minix/servers/vm/map_mem.c

327 lines
9.2 KiB
C
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#define _SYSTEM 1
#include <minix/type.h>
#include <minix/config.h>
#include <minix/const.h>
#include <minix/sysutil.h>
#include <minix/syslib.h>
#include <limits.h>
#include <errno.h>
#include <assert.h>
#include <stdint.h>
#include <memory.h>
#include "vm.h"
#include "proto.h"
#include "util.h"
#include "glo.h"
#include "region.h"
#include "sanitycheck.h"
/*===========================================================================*
* split_phys *
*===========================================================================*/
PRIVATE int split_phys(struct phys_region *pr, vir_bytes point)
{
struct phys_region *newpr, *q, *prev;
struct phys_block *newpb;
struct phys_block *pb = pr->ph;
/* Split the phys region into 2 parts by @point. */
if(pr->offset >= point || pr->offset + pb->length <= point)
return OK;
if(!SLABALLOC(newpb))
return ENOMEM;
/* Split phys block. */
*newpb = *pb;
pb->length = point - pr->offset;
newpb->length -= pb->length;
newpb->phys += pb->length;
/* Split phys regions in a list. */
for(q = pb->firstregion; q; q = q->next_ph_list) {
if(!SLABALLOC(newpr))
return ENOMEM;
*newpr = *q;
newpr->ph = newpb;
newpr->offset += pb->length;
/* Link to the vir region's phys region list. */
physr_insert(newpr->parent->phys, newpr);
/* Link to the next_ph_list. */
if(q == pb->firstregion) {
newpb->firstregion = newpr;
prev = newpr;
} else {
prev->next_ph_list = newpr;
prev = newpr;
}
}
prev->next_ph_list = NULL;
return OK;
}
/*===========================================================================*
* rm_phys_regions *
*===========================================================================*/
PRIVATE void rm_phys_regions(struct vir_region *region,
vir_bytes begin, vir_bytes length)
{
/* Remove all phys regions between @begin and @begin+length.
*
* Don't update the page table, because we will update it at map_memory()
* later.
*/
struct phys_region *pr;
physr_iter iter;
physr_start_iter(region->phys, &iter, begin, AVL_GREATER_EQUAL);
while((pr = physr_get_iter(&iter)) && pr->offset < begin + length) {
pb_unreferenced(region, pr);
physr_remove(region->phys, pr->offset);
physr_start_iter(region->phys, &iter, begin,
AVL_GREATER_EQUAL);
SLABFREE(pr);
}
}
/*===========================================================================*
* clean_phys_regions *
*===========================================================================*/
PRIVATE void clean_phys_regions(struct vir_region *region,
vir_bytes offset, vir_bytes length)
{
/* Consider @offset as the start address and @offset+length as the end address.
* If there are phys regions crossing the start address or the end address,
* split them into 2 parts.
*
* We assume that the phys regions are listed in order and don't overlap.
*/
struct phys_region *pr;
physr_iter iter;
physr_start_iter_least(region->phys, &iter);
while((pr = physr_get_iter(&iter))) {
/* If this phys region crosses the start address, split it. */
if(pr->offset < offset
&& pr->offset + pr->ph->length > offset) {
split_phys(pr, offset);
physr_start_iter_least(region->phys, &iter);
}
/* If this phys region crosses the end address, split it. */
else if(pr->offset < offset + length
&& pr->offset + pr->ph->length > offset + length) {
split_phys(pr, offset + length);
physr_start_iter_least(region->phys, &iter);
}
else {
physr_incr_iter(&iter);
}
}
}
/*===========================================================================*
* do_map_memory *
*===========================================================================*/
PRIVATE int do_map_memory(struct vmproc *vms, struct vmproc *vmd,
struct vir_region *vrs, struct vir_region *vrd,
vir_bytes offset_s, vir_bytes offset_d,
vir_bytes length, int flag)
{
struct phys_region *prs;
struct phys_region *newphysr;
struct phys_block *pb;
physr_iter iter;
u32_t pt_flag = PTF_PRESENT | PTF_USER;
vir_bytes end;
/* Search for the first phys region in the source process. */
physr_start_iter(vrs->phys, &iter, offset_s, AVL_EQUAL);
prs = physr_get_iter(&iter);
if(!prs)
panic("map_memory: no aligned phys region: %d", 0);
/* flag: 0 -> read-only
* 1 -> writable
* -1 -> share as COW, so read-only
*/
if(flag > 0)
pt_flag |= PTF_WRITE;
/* Map phys blocks in the source process to the destination process. */
end = offset_d + length;
while((prs = physr_get_iter(&iter)) && offset_d < end) {
/* If a SMAP share was requested but the phys block has already
* been shared as COW, copy the block for the source phys region
* first.
