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 <th...@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
