From 48811c44349ffbb778d3e36b53beb03ad43a979c Mon Sep 17 00:00:00 2001 From: Lu Baolu Date: Wed, 18 Aug 2021 21:48:49 +0800 Subject: iommu/vt-d: Allow devices to have more than 32 outstanding PRs The minimum per-IOMMU PRQ queue size is one 4K page, this is more entries than the hardcoded limit of 32 in the current VT-d code. Some devices can support up to 512 outstanding PRQs but underutilized by this limit of 32. Although, 32 gives some rough fairness when multiple devices share the same IOMMU PRQ queue, but far from optimal for customized use case. This extends the per-IOMMU PRQ queue size to four 4K pages and let the devices have as many outstanding page requests as they can. Signed-off-by: Jacob Pan Signed-off-by: Lu Baolu Link: https://lore.kernel.org/r/20210720013856.4143880-1-baolu.lu@linux.intel.com Link: https://lore.kernel.org/r/20210818134852.1847070-7-baolu.lu@linux.intel.com Signed-off-by: Joerg Roedel --- include/linux/intel-svm.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'include/linux/intel-svm.h') diff --git a/include/linux/intel-svm.h b/include/linux/intel-svm.h index 10fa80eef13a..57cceecbe37f 100644 --- a/include/linux/intel-svm.h +++ b/include/linux/intel-svm.h @@ -14,6 +14,11 @@ #define SVM_REQ_EXEC (1<<1) #define SVM_REQ_PRIV (1<<0) +/* Page Request Queue depth */ +#define PRQ_ORDER 2 +#define PRQ_RING_MASK ((0x1000 << PRQ_ORDER) - 0x20) +#define PRQ_DEPTH ((0x1000 << PRQ_ORDER) >> 5) + /* * The SVM_FLAG_SUPERVISOR_MODE flag requests a PASID which can be used only * for access to kernel addresses. No IOTLB flushes are automatically done -- cgit v1.2.3