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iommu/vt-d: Report page request faults for guest SVA

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A pasid might be bound to a page table from a VM guest via the iommu
ops.sva_bind_gpasid. In this case, when a DMA page fault is detected
on the physical IOMMU, we need to inject the page fault request into
the guest. After the guest completes handling the page fault, a page
response need to be sent back via the iommu ops.page_response().

This adds support to report a page request fault. Any external module
which is interested in handling this fault should regiester a notifier
with iommu_register_device_fault_handler().

Co-developed-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Co-developed-by: Liu Yi L <yi.l.liu@intel.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20200724014925.15523-11-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
This commit is contained in:
Lu Baolu 2020-07-24 09:49:23 +08:00 committed by Joerg Roedel
parent 19abcf70c2
commit eb8d93ea3c
1 changed files with 85 additions and 18 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

103
drivers/iommu/intel/svm.c
View file

@ -811,8 +811,63 @@ static void intel_svm_drain_prq(struct device *dev, int pasid)
}
}
static int prq_to_iommu_prot(struct page_req_dsc *req)
{
int prot = 0;
if (req->rd_req)
prot |= IOMMU_FAULT_PERM_READ;
if (req->wr_req)
prot |= IOMMU_FAULT_PERM_WRITE;
if (req->exe_req)
prot |= IOMMU_FAULT_PERM_EXEC;
if (req->pm_req)
prot |= IOMMU_FAULT_PERM_PRIV;
return prot;
}
static int
intel_svm_prq_report(struct device *dev, struct page_req_dsc *desc)
{
struct iommu_fault_event event;
if (!dev || !dev_is_pci(dev))
return -ENODEV;
/* Fill in event data for device specific processing */
memset(&event, 0, sizeof(struct iommu_fault_event));
event.fault.type = IOMMU_FAULT_PAGE_REQ;
event.fault.prm.addr = desc->addr;
event.fault.prm.pasid = desc->pasid;
event.fault.prm.grpid = desc->prg_index;
event.fault.prm.perm = prq_to_iommu_prot(desc);
if (desc->lpig)
event.fault.prm.flags |= IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE;
if (desc->pasid_present) {
event.fault.prm.flags |= IOMMU_FAULT_PAGE_REQUEST_PASID_VALID;
event.fault.prm.flags |= IOMMU_FAULT_PAGE_RESPONSE_NEEDS_PASID;
}
if (desc->priv_data_present) {
/*
* Set last page in group bit if private data is present,
* page response is required as it does for LPIG.
* iommu_report_device_fault() doesn't understand this vendor
* specific requirement thus we set last_page as a workaround.
*/
event.fault.prm.flags |= IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE;
event.fault.prm.flags |= IOMMU_FAULT_PAGE_REQUEST_PRIV_DATA;
memcpy(event.fault.prm.private_data, desc->priv_data,
sizeof(desc->priv_data));
}
return iommu_report_device_fault(dev, &event);
}
static irqreturn_t prq_event_thread(int irq, void *d)
{
struct intel_svm_dev *sdev = NULL;
struct intel_iommu *iommu = d;
struct intel_svm *svm = NULL;
int head, tail, handled = 0;
@ -824,7 +879,6 @@ static irqreturn_t prq_event_thread(int irq, void *d)
tail = dmar_readq(iommu->reg + DMAR_PQT_REG) & PRQ_RING_MASK;
head = dmar_readq(iommu->reg + DMAR_PQH_REG) & PRQ_RING_MASK;
while (head != tail) {
struct intel_svm_dev *sdev;
struct vm_area_struct *vma;
struct page_req_dsc *req;
struct qi_desc resp;
@ -860,6 +914,20 @@ static irqreturn_t prq_event_thread(int irq, void *d)
}
}
if (!sdev || sdev->sid != req->rid) {
struct intel_svm_dev *t;
sdev = NULL;
rcu_read_lock();
list_for_each_entry_rcu(t, &svm->devs, list) {
if (t->sid == req->rid) {
sdev = t;
break;
}
}
rcu_read_unlock();
}
result = QI_RESP_INVALID;
/* Since we're using init_mm.pgd directly, we should never take
* any faults on kernel addresses. */
@ -870,6 +938,17 @@ static irqreturn_t prq_event_thread(int irq, void *d)
if (!is_canonical_address(address))
goto bad_req;
/*
* If prq is to be handled outside iommu driver via receiver of
* the fault notifiers, we skip the page response here.
*/
if (svm->flags & SVM_FLAG_GUEST_MODE) {
if (sdev && !intel_svm_prq_report(sdev->dev, req))
goto prq_advance;
else
goto bad_req;
}
/* If the mm is already defunct, don't handle faults. */
if (!mmget_not_zero(svm->mm))
goto bad_req;
@ -888,24 +967,11 @@ static irqreturn_t prq_event_thread(int irq, void *d)
goto invalid;
result = QI_RESP_SUCCESS;
invalid:
invalid:
mmap_read_unlock(svm->mm);
mmput(svm->mm);
bad_req:
/* Accounting for major/minor faults? */
rcu_read_lock();
list_for_each_entry_rcu(sdev, &svm->devs, list) {
if (sdev->sid == req->rid)
break;
}
/* Other devices can go away, but the drivers are not permitted
* to unbind while any page faults might be in flight. So it's
* OK to drop the 'lock' here now we have it. */
rcu_read_unlock();
if (WARN_ON(&sdev->list == &svm->devs))
sdev = NULL;
bad_req:
WARN_ON(!sdev);
if (sdev && sdev->ops && sdev->ops->fault_cb) {
int rwxp = (req->rd_req << 3) | (req->wr_req << 2) |
(req->exe_req << 1) | (req->pm_req);
@ -916,7 +982,7 @@ static irqreturn_t prq_event_thread(int irq, void *d)
and these can be NULL. Do not use them below this point! */
sdev = NULL;
svm = NULL;
no_pasid:
no_pasid:
if (req->lpig || req->priv_data_present) {
/*
* Per VT-d spec. v3.0 ch7.7, system software must
@ -941,6 +1007,7 @@ static irqreturn_t prq_event_thread(int irq, void *d)
resp.qw3 = 0;
qi_submit_sync(iommu, &resp, 1, 0);
}
prq_advance:
head = (head + sizeof(*req)) & PRQ_RING_MASK;
}