Re: [PATCH v4 2/2] pcie: Specify 0 for ARI next function numbers

[Igor Mammedov <imammedo@redhat.com>]

On Tue,  4 Jul 2023 21:22:14 +0900
Akihiko Odaki <akihiko.odaki@daynix.com> wrote:

> The current implementers of ARI are all SR-IOV devices. The ARI next
> function number field is undefined for VF .
                                           ^
add a reference to a spec (spec name, rev, chapter) where it's declared
so reviewer or whoever reads it later could easily find relevant
documentation.

>The PF should end the linked
> list formed with the field by specifying 0.
ditto

> 
> For migration, the field will keep having 1 as its value on the old
> virt models.
> 
> Fixes: 2503461691 ("pcie: Add some SR/IOV API documentation in docs/pcie_sriov.txt")
> Fixes: 44c2c09488 ("hw/nvme: Add support for SR-IOV")
> Fixes: 3a977deebe ("Intrdocue igb device emulation")
> Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
> ---
>  include/hw/pci/pci.h | 2 ++
>  hw/core/machine.c    | 1 +
>  hw/pci/pci.c         | 2 ++
>  hw/pci/pcie.c        | 2 +-
>  4 files changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
> index e6d0574a29..9c5b5eb206 100644
> --- a/include/hw/pci/pci.h
> +++ b/include/hw/pci/pci.h
> @@ -209,6 +209,8 @@ enum {
>      QEMU_PCIE_CAP_CXL = (1 << QEMU_PCIE_CXL_BITNR),
>  #define QEMU_PCIE_ERR_UNC_MASK_BITNR 11
>      QEMU_PCIE_ERR_UNC_MASK = (1 << QEMU_PCIE_ERR_UNC_MASK_BITNR),
> +#define QEMU_PCIE_ARI_NEXTFN_1_BITNR 12
> +    QEMU_PCIE_ARI_NEXTFN_1 = (1 << QEMU_PCIE_ARI_NEXTFN_1_BITNR),
>  };
>  
>  typedef struct PCIINTxRoute {
> diff --git a/hw/core/machine.c b/hw/core/machine.c
> index 46f8f9a2b0..f0d35c6401 100644
> --- a/hw/core/machine.c
> +++ b/hw/core/machine.c
> @@ -41,6 +41,7 @@
>  
>  GlobalProperty hw_compat_8_0[] = {
>      { "migration", "multifd-flush-after-each-section", "on"},
> +    { TYPE_PCI_DEVICE, "x-pcie-ari-nextfn-1", "on" },
>  };
>  const size_t hw_compat_8_0_len = G_N_ELEMENTS(hw_compat_8_0);
>  
> diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> index e2eb4c3b4a..45a9bc0da8 100644
> --- a/hw/pci/pci.c
> +++ b/hw/pci/pci.c
> @@ -82,6 +82,8 @@ static Property pci_props[] = {
>      DEFINE_PROP_UINT32("acpi-index",  PCIDevice, acpi_index, 0),
>      DEFINE_PROP_BIT("x-pcie-err-unc-mask", PCIDevice, cap_present,
>                      QEMU_PCIE_ERR_UNC_MASK_BITNR, true),
> +    DEFINE_PROP_BIT("x-pcie-ari-nextfn-1", PCIDevice, cap_present,
> +                    QEMU_PCIE_ARI_NEXTFN_1_BITNR, false),
>      DEFINE_PROP_END_OF_LIST()
>  };
>  
> diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c
> index 9a3f6430e8..cf09e03a10 100644
> --- a/hw/pci/pcie.c
> +++ b/hw/pci/pcie.c
> @@ -1030,7 +1030,7 @@ void pcie_sync_bridge_lnk(PCIDevice *bridge_dev)
>  /* ARI */
>  void pcie_ari_init(PCIDevice *dev, uint16_t offset)
>  {
> -    uint16_t nextfn = 1;
> +    uint16_t nextfn = dev->cap_present & QEMU_PCIE_ARI_NEXTFN_1 ? 1 : 0;
>  
>      pcie_add_capability(dev, PCI_EXT_CAP_ID_ARI, PCI_ARI_VER,
>                          offset, PCI_ARI_SIZEOF);