Re: [Qemu-devel] [PATCH v3 4/5] intel-iommu: add Intel IOMMU emulation to q35 and add a machine option "iommu" as a switch

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

On Mon, Aug 11, 2014 at 03:05:01PM +0800, Le Tan wrote:
> Add Intel IOMMU emulation to q35 chipset and expose it to the guest.
> 1. Add a machine option. Users can use "-machine iommu=on|off" in the command
> line to enable/disable Intel IOMMU. The default is off.
> 2. Accroding to the machine option, q35 will initialize the Intel IOMMU and
> use pci_setup_iommu() to setup q35_host_dma_iommu() as the IOMMU function for
> the pci bus.
> 3. q35_host_dma_iommu() will return different address space according to the
> bus_num and devfn of the device.
> 
> Signed-off-by: Le Tan <tamlokveer@gmail.com>
> ---
>  hw/core/machine.c         | 27 +++++++++++++++++---
>  hw/pci-host/q35.c         | 64 +++++++++++++++++++++++++++++++++++++++++++----
>  include/hw/boards.h       |  1 +
>  include/hw/pci-host/q35.h |  2 ++
>  qemu-options.hx           |  5 +++-
>  vl.c                      |  4 +++
>  6 files changed, 94 insertions(+), 9 deletions(-)
> 
> diff --git a/hw/core/machine.c b/hw/core/machine.c
> index 7a66c57..f0046d6 100644
> --- a/hw/core/machine.c
> +++ b/hw/core/machine.c
> @@ -235,6 +235,20 @@ 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_initfn(Object *obj)
>  {
>      object_property_add_str(obj, "accel",
> @@ -270,10 +284,17 @@ static void machine_initfn(Object *obj)
>                               machine_set_dump_guest_core,
>                               NULL);
>      object_property_add_bool(obj, "mem-merge",
> -                             machine_get_mem_merge, machine_set_mem_merge, NULL);
> -    object_property_add_bool(obj, "usb", machine_get_usb, machine_set_usb, NULL);
> +                             machine_get_mem_merge,
> +                             machine_set_mem_merge, NULL);
> +    object_property_add_bool(obj, "usb",
> +                             machine_get_usb,
> +                             machine_set_usb, NULL);
>      object_property_add_str(obj, "firmware",
> -                            machine_get_firmware, machine_set_firmware, NULL);
> +                            machine_get_firmware,
> +                            machine_set_firmware, NULL);
> +    object_property_add_bool(obj, "iommu",
> +                             machine_get_iommu,
> +                             machine_set_iommu, NULL);
>  }
>  
>  static void machine_finalize(Object *obj)
> diff --git a/hw/pci-host/q35.c b/hw/pci-host/q35.c
> index a0a3068..3342711 100644
> --- a/hw/pci-host/q35.c
> +++ b/hw/pci-host/q35.c
> @@ -347,6 +347,53 @@ 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 **pvtd_as;
> +    VTDAddressSpace *vtd_as;
> +    int bus_num = pci_bus_num(bus);
> +
> +    assert(devfn >= 0);
> +
> +    pvtd_as = s->address_spaces[bus_num];
> +    if (!pvtd_as) {
> +        /* No corresponding free() */
> +        pvtd_as = g_malloc0(sizeof(VTDAddressSpace *) *
> +                            VTD_PCI_SLOT_MAX * VTD_PCI_FUNC_MAX);
> +        s->address_spaces[bus_num] = pvtd_as;
> +    }
> +
> +    vtd_as = *(pvtd_as + devfn);

pvtd_as[devfn] is cleaner.
In fact, you can then drop vtd_as local variable, use pvtd_as[devfn]
directly.

