| Message ID | 1531202789-31006-4-git-send-email-junyan.he@gmx.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, 10 Jul 2018 14:06:25 +0800 junyan.he@gmx.com wrote: > From: Junyan He <junyan.he@intel.com> > > When QEMU emulates vNVDIMM labels and migrates vNVDIMM devices, it > needs to know whether the backend storage is a real persistent memory, > in order to decide whether special operations should be performed to > ensure the data persistence. > > This boolean option 'pmem' allows users to specify whether the backend > storage of memory-backend-file is a real persistent memory. If > 'pmem=on', QEMU will set the flag RAM_PMEM in the RAM block of the > corresponding memory region. If 'pmem' is set while lack of libpmem > support, a error is generated. > > Signed-off-by: Junyan He <junyan.he@intel.com> > Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com> > Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> > --- > backends/hostmem-file.c | 42 +++++++++++++++++++++++++++++++++++++++++- > docs/nvdimm.txt | 23 +++++++++++++++++++++++ > exec.c | 9 +++++++++ > include/exec/memory.h | 4 ++++ > include/exec/ram_addr.h | 3 +++ > qemu-options.hx | 7 +++++++ > 6 files changed, 87 insertions(+), 1 deletion(-) > > diff --git a/backends/hostmem-file.c b/backends/hostmem-file.c > index 34c68bb..dbdaf17 100644 > --- a/backends/hostmem-file.c > +++ b/backends/hostmem-file.c > @@ -12,6 +12,7 @@ > #include "qemu/osdep.h" > #include "qapi/error.h" > #include "qemu-common.h" > +#include "qemu/error-report.h" > #include "sysemu/hostmem.h" > #include "sysemu/sysemu.h" > #include "qom/object_interfaces.h" > @@ -34,6 +35,7 @@ struct HostMemoryBackendFile { > bool discard_data; > char *mem_path; > uint64_t align; > + bool is_pmem; > }; > > static void > @@ -59,7 +61,8 @@ file_backend_memory_alloc(HostMemoryBackend *backend, Error **errp) > memory_region_init_ram_from_file(&backend->mr, OBJECT(backend), > path, > backend->size, fb->align, > - backend->share ? RAM_SHARED : 0, > + (backend->share ? RAM_SHARED : 0) | > + (fb->is_pmem ? RAM_PMEM : 0), > fb->mem_path, errp); > g_free(path); > } > @@ -131,6 +134,40 @@ static void file_memory_backend_set_align(Object *o, Visitor *v, > error_propagate(errp, local_err); > } > > +static bool file_memory_backend_get_pmem(Object *o, Error **errp) > +{ > + return MEMORY_BACKEND_FILE(o)->is_pmem; > +} > + > +static void file_memory_backend_set_pmem(Object *o, bool value, Error **errp) > +{ > + HostMemoryBackend *backend = MEMORY_BACKEND(o); > + HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); > + > + if (host_memory_backend_mr_inited(backend)) { > + error_setg(errp, "cannot change property 'pmem' of %s '%s'", > + object_get_typename(o), > + object_get_canonical_path_component(o)); > + return; > + } > + > +#ifndef CONFIG_LIBPMEM > + if (value) { > + Error *local_err = NULL; > + error_setg(&local_err, > + "Lack of libpmem support while setting the 'pmem=on'" > + " of %s '%s'. We can not ensure the persistence of it" maybe s/We can not ensure the persistence of it/we can't ensure data persistence/ and drop the rest. > + " without libpmem support, this may cause serious" > + " problems." , object_get_typename(o), > + object_get_canonical_path_component(o)); > + error_propagate(errp, local_err); > + return; > + } > +#endif > + > + fb->is_pmem = value; > +} > + > static void file_backend_unparent(Object *obj) > { > HostMemoryBackend *backend = MEMORY_BACKEND(obj); > @@ -162,6 +199,9 @@ file_backend_class_init(ObjectClass *oc, void *data) > file_memory_backend_get_align, > file_memory_backend_set_align, > NULL, NULL, &error_abort); > + object_class_property_add_bool(oc, "pmem", > + file_memory_backend_get_pmem, file_memory_backend_set_pmem, > + &error_abort); > } > > static void file_backend_instance_finalize(Object *o) > diff --git a/docs/nvdimm.txt b/docs/nvdimm.txt > index 24b443b..b8bb43a 100644 > --- a/docs/nvdimm.txt > +++ b/docs/nvdimm.txt > @@ -173,3 +173,26 @@ There are currently two valid values for this option: > the NVDIMMs in the event of power loss. This implies that the > platform also supports flushing