From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f202.google.com (mail-pg1-f202.google.com [209.85.215.202]) (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 BEA213A0E95 for ; Mon, 6 Apr 2026 23:47:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775519281; cv=none; b=RRVv1u6Bo1F7ZVBnVtZfHtPydqhC50Iw38QsJwJcfHumz+cg2i/ZkZoRD6GnWZa4P6A439fXCOwXhoe7zXY7AV19taC7o8sCjjqDTl98KhYgIHG9e+RApPLB1b+qXVhqGAiDSy9lYqKjDr3tFJ/jepTydE0JcFEKRTQhzMYecw0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775519281; c=relaxed/simple; bh=x8NG4mfnBIGaHvidp37eSv1frVOu1FSrxdYuqYUhhkE=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=gFAuh3p0kHJLWYwX38w7k6kdPVPeaPIGarxpDJROjhrQCL0oErUOD+uxfew0/F4ORqzS5BDDvRsd+rcXLCLVBSwhZfcTS6XzvZLPPv6TkCw7fnJvNjFF8/XEsmLv38W0X3wTLxSjDaRgosWaileP1HcX0MJ2gjS/yYr/E7TzJrI= 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=RlOdkhg5; arc=none smtp.client-ip=209.85.215.202 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="RlOdkhg5" Received: by mail-pg1-f202.google.com with SMTP id 41be03b00d2f7-c7691378914so1917947a12.0 for ; Mon, 06 Apr 2026 16:47:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1775519278; x=1776124078; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=hwcEAbY2bOvu6u/DfZ78E/6y5JAOUHxIU/exu8Slvng=; b=RlOdkhg588nOfN1W1XRJAe5zNNUXAoHDM6cS8/vGfCvFRq0opVtIvHkJyGKhsG09Mg 8XCYEMBmroxFu4LD3sEZjH5V5yjxBFofjpRehY6CKFmr8w9/I88RMcFRQbf2Z8y33gUs 7tn+RIX/GJXDB+a8J7a05mbV7Gh+vq+JWNCF2aWPSHmeEG6uMBF52RuvkGUWyOGF7hu8 tAVF9gC2QuOCLJ2BH+HI57DaOH8kFZWxeBLNoXwSDuhw56r9L8GGHdAA6bFzvzXcFIol t5aTC8j4Q6M5sJIGvvxnEEgNre3KAHLoiP8AfDECQYnuV9eyyidhbk0NN3fGvQiRZBBX sWbg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1775519278; x=1776124078; h=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=hwcEAbY2bOvu6u/DfZ78E/6y5JAOUHxIU/exu8Slvng=; b=EWfruz781FMbuwx+SvEXsMCPl42tFbDOpYHyjUdcOjUKl6z6UplyXbOevRJEr1ylBo LTYpyhblsQi5rRKDSqOY5E5kt/pj43EqF/3XQ06F6rIHzNti+qKwYiDzqRsk7+sYYMvi pkMSzRDUef1SOR94+ZIP/ml05PssEud7V6bLs1BP5cJVQwW/VJRWHCyfestj2abZv4Cn ZnpIZ8zWg2GXT1fFCsTKdDIg77Y4CBJECVq0Q/QffIxCDebNBKWj4CYEy5FBTXGUonKc C9GA3XkJvjPHG1BaHKo7VW/ls7+O/Bjmma4WtcZCsFvYr0bShpw9ikfFLfzKFPEg32e6 w+DA== X-Forwarded-Encrypted: i=1; AJvYcCX59+msoJkKWyzWKA6BMaov1offHf2jgksikK9nfsUWPzto1oQUDosCpnlyOR2z4PWHDbaOm6e2kaKonHw=@vger.kernel.org X-Gm-Message-State: AOJu0Ywj4PRwYUMd9FzTQ4/smzCgz52wQvefq5K+Nl1ejrs7dwm1/+zM u4BFBBWTMhwrGtMTqDPsKof3w3kGtcl2fEz8ofGKBh9ygsj2vA+6Q9qKuYZNLMJEk7Q+5ZT6/qb r67tYlw== X-Received: from pgh3.prod.google.com ([2002:a05:6a02:4e03:b0:c73:8e3c:d0d9]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a20:9389:b0:398:7d6e:27f1 with SMTP id adf61e73a8af0-39f2ee005c5mr14221162637.9.1775519277748; Mon, 06 Apr 2026 16:47:57 -0700 (PDT) Date: Mon, 6 Apr 2026 16:47:56 -0700 In-Reply-To: <20260327234023.2659476-9-jmattson@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260327234023.2659476-1-jmattson@google.com> <20260327234023.2659476-9-jmattson@google.com> Message-ID: Subject: Re: [PATCH v7 8/9] KVM: x86: nSVM: Save/restore gPAT with KVM_{GET,SET}_NESTED_STATE From: Sean Christopherson To: Jim Mattson Cc: Paolo Bonzini , Jonathan Corbet , Shuah Khan , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , kvm@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Yosry Ahmed Content-Type: text/plain; charset="us-ascii" On Fri, Mar 27, 2026, Jim Mattson wrote: > @@ -1918,6 +1921,7 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu, > struct vmcb_save_area_cached save_cached; > struct vmcb_ctrl_area_cached ctl_cached; > unsigned long cr0; > + bool use_separate_l2_pat; Land this above "cr0" to preserve the inverted fir tree. > int ret; > > BUILD_BUG_ON(sizeof(struct vmcb_control_area) + sizeof(struct vmcb_save_area) > > @@ -1993,6 +1997,18 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu, > !nested_vmcb_check_save(vcpu, &save_cached, false)) > goto out_free; > > + /* > + * Validate gPAT when the shared PAT quirk is disabled (i.e. L2 > + * has its own gPAT). This is done separately from the > + * vmcb_save_area_cached validation above, because gPAT is L2 > + * state, but the vmcb_save_area_cached is populated with L1 state. > + */ > + use_separate_l2_pat = > + (ctl_cached.misc_ctl & SVM_MISC_ENABLE_NP) && > + !kvm_check_has_quirk(vcpu->kvm, > + KVM_X86_QUIRK_NESTED_SVM_SHARED_PAT); I vote for either: use_separate_l2_pat = (ctl_cached.misc_ctl & SVM_MISC_ENABLE_NP) && !kvm_check_has_quirk(vcpu->kvm, KVM_X86_QUIRK_NESTED_SVM_SHARED_PAT); or use_separate_l2_pat = (ctl_cached.misc_ctl & SVM_MISC_ENABLE_NP); if (kvm_check_has_quirk(vcpu->kvm, KVM_X86_QUIRK_NESTED_SVM_SHARED_PAT)) use_separate_l2_pat = false; > + if (use_separate_l2_pat && !kvm_pat_valid(kvm_state->hdr.svm.gpat)) > + goto out_free; > > /* > * All checks done, we can enter guest mode. Userspace provides > @@ -2017,6 +2033,10 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu, > nested_copy_vmcb_control_to_cache(svm, ctl); > > svm_switch_vmcb(svm, &svm->nested.vmcb02); > + > + if (use_separate_l2_pat) > + vmcb_set_gpat(svm->vmcb, kvm_state->hdr.svm.gpat); > + > nested_vmcb02_prepare_control(svm); > > /* > -- > 2.53.0.1018.g2bb0e51243-goog >