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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 90FEDCCF9FA for ; Thu, 30 Oct 2025 23:40:47 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [127.0.0.1]) by lists.ozlabs.org (Postfix) with ESMTP id 4cyLG606MJz2xnh; Fri, 31 Oct 2025 10:40:46 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; arc=none smtp.remote-ip="2607:f8b0:4864:20::449" ARC-Seal: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1761867645; cv=none; b=TNHhPMkOpiKgw5spz/52052KuTkmxJSUTweflLytW7ulKpj40vehKjK82eb4FnhYHeGLslUjFsSLF5KnsomWYkr2IxKwZwgSeMtQOCe25TxL3rV+k37L+QfAMy2EyGICPOmoTVsHB6T9DPAb16zUDkRJ40mQIhAm3gicJ1HL7WvMVPGXoRvy92EyOIEpCW87aIm7+CSoCvtJm+IukNFK4Lru2j9XIJRuxw0XpSGbzFK92Ovjadocn1oyXnI/ayqussrd9PU7jouD0aWXxP/h6e4kMVULRBanHDaqAJhVuCwMkAGPB9+5AC+vDjGE0HOjtWC1f3RgJVsmH8oetc7ZDA== ARC-Message-Signature: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1761867645; c=relaxed/relaxed; bh=hANv7xEJBy7S5lh8h/UQF87h23G6mY0gbFBLav72O2Q=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=IsVRnY6pnh1yx8TOcmCwtjv10bODn6BJgfYVRxIV7Lbog+xsmtjaexnSlQLtgAWGn8tNHMGF0vhb2zp0zw1GHVwsRforpAQUBTryQRzH/I3CcX26DvEUIN5ZbyvsQdywFiI/cl1v2VSXr+sDw9Oe/o9UkwXsDEv2FLZut3nefxUuH4ymkIA7sp7dOpQ3TjDpf7s5n21hfFfXGEqZIStpBgaJKd98URsKeMO2jkcO5LNA4eFwevIssyf3xgFFtiBjpTGfrwEIkTiUjHdlqzPETQ6U1vPUZUvahpMu+9n/8hNRh7fj7EWY+nRS0JdmCakCgLMj+7ohxWL3gzJfW4gGpA== ARC-Authentication-Results: i=1; lists.ozlabs.org; dmarc=pass (p=reject dis=none) header.from=google.com; dkim=pass (2048-bit key; unprotected) header.d=google.com header.i=@google.com header.a=rsa-sha256 header.s=20230601 header.b=vqNMkeU5; dkim-atps=neutral; spf=pass (client-ip=2607:f8b0:4864:20::449; helo=mail-pf1-x449.google.com; envelope-from=3evcdaqykdmc5rn0wpt11tyr.p1zyv07a22p-qr8yv565.1cyno5.14t@flex--seanjc.bounces.google.com; receiver=lists.ozlabs.org) smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: lists.ozlabs.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=google.com header.i=@google.com header.a=rsa-sha256 header.s=20230601 header.b=vqNMkeU5; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=flex--seanjc.bounces.google.com (client-ip=2607:f8b0:4864:20::449; helo=mail-pf1-x449.google.com; envelope-from=3evcdaqykdmc5rn0wpt11tyr.p1zyv07a22p-qr8yv565.1cyno5.14t@flex--seanjc.bounces.google.com; receiver=lists.ozlabs.org) Received: from mail-pf1-x449.google.com (mail-pf1-x449.google.com [IPv6:2607:f8b0:4864:20::449]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4cyLG44tJqz2xgQ for ; Fri, 31 Oct 2025 10:40:43 +1100 (AEDT) Received: by mail-pf1-x449.google.com with SMTP id d2e1a72fcca58-792722e4ebeso1604392b3a.3 for ; Thu, 30 Oct 2025 16:40:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1761867642; x=1762472442; darn=lists.ozlabs.org; h=content-transfer-encoding:cc:to:from:subject:message-id:references :mime-version:in-reply-to:date:from:to:cc:subject:date:message-id :reply-to; bh=hANv7xEJBy7S5lh8h/UQF87h23G6mY0gbFBLav72O2Q=; b=vqNMkeU5lTrz8GNY+uz3Jor9KiFcK5b6FO4ZXem1zaCQEw8WsDJZZIM3xlKjwJ+/uT wFww6ABFnDAQXrWIE/O5D78azw0BRXVwFrCq2t5itGIv7SdTt7c2CJRHxgu110qaTHrm 7OqE1Fb+t3Shvhzie3+UBvDywYFc4L1gWSxshuDFVA0gOO06M6/S8LwtrsbA5ZkL4A6f 8OIXf36ScZMgh3+9Kpm/L0wtwt/LEgWyqJjL1KLFZBOL7Q9LDT9POqQlx/jiA3SGKrG1 67+6KmUdKq9p7IE3keVXNe5yHehF8xocsayYmUvAAaxZdBY6rg2TyF+qWRmoIMAKxzG0 NGrg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1761867642; x=1762472442; h=content-transfer-encoding:cc:to:from:subject:message-id:references :mime-version:in-reply-to:date:x-gm-message-state:from:to:cc:subject :date:message-id:reply-to; bh=hANv7xEJBy7S5lh8h/UQF87h23G6mY0gbFBLav72O2Q=; b=HBPeIyto+2ZHQk+LNrhSKUSeLYEhXkfAKLNTir7sZ5kFruw5B+MAExYgExBC3em/77 