[PATCH 8/8] iommu/vt-d: Make use of iova deferred flushing

From: Joerg Roedel
Date: Fri Aug 11 2017 - 10:42:01 EST


From: Joerg Roedel <jroedel@xxxxxxx>

Remove the deferred flushing implementation in the Intel
VT-d driver and use the one from the common iova code
instead.

Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
---
drivers/iommu/intel-iommu.c | 197 +++++++++-----------------------------------
1 file changed, 38 insertions(+), 159 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 687f18f..d5e8b86 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -458,31 +458,6 @@ static LIST_HEAD(dmar_rmrr_units);
#define for_each_rmrr_units(rmrr) \
list_for_each_entry(rmrr, &dmar_rmrr_units, list)

-static void flush_unmaps_timeout(unsigned long data);
-
-struct deferred_flush_entry {
- unsigned long iova_pfn;
- unsigned long nrpages;
- struct dmar_domain *domain;
- struct page *freelist;
-};
-
-#define HIGH_WATER_MARK 250
-struct deferred_flush_table {
- int next;
- struct deferred_flush_entry entries[HIGH_WATER_MARK];
-};
-
-struct deferred_flush_data {
- spinlock_t lock;
- int timer_on;
- struct timer_list timer;
- long size;
- struct deferred_flush_table *tables;
-};
-
-static DEFINE_PER_CPU(struct deferred_flush_data, deferred_flush);
-
/* bitmap for indexing intel_iommus */
static int g_num_of_iommus;

@@ -1309,6 +1284,13 @@ static void dma_free_pagelist(struct page *freelist)
}
}

+static void iova_entry_free(unsigned long data)
+{
+ struct page *freelist = (struct page *)data;
+
+ dma_free_pagelist(freelist);
+}
+
/* iommu handling */
static int iommu_alloc_root_entry(struct intel_iommu *iommu)
{
@@ -1622,6 +1604,25 @@ static void iommu_flush_iotlb_psi(struct intel_iommu *iommu,
addr, mask);
}

+static void iommu_flush_iova(struct iova_domain *iovad)
+{
+ struct dmar_domain *domain;
+ int idx;
+
+ domain = container_of(iovad, struct dmar_domain, iovad);
+
+ for_each_domain_iommu(idx, domain) {
+ struct intel_iommu *iommu = g_iommus[idx];
+ u16 did = domain->iommu_did[iommu->seq_id];
+
+ iommu->flush.flush_iotlb(iommu, did, 0, 0, DMA_TLB_DSI_FLUSH);
+
+ if (!cap_caching_mode(iommu->cap))
+ iommu_flush_dev_iotlb(get_iommu_domain(iommu, did),
+ 0, MAX_AGAW_PFN_WIDTH);
+ }
+}
+
static void iommu_disable_protect_mem_regions(struct intel_iommu *iommu)
{
u32 pmen;
@@ -1932,9 +1933,16 @@ static int domain_init(struct dmar_domain *domain, struct intel_iommu *iommu,
{
int adjust_width, agaw;
unsigned long sagaw;
+ int err;

init_iova_domain(&domain->iovad, VTD_PAGE_SIZE, IOVA_START_PFN,
DMA_32BIT_PFN);
+
+ err = init_iova_flush_queue(&domain->iovad,
+ iommu_flush_iova, iova_entry_free);
+ if (err)
+ return err;
+
domain_reserve_special_ranges(domain);

/* calculate AGAW */
@@ -1986,14 +1994,6 @@ static void domain_exit(struct dmar_domain *domain)
if (!domain)
return;

- /* Flush any lazy unmaps that may reference this domain */
- if (!intel_iommu_strict) {
- int cpu;
-
- for_each_possible_cpu(cpu)
- flush_unmaps_timeout(cpu);
- }
-
/* Remove associated devices and clear attached or cached domains */
rcu_read_lock();
domain_remove_dev_info(domain);
@@ -3206,7 +3206,7 @@ static int __init init_dmars(void)
bool copied_tables = false;
struct device *dev;
struct intel_iommu *iommu;
- int i, ret, cpu;
+ int i, ret;

/*
* for each drhd
@@ -3239,22 +3239,6 @@ static int __init init_dmars(void)
goto error;
}

- for_each_possible_cpu(cpu) {
- struct deferred_flush_data *dfd = per_cpu_ptr(&deferred_flush,
- cpu);
-
- dfd->tables = kzalloc(g_num_of_iommus *
- sizeof(struct deferred_flush_table),
- GFP_KERNEL);
- if (!dfd->tables) {
- ret = -ENOMEM;
- goto free_g_iommus;
- }
-
- spin_lock_init(&dfd->lock);
- setup_timer(&dfd->timer, flush_unmaps_timeout, cpu);
- }
-
for_each_active_iommu(iommu, drhd) {
g_iommus[iommu->seq_id] = iommu;

