Hello Zhenzhong
On 4/17/24 11:24, Duan, Zhenzhong wrote:
-----Original Message-----
From: Cédric Le Goater <c...@redhat.com>
Subject: Re: [PATCH v2 3/5] intel_iommu: Add a framework to do
compatibility check with host IOMMU cap/ecap
On 4/17/24 06:21, Duan, Zhenzhong wrote:
-----Original Message-----
From: Cédric Le Goater <c...@redhat.com>
Subject: Re: [PATCH v2 3/5] intel_iommu: Add a framework to do
compatibility check with host IOMMU cap/ecap
Hello,
On 4/16/24 09:09, Duan, Zhenzhong wrote:
Hi Cédric,
-----Original Message-----
From: Cédric Le Goater <c...@redhat.com>
Subject: Re: [PATCH v2 3/5] intel_iommu: Add a framework to do
compatibility check with host IOMMU cap/ecap
On 4/8/24 10:44, Zhenzhong Duan wrote:
From: Yi Liu <yi.l....@intel.com>
If check fails, the host side device(either vfio or vdpa device) should
not
be passed to guest.
Implementation details for different backends will be in following
patches.
Signed-off-by: Yi Liu <yi.l....@intel.com>
Signed-off-by: Yi Sun <yi.y....@linux.intel.com>
Signed-off-by: Zhenzhong Duan <zhenzhong.d...@intel.com>
---
hw/i386/intel_iommu.c | 35
+++++++++++++++++++++++++++++++++++
1 file changed, 35 insertions(+)
diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index 4f84e2e801..a49b587c73 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -35,6 +35,7 @@
#include "sysemu/kvm.h"
#include "sysemu/dma.h"
#include "sysemu/sysemu.h"
+#include "sysemu/iommufd.h"
#include "hw/i386/apic_internal.h"
#include "kvm/kvm_i386.h"
#include "migration/vmstate.h"
@@ -3819,6 +3820,32 @@ VTDAddressSpace
*vtd_find_add_as(IntelIOMMUState *s, PCIBus *bus,
return vtd_dev_as;
}
+static int vtd_check_legacy_hdev(IntelIOMMUState *s,
+ HostIOMMUDevice *hiod,
+ Error **errp)
+{
+ return 0;
+}
+
+static int vtd_check_iommufd_hdev(IntelIOMMUState *s,
+ HostIOMMUDevice *hiod,
+ Error **errp)
+{
+ return 0;
+}
+
+static int vtd_check_hdev(IntelIOMMUState *s,
VTDHostIOMMUDevice
*vtd_hdev,
+ Error **errp)
+{
+ HostIOMMUDevice *hiod = vtd_hdev->dev;
+
+ if (object_dynamic_cast(OBJECT(hiod), TYPE_HIOD_IOMMUFD)) {
+ return vtd_check_iommufd_hdev(s, hiod, errp);
+ }
+
+ return vtd_check_legacy_hdev(s, hiod, errp);
+}
I think we should be using the .get_host_iommu_info() class handler
instead. Can we refactor the code slightly to avoid this check on
the type ?
There is some difficulty ini avoiding this check, the behavior of
vtd_check_legacy_hdev
and vtd_check_iommufd_hdev are different especially after nesting
support introduced.
vtd_check_iommufd_hdev() has much wider check over cap/ecap bits
besides aw_bits.
I think it is important to fully separate the vIOMMU model from the
host IOMMU backing device.
This comment is true for the structures also.
Could we introduce a new HostIOMMUDeviceClass
handler .check_hdev() handler, which would call .get_host_iommu_info() ?
This means that HIOD_LEGACY_INFO and HIOD_IOMMUFD_INFO should be
a common structure 'HostIOMMUDeviceInfo' holding all attributes
for the different backends. Each .get_host_iommu_info() implementation
would translate the specific host iommu device data presentation
into the common 'HostIOMMUDeviceInfo', this is true for host_aw_bits.
'type' could be handled the same way, with a 'HostIOMMUDeviceInfo'
type attribute and host iommu device type definitions, or as you
suggested with a QOM interface. This is more complex however. In
this case, I would suggest to implement a .compatible() handler to
compare the host iommu device type with the vIOMMU type.
The resulting check_hdev routine would look something like :
static int vtd_check_hdev(IntelIOMMUState *s, VTDHostIOMMUDevice *vtd_hdev,
Error **errp)
{
HostIOMMUDevice *hiod = vtd_hdev->dev;
HostIOMMUDeviceClass *hiodc = HOST_IOMMU_DEVICE_GET_CLASS(hiod);
HostIOMMUDevice info;
int host_aw_bits, ret;
ret = hiodc->get_host_iommu_info(hiod, &info, sizeof(info), errp);
if (ret) {
return ret;
}
ret = hiodc->is_compatible(hiod, VIOMMU_INTERFACE(s));
if (ret) {
return ret;
}
if (s->aw_bits > info.aw_bits) {
error_setg(errp, "aw-bits %d > host aw-bits %d",
s->aw_bits, info.aw_bits);
return -EINVAL;
}
}
and the HostIOMMUDeviceClass::is_compatible() handler would call a
vIOMMUInterface::compatible() handler simply returning
IOMMU_HW_INFO_TYPE_INTEL_VTD. How does that sound ?
