Mem: Separate the host and guest views of memory backing store

This patch moves all the memory backing store operations from the
independent memory controllers to the global physical memory. The main
reason for this patch is to allow address striping in a future set of
patches, but at this point it already provides some useful
functionality in that it is now possible to change the number of
memory controllers and their address mapping in combination with
checkpointing. Thus, the host and guest view of the memory backing
store are now completely separate.

With this patch, the individual memory controllers are far simpler as
all responsibility for serializing/unserializing is moved to the
physical memory. Currently, the functionality is more or less moved
from AbstractMemory to PhysicalMemory without any major
changes. However, in a future patch the physical memory will also
resolve any ranges that are interleaved and properly assign the
backing store to the memory controllers, and keep the host memory as a
single contigous chunk per address range.

Functionality for future extensions which involve CPU virtualization
also enable the host to get pointers to the backing store.

1 files changed, 3 insertions, 176 deletions

diff --git a/src/mem/abstract_mem.cc b/src/mem/abstract_mem.cc
index 4d34bec80..086985f8d 100644
--- a/src/mem/abstract_mem.cc
+++ b/src/mem/abstract_mem.cc
@@ -42,19 +42,6 @@
  *          Andreas Hansson
  */
 
-#include <sys/mman.h>
-#include <sys/types.h>
-#include <sys/user.h>
-#include <fcntl.h>
-#include <unistd.h>
-#include <zlib.h>
-
-#include <cerrno>
-#include <cstdio>
-#include <climits>
-#include <iostream>
-#include <string>
-
 #include "arch/registers.hh"
 #include "config/the_isa.hh"
 #include "debug/LLSC.hh"
@@ -72,29 +59,12 @@ AbstractMemory::AbstractMemory(const Params *p) :
 {
     if (size() % TheISA::PageBytes != 0)
         panic("Memory Size not divisible by page size\n");
-
-    if (params()->null)
-        return;
-
-    int map_flags = MAP_ANON | MAP_PRIVATE;
-    pmemAddr = (uint8_t *)mmap(NULL, size(),
-                               PROT_READ | PROT_WRITE, map_flags, -1, 0);
-
-    if (pmemAddr == (void *)MAP_FAILED) {
-        perror("mmap");
-        fatal("Could not mmap!\n");
-    }
-
-    //If requested, initialize all the memory to 0
-    if (p->zero)
-        memset(pmemAddr, 0, size());
 }
 
-
-AbstractMemory::~AbstractMemory()
+void
+AbstractMemory::setBackingStore(uint8_t* pmem_addr)
 {
-    if (pmemAddr)
-        munmap((char*)pmemAddr, size());
+    pmemAddr = pmem_addr;
 }
 
