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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=170.10.133.124; envelope-from=pbonzini@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -25 X-Spam_score: -2.6 X-Spam_bar: -- X-Spam_report: (-2.6 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.513, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-rust@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: QEMU Rust-related patches and discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-rust-bounces+qemu-rust=archiver.kernel.org@nongnu.org Sender: qemu-rust-bounces+qemu-rust=archiver.kernel.org@nongnu.org On 9/29/25 18:12, Zhao Liu wrote: >> + fn snapshot_migration_state(&self, target: &mut i64) -> Result<(), InvalidError> { >> + // SAFETY: as_ptr() is unsafe to ensure that the caller reasons about >> + // the pinning of the data inside the Opaque<>. Here all we do is >> + // access a field. >> + *target = unsafe { &*self.as_ptr() }.expire_time; > > C side checks timer_pending(), which ensures when the timer is > inactive, it always saves u64::MAX. > > But now we save the expire_time directly in Rust. I think this would be > possible to break the migration from Rust timer to C timer, because at > C side, timer_get() checks whether expire_time is -1 and we can't ensure > expire_time won't store -2 (or other unusual negative values). I think this should work in both cases because timer_pending() checks >= 0 and negative values are extremely far in the future. But I'll change it to timer_expire_time_ns() for safety and clarity. Paolo