diff mbox series

[RFC,v3,01/45] multi-process: memory: alloc RAM from file at offset

Message ID 3bf3631115123d4a6a360b41ef0aaa47b40ff08d.1567534653.git.jag.raman@oracle.com (mailing list archive)
State New, archived
Headers show
Series Initial support of multi-process qemu | expand

Commit Message

Jag Raman Sept. 3, 2019, 8:37 p.m. UTC
Allow RAM MemoryRegion to be created from an offset in a file, instead
of allocating at offset of 0 by default. This is needed to synchronize
RAM between QEMU & remote process.
This will be needed for the following patches.

Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
Signed-off-by: John G Johnson <john.g.johnson@oracle.com>
Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
---
 exec.c                    | 11 +++++++----
 include/exec/ram_addr.h   |  2 +-
 include/qemu/mmap-alloc.h |  3 ++-
 memory.c                  |  2 +-
 util/mmap-alloc.c         |  7 ++++---
 util/oslib-posix.c        |  2 +-
 6 files changed, 16 insertions(+), 11 deletions(-)

Comments

Dr. David Alan Gilbert Sept. 4, 2019, 8:11 a.m. UTC | #1
* Jagannathan Raman (jag.raman@oracle.com) wrote:
> Allow RAM MemoryRegion to be created from an offset in a file, instead
> of allocating at offset of 0 by default. This is needed to synchronize
> RAM between QEMU & remote process.
> This will be needed for the following patches.
> 
> Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
> Signed-off-by: John G Johnson <john.g.johnson@oracle.com>
> Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
> ---
>  exec.c                    | 11 +++++++----
>  include/exec/ram_addr.h   |  2 +-
>  include/qemu/mmap-alloc.h |  3 ++-
>  memory.c                  |  2 +-
>  util/mmap-alloc.c         |  7 ++++---
>  util/oslib-posix.c        |  2 +-
>  6 files changed, 16 insertions(+), 11 deletions(-)

I'm surprised this doesn't change something in
vhost-user.c:vhost_user_set_mem_table so that the vhost-user client
knows what it's mapping?

