include/sysemu/hostmem.h | 8 +++++++- backends/hostmem-memfd.c | 2 -- backends/hostmem.c | 27 +++++++++++++++++---------- 3 files changed, 24 insertions(+), 13 deletions(-)
It is currently not possible yet to use "memory-backend-memfd" on s390x
with hugepages enabled. This problem is caused by qemu_maxrampagesize()
not taking memory-backend-memfd objects into account yet, so the code
in s390_memory_init() fails to enable the huge page support there via
s390_set_max_pagesize(). Fix it by looking at the memory-backend-memfd
in the host_memory_backend_pagesize() function, too.
Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=2116496
Signed-off-by: Thomas Huth <thuth@redhat.com>
---
include/sysemu/hostmem.h | 8 +++++++-
backends/hostmem-memfd.c | 2 --
backends/hostmem.c | 27 +++++++++++++++++----------
3 files changed, 24 insertions(+), 13 deletions(-)
diff --git a/include/sysemu/hostmem.h b/include/sysemu/hostmem.h
index 9ff5c16963..d983ae6c01 100644
--- a/include/sysemu/hostmem.h
+++ b/include/sysemu/hostmem.h
@@ -34,10 +34,16 @@ OBJECT_DECLARE_TYPE(HostMemoryBackend, HostMemoryBackendClass,
/* hostmem-file.c */
/**
* @TYPE_MEMORY_BACKEND_FILE:
- * name of backend that uses mmap on a file descriptor
+ * name of backend that uses mmap on a file
*/
#define TYPE_MEMORY_BACKEND_FILE "memory-backend-file"
+/* hostmem-memfd.c */
+/**
+ * @TYPE_MEMORY_BACKEND_MEMFD:
+ * name of backend that uses mmap on a memfd file descriptor
+ */
+#define TYPE_MEMORY_BACKEND_MEMFD "memory-backend-memfd"
/**
* HostMemoryBackendClass:
diff --git a/backends/hostmem-memfd.c b/backends/hostmem-memfd.c
index 3fc85c3db8..1ab2085e49 100644
--- a/backends/hostmem-memfd.c
+++ b/backends/hostmem-memfd.c
@@ -18,8 +18,6 @@
#include "qapi/error.h"
#include "qom/object.h"
-#define TYPE_MEMORY_BACKEND_MEMFD "memory-backend-memfd"
-
OBJECT_DECLARE_SIMPLE_TYPE(HostMemoryBackendMemfd, MEMORY_BACKEND_MEMFD)
diff --git a/backends/hostmem.c b/backends/hostmem.c
index 624bb7ecd3..ebce887105 100644
--- a/backends/hostmem.c
+++ b/backends/hostmem.c
@@ -306,22 +306,29 @@ bool host_memory_backend_is_mapped(HostMemoryBackend *backend)
return backend->is_mapped;
}
-#ifdef __linux__
size_t host_memory_backend_pagesize(HostMemoryBackend *memdev)
{
+ size_t pagesize = 0;
+
+#ifdef __linux__
Object *obj = OBJECT(memdev);
- char *path = object_property_get_str(obj, "mem-path", NULL);
- size_t pagesize = qemu_mempath_getpagesize(path);
- g_free(path);
+ if (object_dynamic_cast(obj, TYPE_MEMORY_BACKEND_FILE)) {
+ char *path = object_property_get_str(obj, "mem-path", NULL);
+ pagesize = qemu_mempath_getpagesize(path);
+ g_free(path);
+ } else if (object_dynamic_cast(obj, TYPE_MEMORY_BACKEND_MEMFD) &&
+ object_property_get_bool(obj, "hugetlb", &error_abort)) {
+ pagesize = object_property_get_int(obj, "hugetlbsize", &error_abort);
+ }
+#endif
+
+ if (!pagesize) {
+ pagesize = qemu_real_host_page_size();
+ }
+
return pagesize;
}
-#else
-size_t host_memory_backend_pagesize(HostMemoryBackend *memdev)
-{
- return qemu_real_host_page_size();
-}
-#endif
static void
host_memory_backend_memory_complete(UserCreatable *uc, Error **errp)
--
2.31.1
