static int shared_pagefault(struct vmproc *vmp, struct vir_region *region,
struct phys_region *ph, int write, vfs_callback_t cb,
void *state, int statelen, int *io)
{
struct vir_region *src_region;
struct vmproc *src_vmp;
struct phys_region *pr;
if(getsrc(region, &src_vmp, &src_region) != OK) {
return EINVAL;
}
assert(ph->ph->phys == MAP_NONE);
pb_free(ph->ph);
if(!(pr = physblock_get(src_region, ph->offset))) {
int r;
if((r=map_pf(src_vmp, src_region, ph->offset, write,
NULL, NULL, 0, io)) != OK)
return r;
if(!(pr = physblock_get(src_region, ph->offset))) {
panic("missing region after pagefault handling");
}
}
pb_link(ph, pr->ph, ph->offset, region);
return OK;
}
static int cache_pagefault(struct vmproc *vmp, struct vir_region *region,
struct phys_region *ph, int write, vfs_callback_t cb,
void *state, int len, int *io)
{
vir_bytes offset = ph->offset;
assert(ph->ph->phys == MAP_NONE);
assert(region->param.pb_cache);
pb_unreferenced(region, ph, 0);
pb_link(ph, region->param.pb_cache, offset, region);
region->param.pb_cache = NULL;
return OK;
}
static int mappedfile_pagefault(struct vmproc *vmp, struct vir_region *region,
struct phys_region *ph, int write, vfs_callback_t cb,
void *state, int statelen, int *io)
{
u32_t allocflags;
int procfd = region->param.file.fdref->fd;
allocflags = vrallocflags(region->flags);
assert(ph->ph->refcount > 0);
assert(region->param.file.inited);
assert(region->param.file.fdref);
assert(region->param.file.fdref->dev != NO_DEV);
/* Totally new block? Create it. */
if(ph->ph->phys == MAP_NONE) {
struct cached_page *cp;
u64_t referenced_offset =
region->param.file.offset + ph->offset;
if(region->param.file.fdref->ino == VMC_NO_INODE) {
cp = find_cached_page_bydev(region->param.file.fdref->dev,
referenced_offset, VMC_NO_INODE, 0, 1);
} else {
cp = find_cached_page_byino(region->param.file.fdref->dev,
region->param.file.fdref->ino, referenced_offset, 1);
}
if(cp) {
int result = OK;
pb_unreferenced(region, ph, 0);
pb_link(ph, cp->page, ph->offset, region);
if(roundup(ph->offset+region->param.file.clearend,
VM_PAGE_SIZE) >= region->length) {
result = cow_block(vmp, region, ph,
region->param.file.clearend);
} else if(result == OK && write) {
result = cow_block(vmp, region, ph, 0);
}
return result;
}
if(!cb) {
#if 0
printf("VM: mem_file: no callback, returning EFAULT\n");
#endif
sys_diagctl_stacktrace(vmp->vm_endpoint);
return EFAULT;
}
if(vfs_request(VMVFSREQ_FDIO, procfd, vmp, referenced_offset,
VM_PAGE_SIZE, cb, NULL, state, statelen) != OK) {
printf("VM: mappedfile_pagefault: vfs_request failed\n");
return ENOMEM;
}
*io = 1;
return SUSPEND;
}
if(!write) {
#if 0
printf("mappedfile_pagefault: nonwrite fault?\n");
#endif
return OK;
}
return cow_block(vmp, region, ph, 0);
}
static int mappedfile_pagefault(struct vmproc *vmp, struct vir_region *region,
struct phys_region *ph, int write, vfs_callback_t cb,
void *state, int statelen, int *io)
{
u32_t allocflags;
int procfd = region->param.file.fdref->fd;
allocflags = vrallocflags(region->flags);
assert(ph->ph->refcount > 0);
assert(region->param.file.inited);
assert(region->param.file.fdref);
assert(region->param.file.fdref->dev != NO_DEV);
/* Totally new block? Create it. */
if(ph->ph->phys == MAP_NONE) {
struct cached_page *cp;
u64_t referenced_offset =
region->param.file.offset + ph->offset;
if(region->param.file.fdref->ino == VMC_NO_INODE) {
cp = find_cached_page_bydev(region->param.file.fdref->dev,
referenced_offset, VMC_NO_INODE, 0, 1);
} else {
cp = find_cached_page_byino(region->param.file.fdref->dev,
region->param.file.fdref->ino, referenced_offset, 1);
}
/*
* Normally, a cache hit saves a round-trip to the file system
* to load the page. However, if the page in the VM cache is
* marked for one-time use, then force a round-trip through the
* file system anyway, so that the FS can update the page by
* by readding it to the cache. Thus, for one-time use pages,
* no caching is performed. This approach is correct even in
* the light of concurrent requests and disappearing processes
* but relies on VM requests to VFS being fully serialized.
*/
if(cp && (!cb || !(cp->flags & VMSF_ONCE))) {
int result = OK;
pb_unreferenced(region, ph, 0);
pb_link(ph, cp->page, ph->offset, region);
if(roundup(ph->offset+region->param.file.clearend,
VM_PAGE_SIZE) >= region->length) {
result = cow_block(vmp, region, ph,
region->param.file.clearend);
} else if(result == OK && write) {
result = cow_block(vmp, region, ph, 0);
}
/* Discard one-use pages after mapping them in. */
if (result == OK && (cp->flags & VMSF_ONCE))
rmcache(cp);
return result;
}
if(!cb) {
#if 0
printf("VM: mem_file: no callback, returning EFAULT\n");
sys_diagctl_stacktrace(vmp->vm_endpoint);
#endif
return EFAULT;
}
if(vfs_request(VMVFSREQ_FDIO, procfd, vmp, referenced_offset,
VM_PAGE_SIZE, cb, NULL, state, statelen) != OK) {
printf("VM: mappedfile_pagefault: vfs_request failed\n");
return ENOMEM;
}
*io = 1;
return SUSPEND;
}
if(!write) {
#if 0
printf("mappedfile_pagefault: nonwrite fault?\n");
#endif
return OK;
}
return cow_block(vmp, region, ph, 0);
}
