From 2f7c68cb55ecb7331f2381deb497c27155f32faf Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Wed, 03 Jan 2024 09:43:39 +0000
Subject: [PATCH] update kernel to 5.10.198

---
 kernel/drivers/iommu/intel/pasid.c |   28 ++++++++++++++++++++--------
 1 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/kernel/drivers/iommu/intel/pasid.c b/kernel/drivers/iommu/intel/pasid.c
index 86fd49a..9b24e82 100644
--- a/kernel/drivers/iommu/intel/pasid.c
+++ b/kernel/drivers/iommu/intel/pasid.c
@@ -24,7 +24,6 @@
 /*
  * Intel IOMMU system wide PASID name space:
  */
-static DEFINE_SPINLOCK(pasid_lock);
 u32 intel_pasid_max_id = PASID_MAX;
 
 int vcmd_alloc_pasid(struct intel_iommu *iommu, u32 *pasid)
@@ -187,6 +186,9 @@
 attach_out:
 	device_attach_pasid_table(info, pasid_table);
 
+	if (!ecap_coherent(info->iommu->ecap))
+		clflush_cache_range(pasid_table->table, (1 << order) * PAGE_SIZE);
+
 	return 0;
 }
 
@@ -259,19 +261,29 @@
 	dir_index = pasid >> PASID_PDE_SHIFT;
 	index = pasid & PASID_PTE_MASK;
 
-	spin_lock(&pasid_lock);
+retry:
 	entries = get_pasid_table_from_pde(&dir[dir_index]);
 	if (!entries) {
 		entries = alloc_pgtable_page(info->iommu->node);
-		if (!entries) {
-			spin_unlock(&pasid_lock);
+		if (!entries)
 			return NULL;
-		}
 
-		WRITE_ONCE(dir[dir_index].val,
-			   (u64)virt_to_phys(entries) | PASID_PTE_PRESENT);
+		/*
+		 * The pasid directory table entry won't be freed after
+		 * allocation. No worry about the race with free and
+		 * clear. However, this entry might be populated by others
+		 * while we are preparing it. Use theirs with a retry.
+		 */
+		if (cmpxchg64(&dir[dir_index].val, 0ULL,
+			      (u64)virt_to_phys(entries) | PASID_PTE_PRESENT)) {
+			free_pgtable_page(entries);
+			goto retry;
+		}
+		if (!ecap_coherent(info->iommu->ecap)) {
+			clflush_cache_range(entries, VTD_PAGE_SIZE);
+			clflush_cache_range(&dir[dir_index].val, sizeof(*dir));
+		}
 	}
-	spin_unlock(&pasid_lock);
 
 	return &entries[index];
 }

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