[PATCH 14/14] iommu/vt-d: Introduce batched cache invalidation

Lu Baolu
2024-09-02T02:31:46Z

From: Tina Zhang <tina.zhang@intel.com>

Converts IOTLB and Dev-IOTLB invalidation to a batched model. Cache tag
invalidation requests for a domain are now accumulated in a qi_batch
structure before being flushed in bulk. It replaces the previous per-
request qi_flush approach with a more efficient batching mechanism.

Co-developed-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Tina Zhang <tina.zhang@intel.com>
Link: https://lore.kernel.org/r/20240815065221.50328-5-tina.zhang@intel.com
---
drivers/iommu/intel/cache.c | 122 +++++++++++++++++++++++++++++++-----
1 file changed, 107 insertions(+), 15 deletions(-)

diff --git a/drivers/iommu/intel/cache.c b/drivers/iommu/intel/cache.c
index 2e997d782beb..e5b89f728ad3 100644
--- a/drivers/iommu/intel/cache.c
+++ b/drivers/iommu/intel/cache.c
@@ -262,6 +262,79 @@ static unsigned long calculate_psi_aligned_address(unsigned long start,
return ALIGN_DOWN(start, VTD_PAGE_SIZE << mask);
}

+static void qi_batch_flush_descs(struct intel_iommu *iommu, struct qi_batch *batch)
+{
+ if (!iommu || !batch->index)
+ return;
+
+ qi_submit_sync(iommu, batch->descs, batch->index, 0);
+
+ /* Reset the index value and clean the whole batch buffer. */
+ memset(batch, 0, sizeof(*batch));
+}
+
+static void qi_batch_increment_index(struct intel_iommu *iommu, struct qi_batch *batch)
+{
+ if (++batch->index == QI_MAX_BATCHED_DESC_COUNT)
+ qi_batch_flush_descs(iommu, batch);
+}
+
+static void qi_batch_add_iotlb(struct intel_iommu *iommu, u16 did, u64 addr,
+ unsigned int size_order, u64 type,
+ struct qi_batch *batch)
+{
+ qi_desc_iotlb(iommu, did, addr, size_order, type, &batch->descs[batch->index]);
+ qi_batch_increment_index(iommu, batch);
+}
+
+static void qi_batch_add_dev_iotlb(struct intel_iommu *iommu, u16 sid, u16 pfsid,
+ u16 qdep, u64 addr, unsigned int mask,
+ struct qi_batch *batch)
+{
+ /*
+ * According to VT-d spec, software is recommended to not submit any Device-TLB
+ * invalidation requests while address remapping hardware is disabled.
+ */
+ if (!(iommu->gcmd & DMA_GCMD_TE))
+ return;
+
+ qi_desc_dev_iotlb(sid, pfsid, qdep, addr, mask, &batch->descs[batch->index]);
+ qi_batch_increment_index(iommu, batch);
+}
+
+static void qi_batch_add_piotlb(struct intel_iommu *iommu, u16 did, u32 pasid,
+ u64 addr, unsigned long npages, bool ih,
+ struct qi_batch *batch)
+{
+ /*
+ * npages == -1 means a PASID-selective invalidation, otherwise,
+ * a positive value for Page-selective-within-PASID invalidation.
+ * 0 is not a valid input.
+ */
+ if (!npages)
+ return;
+
+ qi_desc_piotlb(did, pasid, addr, npages, ih, &batch->descs[batch->index]);
+ qi_batch_increment_index(iommu, batch);
+}
+
+static void qi_batch_add_pasid_dev_iotlb(struct intel_iommu *iommu, u16 sid, u16 pfsid,
+ u32 pasid, u16 qdep, u64 addr,
+ unsigned int size_order, struct qi_batch *batch)
+{
+ /*
+ * According to VT-d spec, software is recommended to not submit any
+ * Device-TLB invalidation requests while address remapping hardware
+ * is disabled.
+ */
+ if (!(iommu->gcmd & DMA_GCMD_TE))
+ return;
+
+ qi_desc_dev_iotlb_pasid(sid, pfsid, pasid, qdep, addr, size_order,
+ &batch->descs[batch->index]);
+ qi_batch_increment_index(iommu, batch);
+}
+
static void cache_tag_flush_iotlb(struct dmar_domain *domain, struct cache_tag *tag,
unsigned long addr, unsigned long pages,
unsigned long mask, int ih)
@@ -270,7 +343,8 @@ static void cache_tag_flush_iotlb(struct dmar_domain *domain, struct cache_tag *
u64 type = DMA_TLB_PSI_FLUSH;

