> From: Lu Baolu <[email protected]> > Sent: Wednesday, April 15, 2020 4:30 PM > > On 2020/4/15 16:18, Tian, Kevin wrote: > >> From: Lu Baolu<[email protected]> > >> Sent: Wednesday, April 15, 2020 1:26 PM > >> > >> Extend qi_submit_sync() function to support multiple descriptors. > >> > >> Signed-off-by: Jacob Pan<[email protected]> > >> Signed-off-by: Lu Baolu<[email protected]> > >> --- > >> drivers/iommu/dmar.c | 39 +++++++++++++++++++++++-------------- > >> include/linux/intel-iommu.h | 1 + > >> 2 files changed, 25 insertions(+), 15 deletions(-) > >> > >> diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c > >> index bb42177e2369..61d049e91f84 100644 > >> --- a/drivers/iommu/dmar.c > >> +++ b/drivers/iommu/dmar.c > >> @@ -1157,12 +1157,11 @@ static inline void reclaim_free_desc(struct > >> q_inval *qi) > >> } > >> } > >> > >> -static int qi_check_fault(struct intel_iommu *iommu, int index) > >> +static int qi_check_fault(struct intel_iommu *iommu, int index, int > >> wait_index) > >> { > >> u32 fault; > >> int head, tail; > >> struct q_inval *qi = iommu->qi; > >> - int wait_index = (index + 1) % QI_LENGTH; > >> int shift = qi_shift(iommu); > >> > >> if (qi->desc_status[wait_index] == QI_ABORT) > >> @@ -1234,12 +1233,12 @@ static int qi_check_fault(struct intel_iommu > >> *iommu, int index) > >> int qi_submit_sync(struct intel_iommu *iommu, struct qi_desc *desc, > >> unsigned int count, unsigned long options) > >> { > >> - int rc; > >> struct q_inval *qi = iommu->qi; > >> - int offset, shift, length; > >> struct qi_desc wait_desc; > >> int wait_index, index; > >> unsigned long flags; > >> + int offset, shift; > >> + int rc, i; > >> > >> if (!qi) > >> return 0; > >> @@ -1248,32 +1247,41 @@ int qi_submit_sync(struct intel_iommu > *iommu, > >> struct qi_desc *desc, > >> rc = 0; > >> > >> raw_spin_lock_irqsave(&qi->q_lock, flags); > >> - while (qi->free_cnt < 3) { > >> + /* > >> + * Check if we have enough empty slots in the queue to submit, > >> + * the calculation is based on: > >> + * # of desc + 1 wait desc + 1 space between head and tail > >> + */ > >> + while (qi->free_cnt < count + 2) { > >> raw_spin_unlock_irqrestore(&qi->q_lock, flags); > >> cpu_relax(); > >> raw_spin_lock_irqsave(&qi->q_lock, flags); > >> } > >> > >> index = qi->free_head; > >> - wait_index = (index + 1) % QI_LENGTH; > >> + wait_index = (index + count) % QI_LENGTH; > >> shift = qi_shift(iommu); > >> - length = 1 << shift; > >> > >> - qi->desc_status[index] = qi->desc_status[wait_index] = QI_IN_USE; > >> + for (i = 0; i < count; i++) { > >> + offset = ((index + i) % QI_LENGTH) << shift; > >> + memcpy(qi->desc + offset, &desc[i], 1 << shift); > >> + qi->desc_status[(index + i) % QI_LENGTH] = QI_IN_USE; > >> + } > > what about doing one memcpy and leave the loop only for updating > > qi status? > > > > One memcpy might cross the table boundary. >
Thanks. you are right. _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
