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authorXiaoyao Li <xiaoyao.li@intel.com>2024-03-20 03:39:07 -0500
committerPaolo Bonzini <pbonzini@redhat.com>2024-04-23 17:35:26 +0200
commitb2e9426c04fdd32d93a3a37db6b0c2e67c88c335 (patch)
treea9834ac90f0493c8a24502d2c6f1c7c97667aa6a /system
parent852f0048f3ea9f14de18eb279a99fccb6d250e8f (diff)
physmem: Introduce ram_block_discard_guest_memfd_range()
When memory page is converted from private to shared, the original private memory is back'ed by guest_memfd. Introduce ram_block_discard_guest_memfd_range() for discarding memory in guest_memfd. Based on a patch by Isaku Yamahata <isaku.yamahata@intel.com>. Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com> Reviewed-by: David Hildenbrand <david@redhat.com> Signed-off-by: Michael Roth <michael.roth@amd.com> Message-ID: <20240320083945.991426-12-michael.roth@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'system')
-rw-r--r--system/physmem.c23
1 files changed, 23 insertions, 0 deletions
diff --git a/system/physmem.c b/system/physmem.c
index 5ebcf5be11..c3d04ca921 100644
--- a/system/physmem.c
+++ b/system/physmem.c
@@ -3721,6 +3721,29 @@ err:
return ret;
}
+int ram_block_discard_guest_memfd_range(RAMBlock *rb, uint64_t start,
+ size_t length)
+{
+ int ret = -1;
+
+#ifdef CONFIG_FALLOCATE_PUNCH_HOLE
+ ret = fallocate(rb->guest_memfd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
+ start, length);
+
+ if (ret) {
+ ret = -errno;
+ error_report("%s: Failed to fallocate %s:%" PRIx64 " +%zx (%d)",
+ __func__, rb->idstr, start, length, ret);
+ }
+#else
+ ret = -ENOSYS;
+ error_report("%s: fallocate not available %s:%" PRIx64 " +%zx (%d)",
+ __func__, rb->idstr, start, length, ret);
+#endif
+
+ return ret;
+}
+
bool ramblock_is_pmem(RAMBlock *rb)
{
return rb->flags & RAM_PMEM;