From: Rosen Penev <rosenp@gmail.com>
To: linux-kernel@vger.kernel.org
Cc: Alexandru Ciobotaru <alcioa@amazon.com>,
The AWS Nitro Enclaves Team <aws-nitro-enclaves-devel@amazon.com>,
Kees Cook <kees@kernel.org>,
"Gustavo A. R. Silva" <gustavoars@kernel.org>,
linux-hardening@vger.kernel.org (open list:KERNEL HARDENING (not
covered by other areas):Keyword:\b__counted_by(_le|_be)?\b)
Subject: [PATCH] virt: nitro_enclaves: Use flexible array for memory pages
Date: Sun, 10 May 2026 21:20:41 -0700 [thread overview]
Message-ID: <20260511042041.378366-1-rosenp@gmail.com> (raw)
Store the per-region page pointers in the memory region allocation
instead of allocating them separately.
Keep the allocated page-pointer capacity separate from the number of
pinned pages so __counted_by() describes the flexible array bounds while
nr_pages continues to track pages that need to be released.
Assisted-by: Codex:GPT-5.5
Signed-off-by: Rosen Penev <rosenp@gmail.com>
---
drivers/virt/nitro_enclaves/ne_misc_dev.c | 15 ++-------------
drivers/virt/nitro_enclaves/ne_misc_dev.h | 2 +-
2 files changed, 3 insertions(+), 14 deletions(-)
diff --git a/drivers/virt/nitro_enclaves/ne_misc_dev.c b/drivers/virt/nitro_enclaves/ne_misc_dev.c
index c91300a73f50..c0045b2cf7f3 100644
--- a/drivers/virt/nitro_enclaves/ne_misc_dev.c
+++ b/drivers/virt/nitro_enclaves/ne_misc_dev.c
@@ -927,19 +927,11 @@ static int ne_set_user_memory_region_ioctl(struct ne_enclave *ne_enclave,
if (rc < 0)
return rc;
- ne_mem_region = kzalloc_obj(*ne_mem_region);
+ max_nr_pages = mem_region.memory_size / NE_MIN_MEM_REGION_SIZE;
+ ne_mem_region = kzalloc_flex(*ne_mem_region, pages, max_nr_pages);
if (!ne_mem_region)
return -ENOMEM;
- max_nr_pages = mem_region.memory_size / NE_MIN_MEM_REGION_SIZE;
-
- ne_mem_region->pages = kzalloc_objs(*ne_mem_region->pages, max_nr_pages);
- if (!ne_mem_region->pages) {
- rc = -ENOMEM;
-
- goto free_mem_region;
- }
-
phys_contig_mem_regions.regions = kzalloc_objs(*phys_contig_mem_regions.regions,
max_nr_pages);
if (!phys_contig_mem_regions.regions) {
@@ -1049,7 +1041,6 @@ static int ne_set_user_memory_region_ioctl(struct ne_enclave *ne_enclave,
put_page(ne_mem_region->pages[i]);
free_mem_region:
kfree(phys_contig_mem_regions.regions);
- kfree(ne_mem_region->pages);
kfree(ne_mem_region);
return rc;
@@ -1398,8 +1389,6 @@ static void ne_enclave_remove_all_mem_region_entries(struct ne_enclave *ne_encla
for (i = 0; i < ne_mem_region->nr_pages; i++)
put_page(ne_mem_region->pages[i]);
- kfree(ne_mem_region->pages);
-
kfree(ne_mem_region);
}
}
diff --git a/drivers/virt/nitro_enclaves/ne_misc_dev.h b/drivers/virt/nitro_enclaves/ne_misc_dev.h
index 2a4d2224baba..f419e04007f8 100644
--- a/drivers/virt/nitro_enclaves/ne_misc_dev.h
+++ b/drivers/virt/nitro_enclaves/ne_misc_dev.h
@@ -28,8 +28,8 @@ struct ne_mem_region {
struct list_head mem_region_list_entry;
u64 memory_size;
unsigned long nr_pages;
- struct page **pages;
u64 userspace_addr;
+ struct page *pages[];
};
/**
--
2.54.0
reply other threads:[~2026-05-11 4:21 UTC|newest]
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