rqF7qyvfytmECLxBXXyifNyA3CHH9HllwC9e+7LF7fDVMDb7lNhAJHDOsNcxNjSkd+Tz 2orrb/GVt68r+oGKh8/bz8GM77hycJcXVUxUxzO9cQq68LctHNRqBBqPlErX/w6AFyqx wAjhcPrfM1A9jXUoud+NaYKitDljmJVoocJG4JY4QH4Cbky+35WZFOgOItPRap/k0WdR p+FAj4J1MKaRiVatA2gvfOPdRS2a2TqGfzhUVH+aS9GGnWS6KX0t02Mxm3sa4rlPzI0Q gBjQ== X-Forwarded-Encrypted: i=1; AJvYcCU7TeMaZdyP+LWhE4VsTUkyHRdBIXwwcVwPHRshMLQE8Vjne86NmBT5pCQZN+l8vxS8wecKM3roUHrHD5k=@lists.ozlabs.org X-Gm-Message-State: AOJu0YzZFH7vSSiz8VSKtJRNJKll6XgSjk/QcywO7PjPxcn2DlSIlNNc Ux8dvHoPukQ/dF4lyZHoFBjmVEXuguxXkFtlWWG4Af4rlvDz8i6efpiAEN4aOaYzUGOr5/bRQGU wVeoKpQ== X-Google-Smtp-Source: AGHT+IH6kktSpJB8uW8dOccHej0bRJlF9t4mdGsOdXoLRdKSPbgGpCfMdKkfH5SPES5/Onbr9IfT7/Ky4i8= X-Received: from pfbhm7.prod.google.com ([2002:a05:6a00:6707:b0:77e:40c7:d12e]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:3996:b0:7a4:460e:f86a with SMTP id d2e1a72fcca58-7a7796c8a99mr1645968b3a.25.1761867642073; Thu, 30 Oct 2025 16:40:42 -0700 (PDT) Date: Thu, 30 Oct 2025 16:40:40 -0700 In-Reply-To: <6572689b28a76bd95bc653b1fc1131fa57ed7669.camel@intel.com> X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list Mime-Version: 1.0 References: <20251030200951.3402865-1-seanjc@google.com> <20251030200951.3402865-13-seanjc@google.com> <6572689b28a76bd95bc653b1fc1131fa57ed7669.camel@intel.com> Message-ID: Subject: Re: [PATCH v4 12/28] KVM: TDX: WARN if mirror SPTE doesn't have full RWX when creating S-EPT mapping From: Sean Christopherson To: Kai Huang Cc: "chenhuacai@kernel.org" , "frankja@linux.ibm.com" , "maz@kernel.org" , "borntraeger@linux.ibm.com" , "pjw@kernel.org" , "aou@eecs.berkeley.edu" , "kas@kernel.org" , "maobibo@loongson.cn" , "pbonzini@redhat.com" , "maddy@linux.ibm.com" , "palmer@dabbelt.com" , "imbrenda@linux.ibm.com" , "zhaotianrui@loongson.cn" , "anup@brainfault.org" , "oliver.upton@linux.dev" , "kvm@vger.kernel.org" , "linux-coco@lists.linux.dev" , Yan Y Zhao , "michael.roth@amd.com" , "binbin.wu@linux.intel.com" , Ira Weiny , "loongarch@lists.linux.dev" , "ackerleytng@google.com" , "kvmarm@lists.linux.dev" , "linux-kernel@vger.kernel.org" , "kvm-riscv@lists.infradead.org" , Vishal Annapurve , "linuxppc-dev@lists.ozlabs.org" , "linux-arm-kernel@lists.infradead.org" , "linux-mips@vger.kernel.org" , Rick P Edgecombe , "linux-riscv@lists.infradead.org" , "x86@kernel.org" Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable On Thu, Oct 30, 2025, Kai Huang wrote: > On Thu, 2025-10-30 at 13:09 -0700, Sean Christopherson wrote: > > Pass in the mirror_spte to kvm_x86_ops.set_external_spte() to provide > > symmetry with .remove_external_spte(), and assert in TDX that the mirro= r > > SPTE is shadow-present with full RWX permissions (the TDX-Module doesn'= t > > allow the hypervisor to control protections). > >=20 > > Signed-off-by: Sean Christopherson >=20 > Reviewed-by: Kai Huang >=20 > [...] >=20 > > static int tdx_sept_set_private_spte(struct kvm *kvm, gfn_t gfn, > > - enum pg_level level, kvm_pfn_t pfn) > > + enum pg_level level, u64 mirror_spte) > > { > > struct kvm_tdx *kvm_tdx =3D to_kvm_tdx(kvm); > > + kvm_pfn_t pfn =3D spte_to_pfn(mirror_spte); > > =20 > > /* TODO: handle large pages. */ > > if (KVM_BUG_ON(level !=3D PG_LEVEL_4K, kvm)) > > return -EIO; > > =20 > > + WARN_ON_ONCE(!is_shadow_present_pte(mirror_spte) || > > + (mirror_spte & VMX_EPT_RWX_MASK) !=3D VMX_EPT_RWX_MASK); > > + >=20 > Nit:=C2=A0 >=20 > I am a little bit confused about when to use WARN_ON_ONCE() and > KVM_BUG_ON(). :-) Very loosely: WARN if there's a decent chance carrying on might be fine, KVM_BUG_ON() if there's a good chance carrying on will crash the host and/o= r corrupt the guest, e.g. if KVM suspects a hardware/TDX-Module issue.