Including the type in HostIOMMUDeviceInfo is much simpler to start with.
Thanks,
C.
Understood, besides the new .check_hdev() handler, I think we also need a
new interface
class TYPE_IOMMU_CHECK_HDEV which has two handlers
check_[legacy|iommufd]_hdev(),
and different vIOMMUs have different implementation.
I am not sure to understand. Which class hierarchy would implement this
new "TYPE_IOMMU_CHECK_HDEV" interface ? vIOMMU or host iommu ?
Could you please explain with an update of your diagram :
HostIOMMUDevice
| .get_host_iommu_info()
|
|
.------------------------------------.
| | |
HIODLegacyVFIO [HIODLegacyVDPA] HIODIOMMUFD
| .vdev | [.vdev] | .iommufd
| .devid
| [.ioas_id]
| [.attach_hwpt()]
| [.detach_hwpt()]
|
.----------------------.
| |
HIODIOMMUFDVFIO [HIODIOMMUFDVDPA]
| .vdev | [.vdev]
Sure.
HostIOMMUDevice
| .get_host_iommu_info()
| .check_hdev()
|
.------------------------------.
| |
HIODLegacy HIODIOMMUFD
| | .iommufd
.--------------. | .devid
| | | [.ioas_id]
HIODLegacyVFIO [HIODLegacyVDPA] | [.attach_hwpt()]
| .vdev | [.vdev] | [.detach_hwpt()]
|
.----------------------.
| |
HIODIOMMUFDVFIO [HIODIOMMUFDVDPA]
| .vdev | [.vdev]
HostIOMMUDevice only declare .check_hdev(), but
HIODLegacy and HIODIOMMUFD will implement .check_hdev().
E.g., hiod_legacy_check_hdev() and hiod_iommufd_check_hdev().
int hiod_legacy_check_hdev(HostIOMMUDevice *hiod, IOMMUCheckHDev *viommu, Error
**errp)
{
IOMMUCheckHDevClass *chdc = IOMMU_CHECK_HDEV_GET_CLASS(viommu);
return chdc->check_legacy_hdev(viommu, hiod, errp);
}
int hiod_iommufd_check_hdev(HostIOMMUDevice *hiod, IOMMUCheckHDev *viommu,
Error **errp)
{
IOMMUCheckHDevClass *chdc = IOMMU_CHECK_HDEV_GET_CLASS(viommu);
return chdc->check_iommufd_hdev(viommu, hiod, errp);
}
And we implement interface TYPE_IOMMU_CHECK_HDEV in intel-iommu module.
Certainly, we can also implement the same in other vIOMMUs we want.
See below pseudo change:
diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index 68380d50ca..173c702b9f 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -5521,12 +5521,9 @@ static int vtd_check_hdev(IntelIOMMUState *s,
VTDHostIOMMUDevice *vtd_hdev,
Error **errp)
{
HostIOMMUDevice *hiod = vtd_hdev->dev;
+ HostIOMMUDeviceClass *hiodc = HOST_IOMMU_DEVICE_GET_CLASS(hiod);
- if (object_dynamic_cast(OBJECT(hiod), TYPE_HIOD_IOMMUFD)) {
- return vtd_check_iommufd_hdev(s, vtd_hdev, errp);
- }
-
- return vtd_check_legacy_hdev(s, hiod, errp);
+ return hiodc->check_hdev(IOMMU_CHECK_HDEV(s), hiod, errp);
}
static int vtd_dev_set_iommu_device(PCIBus *bus, void *opaque, int devfn,
@@ -6076,6 +6073,7 @@ static void vtd_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
X86IOMMUClass *x86_class = X86_IOMMU_DEVICE_CLASS(klass);
+ IOMMUCheckHDevClass *chdc = IOMMU_CHECK_HDEV_CLASS(klass);
dc->reset = vtd_reset;
dc->vmsd = &vtd_vmstate;
@@ -6087,6 +6085,8 @@ static void vtd_class_init(ObjectClass *klass, void *data)
dc->user_creatable = true;
set_bit(DEVICE_CATEGORY_MISC, dc->categories);
dc->desc = "Intel IOMMU (VT-d) DMA Remapping device";
+ chdc->check_legacy_hdev = vtd_check_legacy_hdev;
+ chdc->check_iommufd_hdev = vtd_check_iommufd_hdev;
}
static const TypeInfo vtd_info = {
@@ -6094,6 +6094,10 @@ static const TypeInfo vtd_info = {
.parent = TYPE_X86_IOMMU_DEVICE,
.instance_size = sizeof(IntelIOMMUState),
.class_init = vtd_class_init,
+ .interfaces = (InterfaceInfo[]) {
+ { TYPE_IOMMU_CHECK_HDEV },
+ { }
+ }
};
Thanks
Zhenzhong
