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

[Marcel Apfelbaum <marcel@redhat.com>]

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

>> ---
>>   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