From nobody Thu Dec 18 07:12:10 2025 Received: from mail-wm1-f74.google.com (mail-wm1-f74.google.com [209.85.128.74]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C59FC1EF0B5 for ; Thu, 13 Mar 2025 18:11:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.74 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741889509; cv=none; b=Hi20YWlGnQ2XlHNICpIyrhFUeXUsK4SVJGzwD+vwTkuCb14dgc6R+njKoEF1g6x706K1NmotY0c+qD1LJ5HmlxqZR72paQIoFD+VcU0cSUF61xM9AdICutDNNU3sd+pUpyyJHwLmiX1PXIEHU87Tn2zkma5sYL8r1vzWlVx0VFo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741889509; c=relaxed/simple; bh=W4sw0yWx5RkXrhCwq5NJ/AictZZr0NkR62X+pTU0PNo=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=BR5Y0e2a960vdIVS/nw30Otv6JTpFY6s5LiND1ZgWPDP9G6A7WmDbyyThRmCbnkxrxJ1WEoZ96uQXgVpJH1f9r7zs+5iH57a24qPyUZciXpQfFSqRNI4hKYQX05t30KlOyYyg1d6VLOPSv5sZl//h9kjclWHAG8W1GizfGBKYkc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--jackmanb.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=dnjWuWnk; arc=none smtp.client-ip=209.85.128.74 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--jackmanb.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="dnjWuWnk" Received: by mail-wm1-f74.google.com with SMTP id 5b1f17b1804b1-438e4e9a53fso9452735e9.1 for ; Thu, 13 Mar 2025 11:11:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1741889506; x=1742494306; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=SFFEGXNq9QK4O4fqhmQmuGwjZkzkfGXtfnqX8VsiIbA=; b=dnjWuWnkEFu89uIVNUPc8MmayWJxvZFpqJrfh4aQVOhnvRQ5hmrYrEWSip21TPUc2G mqbY6Dhztp75ljnRHtIS8XIvBpcqKzmK8pxOcpZ+sPFi7E4pTJC8ah5BwQn5V0s+u4bR HW3hMFHkNWwzBvpJ7gxsjSW8oEpscFktsnBexcQoXnGc/mpywFzfQItW3qRr9dRKMveP 0ygdAOvbia+kHuv3tNTHHZ1zsG0XvVfMwd5QfWkzDCGBPxCmmRgOmMpMVI54u/phEZFc 6hPkq1gcZbrHH4clPdL4iCX/CFqc5jSMIAtWFElhY3l/x/345lveGHqykcHX//WHyd2F BA+A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1741889506; x=1742494306; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=SFFEGXNq9QK4O4fqhmQmuGwjZkzkfGXtfnqX8VsiIbA=; b=T7oyi1ftrhgEId00cvoXe4K3D9l2nIm235wkZoAc6jfoYyW1aUEadgllwzhuBzs9+g GRqiaplqwVdTnEkhdhFbHg5A+onXro9FNN/pImxRdksolB4Pfi0+rtPcTWKhwvNoejX7 DXJWHkL17U69VuT6At7t+McEJr10og8ZMZnCVRWfSfd+qP/bqesQ6oq8liRFipNGgUHj XEiF2YSlBInLygJvpeBwtPrbTHl8p5XT/4V+XFdCNdfYDSljMgKF4mrJFYpPLTB8VySY qrmOVYggiqANGwW+1FNmkfVqHUJqrYx1rq6fjsRajeCbrtjap5K4+kG+g4DmpSu2deCj /SIQ== X-Gm-Message-State: AOJu0Yzyk9DI7oDPVeAt4ap9ZF66esE3L5JLuak+yQ9MaD5NyQQQ6ZDO ugeZDWIK/nbKN9/8Wvt9P0ACraWn8l8Sh1ucM2qLB/jbljbZyeRiy1P0lMREexxa2NddwVq56BN Rf0S+001lvg== X-Google-Smtp-Source: AGHT+IH1VGtpk3xtUCPvw+qm8+MH2zctSvi1XXF/gGWDnzmEetB35farCcixJ7scWW3mkfOJxNfCCFjLdwFb9g== X-Received: from wmbg20.prod.google.com ([2002:a05:600c:a414:b0:43b:b74b:9350]) (user=jackmanb job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:46cb:b0:43c:f470:7605 with SMTP id 5b1f17b1804b1-43d01bdd4a4mr133112715e9.12.1741889506406; Thu, 13 Mar 2025 11:11:46 -0700 (PDT) Date: Thu, 13 Mar 2025 18:11:22 +0000 In-Reply-To: <20250313-asi-page-alloc-v1-0-04972e046cea@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250313-asi-page-alloc-v1-0-04972e046cea@google.com> X-Mailer: b4 0.14.2 Message-ID: <20250313-asi-page-alloc-v1-3-04972e046cea@google.com> Subject: [PATCH RFC 03/11] x86/mm: Add lookup_pgtable_in_pgd() From: Brendan Jackman