dirty data through the memory > controller on power loss. > + > +guest software that this vNVDIMM device contains a region that cannot > +accept persistent writes. In result, for example, the guest Linux > +NVDIMM driver, marks such vNVDIMM device as read-only. no matter how I've tried to read it above hunk, it doesn't make sense. It's not continuation of the text above it but start as such and doesn't make sense to me on its own. Maybe it should be rephrased or dropped altogether. > + > +If the vNVDIMM backend is on the host persistent memory that can be > +accessed in SNIA NVM Programming Model [1] (e.g., Intel NVDIMM), it's > +suggested to set the 'pmem' option of memory-backend-file to 'on'. When > +'pmem' is 'on' and QEMU is built with libpmem [2] support (configured with > +--enable-libpmem), QEMU will take necessary operations to guarantee the > +persistence of its own writes to the vNVDIMM backend(e.g., in vNVDIMM label > +emulation and live migration). If 'pmem' is 'on' while there is no libpmem > +support, qemu will exit and report a "lack of libpmem suopport" message to ^^^^^^^^^ typo > +ensure the persistence is available. For example, we want to ensure the s/we/if we/ > +persistence for some backend file: > + > + -object memory-backend-file,id=nv_mem,mem-path=/XXX/yyy,size=4G,pmem > + > +References > +---------- > + > +[1] SNIA NVM Programming Model: https://www.snia.org/sites/default/files/technical_work/final/NVMProgrammingModel_v1.2.pdf > +[2] PMDK: http://pmem.io/pmdk/ links are usually tend to disappear/change long term, so pls add exact spec names here (including applicable version) that could be lead to specs using a web search engine. > diff --git a/exec.c b/exec.c > index 1ec539d..1a61b44 100644 > --- a/exec.c > +++ b/exec.c > @@ -2245,6 +2245,9 @@ RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr, > Error *local_err = NULL; > int64_t file_size; > > + /* Just support these ram flags by now. */ > + assert(ram_flags == 0 || (ram_flags & (RAM_SHARED | RAM_PMEM))); > + > if (xen_enabled()) { > error_setg(errp, "-mem-path not supported with Xen"); > return NULL; > @@ -4072,6 +4075,11 @@ err: > return ret; > } > > +bool ramblock_is_pmem(RAMBlock *rb) > +{ > + return rb->flags & RAM_PMEM; > +} > + > #endif > > void page_size_init(void) > @@ -4170,3 +4178,4 @@ void mtree_print_dispatch(fprintf_function mon, void *f, > } > > #endif > + > diff --git a/include/exec/memory.h b/include/exec/memory.h > index 513ec8d..a3baa2a 100644 > --- a/include/exec/memory.h > +++ b/include/exec/memory.h > @@ -123,6 +123,9 @@ typedef struct IOMMUNotifier IOMMUNotifier; > /* RAM can be migrated */ > #define RAM_MIGRATABLE (1 << 4) > > +/* RAM is a persistent kind memory */ > +#define RAM_PMEM (1 << 5) > + > static inline void iommu_notifier_init(IOMMUNotifier *n, IOMMUNotify fn, > IOMMUNotifierFlag flags, > hwaddr start, hwaddr end, > @@ -654,6 +657,7 @@ void memory_region_init_resizeable_ram(MemoryRegion *mr, > * (getpagesize()) will be used. > * @ram_flags: Memory region features: > * - RAM_SHARED: memory must be mmaped with the MAP_SHARED flag > + * - RAM_PMEM: the memory is persistent memory > * Other bits are ignored now. > * @path: the path in which to allocate the RAM. > * @errp: pointer to Error*, to store an error if it happens. > diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h > index bb0a09b..f1f8ac0 100644 > --- a/include/exec/ram_addr.h > +++ b/include/exec/ram_addr.h > @@ -70,6 +70,8 @@ static inline unsigned long int ramblock_recv_bitmap_offset(void *host_addr, > return host_addr_offset >> TARGET_PAGE_BITS; > } > > +bool ramblock_is_pmem(RAMBlock *rb); > + > long qemu_getrampagesize(void); > > /** > @@ -83,6 +85,7 @@ long qemu_getrampagesize(void); > * @ram_flags: specify the properties of the ram block, which can be one > * or bit-or of following values > * - RAM_SHARED: mmap the backing file or device with MAP_SHARED > + * - RAM_PMEM: the backend @mem_path or @fd is persistent memory > * Other bits are ignored. > * @mem_path or @fd: specify the backing file or device > * @errp: pointer to Error*, to store an error if it