PM +0000, Anthony PERARD wrote:
> Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
> Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

Host is really linux sysfs, right?
Better reflect this in naming.
Or maybe even xen-host-pci-device?

> ---
>  Makefile.target      |    3 +
>  hw/host-pci-device.c |  278 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  hw/host-pci-device.h |   75 ++++++++++++++
>  3 files changed, 356 insertions(+), 0 deletions(-)
>  create mode 100644 hw/host-pci-device.c
>  create mode 100644 hw/host-pci-device.h
> 
> diff --git a/Makefile.target b/Makefile.target
> index 63cf769..0ccfd5b 100644
> --- a/Makefile.target
> +++ b/Makefile.target
> @@ -232,6 +232,9 @@ obj-$(CONFIG_NO_XEN) += xen-stub.o
>  
>  obj-i386-$(CONFIG_XEN) += xen_platform.o
>  
> +# Xen PCI Passthrough
> +obj-i386-$(CONFIG_XEN_PCI_PASSTHROUGH) += host-pci-device.o
> +
>  # Inter-VM PCI shared memory
>  CONFIG_IVSHMEM =
>  ifeq ($(CONFIG_KVM), y)
> diff --git a/hw/host-pci-device.c b/hw/host-pci-device.c
> new file mode 100644
> index 0000000..3dacb30
> --- /dev/null
> +++ b/hw/host-pci-device.c
> @@ -0,0 +1,278 @@
> +/*
> + * Copyright (C) 2011       Citrix Ltd.
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2.  See
> + * the COPYING file in the top-level directory.
> + *
> + */
> +
> +#include "qemu-common.h"
> +#include "host-pci-device.h"
> +
> +#define PCI_MAX_EXT_CAP \
> +    ((PCIE_CONFIG_SPACE_SIZE - PCI_CONFIG_SPACE_SIZE) / (PCI_CAP_SIZEOF + 4))
> +
> +enum error_code {
> +    ERROR_SYNTAX = 1,
> +};
> +
> +static int path_to(const HostPCIDevice *d,
> +                   const char *name, char *buf, ssize_t size)
> +{
> +    return snprintf(buf, size, "/sys/bus/pci/devices/%04x:%02x:%02x.%x/%s",
> +                    d->domain, d->bus, d->dev, d->func, name);
> +}
> +
> +static int get_resource(HostPCIDevice *d)
> +{
> +    int i, rc = 0;
> +    FILE *f;
> +    char path[PATH_MAX];
> +    unsigned long long start, end, flags, size;
> +
> +    path_to(d, "resource", path, sizeof (path));
> +    f = fopen(path, "r");
> +    if (!f) {
> +        fprintf(stderr, "Error: Can't open %s: %s\n", path, strerror(errno));
> +        return -errno;
> +    }
> +
> +    for (i = 0; i < PCI_NUM_REGIONS; i++) {
> +        if (fscanf(f, "%llx %llx %llx", &start, &end, &flags) != 3) {
> +            fprintf(stderr, "Error: Syntax error in %s\n", path);
> +            rc = ERROR_SYNTAX;
> +            break;
> +        }
> +        if (start) {
> +            size = end - start + 1;
> +        } else {
> +            size = 0;
> +        }
> +
> +        if (i < PCI_ROM_SLOT) {
> +            d->io_regions[i].base_addr = start;
> +            d->io_regions[i].size = size;
> +            d->io_regions[i].flags = flags;
> +        } else {
> +            d->rom.base_addr = start;
> +            d->rom.size = size;
> +            d->rom.flags = flags;
> +        }
> +    }
> +
> +    fclose(f);
> +    return rc;
> +}
> +
> +static int get_hex_value(HostPCIDevice *d, const char *name,
> +                         unsigned long *pvalue)
> +{
> +    char path[PATH_MAX];
> +    FILE *f;
> +    unsigned long value;
> +
> +    path_to(d, name, path, sizeof (path));
> +    f = fopen(path, "r");
> +    if (!f) {
> +        fprintf(stderr, "Error: Can't open %s: %s\n", path, strerror(errno));
> +        return -errno;
> +    }
> +    if (fscanf(f, "%lx\n", &value) != 1) {
> +        fprintf(stderr, "Error: Syntax error in %s\n", path);
> +        fclose(f);
> +        return ERROR_SYNTAX;
> +    }
> +    fclose(f);
