From nobody Tue Jun 23 23:42:13 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 15859C433EF for ; Thu, 24 Feb 2022 05:16:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230111AbiBXFQv (ORCPT ); Thu, 24 Feb 2022 00:16:51 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41580 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230109AbiBXFQq (ORCPT ); Thu, 24 Feb 2022 00:16:46 -0500 Received: from mail-yw1-x1149.google.com (mail-yw1-x1149.google.com [IPv6:2607:f8b0:4864:20::1149]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EB7D423402F for ; Wed, 23 Feb 2022 21:16:16 -0800 (PST) Received: by mail-yw1-x1149.google.com with SMTP id 00721157ae682-2d0a5824ec6so12349417b3.0 for ; Wed, 23 Feb 2022 21:16:16 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:cc; bh=mMupdIrbmOm80/sZrASEhygALQnDQAhlGvHAY7r7H5w=; b=X6XkcRUhmtAVIiQWY//3Gn68yYt9JlaMc47Vxfs+9cbIeqKDJtChfU2PP1IOBRmR1x ti8C4IVVDHdguNDBsD2+Zu2z/+0wf1X0jjy8HgGHG5uy+eXYp4j1Mytn6RWE7zYG3Pjh qcHknwrb+7+95GUvIDQnxRanAZSZWd6SqEFWEJJ9Xn2MnMnc1Ul9PgDZjLJvsIsLXGX7 AsxVI1BhGqVIogXF3czePdz1Ax326NINXaOl1FH+v9tqYAT57vqsKVzzNH50KPCClXnd VHJRzl7HiQYfXLY0uKpfCjgyCDYQj9/O8D4qmTHjNwlFd2AqpCH4gs/GGlghND4EjnTW b0nw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:cc; bh=mMupdIrbmOm80/sZrASEhygALQnDQAhlGvHAY7r7H5w=; b=72AvGpNT1JYjpVrViE9jcCLUFeiXMIvijmVEvhGwCdlrnpZwJgu+ePK5UYPrMaHhuK aBWCDqr5yX+VcUMoWvgcqkJmc4iilpU7sTYJFqP+9hY+6yQPnTyRp1/+WvdhreyDYN0B 3lq+XCKAXp0yaBeS8AF6gmYmyYj0DAcefDEGsb51EiOZyk82VUJI42P3us5v1XaUYXCe r7qRoMJ9hkyX5/uiPVuBjc6x8Mk/kXwEMo7GKdgjtSKWhwHUSllCFwJDKQf84OTyA7Va YR2Gpx+247WgFIT5YQFbDKb3ik4hHSkWU8Z3VbyldeuJWQYupmkOXyzaZvp+iSTptTKU hKLg== X-Gm-Message-State: AOAM531Jx9tzgu08q6ilC2dM1zAXoRPOV1R4nYktr1MYJA+PxMYJdPcQ ZO+GCpfqc/fnnFynNF0RRlRJoeOv7OIYAclKzg== X-Google-Smtp-Source: ABdhPJwXwzSytvMwsjPP9WzSxgb1djKy65Lz6QLBpdS+tGwETD/J0V3ZhDRlutQHDIbQP4uTSJSAD6d/fMA2MaVCFQ== X-Received: from kaleshsingh.mtv.corp.google.com ([2620:15c:211:200:415c:9be0:c461:440a]) (user=kaleshsingh job=sendgmr) by 2002:a81:1cd8:0:b0:2d6:b74b:5b55 with SMTP id c207-20020a811cd8000000b002d6b74b5b55mr908040ywc.149.1645679776175; Wed, 23 Feb 2022 21:16:16 -0800 (PST) Date: Wed, 23 Feb 2022 21:13:36 -0800 In-Reply-To: <20220224051439.640768-1-kaleshsingh@google.com> Message-Id: <20220224051439.640768-2-kaleshsingh@google.com> Mime-Version: 1.0 References: <20220224051439.640768-1-kaleshsingh@google.com> X-Mailer: git-send-email 2.35.1.473.g83b2b277ed-goog Subject: [PATCH v3 1/8] KVM: arm64: Introduce hyp_alloc_private_va_range() From: Kalesh Singh Cc: will@kernel.org, maz@kernel.org, qperret@google.com, tabba@google.com, surenb@google.com, kernel-team@android.com, Kalesh Singh , James Morse , Alexandru Elisei , Suzuki K Poulose , Catalin Marinas , Mark Rutland , Mark Brown , Masami Hiramatsu , Peter Collingbourne , "Madhavan T. Venkataraman" , Andrew Scull , Paolo Bonzini , Ard Biesheuvel , linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org To: unlisted-recipients:; (no To-header on input) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" hyp_alloc_private_va_range() can be used to reserve private VA ranges in the nVHE hypervisor. Also update __create_hyp_private_mapping() to allow specifying an alignment for the private VA mapping. These will be used to implement stack guard pages for KVM nVHE hypervisor (nVHE Hyp mode / not pKVM), in a subsequent patch in the series. Signed-off-by: Kalesh Singh --- Changes in v3: - Handle null ptr in IS_ERR_OR_NULL checks, per Mark arch/arm64/include/asm/kvm_mmu.h | 4 +++ arch/arm64/kvm/mmu.c | 62 ++++++++++++++++++++------------ 2 files changed, 43 insertions(+), 23 deletions(-) diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_= mmu.h index 81839e9a8a24..0b0c71302b92 100644 --- a/arch/arm64/include/asm/kvm_mmu.h +++ b/arch/arm64/include/asm/kvm_mmu.h @@ -153,6 +153,10 @@ static __always_inline unsigned long __kern_hyp_va(uns= igned long v) int kvm_share_hyp(void *from, void *to); void kvm_unshare_hyp(void *from, void *to); int create_hyp_mappings(void *from, void *to, enum kvm_pgtable_prot prot); +unsigned long hyp_alloc_private_va_range(size_t size, size_t align); +int __create_hyp_private_mapping(phys_addr_t phys_addr, size_t size, + size_t align, unsigned long *haddr, + enum kvm_pgtable_prot prot); int create_hyp_io_mappings(phys_addr_t phys_addr, size_t size, void __iomem **kaddr, void __iomem **haddr); diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index bc2aba953299..fc09536c8197 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -457,22 +457,16 @@ int create_hyp_mappings(void *from, void *to, enum kv= m_pgtable_prot prot) return 0; } =20 -static int __create_hyp_private_mapping(phys_addr_t phys_addr, size_t size, - unsigned long *haddr, - enum kvm_pgtable_prot prot) + +/* + * Allocates a private VA range below io_map_base. + * + * @size: The size of the VA range to reserve. + * @align: The required alignment for the allocation. + */ +unsigned long hyp_alloc_private_va_range(size_t size, size_t align) { unsigned long base; - int ret =3D 0; - - if (!kvm_host_owns_hyp_mappings()) { - base =3D kvm_call_hyp_nvhe(__pkvm_create_private_mapping, - phys_addr, size, prot); - if (IS_ERR_OR_NULL((void *)base)) - return PTR_ERR((void *)base); - *haddr =3D base; - - return 0; - } =20 mutex_lock(&kvm_hyp_pgd_mutex); =20 @@ -484,8 +478,8 @@ static int __create_hyp_private_mapping(phys_addr_t phy= s_addr, size_t size, * * The allocated size is always a multiple of PAGE_SIZE. */ - size =3D PAGE_ALIGN(size + offset_in_page(phys_addr)); - base =3D io_map_base - size; + base =3D io_map_base - PAGE_ALIGN(size); + base =3D ALIGN_DOWN(base, align); =20 /* * Verify that BIT(VA_BITS - 1) hasn't been flipped by @@ -493,20 +487,42 @@ static int __create_hyp_private_mapping(phys_addr_t p= hys_addr, size_t size, * overflowed the idmap/IO address range. */ if ((base ^ io_map_base) & BIT(VA_BITS - 1)) - ret =3D -ENOMEM; + base =3D (unsigned long)ERR_PTR(-ENOMEM); else io_map_base =3D base; =20 mutex_unlock(&kvm_hyp_pgd_mutex); =20 - if (ret) - goto out; + return base; +} + +int __create_hyp_private_mapping(phys_addr_t phys_addr, size_t size, + size_t align, unsigned long *haddr, + enum kvm_pgtable_prot prot) +{ + unsigned long addr; + int ret =3D 0; + + if (!kvm_host_owns_hyp_mappings()) { + addr =3D kvm_call_hyp_nvhe(__pkvm_create_private_mapping, + phys_addr, size, prot); + if (IS_ERR_OR_NULL((void *)addr)) + return addr ? PTR_ERR((void *)addr) : -ENOMEM; + *haddr =3D addr; + + return 0; + } + + size +=3D offset_in_page(phys_addr); + addr =3D hyp_alloc_private_va_range(size, align); + if (IS_ERR_OR_NULL((void *)addr)) + return addr ? PTR_ERR((void *)addr) : -ENOMEM; =20 - ret =3D __create_hyp_mappings(base, size, phys_addr, prot); + ret =3D __create_hyp_mappings(addr, size, phys_addr, prot); if (ret) goto out; =20 - *haddr =3D base + offset_in_page(phys_addr); + *haddr =3D addr + offset_in_page(phys_addr); out: return ret; } @@ -537,7 +553,7 @@ int create_hyp_io_mappings(phys_addr_t phys_addr, size_= t size, return 0; } =20 - ret =3D __create_hyp_private_mapping(phys_addr, size, + ret =3D __create_hyp_private_mapping(phys_addr, size, PAGE_SIZE, &addr, PAGE_HYP_DEVICE); if (ret) { iounmap(*kaddr); @@ -564,7 +580,7 @@ int create_hyp_exec_mappings(phys_addr_t phys_addr, siz= e_t size, =20 BUG_ON(is_kernel_in_hyp_mode()); =20 - ret =3D __create_hyp_private_mapping(phys_addr, size, + ret =3D __create_hyp_private_mapping(phys_addr, size, PAGE_SIZE, &addr, PAGE_HYP_EXEC); if (ret) { *haddr =3D NULL; --=20 2.35.1.473.g83b2b277ed-goog From nobody Tue Jun 23 23:42:13 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7E2EEC433EF for ; Thu, 24 Feb 2022 05:17:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230123AbiBXFRt (ORCPT ); Thu, 24 Feb 2022 00:17:49 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44112 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229865AbiBXFRq (ORCPT ); Thu, 24 Feb 2022 00:17:46 -0500 Received: from mail-yw1-x114a.google.com (mail-yw1-x114a.google.com [IPv6:2607:f8b0:4864:20::114a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BFDB1193DC for ; Wed, 23 Feb 2022 21:17:16 -0800 (PST) Received: by mail-yw1-x114a.google.com with SMTP id 00721157ae682-2d306e372e5so11848457b3.5 for ; Wed, 23 Feb 2022 21:17:16 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:cc; bh=zjkrHmiNRPu+xkjmRYtl/GGfGVxWhgBcWrDndSQY1ZI=; b=Q95PhZkuTj3mTiQTdWyA/cas59PM8HotrPoSBHBleUFfsGDZ+H8BDlNMcgFVXhTr9r /MI8YF1TH+9h5XzoX87kUd9gLIBzeivRDhdtwBvEaGcsB9JIMdTif9wH8Ad+3bWvCj4E qzBrRM/9BbZcs3edkYZnI0yYE9ptbzZ4KXUgpc+Y7Nqw5MVFoSG5XqrjLWTQV8HMt+PU /PN37+AdvRXsrKuxDxtHwLhYEQp8vJyCDk/iWAK7AsShDriIEyv7qTS3glTu3GBYpGBG tLPs8x375wqy623V/UueGb+TWcfsv+OZzuNSMLTGNBT1RgPIQsiBrqEFpIhGFXthhpQd CNAA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:cc; bh=zjkrHmiNRPu+xkjmRYtl/GGfGVxWhgBcWrDndSQY1ZI=; b=bCc1O58h6qpEbPQycW8K1eI701j8IU8WBlMiSXbK41/wo1mHx8tRjXx0gNSQcrFQUT K2KH92nju9RejUpgHwfX9V4mg9TurfxfgoV5/x/bJwSVr9brVeHoUaj0MXQstsQwksf0 2lZZ3H4OGYhSFV/tXfkg5jjr6BRqax0+aP0hM/cuNdI2Dct2pguIoN9E3V3OjYfqlK68 DcktyhiX+mEcgDPmUKiEEK6YmqTI7O/y0w8LlEWHVNNbHGTWYMhoJcr11pGaEoJv353E f7ZvAHaq6jLeXYVrYtf9P53JlrUNx3LHy4EQbyxFkXiKdNmVTLLeogD1f94dZGDL62nJ s9uA== X-Gm-Message-State: AOAM530Dm1L1JTYlf/aIp8mbvWv7m9qY2YlZVnEXsS+mR8Di9qm9Fy2M lDojtbvQ+wuvbVL1UQCMb0txBPRURCg59Y5zMQ== X-Google-Smtp-Source: ABdhPJwTsQs5w3bWg3HLZfUpV1mRpvUXTrwenTjM/5KRDY/s/xsywaNBh5k6hbdm6EBRXI1pEfunZGxTVf+s4otTCg== X-Received: from kaleshsingh.mtv.corp.google.com ([2620:15c:211:200:415c:9be0:c461:440a]) (user=kaleshsingh job=sendgmr) by 2002:a25:6911:0:b0:624:5f4b:2a01 with SMTP id e17-20020a256911000000b006245f4b2a01mr1014225ybc.303.1645679836014; Wed, 23 Feb 2022 21:17:16 -0800 (PST) Date: Wed, 23 Feb 2022 21:13:37 -0800 In-Reply-To: <20220224051439.640768-1-kaleshsingh@google.com> Message-Id: <20220224051439.640768-3-kaleshsingh@google.com> Mime-Version: 1.0 References: <20220224051439.640768-1-kaleshsingh@google.com> X-Mailer: git-send-email 2.35.1.473.g83b2b277ed-goog Subject: [PATCH v3 2/8] KVM: arm64: Introduce pkvm_alloc_private_va_range() From: Kalesh Singh Cc: will@kernel.org, maz@kernel.org, qperret@google.com, tabba@google.com, surenb@google.com, kernel-team@android.com, Kalesh Singh , James Morse , Alexandru Elisei , Suzuki K Poulose , Catalin Marinas , Mark Rutland , Mark Brown , Masami Hiramatsu , Peter Collingbourne , "Madhavan T. Venkataraman" , Andrew Walbran , Andrew Scull , Paolo Bonzini , Ard Biesheuvel , linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org To: unlisted-recipients:; (no To-header on input) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" pkvm_hyp_alloc_private_va_range() can be used to reserve private VA ranges in the pKVM nVHE hypervisor (). Also update __pkvm_create_private_mapping() to allow specifying an alignment for the private VA mapping. These will be used to implement stack guard pages for pKVM nVHE hypervisor (in a subsequent patch in the series). Credits to Quentin Perret for the idea of moving private VA allocation out of __pkvm_create_private_mapping() Signed-off-by: Kalesh Singh --- Changes in v3: - Handle null ptr in IS_ERR_OR_NULL checks, per Mark Changes in v2: - Allow specifying an alignment for the private VA allocations, per Marc arch/arm64/kvm/hyp/include/nvhe/mm.h | 3 +- arch/arm64/kvm/hyp/nvhe/hyp-main.c | 5 +-- arch/arm64/kvm/hyp/nvhe/mm.c | 51 ++++++++++++++++++---------- arch/arm64/kvm/mmu.c | 2 +- 4 files changed, 40 insertions(+), 21 deletions(-) diff --git a/arch/arm64/kvm/hyp/include/nvhe/mm.h b/arch/arm64/kvm/hyp/incl= ude/nvhe/mm.h index 2d08510c6cc1..05d06ad00347 100644 --- a/arch/arm64/kvm/hyp/include/nvhe/mm.h +++ b/arch/arm64/kvm/hyp/include/nvhe/mm.h @@ -20,7 +20,8 @@ int pkvm_cpu_set_vector(enum arm64_hyp_spectre_vector slo= t); int pkvm_create_mappings(void *from, void *to, enum kvm_pgtable_prot prot); int pkvm_create_mappings_locked(void *from, void *to, enum kvm_pgtable_pro= t prot); unsigned long __pkvm_create_private_mapping(phys_addr_t phys, size_t size, - enum kvm_pgtable_prot prot); + size_t align, enum kvm_pgtable_prot prot); +unsigned long pkvm_alloc_private_va_range(size_t size, size_t align); =20 static inline void hyp_vmemmap_range(phys_addr_t phys, unsigned long size, unsigned long *start, unsigned long *end) diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/h= yp-main.c index 5e2197db0d32..96b2312a0f1d 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c @@ -158,9 +158,10 @@ static void handle___pkvm_create_private_mapping(struc= t kvm_cpu_context *host_ct { DECLARE_REG(phys_addr_t, phys, host_ctxt, 1); DECLARE_REG(size_t, size, host_ctxt, 2); - DECLARE_REG(enum kvm_pgtable_prot, prot, host_ctxt, 3); + DECLARE_REG(size_t, align, host_ctxt, 3); + DECLARE_REG(enum kvm_pgtable_prot, prot, host_ctxt, 4); =20 - cpu_reg(host_ctxt, 1) =3D __pkvm_create_private_mapping(phys, size, prot); + cpu_reg(host_ctxt, 1) =3D __pkvm_create_private_mapping(phys, size, align= , prot); } =20 static void handle___pkvm_prot_finalize(struct kvm_cpu_context *host_ctxt) diff --git a/arch/arm64/kvm/hyp/nvhe/mm.c