happens > diff --git a/qemu-options.hx b/qemu-options.hx > index 16208f6..3f92281 100644 > --- a/qemu-options.hx > +++ b/qemu-options.hx > @@ -4057,6 +4057,13 @@ requires an alignment different than the default one used by QEMU, eg > the device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In > such cases, users can specify the required alignment via this option. > > +The @option{pmem} option specifies whether the backing file specified > +by @option{mem-path} is on the persistent memory that can be accessed > +using the SNIA NVM programming model (e.g. Intel NVDIMM). > +If @option{pmem}, QEMU will take necessary operations to did you mean: If @option{pmem} is set to 'on' > +guarantee the persistence of its own writes to @option{mem-path} > +(e.g. in vNVDIMM label emulation and live migration). > + > @item -object memory-backend-ram,id=@var{id},merge=@var{on|off},dump=@var{on|off},share=@var{on|off},prealloc=@var{on|off},size=@var{size},host-nodes=@var{host-nodes},policy=@var{default|preferred|bind|interleave} > > Creates a memory backend object, which can be used to back the guest RAM.
diff --git a/backends/hostmem-file.c b/backends/hostmem-file.c index 34c68bb..dbdaf17 100644 --- a/backends/hostmem-file.c +++ b/backends/hostmem-file.c @@ -12,6 +12,7 @@ #include "qemu/osdep.h" #include "qapi/error.h" #include "qemu-common.h" +#include "qemu/error-report.h" #include "sysemu/hostmem.h" #include "sysemu/sysemu.h" #include "qom/object_interfaces.h" @@ -34,6 +35,7 @@ struct HostMemoryBackendFile { bool discard_data; char *mem_path; uint64_t align; + bool is_pmem; }; static void @@ -59,7 +61,8 @@ file_backend_memory_alloc(HostMemoryBackend *backend, Error **errp) memory_region_init_ram_from_file(&backend->mr, OBJECT(backend), path, backend->size, fb->align, - backend->share ? RAM_SHARED : 0, + (backend->share ? RAM_SHARED : 0) | + (fb->is_pmem ? RAM_PMEM : 0), fb->mem_path, errp); g_free(path); } @@ -131,6 +134,40 @@ static void file_memory_backend_set_align(Object *o, Visitor *v, error_propagate(errp, local_err); } +static bool file_memory_backend_get_pmem(Object *o, Error **errp) +{ + return MEMORY_BACKEND_FILE(o)->is_pmem; +} + +static void file_memory_backend_set_pmem(Object *o, bool value, Error **errp) +{ + HostMemoryBackend *backend = MEMORY_BACKEND(o); + HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); + + if (host_memory_backend_mr_inited(backend)) { + error_setg(errp, "cannot change property 'pmem' of %s '%s'", + object_get_typename(o), + object_get_canonical_path_component(o)); + return; + } + +#ifndef CONFIG_LIBPMEM + if (value) { + Error *local_err = NULL; + error_setg(&local_err, + "Lack of libpmem support while setting the 'pmem=on'" + " of %s '%s'. We can not ensure the persistence of it" + " without libpmem support, this may cause serious" + " problems." , object_get_typename(o), + object_get_canonical_path_component(o)); + error_propagate(errp, local_err); + return; + } +#endif + + fb->is_pmem = value; +} + static void file_backend_unparent(Object *obj) { HostMemoryBackend *backend = MEMORY_BACKEND(obj); @@ -162,6 +199,9 @@ file_backend_class_init(ObjectClass *oc, void *data) file_memory_backend_get_align, file_memory_backend_set_align, NULL, NULL, &error_abort); + object_class_property_add_bool(oc, "pmem", + file_memory_backend_get_pmem, file_memory_backend_set_pmem, + &error_abort); } static void file_backend_instance_finalize(Object *o) diff --git a/docs/nvdimm.txt b/docs/nvdimm.txt index 24b443b..b8bb43a 100644 --- a/docs/nvdimm.txt +++ b/docs/nvdimm.txt @@ -173,3 +173,26 @@ There are currently two valid values for this option: the NVDIMMs in the event of power loss. This implies that the platform also supports flushing dirty data through the memory controller on power loss. + +guest software that this vNVDIMM device contains a region that cannot +accept persistent writes. In result, for example, the guest Linux +NVDIMM driver, marks such vNVDIMM device as read-only. + +If the vNVDIMM backend is on the host persistent memory that can be +accessed in SNIA NVM Programming Model [1] (e.g., Intel NVDIMM), it's +suggested