From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55660) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gRe1I-0008Gk-Lq for qemu-devel@nongnu.org; Tue, 27 Nov 2018 09:07:26 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gRe1C-0007Xo-Sy for qemu-devel@nongnu.org; Tue, 27 Nov 2018 09:07:20 -0500 From: Kevin Wolf Date: Tue, 27 Nov 2018 15:06:40 +0100 Message-Id: <20181127140640.24830-4-kwolf@redhat.com> In-Reply-To: <20181127140640.24830-1-kwolf@redhat.com> References: <20181127140640.24830-1-kwolf@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Subject: [Qemu-devel] [PULL 3/3] nvme: Fix spurious interrupts List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-block@nongnu.org Cc: kwolf@redhat.com, peter.maydell@linaro.org, qemu-devel@nongnu.org From: Keith Busch The code had asserted an interrupt every time it was requested to check for new completion queue entries.This can result in spurious interrupts seen by the guest OS. Fix this by asserting an interrupt only if there are un-acknowledged completion queue entries available. Reported-by: Guenter Roeck Signed-off-by: Keith Busch Tested-by: Guenter Roeck Signed-off-by: Kevin Wolf --- hw/block/nvme.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/hw/block/nvme.c b/hw/block/nvme.c index 9fbe5673cb..7c8c63e8f5 100644 --- a/hw/block/nvme.c +++ b/hw/block/nvme.c @@ -272,7 +272,9 @@ static void nvme_post_cqes(void *opaque) sizeof(req->cqe)); QTAILQ_INSERT_TAIL(&sq->req_list, req, entry); } - nvme_irq_assert(n, cq); + if (cq->tail !=3D cq->head) { + nvme_irq_assert(n, cq); + } } =20 static void nvme_enqueue_req_completion(NvmeCQueue *cq, NvmeRequest *req= ) --=20 2.19.1