Dave

> diff --git a/exec.c b/exec.c
> index 3e78de3..b3f1aa9 100644
> --- a/exec.c
> +++ b/exec.c
> @@ -1885,6 +1885,7 @@ static void *file_ram_alloc(RAMBlock *block,
>                              ram_addr_t memory,
>                              int fd,
>                              bool truncate,
> +                            off_t offset,
>                              Error **errp)
>  {
>      MachineState *ms = MACHINE(qdev_get_machine());
> @@ -1936,7 +1937,8 @@ static void *file_ram_alloc(RAMBlock *block,
>      }
>  
>      area = qemu_ram_mmap(fd, memory, block->mr->align,
> -                         block->flags & RAM_SHARED, block->flags & RAM_PMEM);
> +                         block->flags & RAM_SHARED, block->flags & RAM_PMEM,
> +                         offset);
>      if (area == MAP_FAILED) {
>          error_setg_errno(errp, errno,
>                           "unable to map backing store for guest RAM");
> @@ -2325,7 +2327,7 @@ static void ram_block_add(RAMBlock *new_block, Error **errp, bool shared)
>  #ifdef CONFIG_POSIX
>  RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr,
>                                   uint32_t ram_flags, int fd,
> -                                 Error **errp)
> +                                 off_t offset, Error **errp)
>  {
>      RAMBlock *new_block;
>      Error *local_err = NULL;
> @@ -2370,7 +2372,8 @@ RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr,
>      new_block->used_length = size;
>      new_block->max_length = size;
>      new_block->flags = ram_flags;
> -    new_block->host = file_ram_alloc(new_block, size, fd, !file_size, errp);
> +    new_block->host = file_ram_alloc(new_block, size, fd, !file_size, offset,
> +                                     errp);
>      if (!new_block->host) {
>          g_free(new_block);
>          return NULL;
> @@ -2400,7 +2403,7 @@ RAMBlock *qemu_ram_alloc_from_file(ram_addr_t size, MemoryRegion *mr,
>          return NULL;
>      }
>  
> -    block = qemu_ram_alloc_from_fd(size, mr, ram_flags, fd, errp);
> +    block = qemu_ram_alloc_from_fd(size, mr, ram_flags, fd, 0, errp);
>      if (!block) {
>          if (created) {
>              unlink(mem_path);
> diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h
> index b7b2e60..15837a1 100644
> --- a/include/exec/ram_addr.h
> +++ b/include/exec/ram_addr.h
> @@ -164,7 +164,7 @@ RAMBlock *qemu_ram_alloc_from_file(ram_addr_t size, MemoryRegion *mr,
>                                     Error **errp);
>  RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr,
>                                   uint32_t ram_flags, int fd,
> -                                 Error **errp);
> +                                 off_t offset, Error **errp);
>  
>  RAMBlock *qemu_ram_alloc_from_ptr(ram_addr_t size, void *host,
>                                    MemoryRegion *mr, Error **errp);
> diff --git a/include/qemu/mmap-alloc.h b/include/qemu/mmap-alloc.h
> index e786266..4f57985 100644
> --- a/include/qemu/mmap-alloc.h
> +++ b/include/qemu/mmap-alloc.h
> @@ -25,7 +25,8 @@ void *qemu_ram_mmap(int fd,
>                      size_t size,
>                      size_t align,
>                      bool shared,
> -                    bool is_pmem);
> +                    bool is_pmem,
> +                    off_t start);
>  
>  void qemu_ram_munmap(int fd, void *ptr, size_t size);
>  
