The most recent environment e.g. present in our Fedora Rawhide builds fail to build the tree with clang with the following error: ../src/util/virhostcpu.c:1291:25: error: field 'header' with variable sized type 'struct kvm_msrs' not at the end of a struct or class is a GNU extension [-Werror,-Wgnu-variable-sized-type-not-at-end] struct kvm_msrs header; ^ The problem seems to be that clang doesn't like the new way the 'entries' field in struct kvm_msrs is declared. To work around the issue we can simply allocate the variable dynamically and use the 'entries' member as it was intended to to access the members. Signed-off-by: Peter Krempa <pkrempa(a)redhat.com&gt; --- src/util/virhostcpu.c | 15 ++++++--------- 1 file changed, 6 insertions(+), 9 deletions(-) diff --git a/src/util/virhostcpu.c b/src/util/virhostcpu.c index 54d0166b85..c1e8dc8078 100644 --- a/src/util/virhostcpu.c +++ b/src/util/virhostcpu.c @@ -1287,25 +1287,22 @@ virHostCPUGetMSRFromKVM(unsigned long index, uint64_t *result) { VIR_AUTOCLOSE fd = -1; - struct { - struct kvm_msrs header; - struct kvm_msr_entry entry; - } msr = { - .header = { .nmsrs = 1 }, - .entry = { .index = index }, - }; + g_autofree struct kvm_msrs *msr = g_malloc0(sizeof(struct kvm_msrs) + + sizeof(struct kvm_msr_entry)); + msr->nmsrs = 1; + msr->entries[0].index = index; if ((fd = open(KVM_DEVICE, O_RDONLY)) < 0) { virReportSystemError(errno, _("Unable to open %s"), KVM_DEVICE); return -1; } - if (ioctl(fd, KVM_GET_MSRS, &msr) < 0) { + if (ioctl(fd, KVM_GET_MSRS, msr) < 0) { VIR_DEBUG("Cannot get MSR 0x%lx from KVM", index); return 1; } - *result = msr.entry.data; + *result = msr->entries[0].data; return 0; } -- 2.37.1