On an x86 32bit system (and using the 32bit CodeSourcery toolchain on a x86_64 system) I get:
evensky@machine:~/.../linux-kvm/tools/kvm$ make
CC util/util.o
util/util.c: In function 'mmap_hugetlbfs':
util/util.c:93:17: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]
util/util.c:99:7: error: format '%ld' expects argument of type 'long int', but argument 2 has type 'int' [-Werror=format]
cc1: all warnings being treated as errors
make: *** [util/util.o] Error 1
Thanks,
\dae
On Tue, Dec 13, 2011 at 05:21:46PM +1100, Matt Evans wrote:
> Add a --hugetlbfs commandline option to give a path to hugetlbfs-map guest
> memory (down in kvm__arch_init()). For x86, guest memory is a normal
> ANON mmap() if this option is not provided, otherwise a hugetlbfs mmap.
>
> This maps directly from a hugetlbfs temp file rather than using something
> like MADV_HUGEPAGES so that, if the user asks for hugepages, we definitely
> are using hugepages. (This is particularly useful for architectures that
> don't yet support KVM without hugepages, so we definitely need to use
> them for the whole of guest RAM.)
>
> Signed-off-by: Matt Evans <matt@xxxxxxxxxx>
> ---
> tools/kvm/builtin-run.c | 4 +++-
> tools/kvm/include/kvm/kvm.h | 4 ++--
> tools/kvm/include/kvm/util.h | 4 ++++
> tools/kvm/kvm.c | 4 ++--
> tools/kvm/util.c | 38 ++++++++++++++++++++++++++++++++++++++
> tools/kvm/x86/kvm.c | 20 +++++++++++++++++---
> 6 files changed, 66 insertions(+), 8 deletions(-)
>
> diff --git a/tools/kvm/builtin-run.c b/tools/kvm/builtin-run.c
> index 4411c9e..ab05f8c 100644
> --- a/tools/kvm/builtin-run.c
> +++ b/tools/kvm/builtin-run.c
> @@ -85,6 +85,7 @@ static const char *host_mac;
> static const char *script;
> static const char *guest_name;
> static const char *sandbox;
> +static const char *hugetlbfs_path;
> static struct virtio_net_params *net_params;
> static bool single_step;
> static bool readonly_image[MAX_DISK_IMAGES];
> @@ -437,6 +438,7 @@ static const struct option options[] = {
> tty_parser),
> OPT_STRING('\0', "sandbox", &sandbox, "script",
> "Run this script when booting into custom rootfs"),
> + OPT_STRING('\0', "hugetlbfs", &hugetlbfs_path, "path", "Hugetlbfs path"),
>
> OPT_GROUP("Kernel options:"),
> OPT_STRING('k', "kernel", &kernel_filename, "kernel",
> @@ -924,7 +926,7 @@ int kvm_cmd_run(int argc, const char **argv, const char *prefix)
> guest_name = default_name;
> }
>
> - kvm = kvm__init(dev, ram_size, guest_name);
> + kvm = kvm__init(dev, hugetlbfs_path, ram_size, guest_name);
>
> kvm->single_step = single_step;
>
> diff --git a/tools/kvm/include/kvm/kvm.h b/tools/kvm/include/kvm/kvm.h
> index 5fe6e75..7159952 100644
> --- a/tools/kvm/include/kvm/kvm.h
> +++ b/tools/kvm/include/kvm/kvm.h
> @@ -30,7 +30,7 @@ struct kvm_ext {
> void kvm__set_dir(const char *fmt, ...);
> const char *kvm__get_dir(void);
>
> -struct kvm *kvm__init(const char *kvm_dev, u64 ram_size, const char *name);
> +struct kvm *kvm__init(const char *kvm_dev, const char *hugetlbfs_path, u64 ram_size, const char *name);
> int kvm__recommended_cpus(struct kvm *kvm);
> int kvm__max_cpus(struct kvm *kvm);
> void kvm__init_ram(struct kvm *kvm);
> @@ -54,7 +54,7 @@ int kvm__enumerate_instances(int (*callback)(const char *name, int pid));
> void kvm__remove_socket(const char *name);
>
> void kvm__arch_set_cmdline(char *cmdline, bool video);
> -void kvm__arch_init(struct kvm *kvm, const char *kvm_dev, u64 ram_size, const char *name);
> +void kvm__arch_init(struct kvm *kvm, const char *kvm_dev, const char *hugetlbfs_path, u64 ram_size, const char *name);
> void kvm__arch_setup_firmware(struct kvm *kvm);
> bool kvm__arch_cpu_supports_vm(void);
> void kvm__arch_periodic_poll(struct kvm *kvm);
> diff --git a/tools/kvm/include/kvm/util.h b/tools/kvm/include/kvm/util.h
> index dc2e0b9..1f6fbbd 100644
> --- a/tools/kvm/include/kvm/util.h
> +++ b/tools/kvm/include/kvm/util.h
> @@ -20,6 +20,7 @@
> #include <limits.h>
> #include <sys/param.h>
> #include <sys/types.h>
> +#include <linux/types.h>
>
> #ifdef __GNUC__
> #define NORETURN __attribute__((__noreturn__))
> @@ -75,4 +76,7 @@ static inline void msleep(unsigned int msecs)