b/arch/arm64/kvm/hyp/nvhe/mm.c index 526a7d6fa86f..f35468ec639d 100644 --- a/arch/arm64/kvm/hyp/nvhe/mm.c +++ b/arch/arm64/kvm/hyp/nvhe/mm.c @@ -37,26 +37,46 @@ static int __pkvm_create_mappings(unsigned long start, = unsigned long size, return err; } =20 -unsigned long __pkvm_create_private_mapping(phys_addr_t phys, size_t size, - enum kvm_pgtable_prot prot) +/* + * Allocates a private VA range above __io_map_base. + * + * @size: The size of the VA range to reserve. + * @align: The required alignment for the allocation. + */ +unsigned long pkvm_alloc_private_va_range(size_t size, size_t align) { - unsigned long addr; - int err; + unsigned long base, addr; =20 hyp_spin_lock(&pkvm_pgd_lock); =20 - size =3D PAGE_ALIGN(size + offset_in_page(phys)); - addr =3D __io_map_base; - __io_map_base +=3D size; + addr =3D ALIGN(__io_map_base, align); + + /* The allocated size is always a multiple of PAGE_SIZE */ + base =3D addr + PAGE_ALIGN(size); =20 /* Are we overflowing on the vmemmap ? */ - if (__io_map_base > __hyp_vmemmap) { - __io_map_base -=3D size; + if (base > __hyp_vmemmap) addr =3D (unsigned long)ERR_PTR(-ENOMEM); + else + __io_map_base =3D base; + + hyp_spin_unlock(&pkvm_pgd_lock); + + return addr; +} + +unsigned long __pkvm_create_private_mapping(phys_addr_t phys, size_t size, + size_t align, enum kvm_pgtable_prot prot) +{ + unsigned long addr; + int err; + + size +=3D offset_in_page(phys); + addr =3D pkvm_alloc_private_va_range(size, align); + if (IS_ERR((void *)addr)) goto out; - } =20 - err =3D kvm_pgtable_hyp_map(&pkvm_pgtable, addr, size, phys, prot); + err =3D __pkvm_create_mappings(addr, size, phys, prot); if (err) { addr =3D (unsigned long)ERR_PTR(err); goto out; @@ -64,8 +84,6 @@ unsigned long __pkvm_create_private_mapping(phys_addr_t p= hys, size_t size, =20 addr =3D addr + offset_in_page(phys); out: - hyp_spin_unlock(&pkvm_pgd_lock); - return addr; } =20 @@ -152,11 +170,10 @@ int hyp_map_vectors(void) return 0; =20 phys =3D __hyp_pa(__bp_harden_hyp_vecs); - bp_base =3D (void *)__pkvm_create_private_mapping(phys, - __BP_HARDEN_HYP_VECS_SZ, - PAGE_HYP_EXEC); + bp_base =3D (void *)__pkvm_create_private_mapping(phys, __BP_HARDEN_HYP_V= ECS_SZ, + PAGE_SIZE, PAGE_HYP_EXEC); if (IS_ERR_OR_NULL(bp_base)) - return PTR_ERR(bp_base); + return bp_base ? PTR_ERR(bp_base) : -ENOMEM; =20 __hyp_bp_vect_base =3D bp_base; =20 diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index fc09536c8197..298e6d8439ef 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -505,7 +505,7 @@ int __create_hyp_private_mapping(phys_addr_t phys_addr,= size_t size, =20 if (!kvm_host_owns_hyp_mappings()) { addr =3D kvm_call_hyp_nvhe(__pkvm_create_private_mapping, - phys_addr, size, prot); + phys_addr, size, align, prot); if (IS_ERR_OR_NULL((void *)addr)) return addr ? PTR_ERR((void *)addr) : -ENOMEM; *haddr =3D addr; --=20 2.35.1.473.g83b2b277ed-goog From nobody Tue Jun 23 23:42:13 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B5200C433EF for ; Thu, 24 Feb 2022 05:18:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230124AbiBXFSs (ORCPT ); Thu, 24 Feb 2022 00:18:48 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47406 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229785AbiBXFSr (ORCPT ); Thu, 24 Feb 2022 00:18:47 -0500 Received: from mail-yw1-x114a.google.com (mail-yw1-x114a.google.com [IPv6:2607:f8b0:4864:20::114a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5F631CA30A for ; Wed, 23 Feb 2022 21:18:18 -0800 (PST) Received: by mail-yw1-x114a.google.com with SMTP id 00721157ae682-2d07ae11462so11752047b3.8 for ; Wed, 23 Feb 2022 21:18:18 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:cc; bh=WjbUGG0xKbMDb5kZ3phtYyC+0rOONMmeQOjqy/50x/c=; b=FHuVkJYODfDfl0B/txzDiDC6eLLacjGAf43dVMqRJLxMGNm+ImeYaDBNJD5gfJcv21 Z9ohbr5zf1QC8/F1bTBF+ZtWze2p25FmnoYimvvp8tGfx9BVPZudUp/YbHnPxZvAYx55 BqQBFSvFlWYpbE2iAz3wRpB2MQIzUJu+vUzz+Lh96Jvt7QNRq+kZQU99bHlUuJuxphka SBWOmouo+ZUbL8PlVbbewShLA/QY6RIkqnU5TnnahSBctuqAIesOkiMO0fGPQRCh9HHP 62goySNV+LLta5Vhbshz1OV5YtgqzaIrnFy1jWIOuZFsvFmAUGNSod5QivSRYUMFNxUt nAHw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:cc; bh=WjbUGG0xKbMDb5kZ3phtYyC+0rOONMmeQOjqy/50x/c=; b=vmN/7bQbdYE6aGNj+nM1/T2TuimYFIoML5vi770L1Vj4nixS1lBPnmw2dYiprUlh8d /E3Vg6HiIBe9WJK1Ok8AEaX/B/0//LcGhnQvGAxaDNxb+6LcXErXBIB+VOYmgiEIqAUy C04UGJf9NrapDnAdPX8KQS5LpfZWpD212DXq7d2dkyDFi1sTLFngIXOiKPZIzftQ0LVY 0ixWGanPX+MzPxxwM7sGjpkWdhcjPRQqKJuMXO6VNKmvhaE5tajPYy5kbLqW/qzDoEyJ eKagyZp9GorsICD0LTKzLiEWLaYXmyAKr4Wi0QYND3N+d/2mGs3FqtTO2Kwy6xVSfoQT DN6Q== X-Gm-Message-State: AOAM530/3gINMHRvx9hhjRP57H6TP1K/W03sxq8kE/4Wbjfr1sq6dLtf dfl/5tfZrhzjdq05VJtq5Puhe5y7oGEzyoJTxQ== X-Google-Smtp-Source: ABdhPJx3WSBr6Ord/trpGYMYJOGDBeI1xnyUZY7Sz4G+U3zbWcId4VvxdhF5xjfG8cDbo/CMBLseJWAynlqRPGyAbg== X-Received: from kaleshsingh.mtv.corp.google.com ([2620:15c:211:200:415c:9be0:c461:440a]) (user=kaleshsingh job=sendgmr) by 2002:a25:ae94:0:b0:624:4253:a8b with SMTP id b20-20020a25ae94000000b0062442530a8bmr999641ybj.529.1645679897623; Wed, 23 Feb 2022 21:18:17 -0800 (PST) Date: Wed, 23 Feb 2022 21:13:38 -0800 In-Reply-To: <20220224051439.640768-1-kaleshsingh@google.com> Message-Id: <20220224051439.640768-4-kaleshsingh@google.com> Mime-Version: 1.0 References: <20220224051439.640768-1-kaleshsingh@google.com> X-Mailer: git-send-email 2.35.1.473.g83b2b277ed-goog Subject: [PATCH v3 3/8] KVM: arm64: Add guard pages for KVM nVHE hypervisor stack From: Kalesh Singh Cc: will@kernel.org, maz@kernel.org, qperret@google.com, tabba@google.com, surenb@google.com, kernel-team@android.com, Kalesh Singh , James Morse , Alexandru Elisei , Suzuki K Poulose , Catalin Marinas , Mark Rutland , Mark Brown , Masami Hiramatsu , Peter Collingbourne , "Madhavan T. Venkataraman" , Andrew Walbran , Andrew Scull , Paolo Bonzini , linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org To: unlisted-recipients:; (no To-header on input) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Maps the stack pages in the flexible private VA range and allocates guard pages below the stack as unbacked VA space. The stack is aligned to twice its size to aid overflow detection (implemented in a subsequent patch in the series). Signed-off-by: Kalesh Singh --- Changes in v3: - Handle null ptr in IS_ERR_OR_NULL checks, per Mark arch/arm64/include/asm/kvm_asm.h | 1 + arch/arm64/kvm/arm.c | 32 +++++++++++++++++++++++++++++--- 2 files changed, 30 insertions(+), 3 deletions(-) diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_= asm.h index d5b0386ef765..2e277f2ed671 100644 --- a/arch/arm64/include/asm/kvm_asm.h +++ b/arch/arm64/include/asm/kvm_asm.h @@ -169,6 +169,7 @@ struct kvm_nvhe_init_params { unsigned long tcr_el2; unsigned long tpidr_el2; unsigned long stack_hyp_va; + unsigned long stack_pa; phys_addr_t pgd_pa; unsigned long hcr_el2; unsigned long vttbr; diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index ecc5958e27fe..7a23630c4a7f 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -1541,7 +1541,6 @@ static void cpu_prepare_hyp_mode(int cpu) tcr |=3D (idmap_t0sz & GENMASK(TCR_TxSZ_WIDTH - 1, 0)) << TCR_T0SZ_OFFSET; params->tcr_el2 =3D tcr; =20 - params->stack_hyp_va =3D kern_hyp_va(per_cpu(kvm_arm_hyp_stack_page, cpu)= + PAGE_SIZE); params->pgd_pa =3D kvm_mmu_get_httbr(); if (is_protected_kvm_enabled()) params->hcr_el2 =3D HCR_HOST_NVHE_PROTECTED_FLAGS; @@ -1990,14 +1989,41 @@ static int init_hyp_mode(void) * Map the Hyp stack pages */ for_each_possible_cpu(cpu) { + struct kvm_nvhe_init_params *params =3D per_cpu_ptr_nvhe_sym(kvm_init_pa= rams, cpu); char *stack_page =3D (char *)per_cpu(kvm_arm_hyp_stack_page, cpu); - err =3D create_hyp_mappings(stack_page, stack_page + PAGE_SIZE, - PAGE_HYP); + unsigned long stack_hyp_va, guard_hyp_va; =20 + /* + * Private mappings are allocated downwards from io_map_base + * so allocate the stack first then the guard page. + * + * The stack is aligned to twice its size to facilitate overflow + * detection. + */ + err =3D __create_hyp_private_mapping(__pa(stack_page), PAGE_SIZE, + PAGE_SIZE * 2, &stack_hyp_va, PAGE_HYP); if (err) { kvm_err("Cannot map hyp stack\n"); goto out_err; } + + /* Allocate unbacked private VA range for stack guard page */ + guard_hyp_va =3D hyp_alloc_private_va_range(PAGE_SIZE, PAGE_SIZE); + if (IS_ERR_OR_NULL((void *)guard_hyp_va)) { + err =3D guard_hyp_va ? PTR_ERR((void *)guard_hyp_va) : -ENOMEM; + kvm_err("Cannot allocate hyp stack guard page\n"); + goto out_err; + } + + /* + * Save the stack PA in nvhe_init_params. This will be needed to recreate + * the stack mapping in protected nVHE mode. __hyp_pa() won't do the rig= ht + * thing there, since the stack has been mapped in the flexible private + * VA space. + */ + params->stack_pa =3D __pa(stack_page) + PAGE_SIZE; + + params->stack_hyp_va =3D stack_hyp_va + PAGE_SIZE; } =20 for_each_possible_cpu(cpu) { --=20 2.35.1.473.g83b2b277ed-goog From nobody Tue Jun 23 23:42:13 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 63F24C433EF for ; Thu, 24 Feb 2022 05:19:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230145AbiBXFTu (ORCPT ); Thu, 24 Feb 2022 00:19:50 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52010 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230118AbiBXFTr (ORCPT ); Thu, 24 Feb 2022 00:19:47 -0500 Received: from mail-yw1-x1149.google.com (mail-yw1-x1149.google.com [IPv6:2607:f8b0:4864:20::1149]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7B5A917E363 for ; Wed, 23 Feb 2022 21:19:18 -0800 (PST) Received: by mail-yw1-x1149.google.com with SMTP id 00721157ae682-2d07ae11462so11767017b3.8 for ; Wed, 23 Feb 2022 21:19:18 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:cc; bh=Sc96glvxYslSfkQXo+KXiEGMpwz7KGQFqK1SBX4eD7A=; b=B8lXlAgDd0kVzKodKmL9JcM1dcJSITQumRTkFniujZawZDAhk4wZn+DpIQLhUYO/ch /iD4fAJgbvRXUaHirgctgj7pLUQblkrrsAEJMibl5VJvqZTLUgl49dAk/yK8WdVz6O83 u40dS8aCwVHlq3RLEMzMPcZbJLQzQK8GbGi9dh9cBMwbfhbfitEzE3/zjkDAaPEfZ/kf tG4sTtq9tpZQfTqmU+TA7/OqoQH7nrxa151lCTPVRM1WDtWmB9kRigE239E2/Tc9/Jqz 41uBcTKbyjiUJdTcleBYvwYHxaKNIGvnY6iTRF8DBO069ux3kEvruXCti9dxa2D7yM4V im7A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:cc; bh=Sc96glvxYslSfkQXo+KXiEGMpwz7KGQFqK1SBX4eD7A=; b=OuVVNQg3Vqu6TVkJDuL8rl4L8vIMX3/4a2z3rbMK/DsKh+oie15T/hjfD2MNmypEmj OUFnzT9tx2JJuPfa6A+0ABf+ZOBVgDCTaNP72XDAXVPl2R+ue7GHH+Qrx9WmbBtIKkyw SiwCvOlqKkrIFtn82eNGi4Fme+ONF4FzA4ej2TXode83nMcGcTHC4BH4jYPrg2DcK15A 0rkY1lanwhFZvIvZN2puTzF7vGPFQ7NpYhONIPFjwBwEVcfPnwT7ouJ25o8UHLS/efYH /45OEliQsmLWu+Y2umk+aPrcSRxAZsvLBxPIfhsC46SJuWIq2SfRjhX+iL0eVjkvbjKN C++A== X-Gm-Message-State: AOAM5318Huxo5cYhHcuuNdALpnJEWrL9NELPuOyD1nW+OkD8Vuvdx3Kw q2KMT6LQNs6ELhRqxKnSUuB+f/HsMrFBCPffOQ== X-Google-Smtp-Source: ABdhPJzBUzrWz/IzDAYDQ8eab8JhoYZDYi700gxVQBn86Vj1XDP4YQZMrJTSKaYcX0VoNCNeGZXoRp+1Cxz/wmOKKw== X-Received: from kaleshsingh.mtv.corp.google.com ([2620:15c:211:200:415c:9be0:c461:440a]) (user=kaleshsingh job=sendgmr) by 2002:a25:d449:0:b0:619:c1f1:928b with SMTP id m70-20020a25d449000000b00619c1f1928bmr968656ybf.19.1645679957716; Wed, 23 Feb 2022 21:19:17 -0800 (PST) Date: Wed, 23 Feb 2022 21:13:39 -0800 In-Reply-To: <20220224051439.640768-1-kaleshsingh@google.com> Message-Id: <20220224051439.640768-5-kaleshsingh@google.com> Mime-Version: 1.0 References: <20220224051439.640768-1-kaleshsingh@google.com> X-Mailer: git-send-email 2.35.1.473.g83b2b277ed-goog Subject: [PATCH v3 4/8] KVM: arm64: Add guard pages for pKVM (protected nVHE) hypervisor stack From: Kalesh Singh Cc: will@kernel.org, maz@kernel.org, qperret@google.com, tabba@google.com, surenb@google.com, kernel-team@android.com, Kalesh Singh , James Morse , Alexandru Elisei , Suzuki K Poulose , Catalin Marinas , Mark Rutland , Mark Brown , Masami Hiramatsu , Peter Collingbourne , "Madhavan T. Venkataraman" , Andrew Scull , linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org To: unlisted-recipients:; (no To-header on input) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Maps the stack pages in the flexible private VA range and allocates guard pages below the stack as unbacked VA space. The stack is aligned to twice its size to aid overflow detection (implemented in a subsequent patch in the series). Signed-off-by: Kalesh Singh --- Changes in v3: - Handle null ptr in IS_ERR_OR_NULL checks, per Mark arch/arm64/kvm/hyp/nvhe/setup.c | 25 +++++++++++++++++++++---- 1 file changed, 21 insertions(+), 4 deletions(-) diff --git a/arch/arm64/kvm/hyp/nvhe/setup.c b/arch/arm64/kvm/hyp/nvhe/setu= p.c index 27af337f9fea..5f3a4002f9c5 100644 --- a/arch/arm64/kvm/hyp/nvhe/setup.c +++ b/arch/arm64/kvm/hyp/nvhe/setup.c @@ -105,11 +105,28 @@ static int recreate_hyp_mappings(phys_addr_t phys, un= signed long size, if (ret) return ret; =20 - end =3D (void *)per_cpu_ptr(&kvm_init_params, i)->stack_hyp_va; + /* + * Private mappings are allocated upwards from __io_map_base + * so allocate the guard page first then the stack. + */ + start =3D (void *)pkvm_alloc_private_va_range(PAGE_SIZE, PAGE_SIZE); + if (IS_ERR_OR_NULL(start)) + return start ? PTR_ERR(start) : -ENOMEM; + + /* + * The stack is aligned to twice its size to facilitate overflow + * detection. + */ + end =3D (void *)per_cpu_ptr(&kvm_init_params, i)->stack_pa; start =3D end - PAGE_SIZE; - ret =3D pkvm_create_mappings(start, end, PAGE_HYP); - if (ret) - return ret; + start =3D (void *)__pkvm_create_private_mapping((phys_addr_t)start, + PAGE_SIZE, PAGE_SIZE * 2, PAGE_HYP); + if (IS_ERR_OR_NULL(start)) + return start ? PTR_ERR(start) : -ENOMEM; + end =3D start + PAGE_SIZE; + + /* Update stack_hyp_va to end of the stack's private VA range */ + per_cpu_ptr(&kvm_init_params, i)->stack_hyp_va =3D (unsigned long) end; } =20 /* --=20 2.35.1.473.g83b2b277ed-goog From nobody Tue Jun 23 23:42:13 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3C2D6C433F5 for ; Thu, 24 Feb 2022 05:20:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230136AbiBXFUv (ORCPT ); Thu, 24 Feb 2022 00:20:51 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53238 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229703AbiBXFUt (ORCPT ); Thu, 24 Feb 2022 00:20:49 -0500 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4B16E17F69F for ; Wed, 23 Feb 2022 21:20:20 -0800 (PST) Received: by mail-yb1-xb49.google.com with SMTP id a19-20020a25ca13000000b0061db44646b3so943722ybg.2 for ; Wed, 23 Feb 2022 21:20:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:cc; bh=H4Z1lUqUeabFhmJD3t8xVbX28HOrFIYN1Agzn114BGo=; b=LsQ97pcohFsj9RlBvIOR/HjRRTmpxuoxoVutPu6Mz8f8Qc8IiLUdOvgGwYWo6PkPqP edGd3S6spZfR1eG7lKcxxDMoY93t5dZyarnvaxqB/e8uaJHBjjHxpPojSAfvmbE5SA+q yH5/xwTQQ1ApMBlT4llh7MhcqVVpsUfgYdJ1iKJ6oqJz2HRvD5USeQ38eCXddXx5ogBv kE/jZINSl2wgXKpy0cIapbKMmmLn1hDj7jvYWPvUDNUUSNXkYBs9l0teLhdyiRhTAVOk Py2ZxE/qmDVu81csLNOLFCwMGUyw/uXDQMhoEajwvjW82rbKO4U8DeRxLYT0WkngZ4FK 0i+A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:cc; bh=H4Z1lUqUeabFhmJD3t8xVbX28HOrFIYN1Agzn114BGo=; b=Kk836Pr9nDrMk4CN2Z3UgJrVd2wzbzybrrox53ot+RklZHRUsk4YkYOKFj3MO8BqwM 7aNR3j0TBZn1OaA2sre/ndUuxU2GIuVW476AvTEibl2yjhjv8YvojVPTBSLLpBjK0DB4 d9jIbfx4FMaJPH8UCvjSLFmrxzJyeyGKbiE0ZrbMIF1Jro0423n4yhVnFn7hFnXUu21x INM+RMKGREgDxb/AFI1Mec880fmUQr0vSjMBJ2DHdgqswB9HN7MIWKEmBiW7w1ML84pA UTdjOi0L9zXW1sq1mWLkxS1cS5gGaBXYcSF8dL2u6Bhr2EfzG9VA1YrWj1aUt+nxc3qw s+Yg== X-Gm-Message-State: AOAM530L78e8wAKpBP4x7knh3fix42+atMdVb+q3NtFzQhlA84QnuXb1 sWHbQ8xO82bIizb+F+jbqnFrPIZ/SMNuKfSlpQ== X-Google-Smtp-Source: ABdhPJz5Qiz49suSJpWhdDGBZ/Par4c6tTpWzRj6zIuxEJHxtLIJ4WzGG0ZrNy9JUdjCvZK71gx48FILjtMxJXC9CQ== X-Received: from kaleshsingh.mtv.corp.google.com ([2620:15c:211:200:415c:9be0:c461:440a]) (user=kaleshsingh job=sendgmr) by 2002:a25:374d:0:b0:611:a6c1:b948 with SMTP id e74-20020a25374d000000b00611a6c1b948mr1007735yba.21.1645680019488; Wed, 23 Feb 2022 21:20:19 -0800 (PST) Date: Wed, 23 Feb 2022 21:13:40 -0800 In-Reply-To: <20220224051439.640768-1-kaleshsingh@google.com> Message-Id: <20220224051439.640768-6-kaleshsingh@google.com> Mime-Version: 1.0 References: <20220224051439.640768-1-kaleshsingh@google.com> X-Mailer: git-send-email 2.35.1.473.g83b2b277ed-goog Subject: [PATCH v3 5/8] KVM: arm64: Detect and handle hypervisor stack overflows From: Kalesh Singh Cc: will@kernel.org, maz@kernel.org, qperret@google.com, tabba@google.com, surenb@google.com, kernel-team@android.com, Kalesh Singh , James Morse , Alexandru Elisei , Suzuki K Poulose , Catalin Marinas , Mark Rutland , Mark Brown , Masami Hiramatsu , Peter Collingbourne , "Madhavan T. Venkataraman" , Andrew Walbran , Andrew Scull , Zenghui Yu , linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org To: unlisted-recipients:; (no To-header on input) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The hypervisor stacks (for both nVHE Hyp mode and nVHE protected mode) are aligned to twice their size (PAGE_SIZE), meaning that any valid stack address has PAGE_SHIFT bit as 0. This allows us to conveniently check for overflow in the exception entry without corrupting any GPRs. We won't recover from a stack overflow so panic the hypervisor. Signed-off-by: Kalesh Singh --- Changes in v3: - Remove test_sp_overflow macro, per Mark - Add asmlinkage attribute for hyp_panic, hyp_panic_bad_stack, per Ard arch/arm64/kvm/hyp/nvhe/host.S | 24 ++++++++++++++++++++++++ arch/arm64/kvm/hyp/nvhe/switch.c | 7 ++++++- 2 files changed, 30 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kvm/hyp/nvhe/host.S b/arch/arm64/kvm/hyp/nvhe/host.S index 3d613e721a75..749961bfa5ba 100644 --- a/arch/arm64/kvm/hyp/nvhe/host.S +++ b/arch/arm64/kvm/hyp/nvhe/host.S @@ -153,6 +153,18 @@ SYM_FUNC_END(__host_hvc) =20 .macro invalid_host_el2_vect .align 7 + + /* + * Test whether the SP has overflowed, without corrupting a GPR. + * nVHE hypervisor stacks are aligned so that SP & (1 << PAGE_SHIFT) + * should always be zero. + */ + add sp, sp, x0 // sp' =3D sp + x0 + sub x0, sp, x0 // x0' =3D sp' - x0 =3D (sp + x0) - x0 =3D sp + tbnz x0, #PAGE_SHIFT, .L__hyp_sp_overflow\@ + sub x0, sp, x0 // x0'' =3D sp' - x0' =3D (sp + x0) - sp =3D x0 + sub sp, sp, x0 // sp'' =3D sp' - x0 =3D (sp + x0) - x0 =3D sp + /* If a guest is loaded, panic out of it. */ stp x0, x1, [sp, #-16]! get_loaded_vcpu x0, x1 @@ -165,6 +177,18 @@ SYM_FUNC_END(__host_hvc) * been partially clobbered by __host_enter. */ b hyp_panic + +.L__hyp_sp_overflow\@: + /* + * Reset SP to the top of the stack, to allow handling the hyp_panic. + * This corrupts the stack but is ok, since we won't be attempting + * any unwinding here. + */ + ldr_this_cpu x0, kvm_init_params + NVHE_INIT_STACK_HYP_VA, x1 + mov sp, x0 + + bl hyp_panic_bad_stack + ASM_BUG() .endm =20 .macro invalid_host_el1_vect diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/swi= tch.c index 6410d21d8695..703a5d3f611b 100644 --- a/arch/arm64/kvm/hyp/nvhe/switch.c +++ b/arch/arm64/kvm/hyp/nvhe/switch.c @@ -347,7 +347,7 @@ int __kvm_vcpu_run(struct kvm_vcpu *vcpu) return exit_code; } =20 -void __noreturn hyp_panic(void) +asmlinkage void __noreturn hyp_panic(void) { u64 spsr =3D read_sysreg_el2(SYS_SPSR); u64 elr =3D read_sysreg_el2(SYS_ELR); @@ -369,6 +369,11 @@ void __noreturn hyp_panic(void) unreachable(); } =20 +asmlinkage void __noreturn hyp_panic_bad_stack(void) +{ + hyp_panic(); +} + asmlinkage void kvm_unexpected_el2_exception(void) { return __kvm_unexpected_el2_exception(); --=20 2.35.1.473.g83b2b277ed-goog From nobody Tue Jun 23 23:42:13 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 671E8C433EF for ; Thu, 24 Feb 2022 05:21:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230147AbiBXFVw (ORCPT ); Thu, 24 Feb 2022 00:21:52 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53900 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229744AbiBXFVu (ORCPT ); Thu, 24 Feb 2022 00:21:50 -0500 Received: from mail-yw1-x114a.google.com (mail-yw1-x114a.google.com [IPv6:2607:f8b0:4864:20::114a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3283B189A81 for ; Wed, 23 Feb 2022 21:21:21 -0800 (PST) Received: by mail-yw1-x114a.google.com with SMTP id 00721157ae682-2d11b6259adso11322037b3.19 for ; Wed, 23 Feb 2022 21:21:21 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:cc; bh=v7H+YHEXea4IIqGySI7aLREzIvLtpBuCKjmvH1cIeXQ=; b=NulZA7w/XH6Ovox3Z8EPA5m/C/4Cu5qNglcuNmoAQGiwk4ZsQUEDaqrrza3kj0/rO1 4AIBYeKLpSv0/Y0kyPuD0iIaYP+rfQjHEEPqR6hATVEXSiEGw1puhIgCf0xl4KrRv9Ze bf3X6bGXRtPd3AVhIvpnfTipQKZ7kaRoy2V22FK420mGJNxu4NBXNZkGrPE31FXO18uL p5giufi9NXloDjTBFhB+FZiUOIrIvZ5VdVoH+krscvWKPlnWpw3VycB1f6vXmcZ/3Bcy kQgU10gE8FIBPttAIaRsih5zbrOFWZVcM3EhGsNnh5UyKz3q6san4735fgWDpsuyGnfD vTQQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:cc; bh=v7H+YHEXea4IIqGySI7aLREzIvLtpBuCKjmvH1cIeXQ=; b=nj+Dn9KYSq0InJwzQQdljNl9WvqfGgf3mzeiaNXQdQrWUaMvHGts56s+CgK/NQ6cSF 1cbOfnLRZdIpBgkr07EYqrqIRScoMMz4Bvbh7Sxy8q2thuI2ET9BGSMAoV+QnjTgwuIj 7RUuOAeMtFkFXdmniD+9ALkRY699ha+ZsCn6RxcstSjQDpRYbnUNhPDQzI+QYVzbFky6 bK4sgFcGlF0r82on//gxsXX6pVDNAvfL3T9BSKH4Fx46l5DnBcNwpaHe+ycvB5H64V+z LhbMoJry0709Ek19RD4PkgWgZZ6lq3VABw7zVAVLAbfRGlQ4CDWxoBcf8XEE2Qg8vZvs Kc/w== X-Gm-Message-State: AOAM533sg4s4npNM2HtH/PaMXPeNmBBaQXpi/m4Hgmja2DoXiSTTJwf/ uzkV0mFWshdHBsl/dLoANCkTU67zW5/zY2oQ4Q== X-Google-Smtp-Source: ABdhPJyGTlGm+C/X/WYwJEpFuocVcINp/xR0sgVssDAtD0IXfiwn+elCX3UtU0cHn8Y6Lskq6uXxQyXVu8faJREUXQ== X-Received: from kaleshsingh.mtv.corp.google.com ([2620:15c:211:200:415c:9be0:c461:440a]) (user=kaleshsingh job=sendgmr) by 2002:a25:9108:0:b0:61e:329:700 with SMTP id v8-20020a259108000000b0061e03290700mr976530ybl.369.1645680080321; Wed, 23 Feb 2022 21:21:20 -0800 (PST) Date: Wed, 23 Feb 2022 21:13:41 -0800 In-Reply-To: <20220224051439.640768-1-kaleshsingh@google.com> Message-Id: <20220224051439.640768-7-kaleshsingh@google.com> Mime-Version: 1.0 References: <20220224051439.640768-1-kaleshsingh@google.com> X-Mailer: git-send-email 2.35.1.473.g83b2b277ed-goog Subject: [PATCH v3 6/8] KVM: arm64: Add hypervisor overflow stack From: Kalesh Singh Cc: will@kernel.org, maz@kernel.org, qperret@google.com, tabba@google.com, surenb@google.com, kernel-team@android.com, Kalesh Singh , James Morse , Alexandru Elisei , Suzuki K Poulose , Catalin Marinas , Mark Rutland , Mark Brown , Masami Hiramatsu , Peter Collingbourne , "Madhavan T. Venkataraman" , Andrew Walbran , Andrew Scull , Zenghui Yu , Ard Biesheuvel , Paolo Bonzini , linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org To: unlisted-recipients:; (no To-header on input) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Allocate and switch to 16-byte aligned secondary stack on overflow. This provides us stack space to better handle overflows; and is used in a subsequent patch to dump the hypervisor stacktrace. The overflow stack is only allocated if CONFIG_NVHE_EL2_DEBUG is enabled, as hypervisor stacktraces is a debug feature dependent on CONFIG_NVHE_EL2_DEBUG. Signed-off-by: Kalesh Singh --- arch/arm64/kvm/hyp/nvhe/host.S | 5 +++++ arch/arm64/kvm/hyp/nvhe/switch.c | 5 +++++ 2 files changed, 10 insertions(+) diff --git a/arch/arm64/kvm/hyp/nvhe/host.S b/arch/arm64/kvm/hyp/nvhe/host.S index 749961bfa5ba..367a01e8abed 100644 --- a/arch/arm64/kvm/hyp/nvhe/host.S +++ b/arch/arm64/kvm/hyp/nvhe/host.S @@ -179,6 +179,10 @@ SYM_FUNC_END(__host_hvc) b hyp_panic =20 .L__hyp_sp_overflow\@: +#ifdef CONFIG_NVHE_EL2_DEBUG + /* Switch to the overflow stack */ + adr_this_cpu sp, hyp_overflow_stack + PAGE_SIZE, x0 +#else /* * Reset SP to the top of the stack, to allow handling the hyp_panic. * This corrupts the stack but is ok, since we won't be attempting @@ -186,6 +190,7 @@ SYM_FUNC_END(__host_hvc) */ ldr_this_cpu x0, kvm_init_params + NVHE_INIT_STACK_HYP_VA, x1 mov sp, x0 +#endif =20 bl hyp_panic_bad_stack ASM_BUG() diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/swi= tch.c index 703a5d3f611b..efc20273a352 100644 --- a/arch/arm64/kvm/hyp/nvhe/switch.c +++ b/arch/arm64/kvm/hyp/nvhe/switch.c @@ -34,6 +34,11 @@ DEFINE_PER_CPU(struct kvm_host_data, kvm_host_data); DEFINE_PER_CPU(struct kvm_cpu_context, kvm_hyp_ctxt); DEFINE_PER_CPU(unsigned long, kvm_hyp_vector); =20 +#ifdef CONFIG_NVHE_EL2_DEBUG +DEFINE_PER_CPU(unsigned long [PAGE_SIZE/sizeof(long)], hyp_overflow_stack) + __aligned(16); +#endif + static void __activate_traps(struct kvm_vcpu *vcpu) { u64 val; --=20 2.35.1.473.g83b2b277ed-goog From nobody Tue Jun 23 23:42:13 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 28216C433F5 for ; Thu, 24 Feb 2022 05:22:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230193AbiBXFXC (ORCPT ); Thu, 24 Feb 2022 00:23:02 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55340 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229987AbiBXFWw (ORCPT ); Thu, 24 Feb 2022 00:22:52 -0500 Received: from mail-yw1-x1149.google.com (mail-yw1-x1149.google.com [IPv6:2607:f8b0:4864:20::1149]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DAB18AEF2C for ; Wed, 23 Feb 2022 21:22:21 -0800 (PST) Received: by mail-yw1-x1149.google.com with SMTP id 00721157ae682-2d6994a6942so11337117b3.17 for ; Wed, 23 Feb 2022 21:22:21 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:cc; bh=K66ess7r5mHhZ+jyrx/v31ubR1dLR/5O6RljnD9TbJk=; b=LozXqHfMaTDJaEwKzPinWRR8XkqdwYysp39GImtwCrM0+rogfw04rb+mueZhhhGfGL 23FdMdHjfPe/ucA5NO1Ps2x7QWVTIJkn5r3/w8An+6Yu/OFB26uda3T3TViaharQGbj+ 7lqzJTjK+W3cWbsaENJ9QW4K/1yBNzLwviodZJ0Bmop3eVKvP4pz+i1Le2m2DPlNVJkU D6YZicoBfCDZKRojOUD0ad+qD2XesbCuBtMdPnkVExspbT66sEOb2LAjVrIpfal4EMKl 1ZUgGHWlikvJtJGdsQ/1RJ+WivRUeJ3YDFLrF3XG6Nm86ZogXR2B4GecgXGAI7R39qwJ v2Ew== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:cc; bh=K66ess7r5mHhZ+jyrx/v31ubR1dLR/5O6RljnD9TbJk=; b=VYFnqsKnVM73Ypg+UWQl2bzXvRSsh64vOifx3aNwomG0L8fe4DYIsPCamvGhdLw50A a9n0phaQHY22L0rAE7guaENbbStXAGyMpEe/w/wSNa15hszm48AcPAX9e/7dYq3Ih4Ae n9oFlO38WgTflhwnQygwE/4Hks/wPgMTiAGbRoA/Sgn6b15fmV1CJUocpQPwuaLkdFeO ctCx5RfvCDTwpg6z4mDP2QDXpz8k+qrVXVH6Kq7f1di3Fu8SayixpWHMB60LyMsiM+YJ NwS4TpBEolF3pz/OrTpuux5BpV1mBeLuyhN0l/ug+MUBTtkd+qO9ANoP7bvurGSjHmiF rnqA== X-Gm-Message-State: AOAM533ME/YaqJabvqboqfDHsEABNOoOU1QFawAfnjCdCHl2zIp5N9jv fJ8/n/DtoaEMUu7UoomOly1zgNle0MO4FwAoqA== X-Google-Smtp-Source: ABdhPJw/I4KRWgId8HIW9zGlW2JOH88r+9WEJZxHfHet2WVfgtVJ4oQgjoWSFqxv0u3Uw07d8ZDDCNzupW/Z9K00hw== X-Received: from kaleshsingh.mtv.corp.google.com ([2620:15c:211:200:415c:9be0:c461:440a]) (user=kaleshsingh job=sendgmr) by 2002:a25:2e45:0:b0:624:3b7e:7ffa with SMTP id