| Message ID | 20200804101244.1283503-4-stefanha@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | nvdimm: read-only file support | expand |
On 8/4/20 12:12 PM, Stefan Hajnoczi wrote: > Make it possible to present read-only files to the guest as "unarmed" > NVDIMMs. The Linux NVDIMM device (/dev/pmemX) is read-only. > > Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> > --- > docs/nvdimm.txt | 8 +++++++- > hw/mem/nvdimm.c | 4 ++++ > 2 files changed, 11 insertions(+), 1 deletion(-) > > diff --git a/docs/nvdimm.txt b/docs/nvdimm.txt > index c2c6e441b3..c0b52de111 100644 > --- a/docs/nvdimm.txt > +++ b/docs/nvdimm.txt > @@ -17,7 +17,7 @@ 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=$NVDIMM_SIZE > + -object memory-backend-file,id=mem1,share=on,mem-path=$PATH,size=$NVDIMM_SIZE,readonly=off > -device nvdimm,id=nvdimm1,memdev=mem1 > > Where, > @@ -42,6 +42,12 @@ Where, > "share=off", then guest writes won't be applied to the backend > file and thus will be invisible to other guests. > > + "readonly=on/off" controls whether the the file $PATH is opened read-only or Double "the the". > + read/write (default). "readonly=on" sets the ACPI NFIT NVDIMM Region Mapping NFIT acronym for 'NVDIMM Firmware Interface Table', "NVDIMM" sounds redundant but makes it easier to understand, so OK. > + 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. > + > - "device nvdimm,id=nvdimm1,memdev=mem1" creates a virtual NVDIMM > device whose storage is provided by above memory backend device. > > diff --git a/hw/mem/nvdimm.c b/hw/mem/nvdimm.c > index e1574bc07c..694223450e 100644 > --- a/hw/mem/nvdimm.c > +++ b/hw/mem/nvdimm.c > @@ -151,6 +151,10 @@ static void nvdimm_prepare_memory_region(NVDIMMDevice *nvdimm, Error **errp) > "nvdimm-memory", mr, 0, pmem_size); > memory_region_set_nonvolatile(nvdimm->nvdimm_mr, true); > nvdimm->nvdimm_mr->align = align; > + > + if (memory_region_is_rom(mr)) { > + nvdimm->unarmed = true; /* this device is read-only */ > + } Can you move this hunk before the alias creation? (Just before nvdimm->nvdimm_mr = ...). > } > > static MemoryRegion *nvdimm_md_get_memory_region(MemoryDeviceState *md, I don't understand why MemoryDeviceClass::get_memory_region() implicitly calls DeviceClass::realize()... Anyway unrelated to this patch. With the comments addressed: Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
On Fri, Aug 21, 2020 at 03:03:50PM +0200, Philippe Mathieu-Daudé wrote: > On 8/4/20 12:12 PM, Stefan Hajnoczi wrote: > > Make it possible to present read-only files to the guest as "unarmed" > > NVDIMMs. The Linux NVDIMM device (/dev/pmemX) is read-only. > > > > Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> > > --- > > docs/nvdimm.txt | 8 +++++++- > > hw/mem/nvdimm.c | 4 ++++ > > 2 files changed, 11 insertions(+), 1 deletion(-) > > > > diff --git a/docs/nvdimm.txt b/docs/nvdimm.txt > > index c2c6e441b3..c0b52de111 100644 > > --- a/docs/nvdimm.txt > > +++ b/docs/nvdimm.txt > > @@ -17,7 +17,7 @@ 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=$NVDIMM_SIZE > > + -object memory-backend-file,id=mem1,share=on,mem-path=$PATH,size=$NVDIMM_SIZE,readonly=off > > -device nvdimm,id=nvdimm1,memdev=mem1 > > > > Where, > > @@ -42,6 +42,12 @@ Where, > > "share=off", then guest writes won't be applied to the backend > > file and thus will be invisible to other guests. > > > > + "readonly=on/off" controls whether the the file $PATH is opened read-only or > > Double "the the". Will fix. > > diff --git a/hw/mem/nvdimm.c b/hw/mem/nvdimm.c > > index e1574bc07c..694223450e 100644 > > --- a/hw/mem/nvdimm.c > > +++ b/hw/mem/nvdimm.c > > @@ -151,6 +151,10 @@ static void nvdimm_prepare_memory_region(NVDIMMDevice *nvdimm, Error **errp) > > "nvdimm-memory", mr, 0, pmem_size); > > memory_region_set_nonvolatile(nvdimm->nvdimm_mr, true); > > nvdimm->nvdimm_mr->align = align; > > + > > + if (memory_region_is_rom(mr)) { > > + nvdimm->unarmed = true; /* this device is read-only */ > > + } > > Can you move this hunk before the alias creation? > (Just before nvdimm->nvdimm_mr = ...). Will fix.
diff --git a/docs/nvdimm.txt b/docs/nvdimm.txt index c2c6e441b3..c0b52de111 100644 --- a/docs/nvdimm.txt +++ b/docs/nvdimm.txt @@ -17,7 +17,7 @@ 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=$NVDIMM_SIZE + -object memory-backend-file,id=mem1,share=on,mem-path=$PATH,size=$NVDIMM_SIZE,readonly=off -device nvdimm,id=nvdimm1,memdev=mem1 Where, @@ -42,6 +42,12 @@ Where, "share=off", then guest writes won't be applied to the backend file and thus will be invisible to other guests. + "readonly=on/off" controls whether the the file $PATH is opened read-only or + read/write (default). "readonly=on" sets 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. + - "device nvdimm,id=nvdimm1,memdev=mem1" creates a virtual NVDIMM device whose storage is provided by above memory backend device. diff --git a/hw/mem/nvdimm.c b/hw/mem/nvdimm.c index e1574bc07c..694223450e 100644 --- a/hw/mem/nvdimm.c +++ b/hw/mem/nvdimm.c @@ -151,6 +151,10 @@ static void nvdimm_prepare_memory_region(NVDIMMDevice *nvdimm, Error **errp) "nvdimm-memory", mr, 0, pmem_size); memory_region_set_nonvolatile(nvdimm->nvdimm_mr, true); nvdimm->nvdimm_mr->align = align; + + if (memory_region_is_rom(mr)) { + nvdimm->unarmed = true; /* this device is read-only */ + } } static MemoryRegion *nvdimm_md_get_memory_region(MemoryDeviceState *md,
Make it possible to present read-only files to the guest as "unarmed" NVDIMMs. The Linux NVDIMM device (/dev/pmemX) is read-only. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> --- docs/nvdimm.txt | 8 +++++++- hw/mem/nvdimm.c | 4 ++++ 2 files changed, 11 insertions(+), 1 deletion(-)