Re: [Qemu-devel] [V6 4/4] hw/pci-host: Emulate AMD IOMMU

[David Kiarie]

On Thu, Mar 3, 2016 at 12:17 AM, Michael S. Tsirkin <address@hidden> wrote:
> On Thu, Mar 03, 2016 at 12:09:28AM +0300, David Kiarie wrote:
>>
>>
>> On 22/02/16 14:22, Marcel Apfelbaum wrote:
>> >On 02/21/2016 08:11 PM, David Kiarie wrote:
>> >>Add AMD IOMMU emulation support to q35 chipset
>> >>
>> >>Signed-off-by: David Kiarie <address@hidden>
>> >>---
>> >>  hw/pci-host/piix.c            |  1 +
>> >>  hw/pci-host/q35.c             | 14 ++++++++++++--
>> >>  include/hw/i386/intel_iommu.h |  1 +
>> >>  3 files changed, 14 insertions(+), 2 deletions(-)
>> >>
>> >>diff --git a/hw/pci-host/piix.c b/hw/pci-host/piix.c
>> >>index 41aa66f..ab2e24a 100644
>> >>--- a/hw/pci-host/piix.c
>> >>+++ b/hw/pci-host/piix.c
>> >>@@ -36,6 +36,7 @@
>> >>  #include "hw/i386/ioapic.h"
>> >>  #include "qapi/visitor.h"
>> >>  #include "qemu/error-report.h"
>> >>+#include "hw/i386/amd_iommu.h"
>> >
>> >Hi,
>> >
>> >I think you don't need this include anymore.
>> >
>> >>
>> >>  /*
>> >>   * I440FX chipset data sheet.
>> >>diff --git a/hw/pci-host/q35.c b/hw/pci-host/q35.c
>> >>index 115fb8c..355fb32 100644
>> >>--- a/hw/pci-host/q35.c
>> >>+++ b/hw/pci-host/q35.c
>> >>@@ -31,6 +31,7 @@
>> >>  #include "hw/hw.h"
>> >>  #include "hw/pci-host/q35.h"
>> >>  #include "qapi/visitor.h"
>> >>+#include "hw/i386/amd_iommu.h"
>> >>
>> >>/****************************************************************************
>> >>   * Q35 host
>> >>@@ -505,9 +506,18 @@ 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)) {
>> >>+
>> >>+    if (g_strcmp0(MACHINE(qdev_get_machine())->iommu, INTEL_IOMMU_STR)
>> >>== 0) {
>> >>+        /* Intel IOMMU (VT-d) */
>> >>          mch_init_dmar(mch);
>> >>+    } else if (g_strcmp0(MACHINE(qdev_get_machine())->iommu,
>> >>AMD_IOMMU_STR)
>> >>+               == 0) {
>> >>+        AMDIOMMUState *iommu_state;
>> >>+        PCIDevice *iommu;
>> >>+        PCIBus *bus = PCI_BUS(qdev_get_parent_bus(DEVICE(mch)));
>> >>+        iommu = pci_create_simple(bus, 0x20, TYPE_AMD_IOMMU_DEVICE);
>
> Pls don't hardcode paths like this. Set addr property instead.
>
>> >>+        iommu_state = AMD_IOMMU_DEVICE(iommu);
>> >>+        pci_setup_iommu(bus, bridge_host_amd_iommu, iommu_state);
>> >
>> >pci_setup_iommu third parameter is void*, so you don't need to cast to
>> >AMDIOMMUState
>> >before passing it.
>>
>> This include is necessary for the definition of "AMD_IOMMU_STR" either way
>> so am leaving this as is.
>
> This option parsing is just too ugly.
>
> Looks like it was a mistake to support the iommu
> machine property, but I see no reason to add to the
> existing mess.
>
> Can't users create iommu with -device amd-iommu ?

You mean getting rid of the above code and starting device with
'-device amd-iommu' ? This way am not able to setup IOMMU regions for
devices correctly. IIRC 'pci_setup_iommu' when called from IOMMU code
sets up IOMMU region for IOMMU only. Calling this from the bus sets up
IOMMU regions for all devices though.

I need to setup IOMMU regions for all devices from the bus, to be able
to do that I need to have created the IOMMU device first.

>
> It's necessary if we are to support multiple IOMMUs, anyway.
>
>> >
>> >Thanks,
>> >Marcel
>> >
>> >>      }
>> >>  }
>> >>
>> >>diff --git a/include/hw/i386/intel_iommu.h
>> >>b/include/hw/i386/intel_iommu.h
>> >>index b024ffa..539530c 100644
>> >>--- a/include/hw/i386/intel_iommu.h
>> >>+++ b/include/hw/i386/intel_iommu.h
>> >>@@ -27,6 +27,7 @@
>> >>  #define TYPE_INTEL_IOMMU_DEVICE "intel-iommu"
>> >>  #define INTEL_IOMMU_DEVICE(obj) \
>> >>       OBJECT_CHECK(IntelIOMMUState, (obj), TYPE_INTEL_IOMMU_DEVICE)
>> >>+#define INTEL_IOMMU_STR "intel"
>> >>
>> >>  /* DMAR Hardware Unit Definition address (IOMMU unit) */
>> >>  #define Q35_HOST_BRIDGE_IOMMU_ADDR  0xfed90000ULL
>> >>
>> >