[kvmtool PATCH v9 12/15] PCI: inject PCI device ID on MSI injection

[Marc Zyngier]

On 02/02/17 16:32, Andre Przywara wrote:
> The ITS emulation requires a unique device ID to be passed along the
> MSI payload when kvmtool wants to trigger an MSI in the guest.
> According to the proposed changes to the interface add the PCI
> bus/device/function triple to the structure passed with the ioctl.
> Check the respective capability before actually adding the device ID
> to the kvm_msi struct.
> 
> Signed-off-by: Andre Przywara <andre.przywara at arm.com>
> ---
>  virtio/pci.c | 16 +++++++++++++++-
>  1 file changed, 15 insertions(+), 1 deletion(-)
> 
> diff --git a/virtio/pci.c b/virtio/pci.c
> index 98bf6b7..cecfe8a 100644
> --- a/virtio/pci.c
> +++ b/virtio/pci.c
> @@ -321,14 +321,28 @@ static void virtio_pci__msix_mmio_callback(struct kvm_cpu *vcpu,
>  		update_msix_map(vpci, table, vecnum);
>  }
>  
> -static void virtio_pci__signal_msi(struct kvm *kvm, struct virtio_pci *vpci, int vec)
> +static void virtio_pci__signal_msi(struct kvm *kvm, struct virtio_pci *vpci,
> +				   int vec)
>  {
> +	static int needs_devid = 0;
>  	struct kvm_msi msi = {
>  		.address_lo = vpci->msix_table[vec].msg.address_lo,
>  		.address_hi = vpci->msix_table[vec].msg.address_hi,
>  		.data = vpci->msix_table[vec].msg.data,
>  	};
>  
> +	if (needs_devid == 0) {
> +		if (kvm__supports_vm_extension(kvm, KVM_CAP_MSI_DEVID))

Grump... Pretty horrible, even if it works. Even if we will never end-up
in a situation where we can mix ITS and non-ITS MSIs, could we instead
store this as a flag in the virtio_pci device?

> +			needs_devid = 1;
> +		else
> +			needs_devid = -1;
> +	}
> +
> +	if (needs_devid > 0) {
> +		msi.flags = KVM_MSI_VALID_DEVID;
> +		msi.devid = vpci->dev_hdr.dev_num << 3;
> +	}
> +
>  	ioctl(kvm->vm_fd, KVM_SIGNAL_MSI, &msi);
>  }
>  
> 

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...