On 21/03/13 07:45, Alex Williamson wrote:
On Tue, 2013-03-19 at 18:08 +1100, Alexey Kardashevskiy wrote:
VFIO implements platform independent stuff such as
a PCI driver, BAR access (via read/write on a file descriptor
or direct mapping when possible) and IRQ signaling.
The platform dependent part includes IOMMU initialization
and handling. This patch implements an IOMMU driver for VFIO
which does mapping/unmapping pages for the guest IO and
provides information about DMA window (required by a POWERPC
guest).
The counterpart in QEMU is required to support this functionality.
Changelog:
* documentation updated
* containter enable/disable ioctls added
* request_module(spapr_iommu) added
* various locks fixed
Cc: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Alexey Kardashevskiy <aik@xxxxxxxxx>
---
Looking pretty good. There's one problem with the detach_group,
otherwise just some trivial comments below. What's the status of the
tce code that this depends on? Thanks,
It is done, I am just waiting till other patches of the series will be
reviewed (by guys) and fixed (by me) and then I'll post everything again.
[skipped]
+static int tce_iommu_enable(struct tce_container *container)
+{
+ int ret = 0;
+ unsigned long locked, lock_limit, npages;
+ struct iommu_table *tbl = container->tbl;
+
+ if (!container->tbl)
+ return -ENXIO;
+
+ if (!current->mm)
+ return -ESRCH; /* process exited */
+
+ mutex_lock(&container->lock);
+ if (container->enabled) {
+ mutex_unlock(&container->lock);
+ return -EBUSY;
+ }
+
+ /*
+ * Accounting for locked pages.
+ *
+ * On sPAPR platform, IOMMU translation table contains
+ * an entry per 4K page. Every map/unmap request is sent
+ * by the guest via hypercall and supposed to be handled
+ * quickly, ecpesially in real mode (if such option is
s/ecpesially/especially/
I replaced the whole text by the one written by Ben and David.
[skipped]
+ }
+
+ return -ENOTTY;
+}
+
+static int tce_iommu_attach_group(void *iommu_data,
+ struct iommu_group *iommu_group)
+{
+ int ret;
+ struct tce_container *container = iommu_data;
+ struct iommu_table *tbl = iommu_group_get_iommudata(iommu_group);
+
+ BUG_ON(!tbl);
+ mutex_lock(&container->lock);
+ pr_debug("tce_vfio: Attaching group #%u to iommu %p\n",
+ iommu_group_id(iommu_group), iommu_group);
+ if (container->tbl) {
+ pr_warn("tce_vfio: Only one group per IOMMU container is allowed, existing id=%d, attaching id=%d\n",
+ iommu_group_id(container->tbl->it_group),
+ iommu_group_id(iommu_group));
+ mutex_unlock(&container->lock);
+ return -EBUSY;
+ }
+
+ ret = iommu_take_ownership(tbl);
+ if (!ret)
+ container->tbl = tbl;
+
+ mutex_unlock(&container->lock);
+
+ return ret;
+}
+
+static void tce_iommu_detach_group(void *iommu_data,
+ struct iommu_group *iommu_group)
+{
+ struct tce_container *container = iommu_data;
+ struct iommu_table *tbl = iommu_group_get_iommudata(iommu_group);
+
+ BUG_ON(!tbl);
+ mutex_lock(&container->lock);
+ if (tbl != container->tbl) {
+ pr_warn("tce_vfio: detaching group #%u, expected group is #%u\n",
+ iommu_group_id(iommu_group),
+ iommu_group_id(tbl->it_group));
+ } else if (container->enabled) {
+ pr_err("tce_vfio: detaching group #%u from enabled container\n",
+ iommu_group_id(tbl->it_group));
Hmm, something more than a pr_err needs to happen here. Wouldn't this
imply a disable and going back to an unprivileged container?
Ah. It does not return error code... Then something like that?
...
} else if (container->enabled) {
pr_warn("tce_vfio: detaching group #%u from enabled
container, forcing disable\n",
iommu_group_id(tbl->it_group));
tce_iommu_disable(container);
...
--
Alexey
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