| Message ID | 20200430143424.2787566-6-jean-philippe@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | iommu: Shared Virtual Addressing for SMMUv3 | expand |
On 2020/4/30 22:34, Jean-Philippe Brucker wrote: > When a recoverable page fault is handled by the fault workqueue, find the > associated mm and call handle_mm_fault. > > Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org> > --- > v5->v6: select CONFIG_IOMMU_SVA > --- > drivers/iommu/Kconfig | 1 + > drivers/iommu/io-pgfault.c | 79 +++++++++++++++++++++++++++++++++++++- > 2 files changed, 78 insertions(+), 2 deletions(-) > > diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig > index 4f33e489f0726..1e64ee6592e16 100644 > --- a/drivers/iommu/Kconfig > +++ b/drivers/iommu/Kconfig > @@ -109,6 +109,7 @@ config IOMMU_SVA > > config IOMMU_PAGE_FAULT > bool > + select IOMMU_SVA It would be better to move this to the previous patch. > > config FSL_PAMU > bool "Freescale IOMMU support" > diff --git a/drivers/iommu/io-pgfault.c b/drivers/iommu/io-pgfault.c > index 38732e97faac1..09a71dc4de20a 100644 > --- a/drivers/iommu/io-pgfault.c > +++ b/drivers/iommu/io-pgfault.c > @@ -7,9 +7,12 @@ > > #include <linux/iommu.h> > #include <linux/list.h> > +#include <linux/sched/mm.h> > #include <linux/slab.h> > #include <linux/workqueue.h> > > +#include "iommu-sva.h" > + > /** > * struct iopf_queue - IO Page Fault queue > * @wq: the fault workqueue > @@ -68,8 +71,57 @@ static int iopf_complete_group(struct device *dev, struct iopf_fault *iopf, > static enum iommu_page_response_code > iopf_handle_single(struct iopf_fault *iopf) > { > - /* TODO */ > - return -ENODEV; > + vm_fault_t ret; > + struct mm_struct *mm; > + struct vm_area_struct *vma; > + unsigned int access_flags = 0; > + unsigned int fault_flags = FAULT_FLAG_REMOTE; > + struct iommu_fault_page_request *prm = &iopf->fault.prm; > + enum iommu_page_response_code status = IOMMU_PAGE_RESP_INVALID; > + > + if (!(prm->flags & IOMMU_FAULT_PAGE_REQUEST_PASID_VALID)) > + return status; > + > + mm = iommu_sva_find(prm->pasid); > + if (IS_ERR_OR_NULL(mm)) > + return status; > + > + down_read(&mm->mmap_sem); > + > + vma = find_extend_vma(mm, prm->addr); > + if (!vma) > + /* Unmapped area */ > + goto out_put_mm; > + > + if (prm->perm & IOMMU_FAULT_PERM_READ) > + access_flags |= VM_READ; > + > + if (prm->perm & IOMMU_FAULT_PERM_WRITE) { > + access_flags |= VM_WRITE; > + fault_flags |= FAULT_FLAG_WRITE; > + } > + > + if (prm->perm & IOMMU_FAULT_PERM_EXEC) { > + access_flags |= VM_EXEC; > + fault_flags |= FAULT_FLAG_INSTRUCTION; > + } > + > + if (!(prm->perm & IOMMU_FAULT_PERM_PRIV)) > + fault_flags |= FAULT_FLAG_USER; > + > + if (access_flags & ~vma->vm_flags) > + /* Access fault */ > + goto out_put_mm; > + > + ret = handle_mm_fault(vma, prm->addr, fault_flags); > + status = ret & VM_FAULT_ERROR ? IOMMU_PAGE_RESP_INVALID : > + IOMMU_PAGE_RESP_SUCCESS; > + > +out_put_mm: > + up_read(&mm->mmap_sem); > + mmput(mm); > + > + return status; > } > > static void iopf_handle_group(struct work_struct *work) > @@ -104,6 +156,29 @@ static void iopf_handle_group(struct work_struct *work) > * > * Add a fault to the device workqueue, to be handled by mm. > * > + * This module doesn't handle PCI PASID Stop Marker; IOMMU drivers must discard > + * them before reporting faults. A PASID Stop Marker (LRW = 0b100) doesn't > + * expect a response. It may be generated when disabling a PASID (issuing a > + * PASID stop request) by some PCI devices. > + * > + * The PASID stop request is issued by the device driver before unbind(). Once > + * it completes, no page request is generated for this PASID anymore and > + * outstanding ones have been pushed to the IOMMU (as per PCIe 4.0r1.0 - 6.20.1 > + * and 10.4.1.2 - Managing PASID TLP Prefix Usage). Some PCI devices will wait > + * for all outstanding page requests to come back with a response before > + * completing the PASID stop request. Others do not wait for page responses, and > + * instead issue this Stop Marker that tells us when the PASID can be > + * reallocated. > + * > + * It is safe to discard the Stop Marker because it is an optimization. > + * a. Page requests, which are posted requests, have been flushed to the IOMMU > + * when the stop request completes. > + * b. We flush all fault queues on unbind() before freeing the PASID. > + * > + * So even though the Stop Marker might be issued by the device *after* the stop > + * request completes, outstanding faults will have been dealt with by the time > + * we free the PASID. > + * > * Return: 0 on success and <0 on error. > */ > int iommu_queue_iopf(struct iommu_fault *fault, void *cookie) > The same for the comments. Best regards, baolu
On Sun, May 03, 2020 at 01:54:36PM +0800, Lu Baolu wrote: > On 2020/4/30 22:34, Jean-Philippe Brucker wrote: > > When a recoverable page fault is handled by the fault workqueue, find the > > associated mm and call handle_mm_fault. > > > > Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org> > > --- > > v5->v6: select CONFIG_IOMMU_SVA > > --- > > drivers/iommu/Kconfig | 1 + > > drivers/iommu/io-pgfault.c | 79 +++++++++++++++++++++++++++++++++++++- > > 2 files changed, 78 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig > > index 4f33e489f0726..1e64ee6592e16 100644 > > --- a/drivers/iommu/Kconfig > > +++ b/drivers/iommu/Kconfig > > @@ -109,6 +109,7 @@ config IOMMU_SVA > > config IOMMU_PAGE_FAULT > > bool > > + select IOMMU_SVA > > It would be better to move this to the previous patch. > [...] > > @@ -104,6 +156,29 @@ static void iopf_handle_group(struct work_struct *work) > > * > > * Add a fault to the device workqueue, to be handled by mm. > > * > > + * This module doesn't handle PCI PASID Stop Marker; IOMMU drivers must discard > > + * them before reporting faults. A PASID Stop Marker (LRW = 0b100) doesn't > > + * expect a response. It may be generated when disabling a PASID (issuing a > > + * PASID stop request) by some PCI devices. > > + * > > + * The PASID stop request is issued by the device driver before unbind(). Once > > + * it completes, no page request is generated for this PASID anymore and > > + * outstanding ones have been pushed to the IOMMU (as per PCIe 4.0r1.0 - 6.20.1 > > + * and 10.4.1.2 - Managing PASID TLP Prefix Usage). Some PCI devices will wait > > + * for all outstanding page requests to come back with a response before > > + * completing the PASID stop request. Others do not wait for page responses, and > > + * instead issue this Stop Marker that tells us when the PASID can be > > + * reallocated. > > + * > > + * It is safe to discard the Stop Marker because it is an optimization. > > + * a. Page requests, which are posted requests, have been flushed to the IOMMU > > + * when the stop request completes. > > + * b. We flush all fault queues on unbind() before freeing the PASID. > > + * > > + * So even though the Stop Marker might be issued by the device *after* the stop > > + * request completes, outstanding faults will have been dealt with by the time > > + * we free the PASID. > > + * > > * Return: 0 on success and <0 on error. > > */ > > int iommu_queue_iopf(struct iommu_fault *fault, void *cookie) > > > > The same for the comments. I think I'll squash both patches, probably doesn't make it harder to review. Thanks, Jean
diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig index 4f33e489f0726..1e64ee6592e16 100644 --- a/drivers/iommu/Kconfig +++ b/drivers/iommu/Kconfig @@ -109,6 +109,7 @@ config IOMMU_SVA config IOMMU_PAGE_FAULT bool + select IOMMU_SVA config FSL_PAMU bool "Freescale IOMMU support" diff --git a/drivers/iommu/io-pgfault.c b/drivers/iommu/io-pgfault.c index 38732e97faac1..09a71dc4de20a 100644 --- a/drivers/iommu/io-pgfault.c +++ b/drivers/iommu/io-pgfault.c @@ -7,9 +7,12 @@ #include <linux/iommu.h> #include <linux/list.h> +#include <linux/sched/mm.h> #include <linux/slab.h> #include <linux/workqueue.h> +#include "iommu-sva.h" + /** * struct iopf_queue - IO Page Fault queue * @wq: the fault workqueue @@ -68,8 +71,57 @@ static int iopf_complete_group(struct device *dev, struct iopf_fault *iopf, static enum iommu_page_response_code iopf_handle_single(struct iopf_fault *iopf) { - /* TODO */ - return -ENODEV; + vm_fault_t ret; + struct mm_struct *mm; + struct vm_area_struct *vma; + unsigned int access_flags = 0; + unsigned int fault_flags = FAULT_FLAG_REMOTE; + struct iommu_fault_page_request *prm = &iopf->fault.prm; + enum iommu_page_response_code status = IOMMU_PAGE_RESP_INVALID; + + if (!(prm->flags & IOMMU_FAULT_PAGE_REQUEST_PASID_VALID)) + return status; + + mm = iommu_sva_find(prm->pasid); + if (IS_ERR_OR_NULL(mm)) + return status; + + down_read(&mm->mmap_sem); + + vma = find_extend_vma(mm, prm->addr); + if (!vma) + /* Unmapped area */ + goto out_put_mm; + + if (prm->perm & IOMMU_FAULT_PERM_READ) + access_flags |= VM_READ; + + if (prm->perm & IOMMU_FAULT_PERM_WRITE) { + access_flags |= VM_WRITE; + fault_flags |= FAULT_FLAG_WRITE; + } + + if (prm->perm & IOMMU_FAULT_PERM_EXEC) { + access_flags |= VM_EXEC; + fault_flags |= FAULT_FLAG_INSTRUCTION; + } + + if (!(prm->perm & IOMMU_FAULT_PERM_PRIV)) + fault_flags |= FAULT_FLAG_USER; + + if (access_flags & ~vma->vm_flags) + /* Access fault */ + goto out_put_mm; + + ret = handle_mm_fault(vma, prm->addr, fault_flags); + status = ret & VM_FAULT_ERROR ? IOMMU_PAGE_RESP_INVALID : + IOMMU_PAGE_RESP_SUCCESS; + +out_put_mm: + up_read(&mm->mmap_sem); + mmput(mm); + + return status; } static void iopf_handle_group(struct work_struct *work) @@ -104,6 +156,29 @@ static void iopf_handle_group(struct work_struct *work) * * Add a fault to the device workqueue, to be handled by mm. * + * This module doesn't handle PCI PASID Stop Marker; IOMMU drivers must discard + * them before reporting faults. A PASID Stop Marker (LRW = 0b100) doesn't + * expect a response. It may be generated when disabling a PASID (issuing a + * PASID stop request) by some PCI devices. + * + * The PASID stop request is issued by the device driver before unbind(). Once + * it completes, no page request is generated for this PASID anymore and + * outstanding ones have been pushed to the IOMMU (as per PCIe 4.0r1.0 - 6.20.1 + * and 10.4.1.2 - Managing PASID TLP Prefix Usage). Some PCI devices will wait + * for all outstanding page requests to come back with a response before + * completing the PASID stop request. Others do not wait for page responses, and + * instead issue this Stop Marker that tells us when the PASID can be + * reallocated. + * + * It is safe to discard the Stop Marker because it is an optimization. + * a. Page requests, which are posted requests, have been flushed to the IOMMU + * when the stop request completes. + * b. We flush all fault queues on unbind() before freeing the PASID. + * + * So even though the Stop Marker might be issued by the device *after* the stop + * request completes, outstanding faults will have been dealt with by the time + * we free the PASID. + * * Return: 0 on success and <0 on error. */ int iommu_queue_iopf(struct iommu_fault *fault, void *cookie)
When a recoverable page fault is handled by the fault workqueue, find the associated mm and call handle_mm_fault. Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org> --- v5->v6: select CONFIG_IOMMU_SVA --- drivers/iommu/Kconfig | 1 + drivers/iommu/io-pgfault.c | 79 +++++++++++++++++++++++++++++++++++++- 2 files changed, 78 insertions(+), 2 deletions(-)