From nobody Wed Dec 17 10:46:05 2025 Received: from mail-yw1-f201.google.com (mail-yw1-f201.google.com [209.85.128.201]) (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 F091517BB1E for ; Fri, 12 Jul 2024 17:01:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720803695; cv=none; b=i+4Q1srkMD/aPNrt0r9D9z7UXRRcepQN0ITB+DJ/2Ak6pvLpjvTAsIOTDBZRrAKaBAnkEjYQK9b6JdR+mZa9fkFA/7YlLxJfRcgj0zhP+SWJhTiZlWtrHJfmMjpnzM+9WVsH6t/pero1Rvcxv+c790/6254yOk/cTT55y0Svn+s= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720803695; c=relaxed/simple; bh=Pq52Q/QpIzshTMsDJJlCxL0sB1Cq1Huhd06MZnjx5cY=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=W+iB4qmQWJWdC6AvzLc5a/gMX5c9manL5ndXalJ2m8Np0M74flREKpzFRNqCOe7tT+08VDBnQhhsgvVUDE0CCpL+407U5m/274Nr1r82eQ6XnzM7xDuNalNBWUHjVtjDzgiu+bOS4yEgqh0PiEzOBGxPxOTJUb5CKXTOWhaFuYE= 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=GK3cxh/A; arc=none smtp.client-ip=209.85.128.201 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="GK3cxh/A" Received: by mail-yw1-f201.google.com with SMTP id 00721157ae682-64b5588bcafso38648157b3.1 for ; Fri, 12 Jul 2024 10:01:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1720803693; x=1721408493; 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=3PoEMkqequy1KWINMIJVW/1gdvscCRasMo3UATAb/nU=; b=GK3cxh/AjB6FWdSPKdeITlJVfDdZPAJbSBVQoW77cvR/dS8Bhmhqi9OpFtoNebNjci cJlBQHihDUk6bnC203s/ZGbEQi8jGe9edxjRyDd2H1LhrSHChKx+IiLFfmmLaJu1gb2E v9PA78gfkQrkxc9tHHkcjI/q1YOmnJ+T1UtDpHSmDXyQY8E9lpNXE289YC02dHKfo0mf SCTC7Jlmx+1fRiq5w/XnMk5PSIctdCyzg4YhALk98ocMRhbYyvqRfUALdoTubyTgHNga yWcAvcujYw8P0EnoMmD6/iUpig3B8tIKnjaGFBTusWMYusVicrxGCe6T3skOal2P7RsL aY5Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1720803693; x=1721408493; 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=3PoEMkqequy1KWINMIJVW/1gdvscCRasMo3UATAb/nU=; b=CDz0e5+F72lxQjOL96Aylz+X+LUKSCLyZ/GGOsamM9GKeaa/GQ549wEoz5xQG54++o 5IwFMUjUFTNm1nGuxwRpiPB5Rw3FfxZths3LhUfWfZSQadxWvKEDx8zwRD94uVvphUYZ Z3/vzvtS1E/ugFVZtysD/UfX53H1+v9WDIOwFVq1yKhjtCVFrCwPySc+U94VIDl6riv3 NpHxQI+mTjU7+bMCur668/PaE9kjo0aRyYmK5ebvoKyMliSQaJ4EM2Alheu6N1abS+0j 5FqinQCeC5WL/eirPkjx3TneCVuW2QznptmLeP1a6+roTtDwtfdgRSiSnNJeT2wEicE9 TCDw== X-Forwarded-Encrypted: i=1; AJvYcCVPhi1g9uFOt3QvKrrmlaQkEwqE0nqJM6cOqePu+TEMIMgTk3hFq8ATCksd0JO4Y8tsPU7VXM8r++bPKiREUipPD+v3M0UoSiPI8CqI X-Gm-Message-State: AOJu0YzQsIE9A0Uan5D8/cJyoU1x1kKFnD8WCQSONzMzga43G+yEwBz1 s6N74NZGcR4umZ6PC7cfMNsbXYOljfw/JHskkjG+2/qDNrIcqfMOaTOLhN+qqDf1XW1MTVpRUAr YkPyfHoH/3g== X-Google-Smtp-Source: AGHT+IGAsyCLoTSPrJ2N91yIZy7N9XYfi0+vS82VtwZTogujGpm4xok4sUQDdphNDQnjhHnIeN3tEJvaUVoySQ== X-Received: from beeg.c.googlers.com ([fda3:e722:ac3:cc00:28:9cb1:c0a8:11db]) (user=jackmanb job=sendgmr) by 2002:a05:690c:488a:b0:62c:ea0b:a447 with SMTP id 00721157ae682-658ee69b8aemr3280537b3.2.1720803693133; Fri, 12 Jul 2024 10:01:33 -0700 (PDT) Date: Fri, 12 Jul 2024 17:00:32 +0000 In-Reply-To: <20240712-asi-rfc-24-v1-0-144b319a40d8@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240712-asi-rfc-24-v1-0-144b319a40d8@google.com> X-Mailer: b4 0.14-dev Message-ID: <20240712-asi-rfc-24-v1-14-144b319a40d8@google.com> Subject: [PATCH 14/26] mm: asi: Add basic infrastructure for global non-sensitive mappings From: Brendan Jackman To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , Andy Lutomirski , Peter Zijlstra , Sean Christopherson , Paolo Bonzini , Alexandre Chartre , Liran Alon , Jan Setje-Eilers , Catalin Marinas , Will Deacon , Mark Rutland , Andrew Morton , Mel Gorman , Lorenzo Stoakes , David Hildenbrand , Vlastimil Babka , Michal Hocko , Khalid Aziz , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Valentin Schneider , Paul Turner , Reiji Watanabe , Junaid Shahid , Ofir Weisse , Yosry Ahmed , Patrick Bellasi , KP Singh , Alexandra Sandulescu , Matteo Rizzo , Jann Horn Cc: x86@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, kvm@vger.kernel.org, Brendan Jackman Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable From: Junaid Shahid A pseudo-PGD is added to store global non-sensitive ASI mappings. Actual ASI PGDs copy entries from this pseudo-PGD during asi_init(). Memory can be mapped as globally non-sensitive by calling asi_map() with ASI_GLOBAL_NONSENSITIVE. Page tables allocated for global non-sensitive mappings are never freed. While a previous version used init_mm.asi[0] as the special global nonsensitive domain, here we have tried to avoid special-casing index 0. So now we have a special global variable for that. For this to work we need to make sure that nobody assumes that asi is a member of asi->mm->asi (also that nobody assumes a struct asi is embedded in a struct mm - but that seems like a weird assumption to make anyway, when you already have the .mm pointer). I currently believe that this is worth it for the reduced level of magic in the code. Signed-off-by: Junaid Shahid Signed-off-by: Brendan Jackman --- arch/x86/include/asm/asi.h | 3 +++ arch/x86/mm/asi.c | 37 +++++++++++++++++++++++++++++++++++++ arch/x86/mm/init_64.c | 25 ++++++++++++++++--------- arch/x86/mm/mm_internal.h | 3 +++ include/asm-generic/asi.h | 2 ++ 5 files changed, 61 insertions(+), 9 deletions(-) diff --git a/arch/x86/include/asm/asi.h b/arch/x86/include/asm/asi.h index 9aad843eb6df..2d86a5c17f2b 100644 --- a/arch/x86/include/asm/asi.h +++ b/arch/x86/include/asm/asi.h @@ -78,6 +78,9 @@ */ #define ASI_MAX_NUM ((1 << ASI_MAX_NUM_ORDER) - 1) =20 +extern struct asi __asi_global_nonsensitive; +#define ASI_GLOBAL_NONSENSITIVE (&__asi_global_nonsensitive) + struct asi_hooks { /* * Both of these functions MUST be idempotent and re-entrant. They will diff --git a/arch/x86/mm/asi.c b/arch/x86/mm/asi.c index e43b206450ad..807d51497f43 100644 --- a/arch/x86/mm/asi.c +++ b/arch/x86/mm/asi.c @@ -11,6 +11,7 @@ #include #include =20 +#include "mm_internal.h" #include "../../../mm/internal.h" =20 static struct asi_class asi_class[ASI_MAX_NUM]; @@ -19,6 +20,13 @@ static DEFINE_SPINLOCK(asi_class_lock); DEFINE_PER_CPU_ALIGNED(struct asi *, curr_asi); EXPORT_SYMBOL(curr_asi); =20 +static __aligned(PAGE_SIZE) pgd_t asi_global_nonsensitive_pgd[PTRS_PER_PGD= ]; + +struct asi __asi_global_nonsensitive =3D { + .pgd =3D asi_global_nonsensitive_pgd, + .mm =3D &init_mm, +}; + static inline bool asi_class_registered(int index) { return asi_class[index].name !=3D NULL; @@ -154,6 +162,31 @@ void __init asi_check_boottime_disable(void) pr_info("ASI enablement ignored due to incomplete implementation.