> diff --git a/memory.c b/memory.c
> index 5d8c9a9..debed5e 100644
> --- a/memory.c
> +++ b/memory.c
> @@ -1622,7 +1622,7 @@ void memory_region_init_ram_from_fd(MemoryRegion *mr,
>      mr->destructor = memory_region_destructor_ram;
>      mr->ram_block = qemu_ram_alloc_from_fd(size, mr,
>                                             share ? RAM_SHARED : 0,
> -                                           fd, &err);
> +                                           fd, 0, &err);
>      mr->dirty_log_mask = tcg_enabled() ? (1 << DIRTY_MEMORY_CODE) : 0;
>      if (err) {
>          mr->size = int128_zero();
> diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c
> index f7f177d..4b727bd 100644
> --- a/util/mmap-alloc.c
> +++ b/util/mmap-alloc.c
> @@ -86,7 +86,8 @@ void *qemu_ram_mmap(int fd,
>                      size_t size,
>                      size_t align,
>                      bool shared,
> -                    bool is_pmem)
> +                    bool is_pmem,
> +                    off_t start)
>  {
>      int flags;
>      int map_sync_flags = 0;
> @@ -147,7 +148,7 @@ void *qemu_ram_mmap(int fd,
>      offset = QEMU_ALIGN_UP((uintptr_t)guardptr, align) - (uintptr_t)guardptr;
>  
>      ptr = mmap(guardptr + offset, size, PROT_READ | PROT_WRITE,
> -               flags | map_sync_flags, fd, 0);
> +               flags | map_sync_flags, fd, start);
>  
>      if (ptr == MAP_FAILED && map_sync_flags) {
>          if (errno == ENOTSUP) {
> @@ -172,7 +173,7 @@ void *qemu_ram_mmap(int fd,
>           * we will remove these flags to handle compatibility.
>           */
>          ptr = mmap(guardptr + offset, size, PROT_READ | PROT_WRITE,
> -                   flags, fd, 0);
> +                   flags, fd, start);
>      }
>  
>      if (ptr == MAP_FAILED) {
> diff --git a/util/oslib-posix.c b/util/oslib-posix.c
> index fe0309c..f6a243f 100644
> --- a/util/oslib-posix.c
> +++ b/util/oslib-posix.c
> @@ -204,7 +204,7 @@ void *qemu_memalign(size_t alignment, size_t size)
>  void *qemu_anon_ram_alloc(size_t size, uint64_t *alignment, bool shared)
>  {
>      size_t align = QEMU_VMALLOC_ALIGN;
> -    void *ptr = qemu_ram_mmap(-1, size, align, shared, false);
> +    void *ptr = qemu_ram_mmap(-1, size, align, shared, false, 0);
>  
>      if (ptr == MAP_FAILED) {
>          return NULL;
> -- 
> 1.8.3.1
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
Jag Raman Sept. 5, 2019, 3:07 p.m. UTC | #2
On 9/4/2019 4:11 AM, Dr. David Alan Gilbert wrote:
> * Jagannathan Raman (jag.raman@oracle.com) wrote:
>> Allow RAM MemoryRegion to be created from an offset in a file, instead
>> of allocating at offset of 0 by default. This is needed to synchronize
>> RAM between QEMU & remote process.
>> This will be needed for the following patches.
>>
>> Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
>> Signed-off-by: John G Johnson <john.g.johnson@oracle.com>
>> Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
>> ---
>>   exec.c                    | 11 +++++++----
>>   include/exec/ram_addr.h   |  2 +-
>>   include/qemu/mmap-alloc.h |  3 ++-
>>   memory.c                  |  2 +-
>>   util/mmap-alloc.c         |  7 ++++---
>>   util/oslib-posix.c        |  2 +-
>>   6 files changed, 16 insertions(+), 11 deletions(-)
> 
> I'm surprised this doesn't change something in
> vhost-user.c:vhost_user_set_mem_table so that the vhost-user client
> knows what it's mapping?