To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, Andrew Morton , David Rientjes , Vlastimil Babka , David Hildenbrand Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Mike Rapoport , Junaid Shahid , Reiji Watanabe , Patrick Bellasi , Brendan Jackman , Yosry Ahmed Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable This is the same thing as lookup_address_in_pgd(), but it returns the pagetable unconditionally instead of returning NULL when the pagetable is none. This will be used for looking up and modifying pages that are *_none() in order to map memory into the ASI restricted address space. For a [PATCH], if this logic is needed, the surrounding code should probably first be somewhat refactored. It now looks pretty repetitive, and it's confusing that lookup_address_in_pgd() returns NULL when pmd_none() but note when pte_none(). For now here's something that works. Signed-off-by: Brendan Jackman --- arch/x86/include/asm/pgtable_types.h | 2 ++ arch/x86/mm/pat/set_memory.c | 34 ++++++++++++++++++++++++++++++++= ++ 2 files changed, 36 insertions(+) diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pg= table_types.h index 4b804531b03c3ce5cc48f0a75cb75d58b985777a..e09b509e525534f31c986d705e0= 7b25dd9c04cb7 100644 --- a/arch/x86/include/asm/pgtable_types.h +++ b/arch/x86/include/asm/pgtable_types.h @@ -572,6 +572,8 @@ extern pte_t *lookup_address_in_pgd(pgd_t *pgd, unsigne= d long address, unsigned int *level); pte_t *lookup_address_in_pgd_attr(pgd_t *pgd, unsigned long address, unsigned int *level, bool *nx, bool *rw); +extern pte_t *lookup_pgtable_in_pgd(pgd_t *pgd, unsigned long address, + unsigned int *level); extern pmd_t *lookup_pmd_address(unsigned long address); extern phys_addr_t slow_virt_to_phys(void *__address); extern int __init kernel_map_pages_in_pgd(pgd_t *pgd, u64 pfn, diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c index ef4514d64c0524e5854fa106e3f37ff1e1ba10a2..d066bf2c9e93e126757bd32a7a6= 66db89b2488b6 100644 --- a/arch/x86/mm/pat/set_memory.c +++ b/arch/x86/mm/pat/set_memory.c @@ -658,6 +658,40 @@ static inline pgprot_t verify_rwx(pgprot_t old, pgprot= _t new, unsigned long star return new; } =20 +/* + * Lookup the page table entry for a virtual address in a specific pgd. Re= turn + * the pointer to the entry, without implying that any mapping actually ex= ists + * (the returned value may be zero). + */ +pte_t *lookup_pgtable_in_pgd(pgd_t *pgd, unsigned long address, unsigned i= nt *level) +{ + p4d_t *p4d; + pud_t *pud; + pmd_t *pmd; + + *level =3D PG_LEVEL_256T; + if (pgd_none(*pgd)) + return (pte_t *)pgd; + + *level =3D PG_LEVEL_512G; + p4d =3D p4d_offset(pgd, address); + if (p4d_none(*p4d) || p4d_leaf(*p4d) || !p4d_present(*p4d)) + return (pte_t *)p4d; + + *level =3D PG_LEVEL_1G; + pud =3D pud_offset(p4d, address); + if (pud_none(*pud) || pud_leaf(*pud) || !pud_present(*pud)) + return (pte_t *)pud; + + *level =3D PG_LEVEL_2M; + pmd =3D pmd_offset(pud, address); + if (pmd_none(*pmd) || pmd_leaf(*pmd) || !pmd_present(*pmd)) + return (pte_t *)pmd; + + *level =3D PG_LEVEL_4K; + return pte_offset_kernel(pmd, address); +} + /* * Lookup the page table entry for a virtual address in a specific pgd. * Return a pointer to the entry (or NULL if the entry does not exist), --=20 2.49.0.rc1.451.g8f38331e32-goog