-----Original Message-----
From: Joao Martins <joao.m.mart...@oracle.com>
Subject: Re: [PATCH v4 05/12] vfio/iommufd: Introduce auto domain
creation
On 16/07/2024 17:44, Joao Martins wrote:
On 16/07/2024 17:04, Eric Auger wrote:
Hi Joao,
On 7/12/24 13:46, Joao Martins wrote:
There's generally two modes of operation for IOMMUFD:
* The simple user API which intends to perform relatively simple things
with IOMMUs e.g. DPDK. It generally creates an IOAS and attach to VFIO
It generally creates? can you explicit what is "it"
'It' here refers to the process/API-user
I am confused by this automatic terminology again (not your fault). the
doc says:
"
*
Automatic domain - refers to an iommu domain created automatically
when attaching a device to an IOAS object. This is compatible to the
semantics of VFIO type1.
*
Manual domain - refers to an iommu domain designated by the user as
the target pagetable to be attached to by a device. Though currently
there are no uAPIs to directly create such domain, the datastructure
and algorithms are ready for handling that use case.
"
in 1) the device is attached to the ioas id (using the auto domain if I am
not wrong)
Here you attach to an hwpt id. Isn't it a manual domain?
Correct.
The 'auto domains' generally refers to the kernel-equivalent own
automatic
attaching to a new pagetable.
Here I call 'auto domains' in the userspace version too because we are
doing the
exact same but from userspace, using the manual API in IOMMUFD.
and mainly performs IOAS_MAP and UNMAP.
* The native IOMMUFD API where you have fine grained control of the
IOMMU domain and model it accordingly. This is where most new
feature
are being steered to.
For dirty tracking 2) is required, as it needs to ensure that
the stage-2/parent IOMMU domain will only attach devices
that support dirty tracking (so far it is all homogeneous in x86, likely
not the case for smmuv3). Such invariant on dirty tracking provides a
useful guarantee to VMMs that will refuse incompatible device
attachments for IOMMU domains.
Dirty tracking insurance is enforced via HWPT_ALLOC, which is
responsible for creating an IOMMU domain. This is contrast to the
'simple API' where the IOMMU domain is created by IOMMUFD
automatically
when it attaches to VFIO (usually referred as autodomains) but it has
the needed handling for mdevs.
To support dirty tracking with the advanced IOMMUFD API, it needs
similar logic, where IOMMU domains are created and devices attached
to
compatible domains. Essentially mimmicing kernel
iommufd_device_auto_get_domain(). With mdevs given there's no
IOMMU domain
it falls back to IOAS attach.
The auto domain logic allows different IOMMU domains to be created
when
DMA dirty tracking is not desired (and VF can provide it), and others
where
it is. Here is not used in this way here given how VFIODevice migration
Here is not used in this way here ?
I meant, 'Here it is not used in this way given (...)'
state is initialized after the device attachment. But such mixed mode of
IOMMU dirty tracking + device dirty tracking is an improvement that
can
be added on. Keep the 'all of nothing' of type1 approach that we have
been using so far between container vs device dirty tracking.
