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Unbreak large mem support by removing kqemu

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kqemu introduces a number of restrictions on the i386 target.  The worst is that
it prevents large memory from working in the default build.

Furthermore, kqemu is fundamentally flawed in a number of ways.  It relies on
the TSC as a time source which will not be reliable on a multiple processor
system in userspace.  Since most modern processors are multicore, this severely
limits the utility of kqemu.

kvm is a viable alternative for people looking to accelerate qemu and has the
benefit of being supported by the upstream Linux kernel.  If someone can
implement work arounds to remove the restrictions introduced by kqemu, I'm
happy to avoid and/or revert this patch.

N.B. kqemu will still function in the 0.11 series but this patch removes it from
the 0.12 series.

Paul, please Ack or Nack this patch.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
This commit is contained in:
Anthony Liguori 2009-08-10 17:07:24 -05:00
parent 0953a80f04
commit 4a1418e07b
24 changed files with 8 additions and 1722 deletions
Download patch file Download diff file Expand all files Collapse all files

121
osdep.c
View file

@ -88,119 +88,6 @@ void qemu_vfree(void *ptr)
#else
#if defined(CONFIG_KQEMU)
#ifdef __OpenBSD__
#include <sys/param.h>
#include <sys/types.h>
#include <sys/mount.h>
#else
#ifndef __FreeBSD__
#include <sys/vfs.h>
#endif
#endif
#include <sys/mman.h>
#include <fcntl.h>
static void *kqemu_vmalloc(size_t size)
{
static int phys_ram_fd = -1;
static int phys_ram_size = 0;
void *ptr;
/* no need (?) for a dummy file on OpenBSD/FreeBSD */
#if defined(__OpenBSD__) || defined(__FreeBSD__) || defined(__DragonFly__)
int map_anon = MAP_ANON;
#else
int map_anon = 0;
const char *tmpdir;
char phys_ram_file[1024];
#ifdef CONFIG_SOLARIS
struct statvfs stfs;
#else
struct statfs stfs;
#endif
if (!size) {
abort ();
}
if (phys_ram_fd < 0) {
tmpdir = getenv("QEMU_TMPDIR");
if (!tmpdir)
#ifdef CONFIG_SOLARIS
tmpdir = "/tmp";
if (statvfs(tmpdir, &stfs) == 0) {
#else
tmpdir = "/dev/shm";
if (statfs(tmpdir, &stfs) == 0) {
#endif
int64_t free_space;
int ram_mb;
free_space = (int64_t)stfs.f_bavail * stfs.f_bsize;
if ((ram_size + 8192 * 1024) >= free_space) {
ram_mb = (ram_size / (1024 * 1024));
fprintf(stderr,
"You do not have enough space in '%s' for the %d MB of QEMU virtual RAM.\n",
tmpdir, ram_mb);
if (strcmp(tmpdir, "/dev/shm") == 0) {
fprintf(stderr, "To have more space available provided you have enough RAM and swap, do as root:\n"
"mount -o remount,size=%dm /dev/shm\n",
ram_mb + 16);
} else {
fprintf(stderr,
"Use the '-m' option of QEMU to diminish the amount of virtual RAM or use the\n"
"QEMU_TMPDIR environment variable to set another directory where the QEMU\n"
"temporary RAM file will be opened.\n");
}
fprintf(stderr, "Or disable the accelerator module with -no-kqemu\n");
exit(1);
}
}
snprintf(phys_ram_file, sizeof(phys_ram_file), "%s/qemuXXXXXX",
tmpdir);
phys_ram_fd = mkstemp(phys_ram_file);
if (phys_ram_fd < 0) {
fprintf(stderr,
"warning: could not create temporary file in '%s'.\n"
"Use QEMU_TMPDIR to select a directory in a tmpfs filesystem.\n"
"Using '/tmp' as fallback.\n",
tmpdir);
snprintf(phys_ram_file, sizeof(phys_ram_file), "%s/qemuXXXXXX",
"/tmp");
phys_ram_fd = mkstemp(phys_ram_file);
if (phys_ram_fd < 0) {
fprintf(stderr, "Could not create temporary memory file '%s'\n",
phys_ram_file);
exit(1);
}
}
unlink(phys_ram_file);
}
size = (size + 4095) & ~4095;
ftruncate(phys_ram_fd, phys_ram_size + size);
#endif /* !(__OpenBSD__ || __FreeBSD__ || __DragonFly__) */
ptr = mmap(NULL,
size,
PROT_WRITE | PROT_READ, map_anon | MAP_SHARED,
phys_ram_fd, phys_ram_size);
if (ptr == MAP_FAILED) {
fprintf(stderr, "Could not map physical memory\n");
exit(1);
}
phys_ram_size += size;
return ptr;
}
static void kqemu_vfree(void *ptr)
{
/* may be useful some day, but currently we do not need to free */
}
#endif
void *qemu_memalign(size_t alignment, size_t size)
{
#if defined(_POSIX_C_SOURCE)
@ -220,19 +107,11 @@ void *qemu_memalign(size_t alignment, size_t size)
/* alloc shared memory pages */
void *qemu_vmalloc(size_t size)
{
#if defined(CONFIG_KQEMU)
if (kqemu_allowed)
return kqemu_vmalloc(size);
#endif
return qemu_memalign(getpagesize(), size);
}
void qemu_vfree(void *ptr)
{
#if defined(CONFIG_KQEMU)
if (kqemu_allowed)
kqemu_vfree(ptr);
#endif
free(ptr);
}