[v2,2/7] libqos: add iteration support to qpci_find_capability()

VIRTIO 1.0 PCI devices have multiple PCI_CAP_ID_VNDR capabilities so we
need a way to iterate over them.  Extend qpci_find_capability() to take
the last address.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 tests/libqos/pci.h |  2 +-
 tests/libqos/pci.c | 18 ++++++++++++------
 2 files changed, 13 insertions(+), 7 deletions(-)

Stefan Hajnoczi <stefanha@redhat.com> writes:

> VIRTIO 1.0 PCI devices have multiple PCI_CAP_ID_VNDR capabilities so we
> need a way to iterate over them.  Extend qpci_find_capability() to take
> the last address.
>
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
>  tests/libqos/pci.h |  2 +-
>  tests/libqos/pci.c | 18 ++++++++++++------
>  2 files changed, 13 insertions(+), 7 deletions(-)
>
> diff --git a/tests/libqos/pci.h b/tests/libqos/pci.h
> index a5389a5845..590c175190 100644
> --- a/tests/libqos/pci.h
> +++ b/tests/libqos/pci.h
> @@ -86,7 +86,7 @@ bool qpci_has_buggy_msi(QPCIDevice *dev);
>  bool qpci_check_buggy_msi(QPCIDevice *dev);
>  
>  void qpci_device_enable(QPCIDevice *dev);
> -uint8_t qpci_find_capability(QPCIDevice *dev, uint8_t id);
> +uint8_t qpci_find_capability(QPCIDevice *dev, uint8_t id, uint8_t start_addr);
>  void qpci_msix_enable(QPCIDevice *dev);
>  void qpci_msix_disable(QPCIDevice *dev);
>  bool qpci_msix_pending(QPCIDevice *dev, uint16_t entry);
> diff --git a/tests/libqos/pci.c b/tests/libqos/pci.c
> index 662ee7a517..b8679dff1d 100644
> --- a/tests/libqos/pci.c
> +++ b/tests/libqos/pci.c
> @@ -115,10 +115,16 @@ void qpci_device_enable(QPCIDevice *dev)
>      g_assert_cmphex(cmd & PCI_COMMAND_MASTER, ==, PCI_COMMAND_MASTER);
>  }
>  
> -uint8_t qpci_find_capability(QPCIDevice *dev, uint8_t id)
> +uint8_t qpci_find_capability(QPCIDevice *dev, uint8_t id, uint8_t start_addr)
>  {
>      uint8_t cap;
> -    uint8_t addr = qpci_config_readb(dev, PCI_CAPABILITY_LIST);
> +    uint8_t addr;
> +
> +    if (start_addr) {
> +        addr = qpci_config_readb(dev, start_addr + PCI_CAP_LIST_NEXT);
> +    } else {
> +        addr = qpci_config_readb(dev, PCI_CAPABILITY_LIST);
> +    }
>  
>      do {
>          cap = qpci_config_readb(dev, addr);
> @@ -138,7 +144,7 @@ void qpci_msix_enable(QPCIDevice *dev)
>      uint8_t bir_table;
>      uint8_t bir_pba;
>  
> -    addr = qpci_find_capability(dev, PCI_CAP_ID_MSIX);
> +    addr = qpci_find_capability(dev, PCI_CAP_ID_MSIX, 0);
>      g_assert_cmphex(addr, !=, 0);
>  
>      val = qpci_config_readw(dev, addr + PCI_MSIX_FLAGS);
> @@ -167,7 +173,7 @@ void qpci_msix_disable(QPCIDevice *dev)
>      uint16_t val;
>  
>      g_assert(dev->msix_enabled);
> -    addr = qpci_find_capability(dev, PCI_CAP_ID_MSIX);
> +    addr = qpci_find_capability(dev, PCI_CAP_ID_MSIX, 0);
>      g_assert_cmphex(addr, !=, 0);
>      val = qpci_config_readw(dev, addr + PCI_MSIX_FLAGS);
>      qpci_config_writew(dev, addr + PCI_MSIX_FLAGS,
> @@ -203,7 +209,7 @@ bool qpci_msix_masked(QPCIDevice *dev, uint16_t entry)
>      uint64_t vector_off = dev->msix_table_off + entry * PCI_MSIX_ENTRY_SIZE;
>  
>      g_assert(dev->msix_enabled);
> -    addr = qpci_find_capability(dev, PCI_CAP_ID_MSIX);
> +    addr = qpci_find_capability(dev, PCI_CAP_ID_MSIX, 0);
>      g_assert_cmphex(addr, !=, 0);
>      val = qpci_config_readw(dev, addr + PCI_MSIX_FLAGS);
>  
> @@ -221,7 +227,7 @@ uint16_t qpci_msix_table_size(QPCIDevice *dev)
>      uint8_t addr;
>      uint16_t control;
>  
> -    addr = qpci_find_capability(dev, PCI_CAP_ID_MSIX);
> +    addr = qpci_find_capability(dev, PCI_CAP_ID_MSIX, 0);
>      g_assert_cmphex(addr, !=, 0);
>  
>      control = qpci_config_readw(dev, addr + PCI_MSIX_FLAGS);

Reviewed-by: Sergio Lopez <slp@redhat.com>

On 11/10/2019 10.56, Stefan Hajnoczi wrote:
> VIRTIO 1.0 PCI devices have multiple PCI_CAP_ID_VNDR capabilities so we
> need a way to iterate over them.  Extend qpci_find_capability() to take
> the last address.
> 
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
>  tests/libqos/pci.h |  2 +-
>  tests/libqos/pci.c | 18 ++++++++++++------
>  2 files changed, 13 insertions(+), 7 deletions(-)
> 
> diff --git a/tests/libqos/pci.h b/tests/libqos/pci.h
> index a5389a5845..590c175190 100644
> --- a/tests/libqos/pci.h
> +++ b/tests/libqos/pci.h
> @@ -86,7 +86,7 @@ bool qpci_has_buggy_msi(QPCIDevice *dev);
>  bool qpci_check_buggy_msi(QPCIDevice *dev);
>  
>  void qpci_device_enable(QPCIDevice *dev);
> -uint8_t qpci_find_capability(QPCIDevice *dev, uint8_t id);
> +uint8_t qpci_find_capability(QPCIDevice *dev, uint8_t id, uint8_t start_addr);

In case you respin, I'd like to suggest to add a comment in front of
that prototype, explaining how the start_addr is meant to work (but the
source code is trivial enough, so there's no need to respin just because
of this, IMHO).

Reviewed-by: Thomas Huth <thuth@redhat.com>