From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f201.google.com (mail-pg1-f201.google.com [209.85.215.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9D3462820B7 for ; Tue, 29 Jul 2025 22:54:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753829692; cv=none; b=kXIxUsJa+eL8Cn+pnk18bp1vIdcUcWnynYGzXnBCkZEuumY05d8BN6m1FIv1o+fIFJdzPGXJnQ/ux2gyTloiVkzbknRib1Zo2ODpYQ/rBFIDGRPaOOz6xamYeeVJMQRzOIN8f+9+B6hp3T8eNWk3hsJMBBrfVw+FEG8/jZ8RHVQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753829692; c=relaxed/simple; bh=+s0ingcyIynwN0QqOokA30dWONviuLrNc+vRCAq2gq4=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=dGUHkTVBB3nO3znDcGmgJa4wR1PsK7NRbxopfpAZ4e7oLRJU0sdArlhn9j2c5axDrUwpfxb/mTaq9npMS0X/dkjyg96299K5rKiSYfA/TWaRt45yp5nlnHxWll1AaBKDG04HnbqI/4HmAmQ74vMPOq9hafIO+h1rlW/Rj1RW204= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=dqNe8cGL; arc=none smtp.client-ip=209.85.215.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="dqNe8cGL" Received: by mail-pg1-f201.google.com with SMTP id 41be03b00d2f7-b3f33295703so7979326a12.1 for ; Tue, 29 Jul 2025 15:54:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1753829690; x=1754434490; darn=lists.linux.dev; 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=9IvAMOvcbhlU5W8QZLEdB4U1p9VX42TgZ9WfVdMPu+g=; b=dqNe8cGLH/6sNayFCq5OUXvzyGGVsMRk2cJd42FXqJSyQkXMYnG++mWP1oZqEST7u0 o5en3t5C5dXor5u78kSVM3MRthTcwYvk52LW7U9FKTXoDDTs+deMjd4lHNaFhg5GCeKw FVrCrrVclvroATwM1ZyJSFKHUTFDwoyAglz4c/vtiWWTveaI0fsv2piSyxcfSqsLA38O DeojbdLgZeMqEXgY2t18gn5Ki/wwP0CSBEf++j6QJaiVj4EVEx9nfUJhrgDfSDEQ5BOV qjwlEyT6qkAuZII7LKeknOMoWQRifsWrThyXzTG5UE4hL5oN1CCj3LnLiNvm3xlD8KOL 7bPg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1753829690; x=1754434490; 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=9IvAMOvcbhlU5W8QZLEdB4U1p9VX42TgZ9WfVdMPu+g=; b=L7orMqO6H62pqXXRchWOQtO3WmFAPNj86Nxe0CyJal/koJ+i8VqNfjYTfjmO8O7IPf utDsAhOzgqnoZdTs/OrlVzgVMjnrr6geFlS8VHzy7xxqEImcza5QshmM6j/qh8mMlhC2 OKk8jma6PaOEWmlljRK7k63O//dXvj3Hhesqo8WPJzx9PzVZ6XTqkO6plPpgN1nm6TR9 c/iAY7/DwPC3qdY8wMvxgKl2wsTNKuSZXUPYYbQlJEvMxppLFhSYpvxZZ4aI5wBHZg0L B3vH+iD/Y5mVDSgSLxTR2U/mnLg6Pxl+ClHx3P9V7zsQFux5nGO3k+8kEDZHSVbjo50u t/5Q== X-Forwarded-Encrypted: i=1; AJvYcCU10QZdmxQ+pikfcevhxV2ueN7UhBCXhFUJ4P78RY3Nuu1gZmvJmXcMMyh1n9T1S0H3fyx290k=@lists.linux.dev X-Gm-Message-State: AOJu0Yz/XANAbov4Pd7qPxRnhAY6EL4Ojg5c8wkTrBmNPk7UsfTQydps unSNt+kzyX7JHlf65OOLCSRXsv8qKgwD4DBgtj6h3kkX11tpK38JqEFxpUGlgZpeyYO7PpLd8SP tD32cTg== X-Google-Smtp-Source: AGHT+IGQQ1/q92PLrkeNoYQwXKazYVHZno9fNiuzRJmcVNPJlU7fDI+A2fWwC+0aM4sd5YoKaOkjLYsx6S8= X-Received: from pjk12.prod.google.com ([2002:a17:90b:558c:b0:31f:3227:1738]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:1e0c:b0:311:abba:53d2 with SMTP id 98e67ed59e1d1-31f5de42527mr1515007a91.17.1753829689699; Tue, 29 Jul 2025 15:54:49 -0700 (PDT) Date: Tue, 29 Jul 2025 15:54:48 -0700 In-Reply-To: <1d9d6e35ebf4658bbe48e6273eefff3267759519.camel@intel.com> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250729193341.621487-1-seanjc@google.com> <20250729193341.621487-3-seanjc@google.com> <1d9d6e35ebf4658bbe48e6273eefff3267759519.camel@intel.com> Message-ID: Subject: Re: [PATCH 2/5] KVM: TDX: Exit with MEMORY_FAULT on unexpected pending S-EPT Violation From: Sean Christopherson To: Rick P Edgecombe Cc: "maz@kernel.org" , "pbonzini@redhat.com" , "oliver.upton@linux.dev" , Vishal Annapurve , Xiaoyao Li , "kvmarm@lists.linux.dev" , Adrian Hunter , "linux-arm-kernel@lists.infradead.org" , "kvm@vger.kernel.org" , "nik.borisov@suse.com" , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable On Tue, Jul 29, 2025, Rick P Edgecombe wrote: > On Tue, 2025-07-29 at 12:33 -0700, Sean Christopherson wrote: > > diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c > > index 3e0d4edee849..c2ef03f39c32 100644 > > --- a/arch/x86/kvm/vmx/tdx.c > > +++ b/arch/x86/kvm/vmx/tdx.c > > @@ -1937,10 +1937,8 @@ static int tdx_handle_ept_violation(struct kvm_v= cpu *vcpu) > > =C2=A0 > > =C2=A0 if (vt_is_tdx_private_gpa(vcpu->kvm, gpa)) { > > =C2=A0 if (tdx_is_sept_violation_unexpected_pending(vcpu)) { > > - pr_warn("Guest access before accepting 0x%llx on vCPU %d\n", > > - gpa, vcpu->vcpu_id); > > - kvm_vm_dead(vcpu->kvm); > > - return -EIO; > > + kvm_prepare_memory_fault_exit(vcpu, gpa, 0, true, false, true); > > + return -EFAULT; > > =C2=A0 } > > =C2=A0 /* > > =C2=A0 * Always treat SEPT violations as write faults.=C2=A0 Ignore t= he >=20 > The vm_dead was added because mirror EPT will KVM_BUG_ON() if there is an > attempt to set the mirror EPT entry when it is already present. And the > unaccepted memory access will trigger an EPT violation for a mirror PTE t= hat is > already set. I think this is a better solution irrespective of the vm_dea= d > changes. In that case, this change will expose KVM to the KVM_BUG_ON(), because noth= ing prevents userspace from re-running the vCPU. Which KVM_BUG_ON() exactly ge= ts hit?