From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.21]) (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 1902A2147E6 for ; Sat, 11 Oct 2025 06:30:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.21 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760164233; cv=none; b=jgaM2IT7R8CVdRS0qNr/ih+dBQDU3xk/AvTxL0ZyEBgnRHnSYKQn6qeAI/t3P68wu9wMJd38f2b40S7w5pEHKESrWjXET1gDTkA3rkRVP5Y52OXRQ4zj3vuSqoLkJvlPZxLREjgPMOqdsDyHEqGP1qCnQDgN3nLHkR6KZF5GM2Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760164233; c=relaxed/simple; bh=864487Lbses3g7FYfEk5gBAA1Q+2nTEqyXpo9mwJjwM=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=RFLeOOtG2xBrzttOfg84j8MCpblzwzRQ008aKLg3ctVHKJyGBkbJpPetpN80saVO81Xy9I0i9zBMXYyCTSAApF2CvDDW09BwqqNhWdk8/7Ze2ChNWdE+Np8XSDbeTpSLnedI+X7bvynDYQHc024fSy9KURx8N3yhdZMgl6exJLI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=lYKA2+ih; arc=none smtp.client-ip=198.175.65.21 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="lYKA2+ih" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1760164232; x=1791700232; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=864487Lbses3g7FYfEk5gBAA1Q+2nTEqyXpo9mwJjwM=; b=lYKA2+ihJ6znCQFxkbDRkCch4QUn7V0ti3CA8+nYDrHI2sWZNYKQbx0n LS3Ac4RrgA/HF7d8BHJ40zGSQy5NkuPxsz4tgqC8Tq5Xk0FNVgYyiKXPH GtmvR6zOCYeun7LkkGHutDShBfq6z8kS1ccHyiQbp97RCS+pZsHUTRiu5 vXN2F3r5FZaTSp3ofaRg/01wXLZJoqBVGsG6TP/AGERT2/2VWaW7Q6Ldn yHD70yW1NTflUUUFlkvDXiLtVnVgliJPs8n2pTVL6HMZ/azJjTTgc9qNt piOUnigfFEQMQdSLLvOY2JQtXjuu6imGZz2qFEr1QgkxEfps7jlFa7mVT A==; X-CSE-ConnectionGUID: rv/h5IrBTv654iGoEzT9JA== X-CSE-MsgGUID: ykM6McuLQKKagdHdXZRjew== X-IronPort-AV: E=McAfee;i="6800,10657,11531"; a="62295796" X-IronPort-AV: E=Sophos;i="6.17,312,1747724400"; d="scan'208";a="62295796" Received: from orviesa010.jf.intel.com ([10.64.159.150]) by orvoesa113.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Oct 2025 23:30:32 -0700 X-CSE-ConnectionGUID: lPvOecqbQc6xhQki/BPBGg== X-CSE-MsgGUID: AgL/RN86S3CGZ7GQ+tjQxg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.19,220,1754982000"; d="scan'208";a="180389437" Received: from allen-sbox.sh.intel.com (HELO [10.239.159.30]) ([10.239.159.30]) by orviesa010-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Oct 2025 23:30:26 -0700 Message-ID: Date: Sat, 11 Oct 2025 14:26:53 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 3/8] x86/mm: Use 'ptdesc' when freeing PMD pages To: Dave Hansen , David Hildenbrand , Joerg Roedel , Will Deacon , Robin Murphy , Kevin Tian , Jason Gunthorpe , Jann Horn , Vasant Hegde , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Alistair Popple , Peter Zijlstra , Uladzislau Rezki , Jean-Philippe Brucker , Andy Lutomirski , Yi Lai Cc: iommu@lists.linux.dev, security@kernel.org, x86@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Dave Hansen References: <20250919054007.472493-1-baolu.lu@linux.intel.com> <20250919054007.472493-4-baolu.lu@linux.intel.com> <9648e990-18e0-4aed-8110-b02f4b45aa47@redhat.com> Content-Language: en-US From: Baolu Lu In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 10/10/25 03:31, Dave Hansen wrote: > On 10/9/25 12:25, David Hildenbrand wrote: >>> >>> @@ -750,8 +750,8 @@ int pud_free_pmd_page(pud_t *pud, unsigned long addr) >>>         for (i = 0; i < PTRS_PER_PMD; i++) { >>>           if (!pmd_none(pmd_sv[i])) { >>> -            pte = (pte_t *)pmd_page_vaddr(pmd_sv[i]); >>> -            pte_free_kernel(&init_mm, pte); >>> +            pt = page_ptdesc(pmd_page(pmd_sv[i])); >>> +            pagetable_dtor_free(pt); >> >> There is pmd_ptdesc() which does >> >>     page_ptdesc(pmd_pgtable_page(pmd)); >> >> It's buried in a >> >>     #if defined(CONFIG_SPLIT_PMD_PTLOCKS) >> >> Can't we just make that always available so we can use it here? > > Yes, that looks like a good idea. I never noticed pmd_ptdesc() when I > was writing this for sure. I updated the patch like this, diff --git a/include/linux/mm.h b/include/linux/mm.h index 6a0bb7fc3148..a0850dc6878e 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -3203,8 +3203,6 @@ pte_t *pte_offset_map_rw_nolock(struct mm_struct *mm, pmd_t *pmd, ((unlikely(pmd_none(*(pmd))) && __pte_alloc_kernel(pmd))? \ NULL: pte_offset_kernel(pmd, address)) -#if defined(CONFIG_SPLIT_PMD_PTLOCKS) - static inline struct page *pmd_pgtable_page(pmd_t *pmd) { unsigned long mask = ~(PTRS_PER_PMD * sizeof(pmd_t) - 1); @@ -3216,6 +3214,8 @@ static inline struct ptdesc *pmd_ptdesc(pmd_t *pmd) return page_ptdesc(pmd_pgtable_page(pmd)); } +#if defined(CONFIG_SPLIT_PMD_PTLOCKS) + static inline spinlock_t *pmd_lockptr(struct mm_struct *mm, pmd_t *pmd) { return ptlock_ptr(pmd_ptdesc(pmd)); diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c index ddf248c3ee7d..c830ccbc2fd8 100644 --- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -729,7 +729,7 @@ int pmd_clear_huge(pmd_t *pmd) int pud_free_pmd_page(pud_t *pud, unsigned long addr) { pmd_t *pmd, *pmd_sv; - pte_t *pte; + struct ptdesc *pt; int i; pmd = pud_pgtable(*pud); @@ -750,8 +750,8 @@ int pud_free_pmd_page(pud_t *pud, unsigned long addr) for (i = 0; i < PTRS_PER_PMD; i++) { if (!pmd_none(pmd_sv[i])) { - pte = (pte_t *)pmd_page_vaddr(pmd_sv[i]); - pte_free_kernel(&init_mm, pte); + pt = pmd_ptdesc(&pmd_sv[i]); + pagetable_dtor_free(pt); } } @@ -772,15 +772,15 @@ int pud_free_pmd_page(pud_t *pud, unsigned long addr) */ int pmd_free_pte_page(pmd_t *pmd, unsigned long addr) { - pte_t *pte; + struct ptdesc *pt; - pte = (pte_t *)pmd_page_vaddr(*pmd); + pt = pmd_ptdesc(pmd); pmd_clear(pmd); /* INVLPG to clear all paging-structure caches */ flush_tlb_kernel_range(addr, addr + PAGE_SIZE-1); - pte_free_kernel(&init_mm, pte); + pagetable_dtor_free(pt); return 1; } Thanks, baolu