to set the 'pmem' option of memory-backend-file to 'on'. When +'pmem' is 'on' and QEMU is built with libpmem [2] support (configured with +--enable-libpmem), QEMU will take necessary operations to guarantee the +persistence of its own writes to the vNVDIMM backend(e.g., in vNVDIMM label +emulation and live migration). If 'pmem' is 'on' while there is no libpmem +support, qemu will exit and report a "lack of libpmem suopport" message to +ensure the persistence is available. For example, we want to ensure the +persistence for some backend file: + + -object memory-backend-file,id=nv_mem,mem-path=/XXX/yyy,size=4G,pmem + +References +---------- + +[1] SNIA NVM Programming Model: https://www.snia.org/sites/default/files/technical_work/final/NVMProgrammingModel_v1.2.pdf +[2] PMDK: http://pmem.io/pmdk/ diff --git a/exec.c b/exec.c index 1ec539d..1a61b44 100644 --- a/exec.c +++ b/exec.c @@ -2245,6 +2245,9 @@ RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr, Error *local_err = NULL; int64_t file_size; + /* Just support these ram flags by now. */ + assert(ram_flags == 0 || (ram_flags & (RAM_SHARED | RAM_PMEM))); + if (xen_enabled()) { error_setg(errp, "-mem-path not supported with Xen"); return NULL; @@ -4072,6 +4075,11 @@ err: return ret; } +bool ramblock_is_pmem(RAMBlock *rb) +{ + return rb->flags & RAM_PMEM; +} + #endif void page_size_init(void) @@ -4170,3 +4178,4 @@ void mtree_print_dispatch(fprintf_function mon, void *f, } #endif + diff --git a/include/exec/memory.h b/include/exec/memory.h index 513ec8d..a3baa2a 100644 --- a/include/exec/memory.h +++ b/include/exec/memory.h @@ -123,6 +123,9 @@ typedef struct IOMMUNotifier IOMMUNotifier; /* RAM can be migrated */ #define RAM_MIGRATABLE (1 << 4) +/* RAM is a persistent kind memory */ +#define RAM_PMEM (1 << 5) + static inline void iommu_notifier_init(IOMMUNotifier *n, IOMMUNotify fn, IOMMUNotifierFlag flags, hwaddr start, hwaddr end, @@ -654,6 +657,7 @@ void memory_region_init_resizeable_ram(MemoryRegion *mr, * (getpagesize()) will be used. * @ram_flags: Memory region features: * - RAM_SHARED: memory must be mmaped with the MAP_SHARED flag + * - RAM_PMEM: the memory is persistent memory * Other bits are ignored now. * @path: the path in which to allocate the RAM. * @errp: pointer to Error*, to store an error if it happens. diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h index bb0a09b..f1f8ac0 100644 --- a/include/exec/ram_addr.h +++ b/include/exec/ram_addr.h @@ -70,6 +70,8 @@ static inline unsigned long int ramblock_recv_bitmap_offset(void *host_addr, return host_addr_offset >> TARGET_PAGE_BITS; } +bool ramblock_is_pmem(RAMBlock *rb); + long qemu_getrampagesize(void); /** @@ -83,6 +85,7 @@ long qemu_getrampagesize(void); * @ram_flags: specify the properties of the ram block, which can be one * or bit-or of following values * - RAM_SHARED: mmap the backing file or device with MAP_SHARED + * - RAM_PMEM: the backend @mem_path or @fd is persistent memory * Other bits are ignored. * @mem_path or @fd: specify the backing file or device * @errp: pointer to Error*, to store an error if it happens diff --git a/qemu-options.hx b/qemu-options.hx index 16208f6..3f92281 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -4057,6 +4057,13 @@ requires an alignment different than the default one used by QEMU, eg the device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In such cases, users can specify the required alignment via this option. +The @option{pmem} option specifies whether the backing file specified +by @option{mem-path} is on the persistent memory that can be accessed +using the SNIA NVM programming model (e.g. Intel NVDIMM). +If @option{pmem}, QEMU will take necessary operations to +guarantee the persistence of its own writes to @option{mem-path} +(e.g. in vNVDIMM label emulation and live migration). + @item -object memory-backend-ram,id=@var{id},merge=@var{on|off},dump=@var{on|off},share=@var{on|off},prealloc=@var{on|off},size=@var{size},host-nodes=@var{host-nodes},policy=@var{default|preferred|bind|interleave} Creates a memory backend object, which can be used to back the guest RAM.