Re: [Qemu-devel] [PATCH v2 2/3] hw/iommu: enable iommu with -device

[Marcel Apfelbaum <marcel@redhat.com>]

On 06/05/2016 12:59 PM, Michael S. Tsirkin wrote:
> On Sun, Jun 05, 2016 at 11:46:13AM +0300, Marcel Apfelbaum wrote:
>> On 06/03/2016 07:07 PM, Michael S. Tsirkin wrote:
>>> On Thu, Jun 02, 2016 at 11:15:54PM +0300, Marcel Apfelbaum wrote:
>>>> Use the standard '-device iommu' instead of '-machine,iommu=on'
>>>> to create the IOMMU device.
>>>>
>>>> Signed-off-by: Marcel Apfelbaum <marcel@redhat.com>
>>>
>>
>> Hi Michael,
>> Thank you for the review.
>>
>>> Why can't we keep support for the old flag?
>>>
>>
>> We can, but IMO we don't need it for several reasons:
>>
>> The current vIOMMU before the fantastic work of Aviv and Peter
>> is not really usable, is there only as a "lab" feature with no
>> clear interesting scenario.
>>
>> If we keep it, we should also support the "x-iommu-type" for
>> AMD IOMMU, so we add "legacy" code we don't want.
>> It is easy to add additional options with -device,
>> but how will we add them to -machine,iommu=on? an extra machine option?
>>
>> Finally, if we do have current users, asking them for a minimum command line
>> change is not such a big deal.
>>
>> Thanks,
>> Marcel
>
> Could you separate -device support from dropping the iommu flag?
> iommu flag would keep meaning intel with no options for compatibility.
>

Yes, is possible. But are you sure the compatibility worth having
an iommu machine option supporting only Intel IOMMU (without AMD) with no options?

Anyway, I will split this patch in two, first one allowing iommu creation
in both ways, the other one  removing the iommu=on option.
We can decide what later if we want the legacy part or not.

