| Message ID | 1270680720-8457-3-git-send-email-cam@cs.ualberta.ca |
|---|---|
| State | New |
| Headers | show |
On 04/08/2010 01:51 AM, Cam Macdonell wrote: > This avoids the need of using qemu_ram_alloc and mmap with MAP_FIXED to map a > host file into guest RAM. This function mmaps the opened file anywhere and adds > the memory to the ram blocks. > > Usage is > > qemu_ram_mmap(fd, size, MAP_SHARED, offset); > --- > cpu-common.h | 1 + > exec.c | 33 +++++++++++++++++++++++++++++++++ > 2 files changed, 34 insertions(+), 0 deletions(-) > > diff --git a/cpu-common.h b/cpu-common.h > index 49c7fb3..87c82fc 100644 > --- a/cpu-common.h > +++ b/cpu-common.h > @@ -32,6 +32,7 @@ static inline void cpu_register_physical_memory(target_phys_addr_t start_addr, > } > > ram_addr_t cpu_get_physical_page_desc(target_phys_addr_t addr); > +ram_addr_t qemu_ram_mmap(int, ram_addr_t, int, int); > Use prototypes with argument names please. That's not the style around it, but that's bad style. > > +ram_addr_t qemu_ram_mmap(int fd, ram_addr_t size, int flags, int offset) > off_t offset > +{ > + RAMBlock *new_block; > + > + size = TARGET_PAGE_ALIGN(size); > + new_block = qemu_malloc(sizeof(*new_block)); > + > + // map the file passed as a parameter to be this part of memory > /* comments */ > + new_block->host = mmap(0, size, PROT_READ|PROT_WRITE, flags, fd, offset); > Error checking. > + > +#ifdef MADV_MERGEABLE > + madvise(new_block->host, size, MADV_MERGEABLE); > +#endif > Won't work (ksm only merges anonymous pages), but keep it there in case it learns about pagecache.
diff --git a/cpu-common.h b/cpu-common.h index 49c7fb3..87c82fc 100644 --- a/cpu-common.h +++ b/cpu-common.h @@ -32,6 +32,7 @@ static inline void cpu_register_physical_memory(target_phys_addr_t start_addr, } ram_addr_t cpu_get_physical_page_desc(target_phys_addr_t addr); +ram_addr_t qemu_ram_mmap(int, ram_addr_t, int, int); ram_addr_t qemu_ram_alloc(ram_addr_t); void qemu_ram_free(ram_addr_t addr); /* This should only be used for ram local to a device. */ diff --git a/exec.c b/exec.c index 467a0e7..2303be7 100644 --- a/exec.c +++ b/exec.c @@ -2811,6 +2811,39 @@ static void *file_ram_alloc(ram_addr_t memory, const char *path) } #endif +ram_addr_t qemu_ram_mmap(int fd, ram_addr_t size, int flags, int offset) +{ + RAMBlock *new_block; + + size = TARGET_PAGE_ALIGN(size); + new_block = qemu_malloc(sizeof(*new_block)); + + // map the file passed as a parameter to be this part of memory + new_block->host = mmap(0, size, PROT_READ|PROT_WRITE, flags, fd, offset); + +#ifdef MADV_MERGEABLE + madvise(new_block->host, size, MADV_MERGEABLE); +#endif + + new_block->offset = last_ram_offset; + new_block->length = size; + + new_block->next = ram_blocks; + ram_blocks = new_block; + + phys_ram_dirty = qemu_realloc(phys_ram_dirty, + (last_ram_offset + size) >> TARGET_PAGE_BITS); + memset(phys_ram_dirty + (last_ram_offset >> TARGET_PAGE_BITS), + 0xff, size >> TARGET_PAGE_BITS); + + last_ram_offset += size; + + if (kvm_enabled()) + kvm_setup_guest_memory(new_block->host, size); + + return new_block->offset; +} + ram_addr_t qemu_ram_alloc(ram_addr_t size) { RAMBlock *new_block;