From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 339A13594F; Sun, 2 Mar 2025 17:04:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.17 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740935050; cv=none; b=PQkeJEQLCfRpmhgVqfjPFihYcB52FFR/SryTBXXUOtYDo9pokiU0bvjM0UY4ycpJN2Xd15W8Ergmh8xV1BuX9OUsp108LAB6pTN2/49LoKkeofGvNWLZEHwKEo8LxarqFXkIrisPgIe69412Z1za2fkOjVIfay9SDCtrP20jm+s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740935050; c=relaxed/simple; bh=J9WBrmbAU7OZTDteavgUdtEXlaP4WWdhY19sHgVOTlk=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=VnW8MSG96u36/mVJaDuyxNEVnnlpwdLAxyy22Th6Ju/Xoi3M6LDjnVYkkbvi1QgXEJ1zKSvP5yE0qZO8URLThUOi8j1G7kxfoOr726gEhQbWTEVK8U3f+eCKe3fErQsatWchz11+oif9mtzTpVqH0n2LtfINCLRPWmat47oCT20= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=VAih4qmY; arc=none smtp.client-ip=198.175.65.17 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="VAih4qmY" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1740935050; x=1772471050; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=J9WBrmbAU7OZTDteavgUdtEXlaP4WWdhY19sHgVOTlk=; b=VAih4qmYRbz8aWevqobU94g2ArhUGQQ5MX8/BosT8CBTLJqutagsbg1o +Q9O33PBBj2CVgHNMZpNtz6bS9qUq27yZAIC0/9bdFwS0krAVb0FZVrta WSrke+d+/KqGsUOf/b0nkR69/fTNYda8diuoOARg6Bk1gFcbVMfHIok4F fKpkNTZgFnbd/s0KQQ9ToLaXp0s2X6A+Sx6ahBQuEq3kRaG9YpZAu2FAs DV2G5MFCUZ3IKvkXVrBuxRl6CZ9ILeXqd0qwuPvroPLP7wwyQpuI1dt2d yzVuiyRnsRC2hmZAATSawpWZamjz+m3FwuGMR9FF6ISKMMXyxor/tTow9 A==; X-CSE-ConnectionGUID: M2wA+ZceTJC2M+v8G2w/Ww== X-CSE-MsgGUID: g9fzfQaDTvatsFS7ONYDiA== X-IronPort-AV: E=McAfee;i="6700,10204,11361"; a="41840151" X-IronPort-AV: E=Sophos;i="6.13,327,1732608000"; d="scan'208";a="41840151" Received: from orviesa006.jf.intel.com ([10.64.159.146]) by orvoesa109.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Mar 2025 09:04:09 -0800 X-CSE-ConnectionGUID: g8BnP3FxTqCP/X5Onneb9g== X-CSE-MsgGUID: DtrXSek3Q0WDsht5gUoWwg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.13,327,1732608000"; d="scan'208";a="117821264" Received: from xiaoyaol-hp-g830.ccr.corp.intel.com (HELO [10.124.247.1]) ([10.124.247.1]) by orviesa006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Mar 2025 09:04:07 -0800 Message-ID: <338901b6-4d10-480d-bd0a-0db8ec4afad5@intel.com> Date: Mon, 3 Mar 2025 01:03:53 +0800 Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 4/4] KVM: TDX: Always honor guest PAT on TDX enabled platforms To: Paolo Bonzini , linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: seanjc@google.com, yan.y.zhao@intel.com References: <20250301073428.2435768-1-pbonzini@redhat.com> <20250301073428.2435768-5-pbonzini@redhat.com> Content-Language: en-US From: Xiaoyao Li In-Reply-To: <20250301073428.2435768-5-pbonzini@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 3/1/2025 3:34 PM, Paolo Bonzini wrote: > From: Yan Zhao > > Always honor guest PAT in KVM-managed EPTs on TDX enabled platforms by > making self-snoop feature a hard dependency for TDX and making quirk > KVM_X86_QUIRK_EPT_IGNORE_GUEST_PAT not a valid quirk once TDX is enabled. > > The quirk KVM_X86_QUIRK_EPT_IGNORE_GUEST_PAT only affects memory type of > KVM-managed EPTs. For the TDX-module-managed private EPT, memory type is > always forced to WB now. > > Honoring guest PAT in KVM-managed EPTs ensures KVM does not invoke > kvm_zap_gfn_range() when attaching/detaching non-coherent DMA devices; > this would cause mirrored EPTs for TDs to be zapped, as well as incorrect > zapping of the private EPT that is managed by the TDX module. > > As a new platform, TDX always comes with self-snoop feature supported and has > no worry to break old not-well-written yet unmodifiable guests. So, simply > force-disable the KVM_X86_QUIRK_EPT_IGNORE_GUEST_PAT quirk for TDX VMs. > > Suggested-by: Sean Christopherson > Signed-off-by: Yan Zhao > Message-ID: <20250224071039.31511-1-yan.y.zhao@intel.com> > [Use disabled_quirks instead of supported_quirks. - Paolo] > Signed-off-by: Paolo Bonzini > --- > arch/x86/kvm/vmx/tdx.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c > index b6f6f6e2f02e..4450fd99cb4c 100644 > --- a/arch/x86/kvm/vmx/tdx.c > +++ b/arch/x86/kvm/vmx/tdx.c > @@ -624,6 +624,7 @@ int tdx_vm_init(struct kvm *kvm) > > kvm->arch.has_protected_state = true; > kvm->arch.has_private_mem = true; > + kvm->arch.disabled_quirks |= KVM_X86_QUIRK_EPT_IGNORE_GUEST_PAT; This doesn't present userspace from dropping the KVM_X86_QUIRK_EPT_IGNORE_GUEST_PAT bit by updating kvm->arch.disabled_quirk via KVM_CAP_DISABLE_QUIRKS. I think we can make inapplicable_quirks per VM in Patch 1 and set kvm->arch.inapplicable_quirks |= KVM_X86_QUIRK_EPT_IGNORE_GUEST_PAT; for TDX VMs. > > /* > * Because guest TD is protected, VMM can't parse the instruction in TD. > @@ -3470,6 +3471,11 @@ int __init tdx_bringup(void) > goto success_disable_tdx; > } > > + if (!cpu_feature_enabled(X86_FEATURE_SELFSNOOP)) { > + pr_err("Self-snoop is required for TDX\n"); > + goto success_disable_tdx; > + } > + > if (!cpu_feature_enabled(X86_FEATURE_TDX_HOST_PLATFORM)) { > pr_err("tdx: no TDX private KeyIDs available\n"); > goto success_disable_tdx;