Signed-off-by: Joao Martins <joao.m.mart...@oracle.com>
---
include/hw/vfio/vfio-common.h | 9 ++++
include/sysemu/iommufd.h | 5 +++
backends/iommufd.c | 30 +++++++++++++
hw/vfio/iommufd.c | 82
+++++++++++++++++++++++++++++++++++
backends/trace-events | 1 +
5 files changed, 127 insertions(+)
diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-
common.h
index 7419466bca92..2dd468ce3c02 100644
--- a/include/hw/vfio/vfio-common.h
+++ b/include/hw/vfio/vfio-common.h
@@ -95,10 +95,17 @@ typedef struct VFIOHostDMAWindow {
typedef struct IOMMUFDBackend IOMMUFDBackend;
+typedef struct VFIOIOASHwpt {
+ uint32_t hwpt_id;
+ QLIST_HEAD(, VFIODevice) device_list;
+ QLIST_ENTRY(VFIOIOASHwpt) next;
+} VFIOIOASHwpt;
+
typedef struct VFIOIOMMUFDContainer {
VFIOContainerBase bcontainer;
IOMMUFDBackend *be;
uint32_t ioas_id;
+ QLIST_HEAD(, VFIOIOASHwpt) hwpt_list;
} VFIOIOMMUFDContainer;
OBJECT_DECLARE_SIMPLE_TYPE(VFIOIOMMUFDContainer,
VFIO_IOMMU_IOMMUFD);
@@ -135,6 +142,8 @@ typedef struct VFIODevice {
HostIOMMUDevice *hiod;
int devid;
IOMMUFDBackend *iommufd;
+ VFIOIOASHwpt *hwpt;
+ QLIST_ENTRY(VFIODevice) hwpt_next;
} VFIODevice;
struct VFIODeviceOps {
diff --git a/include/sysemu/iommufd.h b/include/sysemu/iommufd.h
index 57d502a1c79a..e917e7591d05 100644
--- a/include/sysemu/iommufd.h
+++ b/include/sysemu/iommufd.h
@@ -50,6 +50,11 @@ int
iommufd_backend_unmap_dma(IOMMUFDBackend *be, uint32_t ioas_id,
bool iommufd_backend_get_device_info(IOMMUFDBackend *be,
uint32_t devid,
uint32_t *type, void *data, uint32_t len,
uint64_t *caps, Error **errp);
+bool iommufd_backend_alloc_hwpt(IOMMUFDBackend *be, uint32_t
dev_id,
+ uint32_t pt_id, uint32_t flags,
+ uint32_t data_type, uint32_t data_len,
+ void *data_ptr, uint32_t *out_hwpt,
+ Error **errp);
#define TYPE_HOST_IOMMU_DEVICE_IOMMUFD
TYPE_HOST_IOMMU_DEVICE "-iommufd"
#endif
diff --git a/backends/iommufd.c b/backends/iommufd.c
index 2b3d51af26d2..5d3dfa917415 100644
--- a/backends/iommufd.c
+++ b/backends/iommufd.c
@@ -208,6 +208,36 @@ int
iommufd_backend_unmap_dma(IOMMUFDBackend *be, uint32_t ioas_id,
return ret;
}
+bool iommufd_backend_alloc_hwpt(IOMMUFDBackend *be, uint32_t
dev_id,
+ uint32_t pt_id, uint32_t flags,
+ uint32_t data_type, uint32_t data_len,
+ void *data_ptr, uint32_t *out_hwpt,
+ Error **errp)
+{
+ int ret, fd = be->fd;
+ struct iommu_hwpt_alloc alloc_hwpt = {
+ .size = sizeof(struct iommu_hwpt_alloc),
+ .flags = flags,
+ .dev_id = dev_id,
+ .pt_id = pt_id,
+ .data_type = data_type,
+ .data_len = data_len,
+ .data_uptr = (uint64_t)data_ptr,
+ };
+
+ ret = ioctl(fd, IOMMU_HWPT_ALLOC, &alloc_hwpt);
+ trace_iommufd_backend_alloc_hwpt(fd, dev_id, pt_id, flags,
data_type,
+ data_len, (uint64_t)data_ptr,
+ alloc_hwpt.out_hwpt_id, ret);
+ if (ret) {
+ error_setg_errno(errp, errno, "Failed to allocate hwpt");
+ return false;
+ }
+
+ *out_hwpt = alloc_hwpt.out_hwpt_id;
+ return true;
+}
+
bool iommufd_backend_get_device_info(IOMMUFDBackend *be,
uint32_t devid,
uint32_t *type, void *data, uint32_t len,
uint64_t *caps, Error **errp)
diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c
index 077dea8f1b64..325c7598d5a1 100644
--- a/hw/vfio/iommufd.c
+++ b/hw/vfio/iommufd.c
@@ -212,10 +212,86 @@ static bool
iommufd_cdev_detach_ioas_hwpt(VFIODevice *vbasedev, Error **errp)
return true;
}
+static bool iommufd_cdev_autodomains_get(VFIODevice *vbasedev,
+ VFIOIOMMUFDContainer *container,
+ Error **errp)
+{
+ IOMMUFDBackend *iommufd = vbasedev->iommufd;
+ uint32_t flags = 0;
+ VFIOIOASHwpt *hwpt;
+ uint32_t hwpt_id;
+ int ret;
+
+ /* Try to find a domain */
+ QLIST_FOREACH(hwpt, &container->hwpt_list, next) {
+ ret = iommufd_cdev_attach_ioas_hwpt(vbasedev, hwpt->hwpt_id,
errp);
+ if (ret) {
+ /* -EINVAL means the domain is incompatible with the device.
