From: David Hildenbrand <david@redhat.com>
To: qemu-devel@nongnu.org
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>,
Gavin Shan <gshan@redhat.com>,
Eduardo Habkost <ehabkost@redhat.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
Michal Privoznik <mprivozn@redhat.com>,
David Hildenbrand <david@redhat.com>,
Richard Henderson <richard.henderson@linaro.org>,
Sebastien Boeuf <sebastien.boeuf@intel.com>,
Paolo Bonzini <pbonzini@redhat.com>, Hui Zhu <teawater@gmail.com>
Subject: [PATCH v2 1/3] linux-headers: sync VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE
Date: Fri, 17 Dec 2021 14:40:37 +0100 [thread overview]
Message-ID: <20211217134039.29670-2-david@redhat.com> (raw)
In-Reply-To: <20211217134039.29670-1-david@redhat.com>
Let's synchronize the new feature flag, available in Linux since
v5.16-rc1.
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
include/standard-headers/linux/virtio_mem.h | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/include/standard-headers/linux/virtio_mem.h b/include/standard-headers/linux/virtio_mem.h
index 05e5ade75d..18c74c527c 100644
--- a/include/standard-headers/linux/virtio_mem.h
+++ b/include/standard-headers/linux/virtio_mem.h
@@ -68,9 +68,10 @@
* explicitly triggered (VIRTIO_MEM_REQ_UNPLUG).
*
* There are no guarantees what will happen if unplugged memory is
- * read/written. Such memory should, in general, not be touched. E.g.,
- * even writing might succeed, but the values will simply be discarded at
- * random points in time.
+ * read/written. In general, unplugged memory should not be touched, because
+ * the resulting action is undefined. There is one exception: without
+ * VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE, unplugged memory inside the usable
+ * region can be read, to simplify creation of memory dumps.
*
* It can happen that the device cannot process a request, because it is
* busy. The device driver has to retry later.
@@ -87,6 +88,8 @@
/* node_id is an ACPI PXM and is valid */
#define VIRTIO_MEM_F_ACPI_PXM 0
+/* unplugged memory must not be accessed */
+#define VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE 1
/* --- virtio-mem: guest -> host requests --- */
--
2.31.1
next prev parent reply other threads:[~2021-12-17 13:48 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-17 13:40 [PATCH v2 0/3] virtio-mem: Support VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE David Hildenbrand
2021-12-17 13:40 ` David Hildenbrand [this message]
2021-12-17 13:40 ` [PATCH v2 2/3] " David Hildenbrand
2021-12-17 13:40 ` [PATCH v2 3/3] virtio-mem: Set "unplugged-inaccessible=auto" for the 7.0 machine on x86 David Hildenbrand
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