On 10.08.22 08:32, Thomas Huth wrote: > It is currently not possible yet to use "memory-backend-memfd" on s390x > with hugepages enabled. This problem is caused by qemu_maxrampagesize() > not taking memory-backend-memfd objects into account yet, so the code > in s390_memory_init() fails to enable the huge page support there via > s390_set_max_pagesize(). Fix it by looking at the memory-backend-memfd > in the host_memory_backend_pagesize() function, too. > > Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=2116496 > Signed-off-by: Thomas Huth <thuth@redhat.com> > --- > include/sysemu/hostmem.h | 8 +++++++- > backends/hostmem-memfd.c | 2 -- > backends/hostmem.c | 27 +++++++++++++++++---------- > 3 files changed, 24 insertions(+), 13 deletions(-) > > diff --git a/include/sysemu/hostmem.h b/include/sysemu/hostmem.h > index 9ff5c16963..d983ae6c01 100644 > --- a/include/sysemu/hostmem.h > +++ b/include/sysemu/hostmem.h > @@ -34,10 +34,16 @@ OBJECT_DECLARE_TYPE(HostMemoryBackend, HostMemoryBackendClass, > /* hostmem-file.c */ > /** > * @TYPE_MEMORY_BACKEND_FILE: > - * name of backend that uses mmap on a file descriptor > + * name of backend that uses mmap on a file > */ > #define TYPE_MEMORY_BACKEND_FILE "memory-backend-file" > > +/* hostmem-memfd.c */ > +/** > + * @TYPE_MEMORY_BACKEND_MEMFD: > + * name of backend that uses mmap on a memfd file descriptor > + */ > +#define TYPE_MEMORY_BACKEND_MEMFD "memory-backend-memfd" > > /** > * HostMemoryBackendClass: > diff --git a/backends/hostmem-memfd.c b/backends/hostmem-memfd.c > index 3fc85c3db8..1ab2085e49 100644 > --- a/backends/hostmem-memfd.c > +++ b/backends/hostmem-memfd.c > @@ -18,8 +18,6 @@ > #include "qapi/error.h" > #include "qom/object.h" > > -#define TYPE_MEMORY_BACKEND_MEMFD "memory-backend-memfd" > - > OBJECT_DECLARE_SIMPLE_TYPE(HostMemoryBackendMemfd, MEMORY_BACKEND_MEMFD) > > > diff --git a/backends/hostmem.c b/backends/hostmem.c > index 624bb7ecd3..ebce887105 100644 > --- a/backends/hostmem.c > +++ b/backends/hostmem.c > @@ -306,22 +306,29 @@ bool host_memory_backend_is_mapped(HostMemoryBackend *backend) > return backend->is_mapped; > } > > -#ifdef __linux__ > size_t host_memory_backend_pagesize(HostMemoryBackend *memdev) > { > + size_t pagesize = 0; > + > +#ifdef __linux__ > Object *obj = OBJECT(memdev); > - char *path = object_property_get_str(obj, "mem-path", NULL); > - size_t pagesize = qemu_mempath_getpagesize(path); > > - g_free(path); > + if (object_dynamic_cast(obj, TYPE_MEMORY_BACKEND_FILE)) { > + char *path = object_property_get_str(obj, "mem-path", NULL); > + pagesize = qemu_mempath_getpagesize(path); > + g_free(path); > + } else if (object_dynamic_cast(obj, TYPE_MEMORY_BACKEND_MEMFD) && > + object_property_get_bool(obj, "hugetlb", &error_abort)) { > + pagesize = object_property_get_int(obj, "hugetlbsize", &error_abort); > + } > +#endif Why can't we simply rely on qemu_ram_pagesize(memdev->mr.ram_block); ? -- Thanks, David / dhildenb
On 10/08/2022 09.32, David Hildenbrand wrote: > On 10.08.22 08:32, Thomas Huth wrote: >> It is currently not possible yet to use "memory-backend-memfd" on s390x >> with hugepages enabled. This problem is caused by qemu_maxrampagesize() >> not taking memory-backend-memfd objects into account yet, so the code >> in s390_memory_init() fails to enable the huge page support there via >> s390_set_max_pagesize(). Fix it by looking at the memory-backend-memfd >> in the host_memory_backend_pagesize() function, too. >> >> Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=2116496 >> Signed-off-by: Thomas Huth <thuth@redhat.com> >> --- >> include/sysemu/hostmem.h | 8 +++++++- >> backends/hostmem-memfd.c | 2 -- >> backends/hostmem.c | 27 +++++++++++++++++---------- >> 3 files changed, 24 insertions(+), 13 deletions(-) >> >> diff --git a/include/sysemu/hostmem.h b/include/sysemu/hostmem.h >> index 9ff5c16963..d983ae6c01 100644 >> --- a/include/sysemu/hostmem.h >> +++ b/include/sysemu/hostmem.h >> @@ -34,10 +34,16 @@ OBJECT_DECLARE_TYPE(HostMemoryBackend, HostMemoryBackendClass, >> /* hostmem-file.c */ >> /** >> * @TYPE_MEMORY_BACKEND_FILE: >> - * name of backend that uses mmap on a file descriptor >> + * name of backend that uses mmap on a file >> */ >> #define TYPE_MEMORY_BACKEND_FILE "memory-backend-file" >> >> +/* hostmem-memfd.c */ >> +/** >> + * @TYPE_MEMORY_BACKEND_MEMFD: >> + * name of backend that uses mmap on a memfd file descriptor >> + */ >> +#define TYPE_MEMORY_BACKEND_MEMFD "memory-backend-memfd" >> >> /** >> * HostMemoryBackendClass: >> diff --git a/backends/hostmem-memfd.c b/backends/hostmem-memfd.c >> index 3fc85c3db8..1ab2085e49 100644 >> --- a/backends/hostmem-memfd.c >> +++ b/backends/hostmem-memfd.c >> @@ -18,8 +18,6 @@ >> #include "qapi/error.h" >> #include "qom/object.h" >> >> -#define TYPE_MEMORY_BACKEND_MEMFD "memory-backend-memfd" >> - >> OBJECT_DECLARE_SIMPLE_TYPE(HostMemoryBackendMemfd, MEMORY_BACKEND_MEMFD) >> >> >> diff --git a/backends/hostmem.c b/backends/hostmem.c >> index 624bb7ecd3..ebce887105 100644 >> --- a/backends/hostmem.c >> +++ b/backends/hostmem.c >> @@ -306,22 +306,29 @@ bool host_memory_backend_is_mapped(HostMemoryBackend *backend) >> return backend->is_mapped; >> } >> >> -#ifdef __linux__ >> size_t host_memory_backend_pagesize(HostMemoryBackend *memdev) >> { >> + size_t pagesize = 0; >> + >> +#ifdef __linux__ >> Object *obj = OBJECT(memdev); >> - char *path = object_property_get_str(obj, "mem-path", NULL); >> - size_t pagesize = qemu_mempath_getpagesize(path); >> >> - g_free(path); >> + if (object_dynamic_cast(obj, TYPE_MEMORY_BACKEND_FILE)) { >> + char *path = object_property_get_str(obj, "mem-path", NULL); >> + pagesize = qemu_mempath_getpagesize(path); >> + g_free(path); >> + } else if (object_dynamic_cast(obj, TYPE_MEMORY_BACKEND_MEMFD) && >> + object_property_get_bool(obj, "hugetlb", &error_abort)) { >> + pagesize = object_property_get_int(obj, "hugetlbsize", &error_abort); >> + } >> +#endif > > Why can't we simply rely on > > qemu_ram_pagesize(memdev->mr.ram_block); Good idea! That way, we could even get rid of the "#ifdef __linux__" macros here, I guess ... I'll give it a try and send a v2 if it works. Thomas
On 10.08.22 10:11, Thomas Huth wrote: > On 10/08/2022 09.32, David Hildenbrand wrote: >> On 10.08.22 08:32, Thomas Huth wrote: >>> It is currently not possible yet to use "memory-backend-memfd" on s390x >>> with hugepages enabled. This problem is caused by qemu_maxrampagesize() >>> not taking memory-backend-memfd objects into account yet, so the code >>> in s390_memory_init() fails to enable the huge page support there via >>> s390_set_max_pagesize(). Fix it by looking at the memory-backend-memfd >>> in the host_memory_backend_pagesize() function, too. >>> >>> Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=2116496 >>> Signed-off-by: Thomas Huth <thuth@redhat.com> >>> --- >>> include/sysemu/hostmem.h | 8 +++++++- >>> backends/hostmem-memfd.c | 2 -- >>> backends/hostmem.c | 27 +++++++++++++++++---------- >>> 3 files changed, 24 insertions(+), 13 deletions(-) >>> >>> diff --git a/include/sysemu/hostmem.h b/include/sysemu/hostmem.h >>> index 9ff5c16963..d983ae6c01 100644 >>> --- a/include/sysemu/hostmem.h >>> +++ b/include/sysemu/hostmem.h >>> @@ -34,10 +34,16 @@ OBJECT_DECLARE_TYPE(HostMemoryBackend, HostMemoryBackendClass, >>> /* hostmem-file.c */ >>> /** >>> * @TYPE_MEMORY_BACKEND_FILE: >>> - * name of backend that uses mmap on a file descriptor >>> + * name of backend that uses mmap on a file >>> */ >>> #define TYPE_MEMORY_BACKEND_FILE "memory-backend-file" >>> >>> +/* hostmem-memfd.c */ >>> +/** >>> + * @TYPE_MEMORY_BACKEND_MEMFD: >>> + * name of backend that uses mmap on a memfd file descriptor >>> + */ >>> +#define TYPE_MEMORY_BACKEND_MEMFD "memory-backend-memfd" >>> >>> /** >>> * HostMemoryBackendClass: >>> diff --git a/backends/hostmem-memfd.c b/backends/hostmem-memfd.c >>> index 3fc85c3db8..1ab2085e49 100644 >>> --- a/backends/hostmem-memfd.c >>> +++ b/backends/hostmem-memfd.c >>> @@ -18,8 +18,6 @@ >>> #include "qapi/error.h" >>> #include "qom/object.h" >>> >>> -#define TYPE_MEMORY_BACKEND_MEMFD "memory-backend-memfd" >>> - >>> OBJECT_DECLARE_SIMPLE_TYPE(HostMemoryBackendMemfd, MEMORY_BACKEND_MEMFD) >>> >>> >>> diff --git a/backends/hostmem.c b/backends/hostmem.c >>> index 624bb7ecd3..ebce887105 100644 >>> --- a/backends/hostmem.c >>> +++ b/backends/hostmem.c >>> @@ -306,22 +306,29 @@ bool host_memory_backend_is_mapped(HostMemoryBackend *backend) >>> return backend->is_mapped; >>> } >>> >>> -#ifdef __linux__ >>> size_t host_memory_backend_pagesize(HostMemoryBackend *memdev) >>> { >>> + size_t pagesize = 0; >>> + >>> +#ifdef __linux__ >>> Object *obj = OBJECT(memdev); >>> - char *path = object_property_get_str(obj, "mem-path", NULL); >>> - size_t pagesize = qemu_mempath_getpagesize(path); >>> >>> - g_free(path); >>> + if (object_dynamic_cast(obj, TYPE_MEMORY_BACKEND_FILE)) { >>> + char *path = object_property_get_str(obj, "mem-path", NULL); >>> + pagesize = qemu_mempath_getpagesize(path); >>> + g_free(path); >>> + } else if (object_dynamic_cast(obj, TYPE_MEMORY_BACKEND_MEMFD) && >>> + object_property_get_bool(obj, "hugetlb", &error_abort)) { >>> + pagesize = object_property_get_int(obj, "hugetlbsize", &error_abort); >>> + } >>> +#endif >> >> Why can't we simply rely on >> >> qemu_ram_pagesize(memdev->mr.ram_block); > > Good idea! That way, we could even get rid of the "#ifdef __linux__" macros > here, I guess ... I'll give it a try and send a v2 if it works. At first I wondered if we could have to deal with semi-iniutialized backendds here, but I think we should simply always already have the MR/RamBlock here. -- Thanks, David / dhildenb
