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nvdimm: check -object memory-backend-file, readonly=on option

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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>
This commit is contained in:
Stefan Hajnoczi 2021-01-04 17:13:20 +00:00 committed by Eduardo Habkost
parent 86635aa4e9
commit dbd730e859
2 changed files with 26 additions and 7 deletions
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24
docs/nvdimm.txt
View File

@ -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.

9
hw/mem/nvdimm.c
View File

@ -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);