@@ -3437,10 +3421,9 @@ static int __init init_dmars(void)
disable_dmar_iommu(iommu);
free_dmar_iommu(iommu);
}
-free_g_iommus:
- for_each_possible_cpu(cpu)
- kfree(per_cpu_ptr(&deferred_flush, cpu)->tables);
+
kfree(g_iommus);
+
error:
return ret;
}
@@ -3645,110 +3628,6 @@ static dma_addr_t intel_map_page(struct device *dev, struct page *page,
dir, *dev->dma_mask);
}

-static void flush_unmaps(struct deferred_flush_data *flush_data)
-{
- int i, j;
-
- flush_data->timer_on = 0;
-
- /* just flush them all */
- for (i = 0; i < g_num_of_iommus; i++) {
- struct intel_iommu *iommu = g_iommus[i];
- struct deferred_flush_table *flush_table =
- &flush_data->tables[i];
- if (!iommu)
- continue;
-
- if (!flush_table->next)
- continue;
-
- /* In caching mode, global flushes turn emulation expensive */
- if (!cap_caching_mode(iommu->cap))
- iommu->flush.flush_iotlb(iommu, 0, 0, 0,
- DMA_TLB_GLOBAL_FLUSH);
- for (j = 0; j < flush_table->next; j++) {
- unsigned long mask;
- struct deferred_flush_entry *entry =
- &flush_table->entries[j];
- unsigned long iova_pfn = entry->iova_pfn;
- unsigned long nrpages = entry->nrpages;
- struct dmar_domain *domain = entry->domain;
- struct page *freelist = entry->freelist;
-
- /* On real hardware multiple invalidations are expensive */
- if (cap_caching_mode(iommu->cap))
- iommu_flush_iotlb_psi(iommu, domain,
- mm_to_dma_pfn(iova_pfn),
- nrpages, !freelist, 0);
- else {
- mask = ilog2(nrpages);
- iommu_flush_dev_iotlb(domain,
- (uint64_t)iova_pfn << PAGE_SHIFT, mask);
- }
- free_iova_fast(&domain->iovad, iova_pfn, nrpages);
- if (freelist)
- dma_free_pagelist(freelist);
- }
- flush_table->next = 0;
- }
-
- flush_data->size = 0;
-}
-
-static void flush_unmaps_timeout(unsigned long cpuid)
-{
- struct deferred_flush_data *flush_data = per_cpu_ptr(&deferred_flush, cpuid);
- unsigned long flags;
-
- spin_lock_irqsave(&flush_data->lock, flags);
- flush_unmaps(flush_data);
- spin_unlock_irqrestore(&flush_data->lock, flags);
-}
-
-static void add_unmap(struct dmar_domain *dom, unsigned long iova_pfn,
- unsigned long nrpages, struct page *freelist)
-{
- unsigned long flags;
- int entry_id, iommu_id;
- struct intel_iommu *iommu;
- struct deferred_flush_entry *entry;
- struct deferred_flush_data *flush_data;
-
- flush_data = raw_cpu_ptr(&deferred_flush);
-
- /* Flush all CPUs' entries to avoid deferring too much. If
- * this becomes a bottleneck, can just flush us, and rely on
- * flush timer for the rest.
- */
- if (flush_data->size == HIGH_WATER_MARK) {
- int cpu;
-
- for_each_online_cpu(cpu)
- flush_unmaps_timeout(cpu);
- }
-
- spin_lock_irqsave(&flush_data->lock, flags);
-
- iommu = domain_get_iommu(dom);
- iommu_id = iommu->seq_id;
-
- entry_id = flush_data->tables[iommu_id].next;
- ++(flush_data->tables[iommu_id].next);
-
- entry = &flush_data->tables[iommu_id].entries[entry_id];
- entry->domain = dom;
- entry->iova_pfn = iova_pfn;
- entry->nrpages = nrpages;
- entry->freelist = freelist;
-
- if (!flush_data->timer_on) {
- mod_timer(&flush_data->timer, jiffies + msecs_to_jiffies(10));
- flush_data->timer_on = 1;
- }
- flush_data->size++;
- spin_unlock_irqrestore(&flush_data->lock, flags);
-}
-
static void intel_unmap(struct device *dev, dma_addr_t dev_addr, size_t size)
{
struct dmar_domain *domain;
@@ -3784,7 +3663,8 @@ static void intel_unmap(struct device *dev, dma_addr_t dev_addr, size_t size)
free_iova_fast(&domain->iovad, iova_pfn, dma_to_mm_pfn(nrpages));
dma_free_pagelist(freelist);
} else {
- add_unmap(domain, iova_pfn, nrpages, freelist);
+ queue_iova(&domain->iovad, iova_pfn, nrpages,
+ (unsigned long)freelist);
/*
* queue up the release of the unmap to save the 1/6th of the
* cpu used up by the iotlb flush operation...
@@ -4721,7 +4601,6 @@ static void free_all_cpu_cached_iovas(unsigned int cpu)
static int intel_iommu_cpu_dead(unsigned int cpu)
{
free_all_cpu_cached_iovas(cpu);
- flush_unmaps_timeout(cpu);
return 0;
}

--
2.7.4