Hi Dave,

vhost-user does not use the functions addressed in this patch for
mapping the RAM onto the remote process. It calls mmap() for this
purpose (vu_set_mem_table_exec()).

Thanks!
--
Jag

> 
> Dave
> 
>> diff --git a/exec.c b/exec.c
>> index 3e78de3..b3f1aa9 100644
>> --- a/exec.c
>> +++ b/exec.c
>> @@ -1885,6 +1885,7 @@ static void *file_ram_alloc(RAMBlock *block,
>>                               ram_addr_t memory,
>>                               int fd,
>>                               bool truncate,
>> +                            off_t offset,
>>                               Error **errp)
>>   {
>>       MachineState *ms = MACHINE(qdev_get_machine());
>> @@ -1936,7 +1937,8 @@ static void *file_ram_alloc(RAMBlock *block,
>>       }
>>   
>>       area = qemu_ram_mmap(fd, memory, block->mr->align,
>> -                         block->flags & RAM_SHARED, block->flags & RAM_PMEM);
>> +                         block->flags & RAM_SHARED, block->flags & RAM_PMEM,
>> +                         offset);
>>       if (area == MAP_FAILED) {
>>           error_setg_errno(errp, errno,
>>                            "unable to map backing store for guest RAM");
>> @@ -2325,7 +2327,7 @@ static void ram_block_add(RAMBlock *new_block, Error **errp, bool shared)
>>   #ifdef CONFIG_POSIX
>>   RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr,
>>                                    uint32_t ram_flags, int fd,
>> -                                 Error **errp)
>> +                                 off_t offset, Error **errp)
>>   {
>>       RAMBlock *new_block;
>>       Error *local_err = NULL;
>> @@ -2370,7 +2372,8 @@ RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr,
>>       new_block->used_length = size;
>>       new_block->max_length = size;
>>       new_block->flags = ram_flags;
>> -    new_block->host = file_ram_alloc(new_block, size, fd, !file_size, errp);
>> +    new_block->host = file_ram_alloc(new_block, size, fd, !file_size, offset,
>> +                                     errp);
>>       if (!new_block->host) {
>>           g_free(new_block);
>>           return NULL;
>> @@ -2400,7 +2403,7 @@ RAMBlock *qemu_ram_alloc_from_file(ram_addr_t size, MemoryRegion *mr,
>>           return NULL;
>>       }
>>   
>> -    block = qemu_ram_alloc_from_fd(size, mr, ram_flags, fd, errp);
>> +    block = qemu_ram_alloc_from_fd(size, mr, ram_flags, fd, 0, errp);
>>       if (!block) {
>>           if (created) {
>>               unlink(mem_path);
>> diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h
>> index b7b2e60..15837a1 100644
>> --- a/include/exec/ram_addr.h
>> +++ b/include/exec/ram_addr.h
>> @@ -164,7 +164,7 @@ RAMBlock *qemu_ram_alloc_from_file(ram_addr_t size, MemoryRegion *mr,
>>                                      Error **errp);
>>   RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr,
>>                                    uint32_t ram_flags, int fd,
>> -                                 Error **errp);
>> +                                 off_t offset, Error **errp);
>>   
>>   RAMBlock *qemu_ram_alloc_from_ptr(ram_addr_t size, void *host,
>>                                     MemoryRegion *mr, Error **errp);
>> diff --git a/include/qemu/mmap-alloc.h b/include/qemu/mmap-alloc.h
>> index e786266..4f57985 100644
>> --- a/include/qemu/mmap-alloc.h
>> +++ b/include/qemu/mmap-alloc.h
>> @@ -25,7 +25,8 @@ void *qemu_ram_mmap(int fd,
>>                       size_t size,
>>                       size_t align,
>>                       bool shared,
>> -                    bool is_pmem);
>> +                    bool is_pmem,
>> +                    off_t start);
>>   
>>   void qemu_ram_munmap(int fd, void *ptr, size_t size);
>>   
>> diff --git a/memory.c b/memory.c
>> index 5d8c9a9..debed5e 100644
