From patchwork Mon Jan 22 23:53:12 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Isaku Yamahata X-Patchwork-Id: 13526460 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.15]) (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 38B0A5EE96; Mon, 22 Jan 2024 23:55:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.15 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705967726; cv=none; b=ZHK65deIMjmK3cAn2dJMYqDaxucHGmzJ9phuyEZ98AwSyxsWj5gvG+LKqgei5Qtrvku1JoH5Z17S2xXRzDJGjO2llE0ixFnhUlYDW+cvjWOKmYqKG5sjDhOuAB6fKy8D6siT+wa8uxkaE/5rxgkBFF3kw2ujHmjJ0khSEOzudWg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705967726; c=relaxed/simple; bh=W7n8vjIkmQn8VO13mPbVo91HBk6Ha/DtEnjVAt/VXjw=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=TcIBLcGiscNWcsED5DR7ReFD4HJd0wdSUmM9zQYMmhip+hn+2+LmwgfEORPb9GpZFhzIX7+QohaB7jgKl6c89JzCbPt9X9HsDkp833Jg5xnLadCcF/OpvjSQOboipC7tJu69mldHAqLYxUcqh3+PxqV+rENvu1jid4LZvIFTMAM= 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=fWJAf2LJ; arc=none smtp.client-ip=198.175.65.15 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="fWJAf2LJ" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1705967725; x=1737503725; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=W7n8vjIkmQn8VO13mPbVo91HBk6Ha/DtEnjVAt/VXjw=; b=fWJAf2LJ2AM4Glhh0SoRZzJoe7otcoy+6ZaZZrv1MEFR3Pg1XPe3KUfD 5ip9/GcPG1rZZIi64c5Vjki2HpZwUTrhbSnuQYxt/pQSzeMBWtk5ICVtZ 9Uu6Lstrlm++QaAubCI2DEyWcg352n+Tw0cXG/ZPWPnAi7SvKlbhd3GDw 1npl9GU92JR665ADFtYxDimGkysb3cz8W1jE68RBu02X1gxNCvPus5TNo emLkVm5TGsRezw2uKOQb1/ld7KDc+NQvGREDvHykn7cW1H5Zq0SiE/eiC 9eQIshQM0XhOvMII5hMrvl1CixMzQRfuVdgCdFuakpAB3xUF5aFBUmZvw g==; X-IronPort-AV: E=McAfee;i="6600,9927,10961"; a="1243878" X-IronPort-AV: E=Sophos;i="6.05,212,1701158400"; d="scan'208";a="1243878" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orvoesa107.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Jan 2024 15:55:25 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10961"; a="819888652" X-IronPort-AV: E=Sophos;i="6.05,212,1701158400"; d="scan'208";a="819888652" Received: from ls.sc.intel.com (HELO localhost) ([172.25.112.31]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Jan 2024 15:55:24 -0800 From: isaku.yamahata@intel.com To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org Cc: isaku.yamahata@intel.com, isaku.yamahata@gmail.com, Paolo Bonzini , erdemaktas@google.com, Sean Christopherson , Sagi Shahar , Kai Huang , chen.bo@intel.com, hang.yuan@intel.com, tina.zhang@intel.com, Sean Christopherson Subject: [PATCH v18 036/121] KVM: x86/mmu: Replace hardcoded value 0 for the initial value for SPTE Date: Mon, 22 Jan 2024 15:53:12 -0800 Message-Id: X-Mailer: git-send-email 2.25.1 In-Reply-To: References: Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Isaku Yamahata The TDX support will need the "suppress #VE" bit (bit 63) set as the initial value for SPTE. To reduce code change size, introduce a new macro SHADOW_NONPRESENT_VALUE for the initial value for the shadow page table entry (SPTE) and replace hard-coded value 0 for it. Initialize shadow page tables with their value. The plan is to unconditionally set the "suppress #VE" bit for both AMD and Intel as: 1) AMD hardware uses the bit 63 as NX for present SPTE and ignored for non-present SPTE; 2) for conventional VMX guests, KVM never enables the "EPT-violation #VE" in VMCS control and "suppress #VE" bit is ignored by hardware. Signed-off-by: Sean Christopherson Signed-off-by: Isaku Yamahata --- arch/x86/kvm/mmu/mmu.c | 20 +++++++++++++++----- arch/x86/kvm/mmu/paging_tmpl.h | 2 +- arch/x86/kvm/mmu/spte.h | 2 ++ arch/x86/kvm/mmu/tdp_mmu.c | 14 +++++++------- 4 files changed, 25 insertions(+), 13 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index fa57db06f322..f1cec0f8e3d6 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -567,9 +567,9 @@ static u64 mmu_spte_clear_track_bits(struct kvm *kvm, u64 *sptep) if (!is_shadow_present_pte(old_spte) || !spte_has_volatile_bits(old_spte)) - __update_clear_spte_fast(sptep, 0ull); + __update_clear_spte_fast(sptep, SHADOW_NONPRESENT_VALUE); else - old_spte = __update_clear_spte_slow(sptep, 0ull); + old_spte = __update_clear_spte_slow(sptep, SHADOW_NONPRESENT_VALUE); if (!is_shadow_present_pte(old_spte)) return old_spte; @@ -603,7 +603,7 @@ static u64 mmu_spte_clear_track_bits(struct kvm *kvm, u64 *sptep) */ static void mmu_spte_clear_no_track(u64 *sptep) { - __update_clear_spte_fast(sptep, 0ull); + __update_clear_spte_fast(sptep, SHADOW_NONPRESENT_VALUE); } static u64 mmu_spte_get_lockless(u64 *sptep) @@ -1950,7 +1950,8 @@ static bool kvm_sync_page_check(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp) static int kvm_sync_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, int i) { - if (!sp->spt[i]) + /* sp->spt[i] has initial value of shadow page table allocation */ + if (sp->spt[i] == SHADOW_NONPRESENT_VALUE) return 0; return vcpu->arch.mmu->sync_spte(vcpu, sp, i); @@ -6129,7 +6130,16 @@ int kvm_mmu_create(struct kvm_vcpu *vcpu) vcpu->arch.mmu_page_header_cache.kmem_cache = mmu_page_header_cache; vcpu->arch.mmu_page_header_cache.gfp_zero = __GFP_ZERO; - vcpu->arch.mmu_shadow_page_cache.gfp_zero = __GFP_ZERO; + /* + * When X86_64, initial SEPT entries are initialized with + * SHADOW_NONPRESENT_VALUE. Otherwise zeroed. See + * mmu_memory_cache_alloc_obj(). + */ + if (IS_ENABLED(CONFIG_X86_64)) + vcpu->arch.mmu_shadow_page_cache.init_value = + SHADOW_NONPRESENT_VALUE; + if (!vcpu->arch.mmu_shadow_page_cache.init_value) + vcpu->arch.mmu_shadow_page_cache.gfp_zero = __GFP_ZERO; vcpu->arch.mmu = &vcpu->arch.root_mmu; vcpu->arch.walk_mmu = &vcpu->arch.root_mmu; diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h index 4d4e98fe4f35..bebd73cd61bb 100644 --- a/arch/x86/kvm/mmu/paging_tmpl.h +++ b/arch/x86/kvm/mmu/paging_tmpl.h @@ -911,7 +911,7 @@ static int FNAME(sync_spte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, int gpa_t pte_gpa; gfn_t gfn; - if (WARN_ON_ONCE(!sp->spt[i])) + if (WARN_ON_ONCE(sp->spt[i] == SHADOW_NONPRESENT_VALUE)) return 0; first_pte_gpa = FNAME(get_level1_sp_gpa)(sp); diff --git a/arch/x86/kvm/mmu/spte.h b/arch/x86/kvm/mmu/spte.h index a129951c9a88..4d1799ba2bf8 100644 --- a/arch/x86/kvm/mmu/spte.h +++ b/arch/x86/kvm/mmu/spte.h @@ -149,6 +149,8 @@ static_assert(MMIO_SPTE_GEN_LOW_BITS == 8 && MMIO_SPTE_GEN_HIGH_BITS == 11); #define MMIO_SPTE_GEN_MASK GENMASK_ULL(MMIO_SPTE_GEN_LOW_BITS + MMIO_SPTE_GEN_HIGH_BITS - 1, 0) +#define SHADOW_NONPRESENT_VALUE 0ULL + extern u64 __read_mostly shadow_host_writable_mask; extern u64 __read_mostly shadow_mmu_writable_mask; extern u64 __read_mostly shadow_nx_mask; diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c index 6ae19b4ee5b1..bdeb23ff9e71 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.c +++ b/arch/x86/kvm/mmu/tdp_mmu.c @@ -570,7 +570,7 @@ static inline int tdp_mmu_zap_spte_atomic(struct kvm *kvm, * here since the SPTE is going from non-present to non-present. Use * the raw write helper to avoid an unnecessary check on volatile bits. */ - __kvm_tdp_mmu_write_spte(iter->sptep, 0); + __kvm_tdp_mmu_write_spte(iter->sptep, SHADOW_NONPRESENT_VALUE); return 0; } @@ -707,8 +707,8 @@ static void __tdp_mmu_zap_root(struct kvm *kvm, struct kvm_mmu_page *root, continue; if (!shared) - tdp_mmu_iter_set_spte(kvm, &iter, 0); - else if (tdp_mmu_set_spte_atomic(kvm, &iter, 0)) + tdp_mmu_iter_set_spte(kvm, &iter, SHADOW_NONPRESENT_VALUE); + else if (tdp_mmu_set_spte_atomic(kvm, &iter, SHADOW_NONPRESENT_VALUE)) goto retry; } } @@ -764,8 +764,8 @@ bool kvm_tdp_mmu_zap_sp(struct kvm *kvm, struct kvm_mmu_page *sp) if (WARN_ON_ONCE(!is_shadow_present_pte(old_spte))) return false; - tdp_mmu_set_spte(kvm, kvm_mmu_page_as_id(sp), sp->ptep, old_spte, 0, - sp->gfn, sp->role.level + 1); + tdp_mmu_set_spte(kvm, kvm_mmu_page_as_id(sp), sp->ptep, old_spte, + SHADOW_NONPRESENT_VALUE, sp->gfn, sp->role.level + 1); return true; } @@ -799,7 +799,7 @@ static bool tdp_mmu_zap_leafs(struct kvm *kvm, struct kvm_mmu_page *root, !is_last_spte(iter.old_spte, iter.level)) continue; - tdp_mmu_iter_set_spte(kvm, &iter, 0); + tdp_mmu_iter_set_spte(kvm, &iter, SHADOW_NONPRESENT_VALUE); flush = true; } @@ -1226,7 +1226,7 @@ static bool set_spte_gfn(struct kvm *kvm, struct tdp_iter *iter, * invariant that the PFN of a present * leaf SPTE can never change. * See handle_changed_spte(). */ - tdp_mmu_iter_set_spte(kvm, iter, 0); + tdp_mmu_iter_set_spte(kvm, iter, SHADOW_NONPRESENT_VALUE); if (!pte_write(range->arg.pte)) { new_spte = kvm_mmu_changed_pte_notifier_make_spte(iter->old_spte,