*/
pb = prs->ph;
if(flag >= 0 && pb->refcount > 1
&& pb->share_flag == PBSH_COW) {
map_copy_ph_block(vms, vrs, prs);
pb = prs->ph;
}
/* Allocate a new phys region. */
if(!SLABALLOC(newphysr))
return ENOMEM;
/* Set and link the new phys region to the block. */
newphysr->ph = pb;
newphysr->offset = offset_d;
newphysr->parent = vrd;
newphysr->next_ph_list = pb->firstregion;
pb->firstregion = newphysr;
physr_insert(newphysr->parent->phys, newphysr);
pb->refcount++;
/* If a COW share was requested but the phys block has already
* been shared as SMAP, give up on COW and copy the block for
* the destination phys region now.
*/
if(flag < 0 && pb->refcount > 1
&& pb->share_flag == PBSH_SMAP) {
map_copy_ph_block(vmd, vrd, newphysr);
}
else {
/* See if this is a COW share or SMAP share. */
if(flag < 0) { /* COW share */
pb->share_flag = PBSH_COW;
/* Update the page table for the src process. */
pt_writemap(&vms->vm_pt, offset_s + vrs->vaddr,
pb->phys, pb->length,
pt_flag, WMF_OVERWRITE);
}
else { /* SMAP share */
pb->share_flag = PBSH_SMAP;
}
/* Update the page table for the destination process. */
pt_writemap(&vmd->vm_pt, offset_d + vrd->vaddr,
pb->phys, pb->length, pt_flag, WMF_OVERWRITE);
}
physr_incr_iter(&iter);
offset_d += pb->length;
offset_s += pb->length;
}
return OK;
}
/*===========================================================================*
* map_memory *
*===========================================================================*/
PUBLIC int map_memory(endpoint_t sour, endpoint_t dest,
vir_bytes virt_s, vir_bytes virt_d, vir_bytes length, int flag)
{
/* This is the entry point. This function will be called by handle_memory() when
* VM recieves a map-memory request.
*/
struct vmproc *vms, *vmd;
struct vir_region *vrs, *vrd;
physr_iter iterd;
vir_bytes offset_s, offset_d;
int p;
int r;
if(vm_isokendpt(sour, &p) != OK)
panic("handle_memory: endpoint wrong: %d", sour);
vms = &vmproc[p];
if(vm_isokendpt(dest, &p) != OK)
panic("handle_memory: endpoint wrong: %d", dest);
vmd = &vmproc[p];
vrs = map_lookup(vms, virt_s);
vm_assert(vrs);
vrd = map_lookup(vmd, virt_d);
vm_assert(vrd);
/* Linear address -> offset from start of vir region. */
offset_s = virt_s - vrs->vaddr;
offset_d = virt_d - vrd->vaddr;
/* Make sure that the range in the source process has been mapped
* to physical memory.
*/
map_handle_memory(vms, vrs, offset_s, length, 0);
/* Prepare work. */
#define map_printregion(x, y) (x = x)
#define printf(x, y, z) (z = z)
printf("before clean with offset, length: %d, %d\n", offset_s, length);
map_printregion(vms, vrs);
clean_phys_regions(vrs, offset_s, length);
printf("after clean with offset, length: %d, %d\n", offset_s, length);
map_printregion(vms, vrs);
printf("before clean with offset, length: %d, %d\n", offset_d, length);
map_printregion(vmd, vrd);
clean_phys_regions(vrd, offset_d, length);
printf("after clean with offset, length: %d, %d\n", offset_d, length);
map_printregion(vmd, vrd);
rm_phys_regions(vrd, offset_d, length);
printf("after rm with offset, length: %d, %d\n", offset_d, length);
map_printregion(vmd, vrd);
/* Map memory. */
r = do_map_memory(vms, vmd, vrs, vrd, offset_s, offset_d, length, flag);
printf("after map (dst) with offset, length: %d, %d\n", offset_d, length);
map_printregion(vmd, vrd);
#undef map_printregion
#undef printf
return r;
}
/*===========================================================================*
* unmap_memory *
*===========================================================================*/
PUBLIC int unmap_memory(endpoint_t sour, endpoint_t dest,
vir_bytes virt_s, vir_bytes virt_d, vir_bytes length, int flag)
{
struct vmproc *vmd;
struct vir_region *vrd;
struct phys_region *pr;
struct phys_block *pb;
physr_iter iter;
vir_bytes off, end;
int p;
/* Use information on the destination process to unmap. */
if(vm_isokendpt(dest, &p) != OK)
panic("handle_memory: endpoint wrong: %d", dest);
vmd = &vmproc[p];
vrd = map_lookup(vmd, virt_d);
vm_assert(vrd);
/* Search for the first phys region in the destination process. */
off = virt_d - vrd->vaddr;
physr_start_iter(vrd->phys, &iter, off, AVL_EQUAL);
pr = physr_get_iter(&iter);
if(!pr)
panic("map_memory: no aligned phys region: %d", 0);
/* Copy the phys block now rather than doing COW. */
end = off + length;
while((pr = physr_get_iter(&iter)) && off < end) {
pb = pr->ph;
vm_assert(pb->refcount > 1);
vm_assert(pb->share_flag == PBSH_SMAP);
map_copy_ph_block(vmd, vrd, pr);
physr_incr_iter(&iter);
off += pb->length;
}
return OK;
}