> +    *pvalue = value;
> +    return 0;
> +}
> +
> +static bool pci_dev_is_virtfn(HostPCIDevice *d)
> +{
> +    char path[PATH_MAX];
> +    struct stat buf;
> +
> +    path_to(d, "physfn", path, sizeof (path));
> +    return !stat(path, &buf);
> +}
> +
> +static int host_pci_config_fd(HostPCIDevice *d)
> +{
> +    char path[PATH_MAX];
> +
> +    if (d->config_fd < 0) {
> +        path_to(d, "config", path, sizeof (path));
> +        d->config_fd = open(path, O_RDWR);
> +        if (d->config_fd < 0) {
> +            fprintf(stderr, "HostPCIDevice: Can not open '%s': %s\n",
> +                    path, strerror(errno));
> +        }
> +    }
> +    return d->config_fd;
> +}
> +static int host_pci_config_read(HostPCIDevice *d, int pos, void *buf, int len)
> +{
> +    int fd = host_pci_config_fd(d);
> +    int res = 0;
> +
> +again:
> +    res = pread(fd, buf, len, pos);
> +    if (res != len) {
> +        if (res < 0 && (errno == EINTR || errno == EAGAIN)) {
> +            goto again;
> +        }
> +        fprintf(stderr, "%s: read failed: %s (fd: %i)\n",
> +                __func__, strerror(errno), fd);
> +        return -errno;
> +    }
> +    return 0;
> +}
> +static int host_pci_config_write(HostPCIDevice *d,
> +                                 int pos, const void *buf, int len)
> +{
> +    int fd = host_pci_config_fd(d);
> +    int res = 0;
> +
> +again:
> +    res = pwrite(fd, buf, len, pos);
> +    if (res != len) {
> +        if (res < 0 && (errno == EINTR || errno == EAGAIN)) {
> +            goto again;
> +        }
> +        fprintf(stderr, "%s: write failed: %s\n",
> +                __func__, strerror(errno));
> +        return -errno;
> +    }
> +    return 0;
> +}
> +
> +int host_pci_get_byte(HostPCIDevice *d, int pos, uint8_t *p)
> +{
> +    uint8_t buf;
> +    int rc = host_pci_config_read(d, pos, &buf, 1);
> +    if (rc == 0) {
> +        *p = buf;
> +    }
> +    return rc;
> +}
> +int host_pci_get_word(HostPCIDevice *d, int pos, uint16_t *p)
> +{
> +    uint16_t buf;
> +    int rc = host_pci_config_read(d, pos, &buf, 2);
> +    if (rc == 0) {
> +        *p = le16_to_cpu(buf);
> +    }
> +    return rc;
> +}
> +int host_pci_get_long(HostPCIDevice *d, int pos, uint32_t *p)
> +{
> +    uint32_t buf;
> +    int rc = host_pci_config_read(d, pos, &buf, 4);
> +    if (rc == 0) {
> +        *p = le32_to_cpu(buf);
> +    }
> +    return rc;
> +}
> +int host_pci_get_block(HostPCIDevice *d, int pos, uint8_t *buf, int len)
> +{
> +    return host_pci_config_read(d, pos, buf, len);
> +}
> +
> +int host_pci_set_byte(HostPCIDevice *d, int pos, uint8_t data)
> +{
> +    return host_pci_config_write(d, pos, &data, 1);
> +}
> +int host_pci_set_word(HostPCIDevice *d, int pos, uint16_t data)
> +{
> +    data = cpu_to_le16(data);
> +    return host_pci_config_write(d, pos, &data, 2);
> +}
> +int host_pci_set_long(HostPCIDevice *d, int pos, uint32_t data)
> +{
> +    data = cpu_to_le32(data);
> +    return host_pci_config_write(d, pos, &data, 4);
> +}
> +int host_pci_set_block(HostPCIDevice *d, int pos, uint8_t *buf, int len)
> +{
> +    return host_pci_config_write(d, pos, buf, len);
> +}
> +
> +uint32_t host_pci_find_ext_cap_offset(HostPCIDevice *d, uint32_t cap)
> +{
> +    uint32_t header = 0;
> +    int max_cap = PCI_MAX_EXT_CAP;
> +    int pos = PCI_CONFIG_SPACE_SIZE;
> +
> +    do {
> +        if (host_pci_get_long(d, pos, &header)) {
> +            break;
> +        }
> +        /*
> +         * If we have no capabilities, this is indicated by cap ID,
> +         * cap version and next pointer all being 0.
