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d="scan'208";a="215619877" Received: from liuzhao-optiplex-7080.sh.intel.com (HELO localhost) ([10.239.160.39]) by fmviesa002.fm.intel.com with ESMTP; 24 Nov 2025 00:32:59 -0800 Date: Mon, 24 Nov 2025 16:57:38 +0800 From: Zhao Liu To: Paolo Bonzini Cc: qemu-devel@nongnu.org, qemu-rust@nongnu.org Subject: Re: [PATCH 2/5] rust/hpet: move hpet_offset to HPETRegisters Message-ID: References: <20251117084752.203219-1-pbonzini@redhat.com> <20251117084752.203219-3-pbonzini@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251117084752.203219-3-pbonzini@redhat.com> Received-SPF: pass client-ip=198.175.65.18; envelope-from=zhao1.liu@intel.com; helo=mgamail.intel.com X-Spam_score_int: -45 X-Spam_score: -4.6 X-Spam_bar: ---- X-Spam_report: (-4.6 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.161, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_NONE=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 > @@ -596,11 +598,11 @@ fn callback(&self, regs: &mut HPETRegisters) { > } else { > tn_regs.cmp = tn_regs.cmp64; > } > - self.arm_timer(tn_regs, tn_regs.cmp64); > } else if tn_regs.wrap_flag != 0 { > tn_regs.wrap_flag = 0; > - self.arm_timer(tn_regs, tn_regs.cmp64); > } > + let next_tick = tn_regs.cmp64; > + self.arm_timer(regs, next_tick); I didn't notice this in previous review... arming timer unconditionally is wrong, since the code block is: if tn_regs.is_periodic() && tn_regs.period != 0 { ... self.arm_timer(tn_regs, tn_regs.cmp64); } else if tn_regs.wrap_flag != 0 { ... self.arm_timer(tn_regs, tn_regs.cmp64); } So one-shot mode (with wrap_flag == 0) shouldn't arm timer again, (otherwise, the guest will hang). --- diff --git a/rust/hw/timer/hpet/src/device.rs b/rust/hw/timer/hpet/src/device.rs index 19676af74bc6..179bd18e2045 100644 --- a/rust/hw/timer/hpet/src/device.rs +++ b/rust/hw/timer/hpet/src/device.rs @@ -586,23 +586,33 @@ fn callback(&self, regs: &mut HPETRegisters) { // Mutex. assert!(bql::is_locked()); - let cur_tick: u64 = regs.get_ticks(); - let tn_regs = &mut regs.tn_regs[self.index as usize]; + let next_tick = { + let cur_tick: u64 = regs.get_ticks(); + let tn_regs = &mut regs.tn_regs[self.index as usize]; - if tn_regs.is_periodic() && tn_regs.period != 0 { - while hpet_time_after(cur_tick, tn_regs.cmp64) { - tn_regs.cmp64 += tn_regs.period; - } - if tn_regs.is_32bit_mod() { - tn_regs.cmp = u64::from(tn_regs.cmp64 as u32); // truncate! + if tn_regs.is_periodic() && tn_regs.period != 0 { + while hpet_time_after(cur_tick, tn_regs.cmp64) { + tn_regs.cmp64 += tn_regs.period; + } + if tn_regs.is_32bit_mod() { + tn_regs.cmp = u64::from(tn_regs.cmp64 as u32); // truncate! + } else { + tn_regs.cmp = tn_regs.cmp64; + } + + Some(tn_regs.cmp64) + } else if tn_regs.wrap_flag != 0 { + tn_regs.wrap_flag = 0; + + Some(tn_regs.cmp64) } else { - tn_regs.cmp = tn_regs.cmp64; + None } - } else if tn_regs.wrap_flag != 0 { - tn_regs.wrap_flag = 0; + }; + + if let Some(t) = next_tick { + self.arm_timer(regs, t); } - let next_tick = tn_regs.cmp64; - self.arm_timer(regs, next_tick); self.update_irq(regs, true); }