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=-10.1 required=3.0 tests=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 E21E0C433E0 for ; Tue, 9 Jun 2020 00:56:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BDE0520737 for ; Tue, 9 Jun 2020 00:56:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591664188; bh=8uZj89EysRnr7CDvLiuKG1OmXk9XZZAADOB7HSB/dOM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=fJ5gsf9a1rpAD1/sd9ZtA/NL8kFrRIP6Ujvr1SzHQcUy7oenUtVHy3Og5m7P8B88P 7tU1pdQwWD/umgb9m7h6/hVUN+FW2KLgReeGrV78kVe1RlTThAIMQKqKR9+oD0Sspy Hn84IkY8gS/9b+2xpRntVzdKFH6X1u0y0pbmod00= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726958AbgFHXJC (ORCPT ); Mon, 8 Jun 2020 19:09:02 -0400 Received: from mail.kernel.org ([198.145.29.99]:52694 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728044AbgFHXHy (ORCPT ); Mon, 8 Jun 2020 19:07:54 -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 5379720842; Mon, 8 Jun 2020 23:07:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591657674; bh=8uZj89EysRnr7CDvLiuKG1OmXk9XZZAADOB7HSB/dOM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Xue1XR5Dgm7LLZtvscZR7J4GY9ok7bWoYfifSdpv9JJl4dEjwVKGfZkmmSuyoPNK6 92igR8nQWirt0qMUMqpFHj30c0CSvBK0LEvv2qEf9BHN+PEk39YO4V+N8qtLUn+8Vh wsSoEop2iN+ICmkg8a9gQXVyseZyzSGfHP8Rb7aI= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Jon Doron , Vitaly Kuznetsov , Roman Kagan , Paolo Bonzini , Sasha Levin , kvm@vger.kernel.org, linux-doc@vger.kernel.org Subject: [PATCH AUTOSEL 5.7 082/274] x86/kvm/hyper-v: Explicitly align hcall param for kvm_hyperv_exit Date: Mon, 8 Jun 2020 19:02:55 -0400 Message-Id: <20200608230607.3361041-82-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200608230607.3361041-1-sashal@kernel.org> References: <20200608230607.3361041-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jon Doron [ Upstream commit f7d31e65368aeef973fab788aa22c4f1d5a6af66 ] The problem the patch is trying to address is the fact that 'struct kvm_hyperv_exit' has different layout on when compiling in 32 and 64 bit modes. In 64-bit mode the default alignment boundary is 64 bits thus forcing extra gaps after 'type' and 'msr' but in 32-bit mode the boundary is at 32 bits thus no extra gaps. This is an issue as even when the kernel is 64 bit, the userspace using the interface can be both 32 and 64 bit but the same 32 bit userspace has to work with 32 bit kernel. The issue is fixed by forcing the 64 bit layout, this leads to ABI change for 32 bit builds and while we are obviously breaking '32 bit userspace with 32 bit kernel' case, we're fixing the '32 bit userspace with 64 bit kernel' one. As the interface has no (known) users and 32 bit KVM is rather baroque nowadays, this seems like a reasonable decision. Reviewed-by: Vitaly Kuznetsov Signed-off-by: Jon Doron Message-Id: <20200424113746.3473563-2-arilou@gmail.com> Reviewed-by: Roman Kagan Signed-off-by: Paolo Bonzini Signed-off-by: Sasha Levin --- Documentation/virt/kvm/api.rst | 2 ++ include/uapi/linux/kvm.h | 2 ++ 2 files changed, 4 insertions(+) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index efbbe570aa9b..750d005a75bc 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -5067,9 +5067,11 @@ EOI was received. #define KVM_EXIT_HYPERV_SYNIC 1 #define KVM_EXIT_HYPERV_HCALL 2 __u32 type; + __u32 pad1; union { struct { __u32 msr; + __u32 pad2; __u64 control; __u64 evt_page; __u64 msg_page; diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 428c7dde6b4b..9cdc5356f542 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -189,9 +189,11 @@ struct kvm_hyperv_exit { #define KVM_EXIT_HYPERV_SYNIC 1 #define KVM_EXIT_HYPERV_HCALL 2 __u32 type; + __u32 pad1; union { struct { __u32 msr; + __u32 pad2; __u64 control; __u64 evt_page; __u64 msg_page; -- 2.25.1