| Message ID | 4EE1B0DD.6030004@ozlabs.org |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, 2011-12-09 at 17:55 +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. > > Signed-off-by: Matt Evans <matt@ozlabs.org> > --- > 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 | 45 ++++++++++++++++++++++++++++++++++++++++++ > tools/kvm/x86/kvm.c | 20 +++++++++++++++-- > 6 files changed, 73 insertions(+), 8 deletions(-) > > diff --git a/tools/kvm/builtin-run.c b/tools/kvm/builtin-run.c > index 7969901..0acfe81 100644 > --- a/tools/kvm/builtin-run.c > +++ b/tools/kvm/builtin-run.c > @@ -82,6 +82,7 @@ static const char *guest_mac; > static const char *host_mac; > static const char *script; > static const char *guest_name; > +static const char *hugetlbfs_path; > static struct virtio_net_params *net_params; > static bool single_step; > static bool readonly_image[MAX_DISK_IMAGES]; > @@ -422,6 +423,7 @@ static const struct option options[] = { > OPT_CALLBACK('\0', "tty", NULL, "tty id", > "Remap guest TTY into a pty on the host", > tty_parser), > + OPT_STRING('\0', "hugetlbfs", &hugetlbfs_path, "path", "Hugetlbfs path"), > > OPT_GROUP("Kernel options:"), > OPT_STRING('k', "kernel", &kernel_filename, "kernel", > @@ -807,7 +809,7 @@ 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..90b6a3b 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 +104,43 @@ 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; > + int r; > + struct statfs sfs; > + void *addr; > + > + do { > + /* > + * QEMU seems to work around this returning EINTR... Let's do > + * that too. > + */ > + r = statfs(htlbfs_path, &sfs); > + } while (r && errno == EINTR); > + > + if (r) > + 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); > + ftruncate(fd, size); Getting this thing here: cc1: warnings being treated as errors util.c: In function 'mmap_hugetlbfs': util.c:141:11: error: ignoring return value of 'ftruncate', declared with attribute warn_unused_result make: *** [util.o] Error 1
On Fri, Dec 9, 2011 at 8:55 AM, Matt Evans <matt@ozlabs.org> 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. > > Signed-off-by: Matt Evans <matt@ozlabs.org> > +void *mmap_hugetlbfs(const char *htlbfs_path, u64 size) > +{ > + char mpath[PATH_MAX]; > + int fd; > + int r; > + struct statfs sfs; > + void *addr; > + > + do { > + /* > + * QEMU seems to work around this returning EINTR... Let's do > + * that too. > + */ > + r = statfs(htlbfs_path, &sfs); > + } while (r && errno == EINTR); Can this really happen? What about EAGAIN? The retry logic really wants to live in tools/kvm/read-write.c as a xstatfs() wrapper if we do need this. Pekka -- To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, Dec 9, 2011 at 8:55 AM, Matt Evans <matt@ozlabs.org> 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. > > Signed-off-by: Matt Evans <matt@ozlabs.org> Btw, why don't you want to use MADV_HUGEPAGE for this? You could just do it unconditionally, no? -- To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 09/12/11 18:39, Sasha Levin wrote: > On Fri, 2011-12-09 at 17:55 +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. >> >> Signed-off-by: Matt Evans <matt@ozlabs.org> >> --- >> 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 | 45 ++++++++++++++++++++++++++++++++++++++++++ >> tools/kvm/x86/kvm.c | 20 +++++++++++++++-- >> 6 files changed, 73 insertions(+), 8 deletions(-) >> >> diff --git a/tools/kvm/builtin-run.c b/tools/kvm/builtin-run.c >> index 7969901..0acfe81 100644 >> --- a/tools/kvm/builtin-run.c >> +++ b/tools/kvm/builtin-run.c >> @@ -82,6 +82,7 @@ static const char *guest_mac; >> static const char *host_mac; >> static const char *script; >> static const char *guest_name; >> +static const char *hugetlbfs_path; >> static struct virtio_net_params *net_params; >> static bool single_step; >> static bool readonly_image[MAX_DISK_IMAGES]; >> @@ -422,6 +423,7 @@ static const struct option options[] = { >> OPT_CALLBACK('\0', "tty", NULL, "tty id", >> "Remap guest TTY into a pty on the host", >> tty_parser), >> + OPT_STRING('\0', "hugetlbfs", &hugetlbfs_path, "path", "Hugetlbfs path"), >> >> OPT_GROUP("Kernel options:"), >> OPT_STRING('k', "kernel", &kernel_filename, "kernel", >> @@ -807,7 +809,7 @@ 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..90b6a3b 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 +104,43 @@ 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; >> + int r; >> + struct statfs sfs; >> + void *addr; >> + >> + do { >> + /* >> + * QEMU seems to work around this returning EINTR... Let's do >> + * that too. >> + */ >> + r = statfs(htlbfs_path, &sfs); >> + } while (r && errno == EINTR); >> + >> + if (r) >> + 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); >> + ftruncate(fd, size); > > Getting this thing here: > > cc1: warnings being treated as errors > util.c: In function 'mmap_hugetlbfs': > util.c:141:11: error: ignoring return value of 'ftruncate', declared with attribute warn_unused_result > make: *** [util.o] Error 1 > Ooookay, I swear I'm not seeing that here, GCC 4.6.2 & no extra -W flags added. I've added a check of ftruncate()'s return value, anyway. Thanks, Matt -- To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 09/12/11 19:42, Pekka Enberg wrote: > On Fri, Dec 9, 2011 at 8:55 AM, Matt Evans <matt@ozlabs.org> 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. >> >> Signed-off-by: Matt Evans <matt@ozlabs.org> > > Btw, why don't you want to use MADV_HUGEPAGE for this? You could just > do it unconditionally, no? Well, I'm manually mapping from hugetlbfs as currently* PPC KVM requires hugepages to back guest RAM and MADV_HUGEPAGE is just a hint, no? I also wanted things to work on kernels without transparent hugepages enabled. I think it's safer to do things explicitly, as if the user requests hugepages it's more transparent (I'm thinking benchmarking, etc.) to be definitely using hugepages. Cheers, Matt *: I know Paul's posted patches to implement smallpage support... so this will change in time. -- To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Dec 12, 2011 at 7:17 AM, Matt Evans <matt@ozlabs.org> wrote: > Well, I'm manually mapping from hugetlbfs as currently* PPC KVM requires > hugepages to back guest RAM and MADV_HUGEPAGE is just a hint, no? I also wanted > things to work on kernels without transparent hugepages enabled. I think it's > safer to do things explicitly, as if the user requests hugepages it's more > transparent (I'm thinking benchmarking, etc.) to be definitely using hugepages. OK, makes sense. You should probably mention that in the changelog. -- To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 09/12/11 19:38, Pekka Enberg wrote: > On Fri, Dec 9, 2011 at 8:55 AM, Matt Evans <matt@ozlabs.org> 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. >> >> Signed-off-by: Matt Evans <matt@ozlabs.org> > >> +void *mmap_hugetlbfs(const char *htlbfs_path, u64 size) >> +{ >> + char mpath[PATH_MAX]; >> + int fd; >> + int r; >> + struct statfs sfs; >> + void *addr; >> + >> + do { >> + /* >> + * QEMU seems to work around this returning EINTR... Let's do >> + * that too. >> + */ >> + r = statfs(htlbfs_path, &sfs); >> + } while (r && errno == EINTR); > > Can this really happen? What about EAGAIN? The retry logic really > wants to live in tools/kvm/read-write.c as a xstatfs() wrapper if we > do need this. I don't think it can. As per the comment, I thought QEMU knew something I didn't but I haven't seen any other reason for doing this. I'll remove it, thanks for the sanity jolt. Matt -- To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/tools/kvm/builtin-run.c b/tools/kvm/builtin-run.c index 7969901..0acfe81 100644 --- a/tools/kvm/builtin-run.c +++ b/tools/kvm/builtin-run.c @@ -82,6 +82,7 @@ static const char *guest_mac; static const char *host_mac; static const char *script; static const char *guest_name; +static const char *hugetlbfs_path; static struct virtio_net_params *net_params; static bool single_step; static bool readonly_image[MAX_DISK_IMAGES]; @@ -422,6 +423,7 @@ static const struct option options[] = { OPT_CALLBACK('\0', "tty", NULL, "tty id", "Remap guest TTY into a pty on the host", tty_parser), + OPT_STRING('\0', "hugetlbfs", &hugetlbfs_path, "path", "Hugetlbfs path"), OPT_GROUP("Kernel options:"), OPT_STRING('k', "kernel", &kernel_filename, "kernel", @@ -807,7 +809,7 @@ 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..90b6a3b 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 +104,43 @@ 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; + int r; + struct statfs sfs; + void *addr; + + do { + /* + * QEMU seems to work around this returning EINTR... Let's do + * that too. + */ + r = statfs(htlbfs_path, &sfs); + } while (r && errno == EINTR); + + if (r) + 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); + ftruncate(fd, 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 a116f4b..31671e7 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
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. Signed-off-by: Matt Evans <matt@ozlabs.org> --- 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 | 45 ++++++++++++++++++++++++++++++++++++++++++ tools/kvm/x86/kvm.c | 20 +++++++++++++++-- 6 files changed, 73 insertions(+), 8 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html