if (domain->use_first_level) {
- qi_flush_piotlb(iommu, tag->domain_id, tag->pasid, addr, pages, ih);
+ qi_batch_add_piotlb(iommu, tag->domain_id, tag->pasid, addr,
+ pages, ih, domain->qi_batch);
return;
}

@@ -287,7 +361,8 @@ static void cache_tag_flush_iotlb(struct dmar_domain *domain, struct cache_tag *
}

if (ecap_qis(iommu->ecap))
- qi_flush_iotlb(iommu, tag->domain_id, addr | ih, mask, type);
+ qi_batch_add_iotlb(iommu, tag->domain_id, addr | ih, mask, type,
+ domain->qi_batch);
else
__iommu_flush_iotlb(iommu, tag->domain_id, addr | ih, mask, type);
}
@@ -303,19 +378,20 @@ static void cache_tag_flush_devtlb_psi(struct dmar_domain *domain, struct cache_
sid = PCI_DEVID(info->bus, info->devfn);

if (tag->pasid == IOMMU_NO_PASID) {
- qi_flush_dev_iotlb(iommu, sid, info->pfsid, info->ats_qdep,
- addr, mask);
+ qi_batch_add_dev_iotlb(iommu, sid, info->pfsid, info->ats_qdep,
+ addr, mask, domain->qi_batch);
if (info->dtlb_extra_inval)
- qi_flush_dev_iotlb(iommu, sid, info->pfsid,
- info->ats_qdep, addr, mask);
+ qi_batch_add_dev_iotlb(iommu, sid, info->pfsid, info->ats_qdep,
+ addr, mask, domain->qi_batch);
return;
}

- qi_flush_dev_iotlb_pasid(iommu, sid, info->pfsid, tag->pasid,
- info->ats_qdep, addr, mask);
+ qi_batch_add_pasid_dev_iotlb(iommu, sid, info->pfsid, tag->pasid,
+ info->ats_qdep, addr, mask, domain->qi_batch);
if (info->dtlb_extra_inval)
- qi_flush_dev_iotlb_pasid(iommu, sid, info->pfsid, tag->pasid,
- info->ats_qdep, addr, mask);
+ qi_batch_add_pasid_dev_iotlb(iommu, sid, info->pfsid, tag->pasid,
+ info->ats_qdep, addr, mask,
+ domain->qi_batch);
}

static void cache_tag_flush_devtlb_all(struct dmar_domain *domain, struct cache_tag *tag)
@@ -327,11 +403,11 @@ static void cache_tag_flush_devtlb_all(struct dmar_domain *domain, struct cache_
info = dev_iommu_priv_get(tag->dev);
sid = PCI_DEVID(info->bus, info->devfn);

- qi_flush_dev_iotlb(iommu, sid, info->pfsid, info->ats_qdep, 0,
- MAX_AGAW_PFN_WIDTH);
+ qi_batch_add_dev_iotlb(iommu, sid, info->pfsid, info->ats_qdep, 0,
+ MAX_AGAW_PFN_WIDTH, domain->qi_batch);
if (info->dtlb_extra_inval)
- qi_flush_dev_iotlb(iommu, sid, info->pfsid, info->ats_qdep, 0,
- MAX_AGAW_PFN_WIDTH);
+ qi_batch_add_dev_iotlb(iommu, sid, info->pfsid, info->ats_qdep, 0,
+ MAX_AGAW_PFN_WIDTH, domain->qi_batch);
}

