From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 23A613FFAC2 for ; Tue, 28 Apr 2026 11:10:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777374619; cv=none; b=kUJPyZ8JGUMOM3z9XDjmpXolPA4OpYqFfzJjpRRspbnJ5xqwbzEciG4iUHs64BEi0wcS72PcXYL19yCfyEQl8aVtKwkbu9jlrlm0BNDaLk8d9JEsCioOFBts5OGkUjdQBFckg+jKxTtCpAA8MP0cx5ltHUCEUqFf2glubFQLZYk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777374619; c=relaxed/simple; bh=j4Zp27lfKLT47cSt9lEA0iytxlktaR4GD6hEueak65w=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=rdhqof3kZFreN/2c8UiDUThMB3pljIb50gJ56EqI2Iz8v5mUzKvRgKSPPn6v8tddc2defmUjUc4m5pvy8q/n50s3G3BquoALm+pd+CQH4rh6XEJ6RoUve10xh3W+yF5ce4wbxV88qdpfq26iVviQNvD7IgUbAPzkqKyjtNOXvNs= 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=M3KSOxOy; arc=none smtp.client-ip=170.10.129.124 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="M3KSOxOy" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1777374616; 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=EOywN7PsB9nok987GKX74XlPtbgpdmTNkk2VBiQDudI=; b=M3KSOxOyrL3KipHrF+wtvRQ3VHEBZrNGKu1iuAWs1rWljhSXJoxc3A4IudMYuALfSkGGL6 32jlWKAd5fPEP7lL857HDdyZQE7nnyDKKdhC8QI3whizm2bBBuJ7Evr9Q8NbvmSdQe3AG/ spyV3SuPQaZNCyCehDpTZqv5Vbik958= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-541--2peKKXMPwC8g2fvNBuu7g-1; Tue, 28 Apr 2026 07:10:14 -0400 X-MC-Unique: -2peKKXMPwC8g2fvNBuu7g-1 X-Mimecast-MFC-AGG-ID: -2peKKXMPwC8g2fvNBuu7g_1777374613 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (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-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 8EDCE18003F6; Tue, 28 Apr 2026 11:10:13 +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-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 04D1619560B1; Tue, 28 Apr 2026 11:10:12 +0000 (UTC) From: Paolo Bonzini To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: jon@nutanix.com, d.riley@proxmox.com Subject: [PATCH 26/28] KVM: SVM: enable GMET and set it in MMU role Date: Tue, 28 Apr 2026 07:09:44 -0400 Message-ID: <20260428110946.11466-27-pbonzini@redhat.com> In-Reply-To: <20260428110946.11466-1-pbonzini@redhat.com> References: <20260428110946.11466-1-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 3.0 on 10.30.177.12 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 | 7 +++++-- arch/x86/kvm/svm/svm.c | 16 ++++++++++++++++ arch/x86/kvm/svm/svm.h | 1 + 4 files changed, 27 insertions(+), 3 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 6cf0e5f28ba5..4ac5d25c5616 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -5849,7 +5849,6 @@ 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; @@ -5860,6 +5859,11 @@ 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..a28c5e8d017b 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -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