 void
@@ -443,146 +413,3 @@ AbstractMemory::functionalAccess(PacketPtr pkt)
               pkt->cmdString());
     }
 }
-
-void
-AbstractMemory::serialize(ostream &os)
-{
-    if (!pmemAddr)
-        return;
-
-    gzFile compressedMem;
-    string filename = name() + ".physmem";
-    long _size = range.size();
-
-    SERIALIZE_SCALAR(filename);
-    SERIALIZE_SCALAR(_size);
-
-    // write memory file
-    string thefile = Checkpoint::dir() + "/" + filename.c_str();
-    int fd = creat(thefile.c_str(), 0664);
-    if (fd < 0) {
-        perror("creat");
-        fatal("Can't open physical memory checkpoint file '%s'\n", filename);
-    }
-
-    compressedMem = gzdopen(fd, "wb");
-    if (compressedMem == NULL)
-        fatal("Insufficient memory to allocate compression state for %s\n",
-                filename);
-
-    uint64_t pass_size = 0;
-    // gzwrite fails if (int)len < 0 (gzwrite returns int)
-    for (uint64_t written = 0; written < size(); written += pass_size) {
-        pass_size = (uint64_t)INT_MAX < (size() - written) ?
-            (uint64_t)INT_MAX : (size() - written);
-
-        if (gzwrite(compressedMem, pmemAddr + written,
-                    (unsigned int) pass_size) != (int)pass_size) {
-            fatal("Write failed on physical memory checkpoint file '%s'\n",
-                  filename);
-        }
-    }
-
-    if (gzclose(compressedMem))
-        fatal("Close failed on physical memory checkpoint file '%s'\n",
-              filename);
-
-    list<LockedAddr>::iterator i = lockedAddrList.begin();
-
-    vector<Addr> lal_addr;
-    vector<int> lal_cid;
-    while (i != lockedAddrList.end()) {
-        lal_addr.push_back(i->addr);
-        lal_cid.push_back(i->contextId);
-        i++;
-    }
-    arrayParamOut(os, "lal_addr", lal_addr);
-    arrayParamOut(os, "lal_cid", lal_cid);
-}
-
-void
-AbstractMemory::unserialize(Checkpoint *cp, const string &section)
-{
-    if (!pmemAddr)
-        return;
-
-    gzFile compressedMem;
-    long *tempPage;
-    long *pmem_current;
-    uint64_t curSize;
-    uint32_t bytesRead;
-    const uint32_t chunkSize = 16384;
-
-    string filename;
-
-    UNSERIALIZE_SCALAR(filename);
-
-    filename = cp->cptDir + "/" + filename;
-
-    // mmap memoryfile
-    int fd = open(filename.c_str(), O_RDONLY);
-    if (fd < 0) {
-        perror("open");
-        fatal("Can't open physical memory checkpoint file '%s'", filename);
-    }
-
-    compressedMem = gzdopen(fd, "rb");
-    if (compressedMem == NULL)
-        fatal("Insufficient memory to allocate compression state for %s\n",
-                filename);
-
-    // unmap file that was mmapped in the constructor
-    // This is done here to make sure that gzip and open don't muck with our
-    // nice large space of memory before we reallocate it
-    munmap((char*)pmemAddr, size());
-
-    long _size;
-    UNSERIALIZE_SCALAR(_size);
-    if (_size > params()->range.size())
-        fatal("Memory size has changed! size %lld, param size %lld\n",
-              _size, params()->range.size());
-
-    pmemAddr = (uint8_t *)mmap(NULL, size(),
-        PROT_READ | PROT_WRITE, MAP_ANON | MAP_PRIVATE, -1, 0);
-
-    if (pmemAddr == (void *)MAP_FAILED) {
-        perror("mmap");
-        fatal("Could not mmap physical memory!\n");
-    }
-
-    curSize = 0;
-    tempPage = (long*)malloc(chunkSize);
-    if (tempPage == NULL)
-        fatal("Unable to malloc memory to read file %s\n", filename);
-
-    /* Only copy bytes that are non-zero, so we don't give the VM system hell */
-    while (curSize < size()) {
-        bytesRead = gzread(compressedMem, tempPage, chunkSize);
-        if (bytesRead == 0)
-            break;
-
-        assert(bytesRead % sizeof(long) == 0);
-
-        for (uint32_t x = 0; x < bytesRead / sizeof(long); x++)
-        {
-             if (*(tempPage+x) != 0) {
-                 pmem_current = (long*)(pmemAddr + curSize + x * sizeof(long));
-                 *pmem_current = *(tempPage+x);
-             }
-        }
-        curSize += bytesRead;
-    }
-
-    free(tempPage);
-
-    if (gzclose(compressedMem))
-        fatal("Close failed on physical memory checkpoint file '%s'\n",
-              filename);
-
-    vector<Addr> lal_addr;
-    vector<int> lal_cid;
-    arrayParamIn(cp, section, "lal_addr", lal_addr);
-    arrayParamIn(cp, section, "lal_cid", lal_cid);
-    for(int i = 0; i < lal_addr.size(); i++)
-        lockedAddrList.push_front(LockedAddr(lal_addr[i], lal_cid[i]));
-}