/*
@@ -341,6 +417,7 @@ static void cache_tag_flush_devtlb_all(struct dmar_domain *domain, struct cache_
void cache_tag_flush_range(struct dmar_domain *domain, unsigned long start,
unsigned long end, int ih)
{
+ struct intel_iommu *iommu = NULL;
unsigned long pages, mask, addr;
struct cache_tag *tag;
unsigned long flags;
@@ -349,6 +426,10 @@ void cache_tag_flush_range(struct dmar_domain *domain, unsigned long start,

spin_lock_irqsave(&domain->cache_lock, flags);
list_for_each_entry(tag, &domain->cache_tags, node) {
+ if (iommu && iommu != tag->iommu)
+ qi_batch_flush_descs(iommu, domain->qi_batch);
+ iommu = tag->iommu;
+
switch (tag->type) {
case CACHE_TAG_IOTLB:
case CACHE_TAG_NESTING_IOTLB:
@@ -372,6 +453,7 @@ void cache_tag_flush_range(struct dmar_domain *domain, unsigned long start,

trace_cache_tag_flush_range(tag, start, end, addr, pages, mask);
}
+ qi_batch_flush_descs(iommu, domain->qi_batch);
spin_unlock_irqrestore(&domain->cache_lock, flags);
}

@@ -381,11 +463,16 @@ void cache_tag_flush_range(struct dmar_domain *domain, unsigned long start,
*/
void cache_tag_flush_all(struct dmar_domain *domain)
{
+ struct intel_iommu *iommu = NULL;
struct cache_tag *tag;
unsigned long flags;

spin_lock_irqsave(&domain->cache_lock, flags);
list_for_each_entry(tag, &domain->cache_tags, node) {
+ if (iommu && iommu != tag->iommu)
+ qi_batch_flush_descs(iommu, domain->qi_batch);
+ iommu = tag->iommu;
+
switch (tag->type) {
case CACHE_TAG_IOTLB:
case CACHE_TAG_NESTING_IOTLB:
@@ -399,6 +486,7 @@ void cache_tag_flush_all(struct dmar_domain *domain)

trace_cache_tag_flush_all(tag);
}
+ qi_batch_flush_descs(iommu, domain->qi_batch);
spin_unlock_irqrestore(&domain->cache_lock, flags);
}

@@ -416,6 +504,7 @@ void cache_tag_flush_all(struct dmar_domain *domain)
void cache_tag_flush_range_np(struct dmar_domain *domain, unsigned long start,
unsigned long end)
{
+ struct intel_iommu *iommu = NULL;
unsigned long pages, mask, addr;
struct cache_tag *tag;
unsigned long flags;
@@ -424,7 +513,9 @@ void cache_tag_flush_range_np(struct dmar_domain *domain, unsigned long start,

spin_lock_irqsave(&domain->cache_lock, flags);
list_for_each_entry(tag, &domain->cache_tags, node) {
- struct intel_iommu *iommu = tag->iommu;
+ if (iommu && iommu != tag->iommu)
+ qi_batch_flush_descs(iommu, domain->qi_batch);
+ iommu = tag->iommu;

if (!cap_caching_mode(iommu->cap) || domain->use_first_level) {
iommu_flush_write_buffer(iommu);
@@ -437,5 +528,6 @@ void cache_tag_flush_range_np(struct dmar_domain *domain, unsigned long start,

trace_cache_tag_flush_range_np(tag, start, end, addr, pages, mask);
}
+ qi_batch_flush_descs(iommu, domain->qi_batch);
spin_unlock_irqrestore(&domain->cache_lock, flags);
}
--
2.34.1