>> --- a/memory.c
>> +++ b/memory.c
>> @@ -1622,7 +1622,7 @@ void memory_region_init_ram_from_fd(MemoryRegion *mr,
>>       mr->destructor = memory_region_destructor_ram;
>>       mr->ram_block = qemu_ram_alloc_from_fd(size, mr,
>>                                              share ? RAM_SHARED : 0,
>> -                                           fd, &err);
>> +                                           fd, 0, &err);
>>       mr->dirty_log_mask = tcg_enabled() ? (1 << DIRTY_MEMORY_CODE) : 0;
>>       if (err) {
>>           mr->size = int128_zero();
>> diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c
>> index f7f177d..4b727bd 100644
>> --- a/util/mmap-alloc.c
>> +++ b/util/mmap-alloc.c
>> @@ -86,7 +86,8 @@ void *qemu_ram_mmap(int fd,
>>                       size_t size,
>>                       size_t align,
>>                       bool shared,
>> -                    bool is_pmem)
>> +                    bool is_pmem,
>> +                    off_t start)
>>   {
>>       int flags;
>>       int map_sync_flags = 0;
>> @@ -147,7 +148,7 @@ void *qemu_ram_mmap(int fd,
>>       offset = QEMU_ALIGN_UP((uintptr_t)guardptr, align) - (uintptr_t)guardptr;
>>   
>>       ptr = mmap(guardptr + offset, size, PROT_READ | PROT_WRITE,
>> -               flags | map_sync_flags, fd, 0);
>> +               flags | map_sync_flags, fd, start);
>>   
>>       if (ptr == MAP_FAILED && map_sync_flags) {
>>           if (errno == ENOTSUP) {
>> @@ -172,7 +173,7 @@ void *qemu_ram_mmap(int fd,
>>            * we will remove these flags to handle compatibility.
>>            */
>>           ptr = mmap(guardptr + offset, size, PROT_READ | PROT_WRITE,
>> -                   flags, fd, 0);
>> +                   flags, fd, start);
>>       }
>>   
>>       if (ptr == MAP_FAILED) {
>> diff --git a/util/oslib-posix.c b/util/oslib-posix.c
>> index fe0309c..f6a243f 100644
>> --- a/util/oslib-posix.c
>> +++ b/util/oslib-posix.c
>> @@ -204,7 +204,7 @@ void *qemu_memalign(size_t alignment, size_t size)
>>   void *qemu_anon_ram_alloc(size_t size, uint64_t *alignment, bool shared)
>>   {
>>       size_t align = QEMU_VMALLOC_ALIGN;
>> -    void *ptr = qemu_ram_mmap(-1, size, align, shared, false);
>> +    void *ptr = qemu_ram_mmap(-1, size, align, shared, false, 0);
>>   
>>       if (ptr == MAP_FAILED) {
>>           return NULL;
>> -- 
>> 1.8.3.1
>>
> --
> Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
>
Dr. David Alan Gilbert Sept. 5, 2019, 3:17 p.m. UTC | #3
* Jag Raman (jag.raman@oracle.com) wrote:
> 
> 
> On 9/4/2019 4:11 AM, Dr. David Alan Gilbert wrote:
> > * Jagannathan Raman (jag.raman@oracle.com) wrote:
> > > Allow RAM MemoryRegion to be created from an offset in a file, instead
> > > of allocating at offset of 0 by default. This is needed to synchronize
> > > RAM between QEMU & remote process.
> > > This will be needed for the following patches.
> > > 
> > > Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
> > > Signed-off-by: John G Johnson <john.g.johnson@oracle.com>
> > > Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
> > > ---
> > >   exec.c                    | 11 +++++++----
> > >   include/exec/ram_addr.h   |  2 +-
> > >   include/qemu/mmap-alloc.h |  3 ++-
> > >   memory.c                  |  2 +-
> > >   util/mmap-alloc.c         |  7 ++++---
> > >   util/oslib-posix.c        |  2 +-
> > >   6 files changed, 16 insertions(+), 11 deletions(-)
> > 
> > I'm surprised this doesn't change something in
> > vhost-user.c:vhost_user_set_mem_table so that the vhost-user client
> > knows what it's mapping?
> 
> Hi Dave,
> 
> vhost-user does not use the functions addressed in this patch for
> mapping the RAM onto the remote process. It calls mmap() for this
> purpose (vu_set_mem_table_exec()).

