From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.12]) (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 CBFE926B742; Thu, 7 Aug 2025 09:46:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.12 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754560001; cv=none; b=h/KrZEBnNdbLLuW1zwcK+xkC1emHOJ+DgO3amW+0kfua+rDigqlPBIVLRxA/kWIi4rrelNlVpj9Go3ADGw11hYDiACRcKP8YK2qPqRi9nei3EburDbhejqGbD/UemOHU9fJ3/+vcMnv8uZdxu1xywP9s5syOGexL8OWZPvUaNSU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754560001; c=relaxed/simple; bh=Nj3RxqvjndwtR2WgqYJxO5Hy0j8sDdkvJHOEsOl/tPE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=GgOsgiRDgVJCpiUa9sexyZM/PQUBjcVwsHwGgxkBVKfFe2ZuDFACYKSbndEoWwpViIFR06FgLcLZsC59bC7mhv0R4k95Dvws/6MjFnLpzMEcVfNbLJdpipupJfb+KU1dHkD6vAyMvyY6msmvMQD6oqUaVGvocafNR7yBOjpt6F0= 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=GOdyC5cE; arc=none smtp.client-ip=198.175.65.12 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="GOdyC5cE" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1754560000; x=1786096000; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=Nj3RxqvjndwtR2WgqYJxO5Hy0j8sDdkvJHOEsOl/tPE=; b=GOdyC5cEZJMG1zyGfZtfnQxyLfLvHYe5qGW/EOLoOPcgW3P0leDMNJzv c9n5TLDnjJx4bWW2Qj4+/l2JYeuTSGw9TSsxXV9RKLrhysdyqhNMf8guv olI2DycGm/+1aalGhxBSQRd19hEbmM3lcD7s0wx1rg2BtD/6z8MMTKwKS BHG2sVVTy5IB32w7KL4SPV3lhN0ANrbbhUhhA21+mnptZZkb/Z5Mz8JwS EcufXGtKSUb82gQTphqfXjQJQ07YITEQCOV7jFOr9JUR967982bvpZKSW bLhPNNev7WqsIg3x9Vc32xm9FCmO50xZT8QkPPngRquS6N8LGnCUWl/61 w==; X-CSE-ConnectionGUID: yO07rF7hRNitkmnTMuBpdA== X-CSE-MsgGUID: fPId2izDRv63bg0mJBSWlQ== X-IronPort-AV: E=McAfee;i="6800,10657,11514"; a="68342869" X-IronPort-AV: E=Sophos;i="6.17,271,1747724400"; d="scan'208";a="68342869" Received: from orviesa005.jf.intel.com ([10.64.159.145]) by orvoesa104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Aug 2025 02:46:40 -0700 X-CSE-ConnectionGUID: jaKQCGg1QYKswL9sbyDyFg== X-CSE-MsgGUID: 7NslTzFVTyC98mRhC2aFPQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.17,271,1747724400"; d="scan'208";a="170392330" Received: from yzhao56-desk.sh.intel.com ([10.239.47.19]) by orviesa005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Aug 2025 02:46:34 -0700 From: Yan Zhao To: pbonzini@redhat.com, seanjc@google.com Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, x86@kernel.org, rick.p.edgecombe@intel.com, dave.hansen@intel.com, kas@kernel.org, tabba@google.com, ackerleytng@google.com, quic_eberman@quicinc.com, michael.roth@amd.com, david@redhat.com, vannapurve@google.com, vbabka@suse.cz, thomas.lendacky@amd.com, pgonda@google.com, zhiquan1.li@intel.com, fan.du@intel.com, jun.miao@intel.com, ira.weiny@intel.com, isaku.yamahata@intel.com, xiaoyao.li@intel.com, binbin.wu@linux.intel.com, chao.p.peng@intel.com, yan.y.zhao@intel.com Subject: [RFC PATCH v2 21/23] KVM: TDX: Preallocate PAMT pages to be used in split path Date: Thu, 7 Aug 2025 17:46:03 +0800 Message-ID: <20250807094604.4762-1-yan.y.zhao@intel.com> X-Mailer: git-send-email 2.43.2 In-Reply-To: <20250807093950.4395-1-yan.y.zhao@intel.com> References: <20250807093950.4395-1-yan.y.zhao@intel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: "Kirill A. Shutemov" Preallocate a page to be used in the split_external_spt() path. Kernel needs one PAMT page pair for external_spt and one that provided directly to the TDH.MEM.PAGE.DEMOTE SEAMCALL. Signed-off-by: Kirill A. Shutemov Co-developed-by: Yan Zhao Signed-off-by: Yan Zhao --- RFC v2: - Pulled from git://git.kernel.org/pub/scm/linux/kernel/git/kas/linux.git tdx/dpamt-huge. - Implemented the flow of topup pamt_page_cache in tdp_mmu_split_huge_pages_root() (Yan) --- arch/x86/include/asm/kvm_host.h | 2 ++ arch/x86/kvm/mmu/mmu.c | 1 + arch/x86/kvm/mmu/tdp_mmu.c | 51 +++++++++++++++++++++++++++++++++ 3 files changed, 54 insertions(+) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 6b6c46c27390..508b133df903 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1591,6 +1591,8 @@ struct kvm_arch { #define SPLIT_DESC_CACHE_MIN_NR_OBJECTS (SPTE_ENT_PER_PAGE + 1) struct kvm_mmu_memory_cache split_desc_cache; + struct kvm_mmu_memory_cache pamt_page_cache; + gfn_t gfn_direct_bits; /* diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index f23d8fc59323..e581cee37f64 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -6848,6 +6848,7 @@ static void mmu_free_vm_memory_caches(struct kvm *kvm) kvm_mmu_free_memory_cache(&kvm->arch.split_desc_cache); kvm_mmu_free_memory_cache(&kvm->arch.split_page_header_cache); kvm_mmu_free_memory_cache(&kvm->arch.split_shadow_page_cache); + kvm_mmu_free_memory_cache(&kvm->arch.pamt_page_cache); } void kvm_mmu_uninit_vm(struct kvm *kvm) diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c index eb758aaa4374..064c4e823658 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.c +++ b/arch/x86/kvm/mmu/tdp_mmu.c @@ -1584,6 +1584,27 @@ static bool iter_cross_boundary(struct tdp_iter *iter, gfn_t start, gfn_t end) (iter->gfn + KVM_PAGES_PER_HPAGE(iter->level)) <= end); } +static bool need_topup_mirror_caches(struct kvm *kvm) +{ + int nr = tdx_nr_pamt_pages() * 2; + + return kvm_mmu_memory_cache_nr_free_objects(&kvm->arch.pamt_page_cache) < nr; +} + +static int topup_mirror_caches(struct kvm *kvm) +{ + int r, nr; + + /* One for external_spt, one for TDH.MEM.PAGE.DEMOTE */ + nr = tdx_nr_pamt_pages() * 2; + + r = kvm_mmu_topup_memory_cache(&kvm->arch.pamt_page_cache, nr); + if (r) + return r; + + return 0; +} + static int tdp_mmu_split_huge_pages_root(struct kvm *kvm, struct kvm_mmu_page *root, gfn_t start, gfn_t end, @@ -1656,6 +1677,36 @@ static int tdp_mmu_split_huge_pages_root(struct kvm *kvm, continue; } + if (is_mirror_sp(root) && need_topup_mirror_caches(kvm)) { + int r; + + rcu_read_unlock(); + + if (shared) + read_unlock(&kvm->mmu_lock); + else + write_unlock(&kvm->mmu_lock); + + r = topup_mirror_caches(kvm); + + if (shared) + read_lock(&kvm->mmu_lock); + else + write_lock(&kvm->mmu_lock); + + if (r) { + trace_kvm_mmu_split_huge_page(iter.gfn, + iter.old_spte, + iter.level, r); + return r; + } + + rcu_read_lock(); + + iter.yielded = true; + continue; + } + tdp_mmu_init_child_sp(sp, &iter); if (tdp_mmu_split_huge_page(kvm, &iter, sp, shared)) -- 2.43.2