*/
+ if (ret == -EINVAL) {
+ /*
+ * It is an expected failure and it just means we will try
+ * another domain, or create one if no existing compatible
+ * domain is found. Hence why the error is discarded below.
+ */
+ error_free(*errp);
+ *errp = NULL;
+ continue;
+ }
+
+ return false;
+ } else {
+ vbasedev->hwpt = hwpt;
+ QLIST_INSERT_HEAD(&hwpt->device_list, vbasedev, hwpt_next);
+ return true;
+ }
+ }
+
+ if (!iommufd_backend_alloc_hwpt(iommufd, vbasedev->devid,
+ container->ioas_id, flags,
+ IOMMU_HWPT_DATA_NONE, 0, NULL,
+ &hwpt_id, errp)) {
+ return false;
+ }
+
+ hwpt = g_malloc0(sizeof(*hwpt));
+ hwpt->hwpt_id = hwpt_id;
+ QLIST_INIT(&hwpt->device_list);
+
+ ret = iommufd_cdev_attach_ioas_hwpt(vbasedev, hwpt->hwpt_id,
errp);
+ if (ret) {
+ iommufd_backend_free_id(container->be, hwpt->hwpt_id);
+ g_free(hwpt);
+ return false;
+ }
+
+ vbasedev->hwpt = hwpt;
+ QLIST_INSERT_HEAD(&hwpt->device_list, vbasedev, hwpt_next);
+ QLIST_INSERT_HEAD(&container->hwpt_list, hwpt, next);
+ return true;
+}
+
+static void iommufd_cdev_autodomains_put(VFIODevice *vbasedev,
+ VFIOIOMMUFDContainer *container)
+{
+ VFIOIOASHwpt *hwpt = vbasedev->hwpt;
+
+ QLIST_REMOVE(vbasedev, hwpt_next);
don't you want to reset vbasedev->hwpt = NULL too?
Yeap, Thanks for catching that
+ if (QLIST_EMPTY(&hwpt->device_list)) {
+ QLIST_REMOVE(hwpt, next);
+ iommufd_backend_free_id(container->be, hwpt->hwpt_id);
+ g_free(hwpt);
+ }
+}
+
static bool iommufd_cdev_attach_container(VFIODevice *vbasedev,
VFIOIOMMUFDContainer *container,
Error **errp)
{
+ /* mdevs aren't physical devices and will fail with auto domains */
+ if (!vbasedev->mdev) {
+ return iommufd_cdev_autodomains_get(vbasedev, container,
errp);
+ }
+
return !iommufd_cdev_attach_ioas_hwpt(vbasedev, container-
ioas_id, errp);
}
@@ -224,6 +300,11 @@ static void
iommufd_cdev_detach_container(VFIODevice *vbasedev,
{
Error *err = NULL;
+ if (vbasedev->hwpt) {
+ iommufd_cdev_autodomains_put(vbasedev, container);
+ return;
Where do we detach the device from the hwpt?
In iommufd_backend_free_id() for auto domains
to clarify here I meant *userspace* auto domains
*kernel* auto domains (mdev) goes via DETACH_IOMMUFD_PT
