From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.3 required=3.0 tests=INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLACK,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 79123C43387 for ; Thu, 20 Dec 2018 09:04:48 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id ED6D82176F for ; Thu, 20 Dec 2018 09:04:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org ED6D82176F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ozlabs.ru Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 43L5Rx6rMNzDr9w for ; Thu, 20 Dec 2018 20:04:45 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=ozlabs.ru Authentication-Results: lists.ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=ozlabs.ru (client-ip=107.173.13.209; helo=ozlabs.ru; envelope-from=aik@ozlabs.ru; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=ozlabs.ru Received: from ozlabs.ru (ozlabs.ru [107.173.13.209]) by lists.ozlabs.org (Postfix) with ESMTP id 43L4Z26ZshzDqy9 for ; Thu, 20 Dec 2018 19:24:58 +1100 (AEDT) Received: from fstn1-p1.ozlabs.ibm.com (localhost [IPv6:::1]) by ozlabs.ru (Postfix) with ESMTP id B5A2DAE80381; Thu, 20 Dec 2018 03:24:54 -0500 (EST) From: Alexey Kardashevskiy To: linuxppc-dev@lists.ozlabs.org Subject: [PATCH kernel v7 17/20] powerpc/powernv/npu: Fault user page into the hypervisor's pagetable Date: Thu, 20 Dec 2018 19:23:47 +1100 Message-Id: <20181220082350.58113-18-aik@ozlabs.ru> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20181220082350.58113-1-aik@ozlabs.ru> References: <20181220082350.58113-1-aik@ozlabs.ru> X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Christoph Hellwig , Jose Ricardo Ziviani , kvm@vger.kernel.org, Alexey Kardashevskiy , Alistair Popple , Daniel Henrique Barboza , Alex Williamson , kvm-ppc@vger.kernel.org, linux-kernel@vger.kernel.org, Sam Bobroff , Piotr Jaroszynski , =?UTF-8?q?Leonardo=20Augusto=20Guimar=C3=A3es=20Garcia?= , Reza Arbab , David Gibson Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" When a page fault happens in a GPU, the GPU signals the OS and the GPU driver calls the fault handler which populated a page table; this allows the GPU to complete an ATS request. On the bare metal get_user_pages() is enough as it adds a pte to the kernel page table but under KVM the partition scope tree does not get updated so ATS will still fail. This reads a byte from an effective address which causes HV storage interrupt and KVM updates the partition scope tree. Signed-off-by: Alexey Kardashevskiy --- arch/powerpc/platforms/powernv/npu-dma.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/arch/powerpc/platforms/powernv/npu-dma.c b/arch/powerpc/platforms/powernv/npu-dma.c index c6163b9..12b8421 100644 --- a/arch/powerpc/platforms/powernv/npu-dma.c +++ b/arch/powerpc/platforms/powernv/npu-dma.c @@ -1133,6 +1133,8 @@ int pnv_npu2_handle_fault(struct npu_context *context, uintptr_t *ea, u64 rc = 0, result = 0; int i, is_write; struct page *page[1]; + const char __user *u; + char c; /* mmap_sem should be held so the struct_mm must be present */ struct mm_struct *mm = context->mm; @@ -1145,18 +1147,17 @@ int pnv_npu2_handle_fault(struct npu_context *context, uintptr_t *ea, is_write ? FOLL_WRITE : 0, page, NULL, NULL); - /* - * To support virtualised environments we will have to do an - * access to the page to ensure it gets faulted into the - * hypervisor. For the moment virtualisation is not supported in - * other areas so leave the access out. - */ if (rc != 1) { status[i] = rc; result = -EFAULT; continue; } + /* Make sure partition scoped tree gets a pte */ + u = page_address(page[0]); + if (__get_user(c, u)) + result = -EFAULT; + status[i] = 0; put_page(page[0]); } -- 2.17.1