[+cc linux-pci]
On Fri, Jun 30, 2017 at 12:24 AM, Alexey Kardashevskiy <aik@xxxxxxxxx> wrote:
> From: Yongji Xie <elohimes@xxxxxxxxx>
>
> We introduce a new pci_bus_flags, PCI_BUS_FLAGS_MSI_REMAP
> which indicates interrupts of all devices on the bus are
> managed by the hardware enabling IRQ remapping (intel naming).
> When the capability is enabled, a given PCI device can only
> shoot the MSIs assigned for it. In other words, the hardware
> can protect system from invalid MSIs of the device by checking
> the target address and data when there is something wrong
> with MSI part in device or device driver.
This needs a reference to the spec that describes how this MSI protection works.
> The new flag will be set by when the kernel decides that it is safe to
> do so.
We also need some clue about how the kernel makes this decision. That
clue probably doesn't belong in *this* patch, but I didn't see it
anywhere.
> With this flag enabled, we can easily know whether it's safe
> to expose MSI-X tables of PCI BARs to userspace. Some usespace
> drivers such as VFIO may benefit from this.
>
> Signed-off-by: Yongji Xie <xyjxie@xxxxxxxxxxxxxxxxxx>
> Signed-off-by: Alexey Kardashevskiy <aik@xxxxxxxxx>
> ---
> include/linux/pci.h | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 8039f9f0ca05..2c6dbb3dd0da 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -200,6 +200,7 @@ enum pci_bus_flags {
> PCI_BUS_FLAGS_NO_MSI = (__force pci_bus_flags_t) 1,
> PCI_BUS_FLAGS_NO_MMRBC = (__force pci_bus_flags_t) 2,
> PCI_BUS_FLAGS_NO_AERSID = (__force pci_bus_flags_t) 4,
> + PCI_BUS_FLAGS_MSI_REMAP = (__force pci_bus_flags_t) 8,
> };
>
> /* These values come from the PCI Express Spec */
> --
> 2.11.0
>
