From: Chenyi Qiang <chenyi.qiang@intel.com>
To: "Peter Xu" <peterx@redhat.com>,
"David Hildenbrand" <david@redhat.com>,
"Alexey Kardashevskiy" <aik@amd.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Philippe Mathieu-Daudé" <philmd@linaro.org>
Cc: Chenyi Qiang <chenyi.qiang@intel.com>,
qemu-devel@nongnu.org, Gao Chao <chao.gao@intel.com>,
Li Xiaoyao <xiaoyao.li@intel.com>
Subject: [PATCH] ram-block-attributes: Avoid the overkill of shared memory with hugetlbfs backend
Date: Fri, 17 Oct 2025 16:14:23 +0800 [thread overview]
Message-ID: <20251017081445.175342-1-chenyi.qiang@intel.com> (raw)
Currently, private memory and shared memory have different backend in
CoCo VMs. It is possible for users to specify the shared memory with
hugetlbfs backend while private memory with guest_memfd backend only
supports 4K page size. In this case, ram_block->page_size is different
from the host page size which will trigger the assertion when getting
block size. Relax the restriction to allow shared memory to use
hugetlbfs backend.
Fixes: 5d6483edaa92 ("ram-block-attributes: Introduce RamBlockAttributes to manage RAMBlock with guest_memfd")
Signed-off-by: Chenyi Qiang <chenyi.qiang@intel.com>
---
system/ram-block-attributes.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/system/ram-block-attributes.c b/system/ram-block-attributes.c
index 68e8a027032..0f39ccf9090 100644
--- a/system/ram-block-attributes.c
+++ b/system/ram-block-attributes.c
@@ -28,10 +28,11 @@ ram_block_attributes_get_block_size(const RamBlockAttributes *attr)
* Because page conversion could be manipulated in the size of at least 4K
* or 4K aligned, Use the host page size as the granularity to track the
* memory attribute.
+ * When hugetlbfs is used as backend of shared memory, ram_block->page_size
+ * is different from host page size. So it is not appropriate to use
+ * ram_block->page_size here.
*/
- g_assert(attr && attr->ram_block);
- g_assert(attr->ram_block->page_size == qemu_real_host_page_size());
- return attr->ram_block->page_size;
+ return qemu_real_host_page_size();
}
--
2.43.5
next reply other threads:[~2025-10-17 8:15 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-17 8:14 Chenyi Qiang [this message]
2025-10-17 13:57 ` [PATCH] ram-block-attributes: Avoid the overkill of shared memory with hugetlbfs backend Peter Xu
2025-10-17 15:13 ` David Hildenbrand
2025-10-20 10:32 ` Chenyi Qiang
2025-10-20 11:31 ` David Hildenbrand
2025-10-20 11:48 ` Chenyi Qiang
2025-10-20 11:34 ` David Hildenbrand
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