> +         */
> +        if (header == 0) {
> +            break;
> +        }
> +
> +        if (PCI_EXT_CAP_ID(header) == cap) {
> +            return pos;
> +        }
> +
> +        pos = PCI_EXT_CAP_NEXT(header);
> +        if (pos < PCI_CONFIG_SPACE_SIZE) {
> +            break;
> +        }
> +
> +        max_cap--;
> +    } while (max_cap > 0);
> +
> +    return 0;
> +}
> +
> +HostPCIDevice *host_pci_device_get(uint8_t bus, uint8_t dev, uint8_t func)
> +{
> +    HostPCIDevice *d = NULL;
> +    unsigned long v = 0;
> +
> +    d = g_new0(HostPCIDevice, 1);
> +
> +    d->config_fd = -1;
> +    d->domain = 0;
> +    d->bus = bus;
> +    d->dev = dev;
> +    d->func = func;
> +
> +    if (host_pci_config_fd(d) == -1) {
> +        goto error;
> +    }
> +    if (get_resource(d) != 0) {
> +        goto error;
> +    }
> +
> +    if (get_hex_value(d, "vendor", &v)) {
> +        goto error;
> +    }
> +    d->vendor_id = v;
> +    if (get_hex_value(d, "device", &v)) {
> +        goto error;
> +    }
> +    d->device_id = v;
> +    d->is_virtfn = pci_dev_is_virtfn(d);
> +
> +    return d;
> +error:
> +    if (d->config_fd >= 0) {
> +        close(d->config_fd);
> +    }
> +    g_free(d);
> +    return NULL;
> +}
> +
> +void host_pci_device_put(HostPCIDevice *d)
> +{
> +    if (d->config_fd >= 0) {
> +        close(d->config_fd);
> +    }
> +    g_free(d);
> +}
> diff --git a/hw/host-pci-device.h b/hw/host-pci-device.h
> new file mode 100644
> index 0000000..c8880eb
> --- /dev/null
> +++ b/hw/host-pci-device.h
> @@ -0,0 +1,75 @@
> +#ifndef HW_HOST_PCI_DEVICE
> +#  define HW_HOST_PCI_DEVICE
> +
> +#include "pci.h"
> +
> +/*
> + * from linux/ioport.h
> + * IO resources have these defined flags.
> + */
> +#define IORESOURCE_BITS         0x000000ff      /* Bus-specific bits */
> +
> +#define IORESOURCE_TYPE_BITS    0x00000f00      /* Resource type */
> +#define IORESOURCE_IO           0x00000100
> +#define IORESOURCE_MEM          0x00000200
> +#define IORESOURCE_IRQ          0x00000400
> +#define IORESOURCE_DMA          0x00000800
> +
> +#define IORESOURCE_PREFETCH     0x00001000      /* No side effects */
> +#define IORESOURCE_READONLY     0x00002000
> +#define IORESOURCE_CACHEABLE    0x00004000
> +#define IORESOURCE_RANGELENGTH  0x00008000
> +#define IORESOURCE_SHADOWABLE   0x00010000
> +
> +#define IORESOURCE_SIZEALIGN    0x00020000      /* size indicates alignment */
> +#define IORESOURCE_STARTALIGN   0x00040000      /* start field is alignment */
> +
> +#define IORESOURCE_MEM_64       0x00100000
> +
> +    /* Userland may not map this resource */
> +#define IORESOURCE_EXCLUSIVE    0x08000000
> +#define IORESOURCE_DISABLED     0x10000000
> +#define IORESOURCE_UNSET        0x20000000
> +#define IORESOURCE_AUTO         0x40000000
> +    /* Driver has marked this resource busy */
> +#define IORESOURCE_BUSY         0x80000000
> +
> +
> +typedef struct HostPCIIORegion {
> +    unsigned long flags;
> +    pcibus_t base_addr;
> +    pcibus_t size;
> +} HostPCIIORegion;
> +
> +typedef struct HostPCIDevice {
> +    uint16_t domain;
> +    uint8_t bus;
> +    uint8_t dev;
> +    uint8_t func;
> +
> +    uint16_t vendor_id;
> +    uint16_t device_id;
> +
> +    HostPCIIORegion io_regions[PCI_NUM_REGIONS - 1];
> +    HostPCIIORegion rom;
> +
> +    bool is_virtfn;
> +
> +    int config_fd;
> +} HostPCIDevice;
> +
> +HostPCIDevice *host_pci_device_get(uint8_t bus, uint8_t dev, uint8_t func);
> +void host_pci_device_put(HostPCIDevice *pci_dev);
> +
> +int host_pci_get_byte(HostPCIDevice *d, int pos, uint8_t *p);
> +int host_pci_get_word(HostPCIDevice *d, int pos, uint16_t *p);
> +int host_pci_get_long(HostPCIDevice *d, int pos, uint32_t *p);
> +int host_pci_get_block(HostPCIDevice *d, int pos, uint8_t *buf, int len);
> +int host_pci_set_byte(HostPCIDevice *d, int pos, uint8_t data);
> +int host_pci_set_word(HostPCIDevice *d, int pos, uint16_t data);
> +int host_pci_set_long(HostPCIDevice *d, int pos, uint32_t data);
> +int host_pci_set_block(HostPCIDevice *d, int pos, uint8_t *buf, int len);
> +
> +uint32_t host_pci_find_ext_cap_offset(HostPCIDevice *s, uint32_t cap);
> +
> +#endif /* !HW_HOST_PCI_DEVICE */
> -- 
> Anthony PERARD