It should at least check that the file it's sending over set-mem-table
has a 0 offset, otherwise things could get confused if someone tries
to run a vhost-user device on a system that's also running multi-process
(which should be a whole world of fun!)

dave

> Thanks!
> --
> Jag
> 
> > 
> > Dave
> > 
> > > diff --git a/exec.c b/exec.c
> > > index 3e78de3..b3f1aa9 100644
> > > --- a/exec.c
> > > +++ b/exec.c
> > > @@ -1885,6 +1885,7 @@ static void *file_ram_alloc(RAMBlock *block,
> > >                               ram_addr_t memory,
> > >                               int fd,
> > >                               bool truncate,
> > > +                            off_t offset,
> > >                               Error **errp)
> > >   {
> > >       MachineState *ms = MACHINE(qdev_get_machine());
> > > @@ -1936,7 +1937,8 @@ static void *file_ram_alloc(RAMBlock *block,
> > >       }
> > >       area = qemu_ram_mmap(fd, memory, block->mr->align,
> > > -                         block->flags & RAM_SHARED, block->flags & RAM_PMEM);
> > > +                         block->flags & RAM_SHARED, block->flags & RAM_PMEM,
> > > +                         offset);
> > >       if (area == MAP_FAILED) {
> > >           error_setg_errno(errp, errno,
> > >                            "unable to map backing store for guest RAM");
> > > @@ -2325,7 +2327,7 @@ static void ram_block_add(RAMBlock *new_block, Error **errp, bool shared)
> > >   #ifdef CONFIG_POSIX
> > >   RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr,
> > >                                    uint32_t ram_flags, int fd,
> > > -                                 Error **errp)
> > > +                                 off_t offset, Error **errp)
> > >   {
> > >       RAMBlock *new_block;
> > >       Error *local_err = NULL;
> > > @@ -2370,7 +2372,8 @@ RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr,
> > >       new_block->used_length = size;
> > >       new_block->max_length = size;
> > >       new_block->flags = ram_flags;
> > > -    new_block->host = file_ram_alloc(new_block, size, fd, !file_size, errp);
> > > +    new_block->host = file_ram_alloc(new_block, size, fd, !file_size, offset,
> > > +                                     errp);
> > >       if (!new_block->host) {
> > >           g_free(new_block);
> > >           return NULL;
> > > @@ -2400,7 +2403,7 @@ RAMBlock *qemu_ram_alloc_from_file(ram_addr_t size, MemoryRegion *mr,
> > >           return NULL;
> > >       }
> > > -    block = qemu_ram_alloc_from_fd(size, mr, ram_flags, fd, errp);
> > > +    block = qemu_ram_alloc_from_fd(size, mr, ram_flags, fd, 0, errp);
> > >       if (!block) {
> > >           if (created) {
> > >               unlink(mem_path);
> > > diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h
> > > index b7b2e60..15837a1 100644
> > > --- a/include/exec/ram_addr.h
> > > +++ b/include/exec/ram_addr.h
> > > @@ -164,7 +164,7 @@ RAMBlock *qemu_ram_alloc_from_file(ram_addr_t size, MemoryRegion *mr,
> > >                                      Error **errp);
> > >   RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr,
> > >                                    uint32_t ram_flags, int fd,
> > > -                                 Error **errp);
> > > +                                 off_t offset, Error **errp);
> > >   RAMBlock *qemu_ram_alloc_from_ptr(ram_addr_t size, void *host,
> > >                                     MemoryRegion *mr, Error **errp);
> > > diff --git a/include/qemu/mmap-alloc.h b/include/qemu/mmap-alloc.h
> > > index e786266..4f57985 100644
> > > --- a/include/qemu/mmap-alloc.h
> > > +++ b/include/qemu/mmap-alloc.h
> > > @@ -25,7 +25,8 @@ void *qemu_ram_mmap(int fd,
> > >                       size_t size,
> > >                       size_t align,
> > >                       bool shared,
> > > -                    bool is_pmem);
> > > +                    bool is_pmem,
> > > +                    off_t start);
> > >   void qemu_ram_munmap(int fd, void *ptr, size_t size);
> > > diff --git a/memory.c b/memory.c
> > > index 5d8c9a9..debed5e 100644
> > > --- a/memory.c
> > > +++ b/memory.c
> > > @@ -1622,7 +1622,7 @@ void memory_region_init_ram_from_fd(MemoryRegion *mr,
> > >       mr->destructor = memory_region_destructor_ram;
> > >       mr->ram_block = qemu_ram_alloc_from_fd(size, mr,
> > >                                              share ? RAM_SHARED : 0,
> > > -                                           fd, &err);
> > > +                                           fd, 0, &err);
> > >       mr->dirty_log_mask = tcg_enabled() ? (1 << DIRTY_MEMORY_CODE) : 0;
> > >       if (err) {
> > >           mr->size = int128_zero();
> > > diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c
> > > index f7f177d..4b727bd 100644
> > > --- a/util/mmap-alloc.c
> > > +++ b/util/mmap-alloc.c
> > > @@ -86,7 +86,8 @@ void *qemu_ram_mmap(int fd,
> > >                       size_t size,
> > >                       size_t align,
> > >                       bool shared,
> > > -                    bool is_pmem)
> > > +                    bool is_pmem,
> > > +                    off_t start)
> > >   {
> > >       int flags;
> > >       int map_sync_flags = 0;
> > > @@ -147,7 +148,7 @@ void *qemu_ram_mmap(int fd,
> > >       offset = QEMU_ALIGN_UP((uintptr_t)guardptr, align) - (uintptr_t)guardptr;
> > >       ptr = mmap(guardptr + offset, size, PROT_READ | PROT_WRITE,
> > > -               flags | map_sync_flags, fd, 0);
> > > +               flags | map_sync_flags, fd, start);
> > >       if (ptr == MAP_FAILED && map_sync_flags) {
> > >           if (errno == ENOTSUP) {
> > > @@ -172,7 +173,7 @@ void *qemu_ram_mmap(int fd,
> > >            * we will remove these flags to handle compatibility.
> > >            */
> > >           ptr = mmap(guardptr + offset, size, PROT_READ | PROT_WRITE,
> > > -                   flags, fd, 0);
> > > +                   flags, fd, start);
> > >       }
> > >       if (ptr == MAP_FAILED) {
> > > diff --git a/util/oslib-posix.c b/util/oslib-posix.c
> > > index fe0309c..f6a243f 100644
> > > --- a/util/oslib-posix.c
> > > +++ b/util/oslib-posix.c
> > > @@ -204,7 +204,7 @@ void *qemu_memalign(size_t alignment, size_t size)
> > >   void *qemu_anon_ram_alloc(size_t size, uint64_t *alignment, bool shared)
> > >   {
> > >       size_t align = QEMU_VMALLOC_ALIGN;
> > > -    void *ptr = qemu_ram_mmap(-1, size, align, shared, false);
> > > +    void *ptr = qemu_ram_mmap(-1, size, align, shared, false, 0);
> > >       if (ptr == MAP_FAILED) {
> > >           return NULL;
> > > -- 
> > > 1.8.3.1
> > > 
> > --
> > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
> > 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
diff mbox series