> {
> usleep(MSECS_TO_USECS(msecs));
> }
> +
> +void *mmap_hugetlbfs(const char *htlbfs_path, u64 size);
> +
> #endif /* KVM__UTIL_H */
> diff --git a/tools/kvm/kvm.c b/tools/kvm/kvm.c
> index c54f886..35ca2c5 100644
> --- a/tools/kvm/kvm.c
> +++ b/tools/kvm/kvm.c
> @@ -306,7 +306,7 @@ int kvm__max_cpus(struct kvm *kvm)
> return ret;
> }
>
> -struct kvm *kvm__init(const char *kvm_dev, u64 ram_size, const char *name)
> +struct kvm *kvm__init(const char *kvm_dev, const char *hugetlbfs_path, u64 ram_size, const char *name)
> {
> struct kvm *kvm;
> int ret;
> @@ -339,7 +339,7 @@ struct kvm *kvm__init(const char *kvm_dev, u64 ram_size, const char *name)
> if (kvm__check_extensions(kvm))
> die("A required KVM extention is not supported by OS");
>
> - kvm__arch_init(kvm, kvm_dev, ram_size, name);
> + kvm__arch_init(kvm, kvm_dev, hugetlbfs_path, ram_size, name);
>
> kvm->name = name;
>
> diff --git a/tools/kvm/util.c b/tools/kvm/util.c
> index 4efbce9..f0a4bf7 100644
> --- a/tools/kvm/util.c
> +++ b/tools/kvm/util.c
> @@ -4,6 +4,11 @@
>
> #include "kvm/util.h"
>
> +#include <linux/magic.h> /* For HUGETLBFS_MAGIC */
> +#include <sys/mman.h>
> +#include <sys/stat.h>
> +#include <sys/statfs.h>
> +
> static void report(const char *prefix, const char *err, va_list params)
> {
> char msg[1024];
> @@ -99,3 +104,36 @@ size_t strlcat(char *dest, const char *src, size_t count)
>
> return res;
> }
> +
> +void *mmap_hugetlbfs(const char *htlbfs_path, u64 size)
> +{
> + char mpath[PATH_MAX];
> + int fd;
> + struct statfs sfs;
> + void *addr;
> +
> + if (statfs(htlbfs_path, &sfs) < 0)
> + die("Can't stat %s\n", htlbfs_path);
> +
> + if (sfs.f_type != HUGETLBFS_MAGIC) {
> + die("%s is not hugetlbfs!\n", htlbfs_path);
> + }
> +
> + if (sfs.f_bsize == 0 || (unsigned long)sfs.f_bsize > size) {
> + die("Can't use hugetlbfs pagesize %ld for mem size %lld\n",
> + sfs.f_bsize, size);
> + }
> +
> + snprintf(mpath, PATH_MAX, "%s/kvmtoolXXXXXX", htlbfs_path);
> + fd = mkstemp(mpath);
> + if (fd < 0)
> + die("Can't open %s for hugetlbfs map\n", mpath);
> + unlink(mpath);
> + if (ftruncate(fd, size) < 0)
> + die("Can't ftruncate for mem mapping size %lld\n",
> + size);
> + addr = mmap(NULL, size, PROT_RW, MAP_PRIVATE, fd, 0);
> + close(fd);
> +
> + return addr;
> +}
> diff --git a/tools/kvm/x86/kvm.c b/tools/kvm/x86/kvm.c
> index da4a6b6..bc52ef3 100644
> --- a/tools/kvm/x86/kvm.c
> +++ b/tools/kvm/x86/kvm.c
> @@ -130,8 +130,22 @@ void kvm__arch_set_cmdline(char *cmdline, bool video)
> strcat(cmdline, " console=ttyS0 earlyprintk=serial i8042.noaux=1");
> }
>
> +/* This function wraps the decision between hugetlbfs map (if requested) or normal mmap */
> +static void *mmap_anon_or_hugetlbfs(const char *hugetlbfs_path, u64 size)
> +{
> + if (hugetlbfs_path) {
> + /*
> + * We don't /need/ to map guest RAM from hugetlbfs, but we do so
> + * if the user specifies a hugetlbfs path.
> + */
> + return mmap_hugetlbfs(hugetlbfs_path, size);
> + } else {
> + return mmap(NULL, size, PROT_RW, MAP_ANON_NORESERVE, -1, 0);
> + }
> +}
> +
> /* Architecture-specific KVM init */
> -void kvm__arch_init(struct kvm *kvm, const char *kvm_dev, u64 ram_size, const char *name)
> +void kvm__arch_init(struct kvm *kvm, const char *kvm_dev, const char *hugetlbfs_path, u64 ram_size, const char *name)
> {
> struct kvm_pit_config pit_config = { .flags = 0, };
> int ret;
> @@ -147,9 +161,9 @@ void kvm__arch_init(struct kvm *kvm, const char *kvm_dev, u64 ram_size, const ch
> kvm->ram_size = ram_size;
>
> if (kvm->ram_size < KVM_32BIT_GAP_START) {
> - kvm->ram_start = mmap(NULL, ram_size, PROT_RW, MAP_ANON_NORESERVE, -1, 0);
> + kvm->ram_start = mmap_anon_or_hugetlbfs(hugetlbfs_path, ram_size);
> } else {
> - kvm->ram_start = mmap(NULL, ram_size + KVM_32BIT_GAP_SIZE, PROT_RW, MAP_ANON_NORESERVE, -1, 0);
> + kvm->ram_start = mmap_anon_or_hugetlbfs(hugetlbfs_path, ram_size + KVM_32BIT_GAP_SIZE);
> if (kvm->ram_start != MAP_FAILED) {
> /*
> * We mprotect the gap (see kvm__init_ram() for details) PROT_NONE so that
> --
> 1.7.0.4
>
> --
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