Re: [Qemu-devel] [PATCH 03/11] qemu: add routines to manage PCI capabilities

[Isaku Yamahata]

On Mon, May 25, 2009 at 03:25:20PM +0300, Michael S. Tsirkin wrote:
> Add routines to manage PCI capability list. First user will be MSI-X.
> 
> Signed-off-by: Michael S. Tsirkin <address@hidden>
> ---
>  hw/pci.c |   98 
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++------
>  hw/pci.h |   18 +++++++++++-
>  2 files changed, 106 insertions(+), 10 deletions(-)
> 
> diff --git a/hw/pci.c b/hw/pci.c
> index 5dcfb4e..6bc3819 100644
> --- a/hw/pci.c
> +++ b/hw/pci.c
> @@ -130,12 +130,13 @@ void pci_device_save(PCIDevice *s, QEMUFile *f)
>      int version = s->cap_present ? 3 : 2;
>      int i;
>  
> -    qemu_put_be32(f, version); /* PCI device version */
> +    /* PCI device version and capabilities */
> +    qemu_put_be32(f, version);
> +    if (version >= 3)
> +        qemu_put_be32(f, s->cap_present);
>      qemu_put_buffer(f, s->config, 256);
>      for (i = 0; i < 4; i++)
>          qemu_put_be32(f, s->irq_state[i]);
> -    if (version >= 3)
> -        qemu_put_be32(f, s->cap_present);
>  }
>  
>  int pci_device_load(PCIDevice *s, QEMUFile *f)
> @@ -146,12 +147,6 @@ int pci_device_load(PCIDevice *s, QEMUFile *f)
>      version_id = qemu_get_be32(f);
>      if (version_id > 3)
>          return -EINVAL;
> -    qemu_get_buffer(f, s->config, 256);
> -    pci_update_mappings(s);
> -
> -    if (version_id >= 2)
> -        for (i = 0; i < 4; i ++)
> -            s->irq_state[i] = qemu_get_be32(f);
>      if (version_id >= 3)
>          s->cap_present = qemu_get_be32(f);
>      else
> @@ -160,6 +155,18 @@ int pci_device_load(PCIDevice *s, QEMUFile *f)
>      if (s->cap_present & ~s->cap_supported)
>          return -EINVAL;
>  
> +    qemu_get_buffer(f, s->config, 256);
> +    pci_update_mappings(s);
> +
> +    if (version_id >= 2)
> +        for (i = 0; i < 4; i ++)
> +            s->irq_state[i] = qemu_get_be32(f);
> +    /* Clear mask and used bits for capabilities.
> +       Must be restored separately, since capabilities can
> +       be placed anywhere in config space. */
> +    memset(s->used, 0, PCI_CONFIG_SPACE_SIZE);
> +    for (i = PCI_CONFIG_HEADER_SIZE; i < PCI_CONFIG_SPACE_SIZE; ++i)
> +        s->mask[i] = 0xff;
>      return 0;
>  }
>  
> @@ -870,3 +877,76 @@ PCIDevice *pci_create_simple(PCIBus *bus, int devfn, 
> const char *name)
>  
>      return (PCIDevice *)dev;
>  }
> +
> +static int pci_find_space(PCIDevice *pdev, uint8_t size)
> +{
> +    int offset = PCI_CONFIG_HEADER_SIZE;
> +    int i;
> +    for (i = PCI_CONFIG_HEADER_SIZE; i < PCI_CONFIG_SPACE_SIZE; ++i)
> +        if (pdev->used[i])
> +            offset = i + 1;
> +        else if (i - offset + 1 == size)
> +            return offset;
> +    return 0;
> +}
> +
> +static uint8_t pci_find_capability_list(PCIDevice *pdev, uint8_t cap_id,
> +                                        uint8_t *prev_p)
> +{
> +    uint8_t next, prev;
> +
> +    if (!(pdev->config[PCI_STATUS] & PCI_STATUS_CAP_LIST))
> +        return 0;
> +
> +    for (prev = PCI_CAPABILITY_LIST; (next = pdev->config[prev]);
> +         prev = next + PCI_CAP_LIST_NEXT)
> +        if (pdev->config[next + PCI_CAP_LIST_ID] != cap_id)

