Re: [Qemu-devel] [PATCH v6 2/2] enable multi-function hot-add

[Alex Williamson <alex.williamson@redhat.com>]

On Tue, 2015-10-27 at 20:51 +0800, Cao jin wrote:
> Enable PCIe device multi-function hot-add, just ensure function 0 is added
> last, then driver will got the notification to scan the slot.
> 
> Signed-off-by: Cao jin <caoj.fnst@cn.fujitsu.com>
> ---
>  hw/pci/pci.c         | 40 +++++++++++++++++++++++++++++++++++++++-
>  hw/pci/pci_host.c    | 13 +++++++++++--
>  hw/pci/pcie.c        | 18 +++++++++---------
>  include/hw/pci/pci.h |  1 +
>  4 files changed, 60 insertions(+), 12 deletions(-)

> diff --git a/hw/pci/pci_host.c b/hw/pci/pci_host.c
> index 3e26f92..63d7d2f 100644
> --- a/hw/pci/pci_host.c
> +++ b/hw/pci/pci_host.c
> @@ -20,6 +20,7 @@
>  
>  #include "hw/pci/pci.h"
>  #include "hw/pci/pci_host.h"
> +#include "hw/pci/pci_bus.h"
>  #include "trace.h"
>  
>  /* debug PCI */
> @@ -75,7 +76,11 @@ void pci_data_write(PCIBus *s, uint32_t addr, uint32_t val, int len)
>      PCIDevice *pci_dev = pci_dev_find_by_addr(s, addr);
>      uint32_t config_addr = addr & (PCI_CONFIG_SPACE_SIZE - 1);
>  
> -    if (!pci_dev) {
> +    /* non-zero functions are only exposed when function 0 is present,
> +     * allowing direct removal of unexposed functions.
> +     */
> +    if (!pci_dev ||
> +        (pci_dev->qdev.hotplugged && !pci_get_function_0(pci_dev))) {
>          return;
>      }
>  
> @@ -91,7 +96,11 @@ uint32_t pci_data_read(PCIBus *s, uint32_t addr, int len)
>      uint32_t config_addr = addr & (PCI_CONFIG_SPACE_SIZE - 1);
>      uint32_t val;
>  
> -    if (!pci_dev) {
> +    /* non-zero functions are only exposed when function 0 is present,
> +     * allowing direct removal of unexposed functions.
> +     */
> +    if (!pci_dev ||
> +        (pci_dev->qdev.hotplugged && !pci_get_function_0(pci_dev))) {
>          return ~0x0;
>      }


Don't we need to do this in pci_host_config_read_common() and
pci_host_config_write_common() instead?  Otherwise I don't think we
catch config access via mmcfg.  Thanks,

Alex