b5-20020a252e45000000b006243b7e7ffamr988328ybn.293.1645680141135; Wed, 23 Feb 2022 21:22:21 -0800 (PST) Date: Wed, 23 Feb 2022 21:13:42 -0800 In-Reply-To: <20220224051439.640768-1-kaleshsingh@google.com> Message-Id: <20220224051439.640768-8-kaleshsingh@google.com> Mime-Version: 1.0 References: <20220224051439.640768-1-kaleshsingh@google.com> X-Mailer: git-send-email 2.35.1.473.g83b2b277ed-goog Subject: [PATCH v3 7/8] KVM: arm64: Unwind and dump nVHE HYP stacktrace From: Kalesh Singh Cc: will@kernel.org, maz@kernel.org, qperret@google.com, tabba@google.com, surenb@google.com, kernel-team@android.com, Kalesh Singh , James Morse , Alexandru Elisei , Suzuki K Poulose , Catalin Marinas , Mark Rutland , Mark Brown , Masami Hiramatsu , Peter Collingbourne , "Madhavan T. Venkataraman" , Andrew Scull , Paolo Bonzini , Ard Biesheuvel , linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org To: unlisted-recipients:; (no To-header on input) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Unwind the stack in EL1, when CONFIG_NVHE_EL2_DEBUG is enabled. This is possible because CONFIG_NVHE_EL2_DEBUG disables the host stage 2 protection which allows host to access the hypervisor stack pages in EL1. Unwinding and dumping hyp call traces is gated on CONFIG_NVHE_EL2_DEBUG to avoid the potential leaking of information to the host. A simple stack overflow test produces the following output: [ 580.376051][ T412] kvm: nVHE hyp panic at: ffffffc0116145c4! [ 580.378034][ T412] kvm [412]: nVHE HYP call trace: [ 580.378591][ T412] kvm [412]: [] [ 580.378993][ T412] kvm [412]: [] [ 580.379386][ T412] kvm [412]: [] // Non-terminating= recursive call [ 580.379772][ T412] kvm [412]: [] [ 580.380158][ T412] kvm [412]: [] [ 580.380544][ T412] kvm [412]: [] [ 580.380928][ T412] kvm [412]: [] . . . Since nVHE hyp symbols are not included by kallsyms to avoid issues with aliasing, we fallback to the vmlinux addresses. Symbolizing the addresses is handled in the next patch in this series. Signed-off-by: Kalesh Singh --- Changes in v3: - The nvhe hyp stack unwinder now makes use of the core logic from the regular kernel unwinder to avoid duplication, per Mark Changes in v2: - Add cpu_prepare_nvhe_panic_info() - Move updating the panic info to hyp_panic(), so that unwinding also works for conventional nVHE Hyp-mode. arch/arm64/include/asm/kvm_asm.h | 19 +++ arch/arm64/include/asm/stacktrace.h | 12 ++ arch/arm64/kernel/stacktrace.c | 210 +++++++++++++++++++++++++--- arch/arm64/kvm/Kconfig | 5 +- arch/arm64/kvm/arm.c | 2 +- arch/arm64/kvm/handle_exit.c | 3 + arch/arm64/kvm/hyp/nvhe/switch.c | 18 +++ 7 files changed, 243 insertions(+), 26 deletions(-) diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_= asm.h index 2e277f2ed671..16efdf150a37 100644 --- a/arch/arm64/include/asm/kvm_asm.h +++ b/arch/arm64/include/asm/kvm_asm.h @@ -176,6 +176,25 @@ struct kvm_nvhe_init_params { unsigned long vtcr; }; =20 +#ifdef CONFIG_NVHE_EL2_DEBUG +/* + * Used by the host in EL1 to dump the nVHE hypervisor backtrace on + * hyp_panic. This is possible because CONFIG_NVHE_EL2_DEBUG disables + * the host stage 2 protection. See: __hyp_do_panic() + * + * @hyp_stack_base: hyp VA of the hyp_stack base. + * @hyp_overflow_stack_base: hyp VA of the hyp_overflow_stack base. + * @fp: hyp FP where the backtrace begins. + * @pc: hyp PC where the backtrace begins. + */ +struct kvm_nvhe_panic_info { + unsigned long hyp_stack_base; + unsigned long hyp_overflow_stack_base; + unsigned long fp; + unsigned long pc; +}; +#endif /* CONFIG_NVHE_EL2_DEBUG */ + /* Translate a kernel address @ptr into its equivalent linear mapping */ #define kvm_ksym_ref(ptr) \ ({ \ diff --git a/arch/arm64/include/asm/stacktrace.h b/arch/arm64/include/asm/s= tacktrace.h index e77cdef9ca29..18611a51cf14 100644 --- a/arch/arm64/include/asm/stacktrace.h +++ b/arch/arm64/include/asm/stacktrace.h @@ -22,6 +22,10 @@ enum stack_type { STACK_TYPE_OVERFLOW, STACK_TYPE_SDEI_NORMAL, STACK_TYPE_SDEI_CRITICAL, +#ifdef CONFIG_NVHE_EL2_DEBUG + STACK_TYPE_KVM_NVHE_HYP, + STACK_TYPE_KVM_NVHE_OVERFLOW, +#endif /* CONFIG_NVHE_EL2_DEBUG */ __NR_STACK_TYPES }; =20 @@ -147,4 +151,12 @@ static inline bool on_accessible_stack(const struct ta= sk_struct *tsk, return false; } =20 +#ifdef CONFIG_NVHE_EL2_DEBUG +void kvm_nvhe_dump_backtrace(unsigned long hyp_offset); +#else +static inline void kvm_nvhe_dump_backtrace(unsigned long hyp_offset) +{ +} +#endif /* CONFIG_NVHE_EL2_DEBUG */ + #endif /* __ASM_STACKTRACE_H */ diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c index e4103e085681..6ec85cb69b1f 100644 --- a/arch/arm64/kernel/stacktrace.c +++ b/arch/arm64/kernel/stacktrace.c @@ -15,6 +15,8 @@ =20 #include #include +#include +#include #include #include =20 @@ -64,26 +66,15 @@ NOKPROBE_SYMBOL(start_backtrace); * records (e.g. a cycle), determined based on the location and fp value o= f A * and the location (but not the fp value) of B. */ -static int notrace unwind_frame(struct task_struct *tsk, - struct stackframe *frame) +static int notrace __unwind_frame(struct stackframe *frame, struct stack_i= nfo *info, + unsigned long (*translate_fp)(unsigned long, enum stack_type)) { unsigned long fp =3D frame->fp; - struct stack_info info; - - if (!tsk) - tsk =3D current; - - /* Final frame; nothing to unwind */ - if (fp =3D=3D (unsigned long)task_pt_regs(tsk)->stackframe) - return -ENOENT; =20 if (fp & 0x7) return -EINVAL; =20 - if (!on_accessible_stack(tsk, fp, 16, &info)) - return -EINVAL; - - if (test_bit(info.type, frame->stacks_done)) + if (test_bit(info->type, frame->stacks_done)) return -EINVAL; =20 /* @@ -94,28 +85,62 @@ static int notrace unwind_frame(struct task_struct *tsk, * * TASK -> IRQ -> OVERFLOW -> SDEI_NORMAL * TASK -> SDEI_NORMAL -> SDEI_CRITICAL -> OVERFLOW + * KVM_NVHE_HYP -> KVM_NVHE_OVERFLOW * * ... but the nesting itself is strict. Once we transition from one * stack to another, it's never valid to unwind back to that first * stack. */ - if (info.type =3D=3D frame->prev_type) { + if (info->type =3D=3D frame->prev_type) { if (fp <=3D frame->prev_fp) return -EINVAL; } else { set_bit(frame->prev_type, frame->stacks_done); } =20 + /* Record fp as prev_fp before attempting to get the next fp */ + frame->prev_fp =3D fp; + + /* + * If fp is not from the current address space perform the + * necessary translation before dereferencing it to get next fp. + */ + if (translate_fp) + fp =3D translate_fp(fp, info->type); + if (!fp) + return -EINVAL; + /* * Record this frame record's values and location. The prev_fp and - * prev_type are only meaningful