Thanks,
Marcel

>>>> ---
>>>>   hw/core/machine.c     | 20 --------------------
>>>>   hw/i386/intel_iommu.c | 17 +++++++++++++++++
>>>>   hw/pci-host/q35.c     | 28 ----------------------------
>>>>   qemu-options.hx       |  3 ---
>>>>   4 files changed, 17 insertions(+), 51 deletions(-)
>>>>
>>>> diff --git a/hw/core/machine.c b/hw/core/machine.c
>>>> index ccdd5fa..8f94301 100644
>>>> --- a/hw/core/machine.c
>>>> +++ b/hw/core/machine.c
>>>> @@ -300,20 +300,6 @@ static void machine_set_firmware(Object *obj, const char *value, Error **errp)
>>>>       ms->firmware = g_strdup(value);
>>>>   }
>>>>
>>>> -static bool machine_get_iommu(Object *obj, Error **errp)
>>>> -{
>>>> -    MachineState *ms = MACHINE(obj);
>>>> -
>>>> -    return ms->iommu;
>>>> -}
>>>> -
>>>> -static void machine_set_iommu(Object *obj, bool value, Error **errp)
>>>> -{
>>>> -    MachineState *ms = MACHINE(obj);
>>>> -
>>>> -    ms->iommu = value;
>>>> -}
>>>> -
>>>>   static void machine_set_suppress_vmdesc(Object *obj, bool value, Error **errp)
>>>>   {
>>>>       MachineState *ms = MACHINE(obj);
>>>> @@ -493,12 +479,6 @@ static void machine_initfn(Object *obj)
>>>>       object_property_set_description(obj, "firmware",
>>>>                                       "Firmware image",
>>>>                                       NULL);
>>>> -    object_property_add_bool(obj, "iommu",
>>>> -                             machine_get_iommu,
>>>> -                             machine_set_iommu, NULL);
>>>> -    object_property_set_description(obj, "iommu",
>>>> -                                    "Set on/off to enable/disable Intel IOMMU (VT-d)",
>>>> -                                    NULL);
>>>>       object_property_add_bool(obj, "suppress-vmdesc",
>>>>                                machine_get_suppress_vmdesc,
>>>>                                machine_set_suppress_vmdesc, NULL);
>>>> diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
>>>> index 347718f..9af5d6b 100644
>>>> --- a/hw/i386/intel_iommu.c
>>>> +++ b/hw/i386/intel_iommu.c
>>>> @@ -24,6 +24,8 @@
>>>>   #include "exec/address-spaces.h"
>>>>   #include "intel_iommu_internal.h"
>>>>   #include "hw/pci/pci.h"
>>>> +#include "hw/pci/pci_bus.h"
>>>> +#include "hw/i386/pc.h"
>>>>
>>>>   /*#define DEBUG_INTEL_IOMMU*/
>>>>   #ifdef DEBUG_INTEL_IOMMU
>>>> @@ -2014,8 +2016,20 @@ static void vtd_reset(DeviceState *dev)
>>>>       vtd_init(s);
>>>>   }
>>>>
>>>> +static AddressSpace *vtd_host_dma_iommu(PCIBus *bus, void *opaque, int devfn)
>>>> +{
>>>> +    IntelIOMMUState *s = opaque;
>>>> +    VTDAddressSpace *vtd_as;
>>>> +
>>>> +    assert(0 <= devfn && devfn <= VTD_PCI_DEVFN_MAX);
>>>> +
>>>> +    vtd_as = vtd_find_add_as(s, bus, devfn);
>>>> +    return &vtd_as->as;
>>>> +}
>>>> +
>>>>   static void vtd_realize(DeviceState *dev, Error **errp)
>>>>   {
>>>> +    PCIBus *bus = PC_MACHINE(qdev_get_machine())->bus;
>>>>       IntelIOMMUState *s = INTEL_IOMMU_DEVICE(dev);
>>>>
>>>>       VTD_DPRINTF(GENERAL, "");
>>>> @@ -2029,6 +2043,9 @@ static void vtd_realize(DeviceState *dev, Error **errp)
>>>>       s->vtd_as_by_busptr = g_hash_table_new_full(vtd_uint64_hash, vtd_uint64_equal,
>>>>                                                 g_free, g_free);
>>>>       vtd_init(s);
>>>> +    sysbus_mmio_map(SYS_BUS_DEVICE(s), 0, Q35_HOST_BRIDGE_IOMMU_ADDR);
>>>> +    bus->iommu_fn = vtd_host_dma_iommu;
>>>> +    bus->iommu_opaque = dev;
>>>>   }
>>>>
>>>>   static void vtd_class_init(ObjectClass *klass, void *data)
>>>> diff --git a/hw/pci-host/q35.c b/hw/pci-host/q35.c
>>>> index 70f897e..ea684c7 100644
>>>> --- a/hw/pci-host/q35.c
>>>> +++ b/hw/pci-host/q35.c
>>>> @@ -424,30 +424,6 @@ static void mch_reset(DeviceState *qdev)
>>>>       mch_update(mch);
>>>>   }
>>>>
>>>> -static AddressSpace *q35_host_dma_iommu(PCIBus *bus, void *opaque, int devfn)
>>>> -{
>>>> -    IntelIOMMUState *s = opaque;
>>>> -    VTDAddressSpace *vtd_as;
>>>> -
>>>> -    assert(0 <= devfn && devfn <= VTD_PCI_DEVFN_MAX);
>>>> -
>>>> -    vtd_as = vtd_find_add_as(s, bus, devfn);
>>>> -    return &vtd_as->as;
>>>> -}
>>>> -
>>>> -static void mch_init_dmar(MCHPCIState *mch)
>>>> -{
>>>> -    PCIBus *pci_bus = PCI_BUS(qdev_get_parent_bus(DEVICE(mch)));
>>>> -
>>>> -    mch->iommu = INTEL_IOMMU_DEVICE(qdev_create(NULL, TYPE_INTEL_IOMMU_DEVICE));
>>>> -    object_property_add_child(OBJECT(mch), "intel-iommu",
>>>> -                              OBJECT(mch->iommu), NULL);
>>>> -    qdev_init_nofail(DEVICE(mch->iommu));
>>>> -    sysbus_mmio_map(SYS_BUS_DEVICE(mch->iommu), 0, Q35_HOST_BRIDGE_IOMMU_ADDR);
>>>> -
>>>> -    pci_setup_iommu(pci_bus, q35_host_dma_iommu, mch->iommu);
>>>> -}
>>>> -
>>>>   static void mch_realize(PCIDevice *d, Error **errp)
>>>>   {
>>>>       int i;
>>>> @@ -506,10 +482,6 @@ static void mch_realize(PCIDevice *d, Error **errp)
>>>>                    mch->pci_address_space, &mch->pam_regions[i+1],
>>>>                    PAM_EXPAN_BASE + i * PAM_EXPAN_SIZE, PAM_EXPAN_SIZE);
>>>>       }
>>>> -    /* Intel IOMMU (VT-d) */
>>>> -    if (object_property_get_bool(qdev_get_machine(), "iommu", NULL)) {
>>>> -        mch_init_dmar(mch);
>>>> -    }
>>>>   }
>>>>
>>>>   uint64_t mch_mcfg_base(void)
>>>> diff --git a/qemu-options.hx b/qemu-options.hx
>>>> index 6106520..2953baf 100644
>>>> --- a/qemu-options.hx
>>>> +++ b/qemu-options.hx
>>>> @@ -38,7 +38,6 @@ DEF("machine", HAS_ARG, QEMU_OPTION_machine, \
>>>>       "                kvm_shadow_mem=size of KVM shadow MMU\n"
>>>>       "                dump-guest-core=on|off include guest memory in a core dump (default=on)\n"
>>>>       "                mem-merge=on|off controls memory merge support (default: on)\n"
>>>> -    "                iommu=on|off controls emulated Intel IOMMU (VT-d) support (default=off)\n"
>>>>       "                igd-passthru=on|off controls IGD GFX passthrough support (default=off)\n"
>>>>       "                aes-key-wrap=on|off controls support for AES key wrapping (default=on)\n"
>>>>       "                dea-key-wrap=on|off controls support for DEA key wrapping (default=on)\n"
>>>> @@ -73,8 +72,6 @@ Include guest memory in a core dump. The default is on.
>>>>   Enables or disables memory merge support. This feature, when supported by
>>>>   the host, de-duplicates identical memory pages among VMs instances
>>>>   (enabled by default).
>>>> -@item iommu=on|off
>>>> -Enables or disables emulated Intel IOMMU (VT-d) support. The default is off.
>>>>   @item aes-key-wrap=on|off
>>>>   Enables or disables AES key wrapping support on s390-ccw hosts. This feature
>>>>   controls whether AES wrapping keys will be created to allow
>>>> --
>>>> 2.4.3