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[219.106.231.132]) by smtp.gmail.com with ESMTPSA id a16-20020a170902ecd000b0016c20d40ee7sm13757800plh.174.2022.07.20.04.13.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 20 Jul 2022 04:13:50 -0700 (PDT) From: Ake Koomsin To: qemu-devel@nongnu.org Cc: Dmitry Fleytman , Jason Wang , Ake Koomsin Subject: [PATCH] e1000e: Fix possible interrupt loss when using MSI Date: Wed, 20 Jul 2022 20:13:03 +0900 Message-Id: <20220720111303.10628-1-ake@igel.co.jp> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Received-SPF: pass client-ip=2607:f8b0:4864:20::1032; envelope-from=ake@igel.co.jp; helo=mail-pj1-x1032.google.com X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-Mailman-Approved-At: Wed, 20 Jul 2022 09:17:32 -0400 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" Commit "e1000e: Prevent MSI/MSI-X storms" introduced msi_causes_pending to prevent interrupt storms problem. It was tested with MSI-X. In case of MSI, the guest can rely solely on interrupts to clear ICR. Upon clearing all pending interrupts, msi_causes_pending gets cleared. However, when e1000e_itr_should_postpone() in e1000e_send_msi() returns true, MSI never gets fired by e1000e_intrmgr_on_throttling_timer() because msi_causes_pending is still set. This results in interrupt loss. To prevent this, we need to clear msi_causes_pending when MSI is going to get fired by the throttling timer. The guest can then receive interrupts eventually. Signed-off-by: Ake Koomsin --- hw/net/e1000e_core.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/hw/net/e1000e_core.c b/hw/net/e1000e_core.c index 2c51089a82..208e3e0d79 100644 --- a/hw/net/e1000e_core.c +++ b/hw/net/e1000e_core.c @@ -159,6 +159,8 @@ e1000e_intrmgr_on_throttling_timer(void *opaque) if (msi_enabled(timer->core->owner)) { trace_e1000e_irq_msi_notify_postponed(); + /* Clear msi_causes_pending to fire MSI eventually */ + timer->core->msi_causes_pending = 0; e1000e_set_interrupt_cause(timer->core, 0); } else { trace_e1000e_irq_legacy_notify_postponed();