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=-13.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 D5209C6379F for ; Tue, 27 Oct 2020 00:46:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9E6C020829 for ; Tue, 27 Oct 2020 00:46:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603759608; bh=7qDKrIH5KNymgmUgST0I3iXpf5p0CWrV8Pqgx/ukEt0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=yI9o7VA+MJFodMRpKFpZliMNLDf0jRGe79JUq6Ue2B+1S6dNcepKQlcVItJE/pJg6 N+aVGIuGnIFUnMUJX6xoRH2nU30IhhXDqho+5XDqmukrgJQ/coV3hO5oTyHlMvhoMR 39LwySv12txSPLqNySh72cNPkDIXQieY3CyEcMyo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2502234AbgJ0AmA (ORCPT ); Mon, 26 Oct 2020 20:42:00 -0400 Received: from mail.kernel.org ([198.145.29.99]:47594 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2408733AbgJZXtc (ORCPT ); Mon, 26 Oct 2020 19:49:32 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 923FA20874; Mon, 26 Oct 2020 23:49:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603756171; bh=7qDKrIH5KNymgmUgST0I3iXpf5p0CWrV8Pqgx/ukEt0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dVUD7rXfphylDjWgZSv8+XpknEweDxAc4omrX9HeQE6Goq13cka/5NxlpgCRCXnPH XgLC3cndXNa33og6mcq9TmfpDvMMWWeO0Mtse7u2NHFlLtJ7nWfMLJ1rFuXGDO2/S2 GSLfaS/1vsMQOA8kUh3nTDaAmegsBf1mLjxh6q+c= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Nicholas Piggin , Paul Mackerras , Michael Ellerman , Sasha Levin , linuxppc-dev@lists.ozlabs.org, kvm-ppc@vger.kernel.org Subject: [PATCH AUTOSEL 5.9 020/147] powerpc/64s: handle ISA v3.1 local copy-paste context switches Date: Mon, 26 Oct 2020 19:46:58 -0400 Message-Id: <20201026234905.1022767-20-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20201026234905.1022767-1-sashal@kernel.org> References: <20201026234905.1022767-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Nicholas Piggin [ Upstream commit dc462267d2d7aacffc3c1d99b02d7a7c59db7c66 ] The ISA v3.1 the copy-paste facility has a new memory move functionality which allows the copy buffer to be pasted to domestic memory (RAM) as opposed to foreign memory (accelerator). This means the POWER9 trick of avoiding the cp_abort on context switch if the process had not mapped foreign memory does not work on POWER10. Do the cp_abort unconditionally there. KVM must also cp_abort on guest exit to prevent copy buffer state leaking between contexts. Signed-off-by: Nicholas Piggin Acked-by: Paul Mackerras Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200825075535.224536-1-npiggin@gmail.com Signed-off-by: Sasha Levin --- arch/powerpc/kernel/process.c | 16 +++++++++------- arch/powerpc/kvm/book3s_hv.c | 7 +++++++ arch/powerpc/kvm/book3s_hv_rmhandlers.S | 8 ++++++++ 3 files changed, 24 insertions(+), 7 deletions(-) diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 73a57043ee662..3f2dc0675ea7a 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -1256,15 +1256,17 @@ struct task_struct *__switch_to(struct task_struct *prev, restore_math(current->thread.regs); /* - * The copy-paste buffer can only store into foreign real - * addresses, so unprivileged processes can not see the - * data or use it in any way unless they have foreign real - * mappings. If the new process has the foreign real address - * mappings, we must issue a cp_abort to clear any state and - * prevent snooping, corruption or a covert channel. + * On POWER9 the copy-paste buffer can only paste into + * foreign real addresses, so unprivileged processes can not + * see the data or use it in any way unless they have + * foreign real mappings. If the new process has the foreign + * real address mappings, we must issue a cp_abort to clear + * any state and prevent snooping, corruption or a covert + * channel. ISA v3.1 supports paste into local memory. */ if (current->mm && - atomic_read(¤t->mm->context.vas_windows)) + (cpu_has_feature(CPU_FTR_ARCH_31) || + atomic_read(¤t->mm->context.vas_windows))) asm volatile(PPC_CP_ABORT); } #endif /* CONFIG_PPC_BOOK3S_64 */ diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 4ba06a2a306cf..3bd3118c76330 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -3530,6 +3530,13 @@ static int kvmhv_load_hv_regs_and_go(struct kvm_vcpu *vcpu, u64 time_limit, */ asm volatile("eieio; tlbsync; ptesync"); + /* + * cp_abort is required if the processor supports local copy-paste + * to clear the copy buffer that was under control of the guest. + */ + if (cpu_has_feature(CPU_FTR_ARCH_31)) + asm volatile(PPC_CP_ABORT); + mtspr(SPRN_LPID, vcpu->kvm->arch.host_lpid); /* restore host LPID */ isync(); diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S index 799d6d0f4eade..cd9995ee84419 100644 --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S @@ -1830,6 +1830,14 @@ END_FTR_SECTION_IFSET(CPU_FTR_P9_RADIX_PREFETCH_BUG) 2: #endif /* CONFIG_PPC_RADIX_MMU */ + /* + * cp_abort is required if the processor supports local copy-paste + * to clear the copy buffer that was under control of the guest. + */ +BEGIN_FTR_SECTION + PPC_CP_ABORT +END_FTR_SECTION_IFSET(CPU_FTR_ARCH_31) + /* * POWER7/POWER8 guest -> host partition switch code. * We don't have to lock against tlbies but we do -- 2.25.1