\n"); } =20 +static int __init asi_global_init(void) +{ + if (!boot_cpu_has(X86_FEATURE_ASI)) + return 0; + + /* + * Lower-level pagetables for global nonsensitive mappings are shared, + * but the PGD has to be copied into each domain during asi_init. To + * avoid needing to synchronize new mappings into pre-existing domains + * we just pre-allocate all of the relevant level N-1 entries so that + * the global nonsensitive PGD already has pointers that can be copied + * when new domains get asi_init()ed. + */ + preallocate_sub_pgd_pages(asi_global_nonsensitive_pgd, + PAGE_OFFSET, + PAGE_OFFSET + PFN_PHYS(max_pfn) - 1, + "ASI Global Non-sensitive direct map"); + preallocate_sub_pgd_pages(asi_global_nonsensitive_pgd, + VMALLOC_START, VMALLOC_END, + "ASI Global Non-sensitive vmalloc"); + + return 0; +} +subsys_initcall(asi_global_init) + static void __asi_destroy(struct asi *asi) { WARN_ON_ONCE(asi->ref_count <=3D 0); @@ -168,6 +201,7 @@ int asi_init(struct mm_struct *mm, int asi_index, struc= t asi **out_asi) { struct asi *asi; int err =3D 0; + uint i; =20 *out_asi =3D NULL; =20 @@ -203,6 +237,9 @@ int asi_init(struct mm_struct *mm, int asi_index, struc= t asi **out_asi) asi->mm =3D mm; asi->index =3D asi_index; =20 + for (i =3D KERNEL_PGD_BOUNDARY; i < PTRS_PER_PGD; i++) + set_pgd(asi->pgd + i, asi_global_nonsensitive_pgd[i]); + exit_unlock: if (err) __asi_destroy(asi); diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 7e177856ee4f..f67f4637357c 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -1278,18 +1278,15 @@ static void __init register_page_bootmem_info(void) #endif } =20 -/* - * Pre-allocates page-table pages for the vmalloc area in the kernel page-= table. - * Only the level which needs to be synchronized between all page-tables is - * allocated because the synchronization can be expensive. - */ -static void __init preallocate_vmalloc_pages(void) +/* Initialize empty pagetables at the level below PGD. */ +void __init preallocate_sub_pgd_pages(pgd_t *pgd_table, ulong start, + ulong end, const char *name) { unsigned long addr; const char *lvl; =20 - for (addr =3D VMALLOC_START; addr <=3D VMEMORY_END; addr =3D ALIGN(addr += 1, PGDIR_SIZE)) { - pgd_t *pgd =3D pgd_offset_k(addr); + for (addr =3D start; addr <=3D end; addr =3D ALIGN(addr + 1, PGDIR_SIZE))= { + pgd_t *pgd =3D pgd_offset_pgd(pgd_table, addr); p4d_t *p4d; pud_t *pud; =20 @@ -1325,7 +1322,17 @@ static void __init preallocate_vmalloc_pages(void) * The pages have to be there now or they will be missing in * process page-tables later. */ - panic("Failed to pre-allocate %s pages for vmalloc area\n", lvl); + panic("Failed to pre-allocate %s pages for %s area\n", lvl, name); +} + +/* + * Pre-allocates page-table pages for the vmalloc area in the kernel page-= table. + * Only the level which needs to be synchronized between all page-tables is + * allocated because the synchronization can be expensive. + */ +static void __init preallocate_vmalloc_pages(void) +{ + preallocate_sub_pgd_pages(init_mm.pgd, VMALLOC_START, VMEMORY_END, "vmall= oc"); } =20 void __init mem_init(void) diff --git a/arch/x86/mm/mm_internal.h b/arch/x86/mm/mm_internal.h index 3f37b5c80bb3..1203a977edcd 100644 --- a/arch/x86/mm/mm_internal.h +++ b/arch/x86/mm/mm_internal.h @@ -25,4 +25,7 @@ void update_cache_mode_entry(unsigned entry, enum page_ca= che_mode cache); =20 extern unsigned long tlb_single_page_flush_ceiling; =20 +extern void preallocate_sub_pgd_pages(pgd_t *pgd_table, ulong start, + ulong end, const char *name); + #endif /* __X86_MM_INTERNAL_H */ diff --git a/include/asm-generic/asi.h b/include/asm-generic/asi.h index 3956f995fe6a..fd5a302e0e09 100644 --- a/include/asm-generic/asi.h +++ b/include/asm-generic/asi.h @@ -9,6 +9,8 @@ #define ASI_MAX_NUM_ORDER 0 #define ASI_MAX_NUM 0 =20 +#define ASI_GLOBAL_NONSENSITIVE NULL + #ifndef _ASSEMBLY_ =20 struct asi_hooks {}; --=20 2.45.2.993.g49e7a77208-goog