static bool ufd_check_and_apply(int ufd, MigrationIncomingState *mis)
{
uint64_t asked_features = 0;
static uint64_t supported_features;
/*
* it's not possible to
* request UFFD_API twice per one fd
* userfault fd features is persistent
*/
if (!supported_features) {
if (!receive_ufd_features(&supported_features)) {
error_report("%s failed", __func__);
return false;
}
}
#ifdef UFFD_FEATURE_THREAD_ID
if (migrate_postcopy_blocktime() && mis &&
UFFD_FEATURE_THREAD_ID & supported_features) {
/* kernel supports that feature */
/* don't create blocktime_context if it exists */
if (!mis->blocktime_ctx) {
mis->blocktime_ctx = blocktime_context_new();
}
asked_features |= UFFD_FEATURE_THREAD_ID;
}
#endif
/*
* request features, even if asked_features is 0, due to
* kernel expects UFFD_API before UFFDIO_REGISTER, per
* userfault file descriptor
*/
if (!request_ufd_features(ufd, asked_features)) {
error_report("%s failed: features %" PRIu64, __func__,
asked_features);
return false;
}
if (getpagesize() != ram_pagesize_summary()) {
bool have_hp = false;
/* We've got a huge page */
#ifdef UFFD_FEATURE_MISSING_HUGETLBFS
have_hp = supported_features & UFFD_FEATURE_MISSING_HUGETLBFS;
#endif
if (!have_hp) {
error_report("Userfault on this host does not support huge pages");
return false;
}
}
return true;
}
static bool ufd_check_and_apply(int ufd, MigrationIncomingState *mis)
{
uint64_t asked_features = 0;
static uint64_t supported_features;
/*
* it's not possible to
* request UFFD_API twice per one fd
* userfault fd features is persistent
*/
if (!supported_features) {
if (!receive_ufd_features(&supported_features)) {
error_report("%s failed", __func__);
return false;
}
}
/*
* request features, even if asked_features is 0, due to
* kernel expects UFFD_API before UFFDIO_REGISTER, per
* userfault file descriptor
*/
if (!request_ufd_features(ufd, asked_features)) {
error_report("%s failed: features %" PRIu64, __func__,
asked_features);
return false;
}
if (getpagesize() != ram_pagesize_summary()) {
bool have_hp = false;
/* We've got a huge page */
#ifdef UFFD_FEATURE_MISSING_HUGETLBFS
have_hp = supported_features & UFFD_FEATURE_MISSING_HUGETLBFS;
#endif
if (!have_hp) {
error_report("Userfault on this host does not support huge pages");
return false;
}
}
return true;
}