On 10/08/2022 10.31, David Hildenbrand wrote: > On 10.08.22 10:11, Thomas Huth wrote: >> On 10/08/2022 09.32, David Hildenbrand wrote: >>> On 10.08.22 08:32, Thomas Huth wrote: >>>> It is currently not possible yet to use "memory-backend-memfd" on s390x >>>> with hugepages enabled. This problem is caused by qemu_maxrampagesize() >>>> not taking memory-backend-memfd objects into account yet, so the code >>>> in s390_memory_init() fails to enable the huge page support there via >>>> s390_set_max_pagesize(). Fix it by looking at the memory-backend-memfd >>>> in the host_memory_backend_pagesize() function, too. >>>> >>>> Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=2116496 >>>> Signed-off-by: Thomas Huth <thuth@redhat.com> >>>> --- >>>> include/sysemu/hostmem.h | 8 +++++++- >>>> backends/hostmem-memfd.c | 2 -- >>>> backends/hostmem.c | 27 +++++++++++++++++---------- >>>> 3 files changed, 24 insertions(+), 13 deletions(-) >>>> >>>> diff --git a/include/sysemu/hostmem.h b/include/sysemu/hostmem.h >>>> index 9ff5c16963..d983ae6c01 100644 >>>> --- a/include/sysemu/hostmem.h >>>> +++ b/include/sysemu/hostmem.h >>>> @@ -34,10 +34,16 @@ OBJECT_DECLARE_TYPE(HostMemoryBackend, HostMemoryBackendClass, >>>> /* hostmem-file.c */ >>>> /** >>>> * @TYPE_MEMORY_BACKEND_FILE: >>>> - * name of backend that uses mmap on a file descriptor >>>> + * name of backend that uses mmap on a file >>>> */ >>>> #define TYPE_MEMORY_BACKEND_FILE "memory-backend-file" >>>> >>>> +/* hostmem-memfd.c */ >>>> +/** >>>> + * @TYPE_MEMORY_BACKEND_MEMFD: >>>> + * name of backend that uses mmap on a memfd file descriptor >>>> + */ >>>> +#define TYPE_MEMORY_BACKEND_MEMFD "memory-backend-memfd" >>>> >>>> /** >>>> * HostMemoryBackendClass: >>>> diff --git a/backends/hostmem-memfd.c b/backends/hostmem-memfd.c >>>> index 3fc85c3db8..1ab2085e49 100644 >>>> --- a/backends/hostmem-memfd.c >>>> +++ b/backends/hostmem-memfd.c >>>> @@ -18,8 +18,6 @@ >>>> #include "qapi/error.h" >>>> #include "qom/object.h" >>>> >>>> -#define TYPE_MEMORY_BACKEND_MEMFD "memory-backend-memfd" >>>> - >>>> OBJECT_DECLARE_SIMPLE_TYPE(HostMemoryBackendMemfd, MEMORY_BACKEND_MEMFD) >>>> >>>> >>>> diff --git a/backends/hostmem.c b/backends/hostmem.c >>>> index 624bb7ecd3..ebce887105 100644 >>>> --- a/backends/hostmem.c >>>> +++ b/backends/hostmem.c >>>> @@ -306,22 +306,29 @@ bool host_memory_backend_is_mapped(HostMemoryBackend *backend) >>>> return backend->is_mapped; >>>> } >>>> >>>> -#ifdef __linux__ >>>> size_t host_memory_backend_pagesize(HostMemoryBackend *memdev) >>>> { >>>> + size_t pagesize = 0; >>>> + >>>> +#ifdef __linux__ >>>> Object *obj = OBJECT(memdev); >>>> - char *path = object_property_get_str(obj, "mem-path", NULL); >>>> - size_t pagesize = qemu_mempath_getpagesize(path); >>>> >>>> - g_free(path); >>>> + if (object_dynamic_cast(obj, TYPE_MEMORY_BACKEND_FILE)) { >>>> + char *path = object_property_get_str(obj, "mem-path", NULL); >>>> + pagesize = qemu_mempath_getpagesize(path); >>>> + g_free(path); >>>> + } else if (object_dynamic_cast(obj, TYPE_MEMORY_BACKEND_MEMFD) && >>>> + object_property_get_bool(obj, "hugetlb", &error_abort)) { >>>> + pagesize = object_property_get_int(obj, "hugetlbsize", &error_abort); >>>> + } >>>> +#endif >>> >>> Why can't we simply rely on >>> >>> qemu_ram_pagesize(memdev->mr.ram_block); >> >> Good idea! That way, we could even get rid of the "#ifdef __linux__" macros >> here, I guess ... I'll give it a try and send a v2 if it works. > > At first I wondered if we could have to deal with semi-iniutialized > backendds here, but I think we should simply always already have the > MR/RamBlock here. I'll add an assert(pagesize >= getpagesize()) there, just to be sure. Thomas
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