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

[Michael S. Tsirkin]

On Thu, Mar 03, 2016 at 01:04:31AM +0300, David Kiarie wrote:
> 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.

I agree it's unfortunate, but I don't think internal limitations
should affect the user interface like this.

I wish we had a way to specify initialization order for devices in some
way, such that system devices are created before others.

For now, can you call pci_setup_iommu in the machine done callback?

> >
> > 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
> >> >>
> >> >