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[PULL 3/3] nvdimm: check -object memory-backend-file, readonly=on option
From: |
Eduardo Habkost |
Subject: |
[PULL 3/3] nvdimm: check -object memory-backend-file, readonly=on option |
Date: |
Tue, 2 Feb 2021 14:30:20 -0500 |
From: Stefan Hajnoczi <stefanha@redhat.com>
Check that -device nvdimm,unarmed=on is used when -object
memory-backend-file,readonly=on and document that -device
nvdimm,unarmed=on|off controls whether the NVDIMM appears read-only to
the guest.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Liam Merwick <liam.merwick@oracle.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20210104171320.575838-4-stefanha@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
---
docs/nvdimm.txt | 24 +++++++++++++++++-------
hw/mem/nvdimm.c | 9 +++++++++
2 files changed, 26 insertions(+), 7 deletions(-)
diff --git a/docs/nvdimm.txt b/docs/nvdimm.txt
index c2c6e441b34..0aae682be3e 100644
--- a/docs/nvdimm.txt
+++ b/docs/nvdimm.txt
@@ -17,8 +17,8 @@ following command line options:
-machine pc,nvdimm
-m $RAM_SIZE,slots=$N,maxmem=$MAX_SIZE
- -object memory-backend-file,id=mem1,share=on,mem-path=$PATH,size=$NVDIMM_SIZE
- -device nvdimm,id=nvdimm1,memdev=mem1
+ -object
memory-backend-file,id=mem1,share=on,mem-path=$PATH,size=$NVDIMM_SIZE,readonly=off
+ -device nvdimm,id=nvdimm1,memdev=mem1,unarmed=off
Where,
@@ -31,9 +31,10 @@ Where,
of normal RAM devices and vNVDIMM devices, e.g. $MAX_SIZE should be
>= $RAM_SIZE + $NVDIMM_SIZE here.
- - "object
memory-backend-file,id=mem1,share=on,mem-path=$PATH,size=$NVDIMM_SIZE"
- creates a backend storage of size $NVDIMM_SIZE on a file $PATH. All
- accesses to the virtual NVDIMM device go to the file $PATH.
+ - "object memory-backend-file,id=mem1,share=on,mem-path=$PATH,
+ size=$NVDIMM_SIZE,readonly=off" creates a backend storage of size
+ $NVDIMM_SIZE on a file $PATH. All accesses to the virtual NVDIMM device go
+ to the file $PATH.
"share=on/off" controls the visibility of guest writes. If
"share=on", then guest writes will be applied to the backend
@@ -42,8 +43,17 @@ Where,
"share=off", then guest writes won't be applied to the backend
file and thus will be invisible to other guests.
- - "device nvdimm,id=nvdimm1,memdev=mem1" creates a virtual NVDIMM
- device whose storage is provided by above memory backend device.
+ "readonly=on/off" controls whether the file $PATH is opened read-only or
+ read/write (default).
+
+ - "device nvdimm,id=nvdimm1,memdev=mem1,unarmed=off" creates a read/write
+ virtual NVDIMM device whose storage is provided by above memory backend
+ device.
+
+ "unarmed" controls the ACPI NFIT NVDIMM Region Mapping Structure "NVDIMM
+ State Flags" Bit 3 indicating that the device is "unarmed" and cannot accept
+ persistent writes. Linux guest drivers set the device to read-only when this
+ bit is present. Set unarmed to on when the memdev has readonly=on.
Multiple vNVDIMM devices can be created if multiple pairs of "-object"
and "-device" are provided.
diff --git a/hw/mem/nvdimm.c b/hw/mem/nvdimm.c
index 03c2201b564..e0a9d606e1b 100644
--- a/hw/mem/nvdimm.c
+++ b/hw/mem/nvdimm.c
@@ -146,6 +146,15 @@ static void nvdimm_prepare_memory_region(NVDIMMDevice
*nvdimm, Error **errp)
return;
}
+ if (!nvdimm->unarmed && memory_region_is_rom(mr)) {
+ HostMemoryBackend *hostmem = dimm->hostmem;
+
+ error_setg(errp, "'unarmed' property must be off since memdev %s "
+ "is read-only",
+ object_get_canonical_path_component(OBJECT(hostmem)));
+ return;
+ }
+
nvdimm->nvdimm_mr = g_new(MemoryRegion, 1);
memory_region_init_alias(nvdimm->nvdimm_mr, OBJECT(dimm),
"nvdimm-memory", mr, 0, pmem_size);
--
2.28.0