Re: [Qemu-devel] [Xen-devel] [PATCH V3 02/10] Introduce HostPCIDevice to access a pci device on the host.

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

> +static unsigned long get_value(HostPCIDevice *d, const char *name)
> +{
> +    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 -1;

So the decleration is 'unsigned long' but you return -1 here.

Should the decleration be 'signed long' ?

Or perhaps return the value as parameter and return zero for success
and <= 0 for failure?

> +    }
> +    if (fscanf(f, "%lx\n", &value) != 1) {
> +        fprintf(stderr, "Error: Syntax error in %s\n", path);
> +        value = -1;
> +    }
> +    fclose(f);
> +    return value;
> +}
> +
> +static int pci_dev_is_virtfn(HostPCIDevice *d)
> +{
> +    int rc;
> +    char path[PATH_MAX];
> +    struct stat buf;
> +
> +    path_to(d, "physfn", path, sizeof (path));
> +    rc = !stat(path, &buf);

> +
> +    return rc;

Seems like this could be a 'bool'?

> +}
> +
> +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;
> +
> +    res = pread(fd, buf, len, pos);
> +    if (res < 0) {
> +        fprintf(stderr, "host_pci_config: read failed: %s (fd: %i)\n",
> +                strerror(errno), fd);
> +        return -1;
> +    }
> +    return res;
> +}
> +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;
> +
> +    res = pwrite(fd, buf, len, pos);
> +    if (res < 0) {
> +        fprintf(stderr, "host_pci_config: write failed: %s\n",
> +                strerror(errno));
> +        return -1;
> +    }
> +    return res;
> +}
> +
> +uint8_t host_pci_get_byte(HostPCIDevice *d, int pos)
> +{
> +  uint8_t buf;
> +  host_pci_config_read(d, pos, &buf, 1);

Not checking the return value?
> +  return buf;
> +}
> +uint16_t host_pci_get_word(HostPCIDevice *d, int pos)
> +{
> +  uint16_t buf;
> +  host_pci_config_read(d, pos, &buf, 2);

Here as well?
> +  return le16_to_cpu(buf);

So if we can't read those buffers, won't that mean we end up with
garbage in buf? As we haven't actually written anything to it?

Perhaps we should do:

 if (host_pci..() < 0)
	return 0;
 ... normal case?

> +}
> +uint32_t host_pci_get_long(HostPCIDevice *d, int pos)
> +{
> +  uint32_t buf;
> +  host_pci_config_read(d, pos, &buf, 4);
> +  return le32_to_cpu(buf);
> +}
> +int host_pci_get_block(HostPCIDevice *d, int pos, uint8_t *buf, int len)
> +{
> +  return host_pci_config_read(d, pos, buf, len);

Oh, so that is called.. Hm, not much chance of returning an error there is.

Can we propage the errors in case there is some fundamental failure
when reading/writting the data stream? Say the PCI device gets
unplugged by the user.. won't pread return -EXIO?

> +}
> +
> +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 {
> +        header = host_pci_get_long(d, pos);
> +        /*
> +         * 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;
> +
> +    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;
> +    }
> +
> +    d->vendor_id = get_value(d, "vendor");
> +    d->device_id = get_value(d, "device");
> +    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..d79ba48
> --- /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);
> +
> +uint8_t host_pci_get_byte(HostPCIDevice *d, int pos);
> +uint16_t host_pci_get_word(HostPCIDevice *d, int pos);
> +uint32_t host_pci_get_long(HostPCIDevice *d, int pos);
> +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
> 
> 
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