From 78d5f0f500e6ba8f6cfd0673475ff4d941d705a2 Mon Sep 17 00:00:00 2001
From: Nadav Amit <nadav.amit@gmail.com>
Date: Thu, 8 Apr 2010 23:00:41 +0300
Subject: [PATCH] intel-iommu: Avoid global flushes with caching mode.
While it may be efficient on real hardware, emulation of global
invalidations is very expensive as all shadow entries must be examined.
This patch changes the behaviour when caching mode is enabled (which is
the case when IOMMU emulation takes place). In this case, page specific
invalidation is used instead.
Signed-off-by: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
---
drivers/pci/intel-iommu.c | 19 ++++++++++++++-----
1 file changed, 14 insertions(+), 5 deletions(-)
diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
index 1880ee06d701..9ce79b1bae83 100644
--- a/drivers/pci/intel-iommu.c
+++ b/drivers/pci/intel-iommu.c
@@ -2647,15 +2647,24 @@ static void flush_unmaps(void)
if (!deferred_flush[i].next)
continue;
- iommu->flush.flush_iotlb(iommu, 0, 0, 0,
+ /* 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 < deferred_flush[i].next; j++) {
unsigned long mask;
struct iova *iova = deferred_flush[i].iova[j];
-
- mask = ilog2(mm_to_dma_pfn(iova->pfn_hi - iova->pfn_lo + 1));
- iommu_flush_dev_iotlb(deferred_flush[i].domain[j],
- (uint64_t)iova->pfn_lo << PAGE_SHIFT, mask);
+ struct dmar_domain *domain = deferred_flush[i].domain[j];
+
+ /* On real hardware multiple invalidations are expensive */
+ if (cap_caching_mode(iommu->cap))
+ iommu_flush_iotlb_psi(iommu, domain->id,
+ iova->pfn_lo, iova->pfn_hi - iova->pfn_lo + 1, 0);
+ else {
+ mask = ilog2(mm_to_dma_pfn(iova->pfn_hi - iova->pfn_lo + 1));
+ iommu_flush_dev_iotlb(deferred_flush[i].domain[j],
+ (uint64_t)iova->pfn_lo << PAGE_SHIFT, mask);
+ }
__free_iova(&deferred_flush[i].domain[j]->iovad, iova);
}
deferred_flush[i].next = 0;
--
2.49.0