From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Rybchenko Subject: [PATCH 02/53] net/sfc/base: do not use Tx desc push with TSO descriptors Date: Thu, 16 Nov 2017 08:03:50 +0000 Message-ID: <1510819481-6809-3-git-send-email-arybchenko@solarflare.com> References: <1510819481-6809-1-git-send-email-arybchenko@solarflare.com> Mime-Version: 1.0 Content-Type: text/plain Cc: Mark Spender To: Return-path: Received: from dispatch1-us1.ppe-hosted.com (dispatch1-us1.ppe-hosted.com [67.231.154.164]) by dpdk.org (Postfix) with ESMTP id D24AE1B226 for ; Thu, 16 Nov 2017 09:04:58 +0100 (CET) Received: from pure.maildistiller.com (unknown [10.110.50.29]) by dispatch1-us1.ppe-hosted.com (Proofpoint Essentials ESMTP Server) with ESMTP id 4F7F52005A for ; Thu, 16 Nov 2017 08:04:58 +0000 (UTC) Received: from mx1-us4.ppe-hosted.com (unknown [10.110.49.251]) by pure.maildistiller.com (Proofpoint Essentials ESMTP Server) with ESMTPS id 0DA164006F for ; Thu, 16 Nov 2017 08:04:58 +0000 (UTC) Received: from webmail.solarflare.com (webmail.solarflare.com [12.187.104.26]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1-us4.ppe-hosted.com (Proofpoint Essentials ESMTP Server) with ESMTPS id B4D07B40066 for ; Thu, 16 Nov 2017 08:04:57 +0000 (UTC) In-Reply-To: <1510819481-6809-1-git-send-email-arybchenko@solarflare.com> List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" From: Mark Spender Pushing TSO option descriptors is unsafe if pacer bypass is enabled, so to make sure that doesn't happen never push TSO option descriptors. Signed-off-by: Mark Spender Signed-off-by: Andrew Rybchenko --- drivers/net/sfc/base/ef10_tx.c | 56 ++++++++++++++++++++++++++++++++---------- 1 file changed, 43 insertions(+), 13 deletions(-) diff --git a/drivers/net/sfc/base/ef10_tx.c b/drivers/net/sfc/base/ef10_tx.c index 211d265..2666943 100644 --- a/drivers/net/sfc/base/ef10_tx.c +++ b/drivers/net/sfc/base/ef10_tx.c @@ -473,9 +473,9 @@ ef10_tx_qpost( } /* - * This improves performance by pushing a TX descriptor at the same time as the - * doorbell. The descriptor must be added to the TXQ, so that can be used if the - * hardware decides not to use the pushed descriptor. + * This improves performance by, when possible, pushing a TX descriptor at the + * same time as the doorbell. The descriptor must be added to the TXQ, so that + * can be used if the hardware decides not to use the pushed descriptor. */ void ef10_tx_qpush( @@ -495,16 +495,46 @@ ef10_tx_qpush( offset = id * sizeof (efx_qword_t); EFSYS_MEM_READQ(etp->et_esmp, offset, &desc); - EFX_POPULATE_OWORD_3(oword, - ERF_DZ_TX_DESC_WPTR, wptr, - ERF_DZ_TX_DESC_HWORD, EFX_QWORD_FIELD(desc, EFX_DWORD_1), - ERF_DZ_TX_DESC_LWORD, EFX_QWORD_FIELD(desc, EFX_DWORD_0)); - - /* Guarantee ordering of memory (descriptors) and PIO (doorbell) */ - EFX_DMA_SYNC_QUEUE_FOR_DEVICE(etp->et_esmp, etp->et_mask + 1, wptr, id); - EFSYS_PIO_WRITE_BARRIER(); - EFX_BAR_TBL_DOORBELL_WRITEO(enp, ER_DZ_TX_DESC_UPD_REG, etp->et_index, - &oword); + + /* + * Bug 65776: TSO option descriptors cannot be pushed if pacer bypass is + * enabled on the event queue this transmit queue is attached to. + * + * To ensure the code is safe, it is easiest to simply test the type of + * the descriptor to push, and only push it is if it not a TSO option + * descriptor. + */ + if ((EFX_QWORD_FIELD(desc, ESF_DZ_TX_DESC_IS_OPT) != 1) || + (EFX_QWORD_FIELD(desc, ESF_DZ_TX_OPTION_TYPE) != + ESE_DZ_TX_OPTION_DESC_TSO)) { + /* Push the descriptor and update the wptr. */ + EFX_POPULATE_OWORD_3(oword, ERF_DZ_TX_DESC_WPTR, wptr, + ERF_DZ_TX_DESC_HWORD, EFX_QWORD_FIELD(desc, EFX_DWORD_1), + ERF_DZ_TX_DESC_LWORD, EFX_QWORD_FIELD(desc, EFX_DWORD_0)); + + /* Ensure ordering of memory (descriptors) and PIO (doorbell) */ + EFX_DMA_SYNC_QUEUE_FOR_DEVICE(etp->et_esmp, etp->et_mask + 1, + wptr, id); + EFSYS_PIO_WRITE_BARRIER(); + EFX_BAR_TBL_DOORBELL_WRITEO(enp, ER_DZ_TX_DESC_UPD_REG, + etp->et_index, &oword); + } else { + efx_dword_t dword; + + /* + * Only update the wptr. This is signalled to the hardware by + * only writing one DWORD of the doorbell register. + */ + EFX_POPULATE_OWORD_1(oword, ERF_DZ_TX_DESC_WPTR, wptr); + dword = oword.eo_dword[2]; + + /* Ensure ordering of memory (descriptors) and PIO (doorbell) */ + EFX_DMA_SYNC_QUEUE_FOR_DEVICE(etp->et_esmp, etp->et_mask + 1, + wptr, id); + EFSYS_PIO_WRITE_BARRIER(); + EFX_BAR_TBL_WRITED2(enp, ER_DZ_TX_DESC_UPD_REG, + etp->et_index, &dword, B_FALSE); + } } __checkReturn efx_rc_t -- 2.7.4