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

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

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.

> >>---
> >>  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