typo? ==


> +            break;
> +
> +    *prev_p = prev;
> +    return next;
> +}
> +
> +/* Reserve space and add capability to the linked list in pci config space */
> +int pci_add_capability(PCIDevice *pdev, uint8_t cap_id, uint8_t size)
> +{
> +    uint8_t offset = pci_find_space(pdev, size);
> +    uint8_t *config = pdev->config + offset;
> +    if (!offset)
> +        return -ENOSPC;
> +    config[PCI_CAP_LIST_ID] = cap_id;
> +    config[PCI_CAP_LIST_NEXT] = pdev->config[PCI_CAPABILITY_LIST];
> +    pdev->config[PCI_CAPABILITY_LIST] = offset;
> +    pdev->config[PCI_STATUS] |= PCI_STATUS_CAP_LIST;
> +    memset(pdev->used + offset, 0xFF, size);
> +    /* Make capability read-only by default */
> +    memset(pdev->mask + offset, 0, size);
> +    return offset;
> +}
> +
> +/* Unlink capability from the pci config space. */
> +void pci_del_capability(PCIDevice *pdev, uint8_t cap_id, uint8_t size)
> +{
> +    uint8_t prev, offset = pci_find_capability_list(pdev, cap_id, &prev);
> +    if (!offset)
> +        return;
> +    pdev->config[prev] = pdev->config[offset + PCI_CAP_LIST_NEXT];
> +    /* Make capability writeable again */
> +    memset(pdev->mask + offset, 0xff, size);
> +    memset(pdev->used + offset, 0, size);
> +
> +    if (!pdev->config[PCI_CAPABILITY_LIST])
> +        pdev->config[PCI_STATUS] &= ~PCI_STATUS_CAP_LIST;
> +}
> +
> +/* Reserve space for capability at a known offset (to call after load). */
> +void pci_reserve_capability(PCIDevice *pdev, uint8_t offset, uint8_t size)
> +{
> +    memset(pdev->used + offset, 0xff, size);
> +}
> +
> +uint8_t pci_find_capability(PCIDevice *pdev, uint8_t cap_id)
> +{
> +    uint8_t prev;
> +    return pci_find_capability_list(pdev, cap_id, &prev);
> +}
> diff --git a/hw/pci.h b/hw/pci.h
> index 9139504..40137c6 100644
> --- a/hw/pci.h
> +++ b/hw/pci.h
> @@ -123,6 +123,10 @@ typedef struct PCIIORegion {
>  #define PCI_MIN_GNT          0x3e    /* 8 bits */
>  #define PCI_MAX_LAT          0x3f    /* 8 bits */
>  
> +/* Capability lists */
> +#define PCI_CAP_LIST_ID              0       /* Capability ID */
> +#define PCI_CAP_LIST_NEXT    1       /* Next capability in the list */
> +
>  #define PCI_REVISION            0x08    /* obsolete, use PCI_REVISION_ID */
>  #define PCI_SUBVENDOR_ID        0x2c    /* obsolete, use 
> PCI_SUBSYSTEM_VENDOR_ID */
>  #define PCI_SUBDEVICE_ID        0x2e    /* obsolete, use PCI_SUBSYSTEM_ID */
> @@ -130,7 +134,7 @@ typedef struct PCIIORegion {
>  /* Bits in the PCI Status Register (PCI 2.3 spec) */
>  #define PCI_STATUS_RESERVED1 0x007
>  #define PCI_STATUS_INT_STATUS        0x008
> -#define PCI_STATUS_CAPABILITIES      0x010
> +#define PCI_STATUS_CAP_LIST  0x010
>  #define PCI_STATUS_66MHZ     0x020
>  #define PCI_STATUS_RESERVED2 0x040
>  #define PCI_STATUS_FAST_BACK 0x080
> @@ -160,6 +164,9 @@ struct PCIDevice {
>      /* Used to implement R/W bytes */
>      uint8_t mask[PCI_CONFIG_SPACE_SIZE];
>  
> +    /* Used to allocate config space for capabilities. */
> +    uint8_t used[PCI_CONFIG_SPACE_SIZE];
> +

bitmap? Or will be used for other purpose?

>      /* the following fields are read only */
>      PCIBus *bus;
>      int devfn;
> @@ -194,6 +201,15 @@ void pci_register_io_region(PCIDevice *pci_dev, int 
> region_num,
>                              uint32_t size, int type,
>                              PCIMapIORegionFunc *map_func);
>  
> +int pci_add_capability(PCIDevice *pci_dev, uint8_t cap_id, uint8_t cap_size);
> +
> +void pci_del_capability(PCIDevice *pci_dev, uint8_t cap_id, uint8_t 
> cap_size);
> +
> +void pci_reserve_capability(PCIDevice *pci_dev, uint8_t offset, uint8_t 
> size);
> +
> +uint8_t pci_find_capability(PCIDevice *pci_dev, uint8_t cap_id);
> +
> +
>  uint32_t pci_default_read_config(PCIDevice *d,
>                                   uint32_t address, int len);
>  void pci_default_write_config(PCIDevice *d,

-- 
yamahata