> +    if (!vtd_as) {
> +        vtd_as = g_malloc0(sizeof(*vtd_as));
> +        *(pvtd_as + devfn) = vtd_as;
> +
> +        vtd_as->bus_num = bus_num;
> +        vtd_as->devfn = devfn;
> +        vtd_as->iommu_state = s;
> +        memory_region_init_iommu(&vtd_as->iommu, OBJECT(s), &s->iommu_ops,
> +                                 "intel_iommu", UINT64_MAX);
> +        address_space_init(&vtd_as->as, &vtd_as->iommu, "intel_iommu");
> +    }
> +
> +    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 int mch_init(PCIDevice *d)
>  {
>      int i;
> @@ -363,13 +410,20 @@ static int mch_init(PCIDevice *d)
>      memory_region_add_subregion_overlap(mch->system_memory, 0xa0000,
>                                          &mch->smram_region, 1);
>      memory_region_set_enabled(&mch->smram_region, false);
> -    init_pam(DEVICE(mch), mch->ram_memory, mch->system_memory, mch->pci_address_space,
> -             &mch->pam_regions[0], PAM_BIOS_BASE, PAM_BIOS_SIZE);
> +    init_pam(DEVICE(mch), mch->ram_memory, mch->system_memory,
> +             mch->pci_address_space, &mch->pam_regions[0], PAM_BIOS_BASE,
> +             PAM_BIOS_SIZE);
>      for (i = 0; i < 12; ++i) {
> -        init_pam(DEVICE(mch), mch->ram_memory, mch->system_memory, mch->pci_address_space,
> -                 &mch->pam_regions[i+1], PAM_EXPAN_BASE + i * PAM_EXPAN_SIZE,
> -                 PAM_EXPAN_SIZE);
> +        init_pam(DEVICE(mch), mch->ram_memory, mch->system_memory,
> +                 mch->pci_address_space, &mch->pam_regions[i+1],
> +                 PAM_EXPAN_BASE + i * PAM_EXPAN_SIZE, PAM_EXPAN_SIZE);

Random formatting changes above? Make it a separate patch please.

> +    }
> +
> +    /* Intel IOMMU (VT-d) */
> +    if (qemu_opt_get_bool(qemu_get_machine_opts(), "iommu", false)) {
> +        mch_init_dmar(mch);
>      }
> +
>      return 0;
>  }
>  
> diff --git a/include/hw/boards.h b/include/hw/boards.h
> index 605a970..dfb6718 100644
> --- a/include/hw/boards.h
> +++ b/include/hw/boards.h
> @@ -123,6 +123,7 @@ struct MachineState {
>      bool mem_merge;
>      bool usb;
>      char *firmware;
> +    bool iommu;
>  
>      ram_addr_t ram_size;
>      ram_addr_t maxram_size;
> diff --git a/include/hw/pci-host/q35.h b/include/hw/pci-host/q35.h
> index d9ee978..025d6e6 100644
> --- a/include/hw/pci-host/q35.h
> +++ b/include/hw/pci-host/q35.h
> @@ -33,6 +33,7 @@
>  #include "hw/acpi/acpi.h"
>  #include "hw/acpi/ich9.h"
>  #include "hw/pci-host/pam.h"
> +#include "hw/i386/intel_iommu.h"
>  
>  #define TYPE_Q35_HOST_DEVICE "q35-pcihost"
>  #define Q35_HOST_DEVICE(obj) \
> @@ -60,6 +61,7 @@ typedef struct MCHPCIState {
>      uint64_t pci_hole64_size;
>      PcGuestInfo *guest_info;
>      uint32_t short_root_bus;
> +    IntelIOMMUState *iommu;
>  } MCHPCIState;
>  
>  typedef struct Q35PCIHost {
> diff --git a/qemu-options.hx b/qemu-options.hx
> index 96516c1..7406a17 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -35,7 +35,8 @@ DEF("machine", HAS_ARG, QEMU_OPTION_machine, \
>      "                kernel_irqchip=on|off controls accelerated irqchip support\n"
>      "                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",
> +    "                mem-merge=on|off controls memory merge support (default: on)\n"
> +    "                iommu=on|off controls emulated Intel IOMMU (VT-d) support (default=off)\n",
>      QEMU_ARCH_ALL)
>  STEXI
>  @item -machine [type=]@var{name}[,prop=@var{value}[,...]]
> @@ -58,6 +59,8 @@ 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.
>  @end table
>  ETEXI
>  
> diff --git a/vl.c b/vl.c
> index a8029d5..2ab1643 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -388,6 +388,10 @@ static QemuOptsList qemu_machine_opts = {
>              .name = PC_MACHINE_MAX_RAM_BELOW_4G,
>              .type = QEMU_OPT_SIZE,
>              .help = "maximum ram below the 4G boundary (32bit boundary)",
> +        },{
> +            .name = "iommu",
> +            .type = QEMU_OPT_BOOL,
> +            .help = "Set on/off to enable/disable Intel IOMMU (VT-d)",
>          },
>          { /* End of list */ }
>      },
> -- 
> 1.9.1