From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 B50E043E480 for ; Thu, 30 Apr 2026 15:08:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777561698; cv=none; b=b//Q/8hjKhpcxpTBarFr/UidYnoshl6cBtp43uKbzUHbt13NVKOGMe+7sYzo7zsvwfHuoigQOqgzcV8MRrDYP7961+6TSIGWcQbdiKxqmvBeVNcVCI+vzVnVoaTI86eLBJwLUbHpHnSrqsAit3LAciGjBdxAj0jgYP/n6LeswIk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777561698; c=relaxed/simple; bh=i3LHV97Zl4iJ8M728cR5ScJiyeerLmUokWWhG56QOA4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=QYoI88skb/xTbfw72x3ewSejzVDAXOmHOJKyOeIXSC/YtYLh7vglzqRrkz6S+6t0jSPzmEQMkBTSOkeNZ+OjIwcGrzjhFldZQQRJ1+Wvru9dC+D01NrKiUriJVYPGFDpFqEkYsl4kQbNifZ0BVAUgOl/G1y3o4eI06Owc5hmvUo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=FnGlbkMr; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="FnGlbkMr" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1777561694; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=mTPB8p8VgH0WxNWI3+gmQlsmxKMQQtISoOqn9ka2noU=; b=FnGlbkMrW5A2PUAsqOlyymZkMCdfX2qPnXYNPVu18TzOUMS8699tR3p2U+R5D94phby9O8 0wW2pHkXNIuv4RrpN9SNJoq92/Irmn6fnFJddkQkj98yaR3FZaAq4XJRJvNaraud87sprb 4Ligzo3Og79BoWXtS2NrbderfnDNj7U= Received: from mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-172-e_aF1ppaOnGspVLdF_O2Pw-1; Thu, 30 Apr 2026 11:08:11 -0400 X-MC-Unique: e_aF1ppaOnGspVLdF_O2Pw-1 X-Mimecast-MFC-AGG-ID: e_aF1ppaOnGspVLdF_O2Pw_1777561690 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (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 mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 51DB019560AF; Thu, 30 Apr 2026 15:08:10 +0000 (UTC) Received: from virtlab1023.lab.eng.rdu2.redhat.lab.eng.rdu2.redhat.com (virtlab1023.lab.eng.rdu2.redhat.com [10.8.1.187]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id BFA0D180045E; Thu, 30 Apr 2026 15:08:09 +0000 (UTC) From: Paolo Bonzini To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: d.riley@proxmox.com, jon@nutanix.com Subject: [PATCH 26/28] KVM: SVM: enable GMET and set it in MMU role Date: Thu, 30 Apr 2026 11:07:45 -0400 Message-ID: <20260430150747.76749-27-pbonzini@redhat.com> In-Reply-To: <20260430150747.76749-1-pbonzini@redhat.com> References: <20260430150747.76749-1-pbonzini@redhat.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 Set the GMET bit in the nested control field. This has effectively no impact as long as NPT page tables are changed to have U=0. Tested-by: David Riley Signed-off-by: Paolo Bonzini --- arch/x86/kvm/mmu/mmu.c | 6 +++++- arch/x86/kvm/svm/nested.c | 9 ++++++--- arch/x86/kvm/svm/svm.c | 16 ++++++++++++++++ arch/x86/kvm/svm/svm.h | 1 + 4 files changed, 28 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 015085ef6e46..31c1803d9d15 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -5855,7 +5855,6 @@ kvm_calc_tdp_mmu_root_page_role(struct kvm_vcpu *vcpu, { union kvm_mmu_page_role role = {0}; - role.access = ACC_ALL; role.cr0_wp = true; role.cr4_smep = kvm_x86_call(tdp_has_smep)(vcpu->kvm); role.efer_nx = true; @@ -5866,6 +5865,11 @@ kvm_calc_tdp_mmu_root_page_role(struct kvm_vcpu *vcpu, role.direct = true; role.has_4_byte_gpte = false; + /* All TDP pages are supervisor-executable */ + role.access = ACC_ALL; + if (role.cr4_smep && shadow_user_mask) + role.access &= ~ACC_USER_MASK; + return role; } diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index 7adfa7da210d..74a1df1cb84f 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -858,7 +858,7 @@ static void nested_vmcb02_prepare_control(struct vcpu_svm *svm) * the latter, L1 runs L2 with shadow page tables that translate L2 GVAs * to L1 GPAs, so the same NPTs can be used for L1 and L2. */ - vmcb02->control.misc_ctl = vmcb01->control.misc_ctl & SVM_MISC_ENABLE_NP; + vmcb02->control.misc_ctl = vmcb01->control.misc_ctl & (SVM_MISC_ENABLE_NP | SVM_MISC_ENABLE_GMET); vmcb02->control.iopm_base_pa = vmcb01->control.iopm_base_pa; vmcb02->control.msrpm_base_pa = vmcb01->control.msrpm_base_pa; vmcb_mark_dirty(vmcb02, VMCB_PERM_MAP); @@ -895,9 +895,12 @@ static void nested_vmcb02_prepare_control(struct vcpu_svm *svm) /* Also overwritten later if necessary. */ vmcb02->control.tlb_ctl = TLB_CONTROL_DO_NOTHING; - /* nested_cr3. */ - if (nested_npt_enabled(svm)) + /* Use vmcb01 MMU and format if guest does not use nNPT */ + if (nested_npt_enabled(svm)) { + vmcb02->control.misc_ctl &= ~SVM_MISC_ENABLE_GMET; + nested_svm_init_mmu_context(vcpu); + } vcpu->arch.tsc_offset = kvm_calc_nested_tsc_offset(vcpu->arch.l1_tsc_offset, vmcb12_ctrl->tsc_offset, diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index e7fdd7a9c280..3895d8794366 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -138,6 +138,9 @@ module_param(pause_filter_count_max, ushort, 0444); bool __ro_after_init npt_enabled = true; module_param_named(npt, npt_enabled, bool, 0444); +bool gmet_enabled = true; +module_param_named(gmet, gmet_enabled, bool, 0444); + /* allow nested virtualization in KVM/SVM */ static int __ro_after_init nested = true; module_param(nested, int, 0444); @@ -1209,6 +1212,10 @@ static void init_vmcb(struct kvm_vcpu *vcpu, bool init_event) save->g_pat = vcpu->arch.pat; save->cr3 = 0; } + + if (gmet_enabled) + control->misc_ctl |= SVM_MISC_ENABLE_GMET; + svm->current_vmcb->asid_generation = 0; svm->asid = 0; @@ -4612,6 +4619,11 @@ svm_patch_hypercall(struct kvm_vcpu *vcpu, unsigned char *hypercall) hypercall[2] = 0xd9; } +static bool svm_tdp_has_smep(struct kvm *kvm) +{ + return gmet_enabled; +} + /* * The kvm parameter can be NULL (module initialization, or invocation before * VM creation). Be sure to check the kvm parameter before using it. @@ -5355,6 +5367,7 @@ struct kvm_x86_ops svm_x86_ops __initdata = { .write_tsc_multiplier = svm_write_tsc_multiplier, .load_mmu_pgd = svm_load_mmu_pgd, + .tdp_has_smep = svm_tdp_has_smep, .check_intercept = svm_check_intercept, .handle_exit_irqoff = svm_handle_exit_irqoff, @@ -5588,6 +5601,9 @@ static __init int svm_hardware_setup(void) if (!boot_cpu_has(X86_FEATURE_NPT)) npt_enabled = false; + if (!npt_enabled || !boot_cpu_has(X86_FEATURE_GMET)) + gmet_enabled = false; + /* Force VM NPT level equal to the host's paging level */ kvm_configure_mmu(npt_enabled, get_npt_level(), get_npt_level(), PG_LEVEL_1G); diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h index a10668d17a16..dd93b3daefa9 100644 --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -44,6 +44,7 @@ static inline struct page *__sme_pa_to_page(unsigned long pa) #define IOPM_SIZE PAGE_SIZE * 3 #define MSRPM_SIZE PAGE_SIZE * 2 +extern bool gmet_enabled; extern bool npt_enabled; extern int nrips; extern int vgif; -- 2.52.0