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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 06C29C433EF for ; Fri, 3 Dec 2021 23:48:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1354491AbhLCXwL (ORCPT ); Fri, 3 Dec 2021 18:52:11 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39464 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1354388AbhLCXwL (ORCPT ); Fri, 3 Dec 2021 18:52:11 -0500 Received: from mail-pg1-x530.google.com (mail-pg1-x530.google.com [IPv6:2607:f8b0:4864:20::530]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B4A81C061354 for ; Fri, 3 Dec 2021 15:48:46 -0800 (PST) Received: by mail-pg1-x530.google.com with SMTP id s137so4577785pgs.5 for ; Fri, 03 Dec 2021 15:48:46 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=jZAmDHsC6a6B1+lUDqpdszqQCD3+V34qAynkOGNqzOs=; b=ZROJNDJMOq5eIJoHp0p2tGr6bzowIDKO97CIqwhIh2xybI8owSYD51r3cZQjUy7SMs /P40psd2IV5qDAXCOCYwHiSHhml5L0HIMnhaLZObQG+0Hv1TAktoB1btbfH4raGuMAMe ell0IVFfKq86nUJQpY0EZXb2dY9wbbgAGzMXedTAW+uehWC6uWCvbOHeg2kpnbzPykUN lX9e0y4K1FLLZBvfJWvyw8HhVNgXjG49W4LKgWJQwTZg4t1woSQEZRu5HpUtfTQJq5h8 rwdbRyd+awbHRbi9DEg9SXwvQGC6Ubgqnzoyn+LSR2ttCXmaRK2RKHh6RimVCyhhdZs8 i/Cw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=jZAmDHsC6a6B1+lUDqpdszqQCD3+V34qAynkOGNqzOs=; b=N/LFrZ+IxQ1U2Rxze/AoPONnGV2mA0qjkh3Xh86uQ0/3p86Apftf8FIAczSzQJ6F5/ yfwcpAcJXmBLLvGDEvfylnUwJleYgKwSY7ee4pIpVIqRh++Qe2ew8+Zgg6hsNQEoH21V r1/th1tvUuJgnXZyhrpdkdDsQ29xNmYZT/M5U07kDS7+GZ4QR18bApgUMjprGuCRGPwG LBAkXWJWYRRPXXnJkTKIYbxJ3M0uH1a2Nxqdjnxc/yTr9OBierbbIpJVlo5v9yyP/zwR hLHxmte28Dua0xfPvIZ1h7099QP7FdkJe3zkLwo0VMFHaXM41DMfyI/wW1AlK5Nk918M jHfQ== X-Gm-Message-State: AOAM5312dqOuswvFv1j94U1RecZY5zM7tliWlP+/7hQRrpj4Aq7wuFZq fdBPt3CKjlf1LeLW8h8A8OtaOA== X-Google-Smtp-Source: ABdhPJxiSrEcmRBZRtgKjhJMnu5tJLdEcIhiCx8GQtfxumShdLMvRSAXNQRAKE0vEMsLMNwHj3EJRQ== X-Received: by 2002:a05:6a00:2353:b0:4ab:1694:6f50 with SMTP id j19-20020a056a00235300b004ab16946f50mr6815870pfj.7.1638575326038; Fri, 03 Dec 2021 15:48:46 -0800 (PST) Received: from google.com (157.214.185.35.bc.googleusercontent.com. [35.185.214.157]) by smtp.gmail.com with ESMTPSA id j6sm4164413pfu.205.2021.12.03.15.48.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 03 Dec 2021 15:48:45 -0800 (PST) Date: Fri, 3 Dec 2021 23:48:42 +0000 From: Sean Christopherson To: Vitaly Kuznetsov Cc: Wanpeng Li , Jim Mattson , Joerg Roedel , kvm@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, Ajay Garg , Paolo Bonzini , "K. Y. Srinivasan" , Haiyang Zhang , Stephen Hemminger , Wei Liu , Dexuan Cui , Arnd Bergmann Subject: Re: [PATCH v2 7/8] KVM: x86: Reject fixeds-size Hyper-V hypercalls with non-zero "var_cnt" Message-ID: References: <20211030000800.3065132-1-seanjc@google.com> <20211030000800.3065132-8-seanjc@google.com> <87y268jhm1.fsf@vitty.brq.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87y268jhm1.fsf@vitty.brq.redhat.com> Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org On Mon, Nov 01, 2021, Vitaly Kuznetsov wrote: > Sean Christopherson writes: > > @@ -2331,6 +2331,11 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu) > > ret = HV_STATUS_OPERATION_DENIED; > > break; > > } > > + if (unlikely(hc.var_cnt)) { > > + ret = HV_STATUS_INVALID_HYPERCALL_INPUT; > > + break; > > + } > > + > > Probably true for HVCALL_RESET_DEBUG_SESSION but I'm not sure about > HVCALL_POST_DEBUG_DATA/HVCALL_RETRIEVE_DEBUG_DATA (note 'fallthrough' > above) -- these are not described well in TLFS. I'll drop the check for all the DEBUG hypercalls and add a note in the changelog to call out that they're probably not supposed to use var_cnt, but that the TLFS documentation isn't clear one way or the other.