Re: [Qemu-devel] [PATCH v3 0/4] enable iommu with -device

["Michael S. Tsirkin" <mst@redhat.com>]

On Mon, Jun 13, 2016 at 05:36:56PM +0300, Marcel Apfelbaum wrote:
> Create the iommu device with '-device intel-iommu' instead of '-machine,iommu=on'.
> 
> The device is part of the machine properties because we wanted
> to ensure is created before any other PCI device.
> 
> The alternative is to skip the bus_master_enable_region at
> the time the device is created. We can create this region
> at machine_done phase. (patch 1)
> 
> Then we need to enable sysbus devices(*) for PC machines (patch 2),
> since intel-iommu is a sysbus device.
> 
> Patch 3 moves the IOMMU init proces into iommu's realize function
> and allows the device creation in both ways.

Looks good. I'm inclined to apply 1-3 initially, see how many
acks will 4 collect.
Could you rebase on my tree pls?

> Finally patch 4 removes the iommu machine property.
> 
> v2 -> v3:
>   - Add machine_done notifier in pci_bus realize and remove it unrealize (Paolo).
>   - Add comments for 'cannot_instantiate_with_device_add_yet' (Markus).
>   - Split adding the -device iommu support and removing the iommu machine property (Michael).
>   - Use pci_setup_iommu as before (Peter)
>   - Mark intel-iommu as not hot-pluggable (Peter)
>   - Rebased on master
> 
> v1 -> v2:
>   - Enable bus_master also on init if the guest OS already booted to enable hotplug (Paolo).
>   - Add a machine_done notifier to PCIBus instead of adding functionality
>     for q35 machine_done callback. The main reason is we don't want to replicate
>     the code for all platforms that support PCI and is also cleaner this way.
>   - Added 'cannot_instantiate_with_device_add_yet' to sysbus devices that lead
>     to crashes if added with -device.
>   - Rebased on master
> 
> 
> (*) Creates a new problem since we have now a bunch of
>     new devices that can be created with -device on Q35:
> 	name "q35-pcihost", bus System
> 	name "sysbus-ohci", bus System, desc "OHCI USB Controller"
> 	name "allwinner-ahci", bus System
> 	name "cfi.pflash01", bus System
> 	name "esp", bus System
> 	name "SUNW,fdtwo", bus System
> 	name "sysbus-ahci", bus System
> 	name "sysbus-fdc", bus System
> 	name "vfio-amd-xgbe", bus System, desc "VFIO AMD XGBE"
> 	name "vfio-calxeda-xgmac", bus System, desc "VFIO Calxeda XGMAC"
> 	name "virtio-mmio", bus System
> 	name "fw_cfg", bus System
> 	name "fw_cfg_io", bus System
> 	name "fw_cfg_mem", bus System
> 	name "generic-sdhci", bus System
> 	name "hpet", bus System
> 	name "i440FX-pcihost", bus System
> 	name "intel-iommu", bus System
> 	name "ioapic", bus System
> 	name "isabus-bridge", bus System
> 	name "kvm-ioapic", bus System
> 	name "kvmclock", bus System
> 	name "kvmvapic", bus System
> 	name "pxb-host", bus System
> 
> Took care of the ones creating immediate issues (like crashes) by marking them
> as 'cannot_instantiate_with_device_add_yet'. I didn't mark them all because:
>   - libvirt will mask them anyway
>   - some of them have already a "protection" in place
>   - it is possible that some of them can be actually used with -device on other platform. 
>   - those are not 'interesting' scenarios.
> If somebody spots devices in the list that cannot be added with -device on any platform
> please let me know and I'll mark them.
> 
> 
> Thanks,
> Marcel
> 
> Marcel Apfelbaum (4):
>   hw/pci: delay bus_master_enable_region initialization
>   q35: allow dynamic sysbus
>   hw/iommu: enable iommu with -device
>   machine: remove iommu property
> 
>  hw/core/machine.c                   | 20 ------------------
>  hw/i386/intel_iommu.c               | 16 ++++++++++++++
>  hw/i386/pc_q35.c                    |  2 +-
>  hw/pci-bridge/pci_expander_bridge.c |  2 ++
>  hw/pci-host/piix.c                  |  2 ++
>  hw/pci-host/q35.c                   | 31 +++------------------------
>  hw/pci/pci.c                        | 42 ++++++++++++++++++++++++++++---------
>  include/hw/pci-host/q35.h           |  1 -
>  include/hw/pci/pci_bus.h            |  2 ++
>  include/sysemu/sysemu.h             |  1 +
>  qemu-options.hx                     |  3 ---
>  vl.c                                |  5 +++++
>  12 files changed, 64 insertions(+), 63 deletions(-)
> 
> -- 
> 2.4.3