Re: [PATCH v4 07/66] physmem: Introduce ram_block_discard_guest_memfd_range()

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 25.01.24 04:22, Xiaoyao Li wrote:
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.

Originally-from: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
Codeveloped-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>
Signed-off-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>
---
Changes in in v4:
- Drop ram_block_convert_range() and open code its implementation in the
   next Patch.
---
  include/exec/cpu-common.h |  2 ++
  system/physmem.c          | 23 +++++++++++++++++++++++
  2 files changed, 25 insertions(+)

diff --git a/include/exec/cpu-common.h b/include/exec/cpu-common.h
index fef3138d29fc..05610efa8b4f 100644
--- a/include/exec/cpu-common.h
+++ b/include/exec/cpu-common.h
@@ -175,6 +175,8 @@ typedef int (RAMBlockIterFunc)(RAMBlock *rb, void *opaque);
int qemu_ram_foreach_block(RAMBlockIterFunc func, void *opaque);
  int ram_block_discard_range(RAMBlock *rb, uint64_t start, size_t length);
+int ram_block_discard_guest_memfd_range(RAMBlock *rb, uint64_t start,
+                                        size_t length);
#endif diff --git a/system/physmem.c b/system/physmem.c
index 4735b0462ed9..fc59470191ef 100644
--- a/system/physmem.c
+++ b/system/physmem.c
@@ -3626,6 +3626,29 @@ 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;


Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>

--
Cheers,

David / dhildenb





[Index of Archives]     [KVM ARM]     [KVM ia64]     [KVM ppc]     [Virtualization Tools]     [Spice Development]     [Libvirt]     [Libvirt Users]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite Questions]     [Linux Kernel]     [Linux SCSI]     [XFree86]

  Powered by Linux