Patch

diff --git a/exec.c b/exec.c
index 3e78de3..b3f1aa9 100644
--- a/exec.c
+++ b/exec.c
@@ -1885,6 +1885,7 @@  static void *file_ram_alloc(RAMBlock *block,
                             ram_addr_t memory,
                             int fd,
                             bool truncate,
+                            off_t offset,
                             Error **errp)
 {
     MachineState *ms = MACHINE(qdev_get_machine());
@@ -1936,7 +1937,8 @@  static void *file_ram_alloc(RAMBlock *block,
     }
 
     area = qemu_ram_mmap(fd, memory, block->mr->align,
-                         block->flags & RAM_SHARED, block->flags & RAM_PMEM);
+                         block->flags & RAM_SHARED, block->flags & RAM_PMEM,
+                         offset);
     if (area == MAP_FAILED) {
         error_setg_errno(errp, errno,
                          "unable to map backing store for guest RAM");
@@ -2325,7 +2327,7 @@  static void ram_block_add(RAMBlock *new_block, Error **errp, bool shared)
 #ifdef CONFIG_POSIX
 RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr,
                                  uint32_t ram_flags, int fd,
-                                 Error **errp)
+                                 off_t offset, Error **errp)
 {
     RAMBlock *new_block;
     Error *local_err = NULL;
@@ -2370,7 +2372,8 @@  RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr,
     new_block->used_length = size;
     new_block->max_length = size;
     new_block->flags = ram_flags;
-    new_block->host = file_ram_alloc(new_block, size, fd, !file_size, errp);
+    new_block->host = file_ram_alloc(new_block, size, fd, !file_size, offset,
+                                     errp);
     if (!new_block->host) {
         g_free(new_block);
         return NULL;
@@ -2400,7 +2403,7 @@  RAMBlock *qemu_ram_alloc_from_file(ram_addr_t size, MemoryRegion *mr,
         return NULL;
     }
 
-    block = qemu_ram_alloc_from_fd(size, mr, ram_flags, fd, errp);
+    block = qemu_ram_alloc_from_fd(size, mr, ram_flags, fd, 0, errp);
     if (!block) {
         if (created) {
             unlink(mem_path);
diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h
index b7b2e60..15837a1 100644
--- a/include/exec/ram_addr.h
+++ b/include/exec/ram_addr.h
@@ -164,7 +164,7 @@  RAMBlock *qemu_ram_alloc_from_file(ram_addr_t size, MemoryRegion *mr,
                                    Error **errp);
 RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr,
                                  uint32_t ram_flags, int fd,
-                                 Error **errp);
+                                 off_t offset, Error **errp);
 
 RAMBlock *qemu_ram_alloc_from_ptr(ram_addr_t size, void *host,
                                   MemoryRegion *mr, Error **errp);
diff --git a/include/qemu/mmap-alloc.h b/include/qemu/mmap-alloc.h
index e786266..4f57985 100644
--- a/include/qemu/mmap-alloc.h
+++ b/include/qemu/mmap-alloc.h
@@ -25,7 +25,8 @@  void *qemu_ram_mmap(int fd,
                     size_t size,
                     size_t align,
                     bool shared,
-                    bool is_pmem);
+                    bool is_pmem,
+                    off_t start);
 
 void qemu_ram_munmap(int fd, void *ptr, size_t size);
 
diff --git a/memory.c b/memory.c
index 5d8c9a9..debed5e 100644
--- a/memory.c
+++ b/memory.c
@@ -1622,7 +1622,7 @@  void memory_region_init_ram_from_fd(MemoryRegion *mr,
     mr->destructor = memory_region_destructor_ram;
     mr->ram_block = qemu_ram_alloc_from_fd(size, mr,
                                            share ? RAM_SHARED : 0,
-                                           fd, &err);
+                                           fd, 0, &err);
     mr->dirty_log_mask = tcg_enabled() ? (1 << DIRTY_MEMORY_CODE) : 0;
     if (err) {
         mr->size = int128_zero();
diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c
index f7f177d..4b727bd 100644
--- a/util/mmap-alloc.c
+++ b/util/mmap-alloc.c
@@ -86,7 +86,8 @@  void *qemu_ram_mmap(int fd,
                     size_t size,
                     size_t align,
                     bool shared,
-                    bool is_pmem)
+                    bool is_pmem,
+                    off_t start)
 {
     int flags;
     int map_sync_flags = 0;
@@ -147,7 +148,7 @@  void *qemu_ram_mmap(int fd,
     offset = QEMU_ALIGN_UP((uintptr_t)guardptr, align) - (uintptr_t)guardptr;
 
     ptr = mmap(guardptr + offset, size, PROT_READ | PROT_WRITE,
-               flags | map_sync_flags, fd, 0);
+               flags | map_sync_flags, fd, start);
 
     if (ptr == MAP_FAILED && map_sync_flags) {
         if (errno == ENOTSUP) {
@@ -172,7 +173,7 @@  void *qemu_ram_mmap(int fd,
          * we will remove these flags to handle compatibility.
          */
         ptr = mmap(guardptr + offset, size, PROT_READ | PROT_WRITE,
-                   flags, fd, 0);
+                   flags, fd, start);
     }
 
     if (ptr == MAP_FAILED) {
diff --git a/util/oslib-posix.c b/util/oslib-posix.c
index fe0309c..f6a243f 100644
--- a/util/oslib-posix.c
+++ b/util/oslib-posix.c
@@ -204,7 +204,7 @@  void *qemu_memalign(size_t alignment, size_t size)
 void *qemu_anon_ram_alloc(size_t size, uint64_t *alignment, bool shared)
 {
     size_t align = QEMU_VMALLOC_ALIGN;
-    void *ptr = qemu_ram_mmap(-1, size, align, shared, false);
+    void *ptr = qemu_ram_mmap(-1, size, align, shared, false, 0);
 
     if (ptr == MAP_FAILED) {
         return NULL;