to the next unwind_frame() invocation. + * prev_type are only meaningful to the next __unwind_frame() invocation. */ frame->fp =3D READ_ONCE_NOCHECK(*(unsigned long *)(fp)); frame->pc =3D READ_ONCE_NOCHECK(*(unsigned long *)(fp + 8)); - frame->prev_fp =3D fp; - frame->prev_type =3D info.type; - frame->pc =3D ptrauth_strip_insn_pac(frame->pc); + frame->prev_type =3D info->type; + + return 0; +} + +static int notrace unwind_frame(struct task_struct *tsk, struct stackframe= *frame) +{ + unsigned long fp =3D frame->fp; + struct stack_info info; + int err; + + if (!tsk) + tsk =3D current; + + /* Final frame; nothing to unwind */ + if (fp =3D=3D (unsigned long)task_pt_regs(tsk)->stackframe) + return -ENOENT; + + if (!on_accessible_stack(tsk, fp, 16, &info)) + return -EINVAL; + + err =3D __unwind_frame(frame, &info, NULL); + if (err) + return err; =20 #ifdef CONFIG_FUNCTION_GRAPH_TRACER if (tsk->ret_stack && @@ -143,20 +168,27 @@ static int notrace unwind_frame(struct task_struct *t= sk, } NOKPROBE_SYMBOL(unwind_frame); =20 -static void notrace walk_stackframe(struct task_struct *tsk, - struct stackframe *frame, - bool (*fn)(void *, unsigned long), void *data) +static void notrace __walk_stackframe(struct task_struct *tsk, struct stac= kframe *frame, + bool (*fn)(void *, unsigned long), void *data, + int (*unwind_frame_fn)(struct task_struct *tsk, struct stackframe *frame= )) { while (1) { int ret; =20 if (!fn(data, frame->pc)) break; - ret =3D unwind_frame(tsk, frame); + ret =3D unwind_frame_fn(tsk, frame); if (ret < 0) break; } } + +static void notrace walk_stackframe(struct task_struct *tsk, + struct stackframe *frame, + bool (*fn)(void *, unsigned long), void *data) +{ + __walk_stackframe(tsk, frame, fn, data, unwind_frame); +} NOKPROBE_SYMBOL(walk_stackframe); =20 static bool dump_backtrace_entry(void *arg, unsigned long where) @@ -210,3 +242,135 @@ noinline notrace void arch_stack_walk(stack_trace_con= sume_fn consume_entry, =20 walk_stackframe(task, &frame, consume_entry, cookie); } + +#ifdef CONFIG_NVHE_EL2_DEBUG +DECLARE_PER_CPU(unsigned long, kvm_arm_hyp_stack_page); +DECLARE_KVM_NVHE_PER_CPU(unsigned long [PAGE_SIZE/sizeof(long)], hyp_overf= low_stack); +DECLARE_KVM_NVHE_PER_CPU(struct kvm_nvhe_panic_info, kvm_panic_info); + +static inline bool kvm_nvhe_on_overflow_stack(unsigned long sp, unsigned l= ong size, + struct stack_info *info) +{ + struct kvm_nvhe_panic_info *panic_info =3D this_cpu_ptr_nvhe_sym(kvm_pani= c_info); + unsigned long low =3D (unsigned long)panic_info->hyp_overflow_stack_base; + unsigned long high =3D low + PAGE_SIZE; + + return on_stack(sp, size, low, high, STACK_TYPE_KVM_NVHE_OVERFLOW, info); +} + +static inline bool kvm_nvhe_on_hyp_stack(unsigned long sp, unsigned long s= ize, + struct stack_info *info) +{ + struct kvm_nvhe_panic_info *panic_info =3D this_cpu_ptr_nvhe_sym(kvm_pani= c_info); + unsigned long low =3D (unsigned long)panic_info->hyp_stack_base; + unsigned long high =3D low + PAGE_SIZE; + + return on_stack(sp, size, low, high, STACK_TYPE_KVM_NVHE_HYP, info); +} + +static inline bool kvm_nvhe_on_accessible_stack(unsigned long sp, unsigned= long size, + struct stack_info *info) +{ + if (info) + info->type =3D STACK_TYPE_UNKNOWN; + + if (kvm_nvhe_on_hyp_stack(sp, size, info)) + return true; + if (kvm_nvhe_on_overflow_stack(sp, size, info)) + return true; + + return false; +} + +static unsigned long kvm_nvhe_hyp_stack_kern_va(unsigned long addr) +{ + struct kvm_nvhe_panic_info *panic_info =3D this_cpu_ptr_nvhe_sym(kvm_pani= c_info); + unsigned long hyp_base, kern_base, hyp_offset; + + hyp_base =3D (unsigned long)panic_info->hyp_stack_base; + hyp_offset =3D addr - hyp_base; + + kern_base =3D (unsigned long)*this_cpu_ptr(&kvm_arm_hyp_stack_page); + + return kern_base + hyp_offset; +} + +static unsigned long kvm_nvhe_overflow_stack_kern_va(unsigned long addr) +{ + struct kvm_nvhe_panic_info *panic_info =3D this_cpu_ptr_nvhe_sym(kvm_pani= c_info); + unsigned long hyp_base, kern_base, hyp_offset; + + hyp_base =3D (unsigned long)panic_info->hyp_overflow_stack_base; + hyp_offset =3D addr - hyp_base; + + kern_base =3D (unsigned long)this_cpu_ptr_nvhe_sym(hyp_overflow_stack); + + return kern_base + hyp_offset; +} + +/* + * Convert KVM nVHE hypervisor stack VA to a kernel VA. + * + * The nVHE hypervisor stack is mapped in the flexible 'private' VA range,= to allow + * for guard pages below the stack. Consequently, the fixed offset address + * translation macros won't work here. + * + * The kernel VA is calculated as an offset from the kernel VA of the hype= rvisor + * stack base. See: kvm_nvhe_hyp_stack_kern_va(), kvm_nvhe_overflow_stack= _kern_va() + */ +static unsigned long kvm_nvhe_stack_kern_va(unsigned long addr, + enum stack_type type) +{ + switch (type) { + case STACK_TYPE_KVM_NVHE_HYP: + return kvm_nvhe_hyp_stack_kern_va(addr); + case STACK_TYPE_KVM_NVHE_OVERFLOW: + return kvm_nvhe_overflow_stack_kern_va(addr); + default: + return 0UL; + } +} + +static int notrace kvm_nvhe_unwind_frame(struct task_struct *tsk, + struct stackframe *frame) +{ + struct stack_info info; + + if (!kvm_nvhe_on_accessible_stack(frame->fp, 16, &info)) + return -EINVAL; + + return __unwind_frame(frame, &info, kvm_nvhe_stack_kern_va); +} + +static bool kvm_nvhe_dump_backtrace_entry(void *arg, unsigned long where) +{ + unsigned long va_mask =3D GENMASK_ULL(vabits_actual - 1, 0); + unsigned long hyp_offset =3D (unsigned long)arg; + + where &=3D va_mask; /* Mask tags */ + where +=3D hyp_offset; /* Convert to kern addr */ + + kvm_err("[<%016lx>] %pB\n", where, (void *)where); + + return true; +} + +static void notrace kvm_nvhe_walk_stackframe(struct task_struct *tsk, + struct stackframe *frame, + bool (*fn)(void *, unsigned long), void *data) +{ + __walk_stackframe(tsk, frame, fn, data, kvm_nvhe_unwind_frame); +} + +void kvm_nvhe_dump_backtrace(unsigned long hyp_offset) +{ + struct kvm_nvhe_panic_info *panic_info =3D this_cpu_ptr_nvhe_sym(kvm_pani= c_info); + struct stackframe frame; + + start_backtrace(&frame, panic_info->fp, panic_info->pc); + pr_err("nVHE HYP call trace:\n"); + kvm_nvhe_walk_stackframe(NULL, &frame, kvm_nvhe_dump_backtrace_entry, + (void *)hyp_offset); + pr_err("---- end of nVHE HYP call trace ----\n"); +} +#endif /* CONFIG_NVHE_EL2_DEBUG */ diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig index 8a5fbbf084df..75f2c8255ff0 100644 --- a/arch/arm64/kvm/Kconfig +++ b/arch/arm64/kvm/Kconfig @@ -51,8 +51,9 @@ config NVHE_EL2_DEBUG depends on KVM help Say Y here to enable the debug mode for the non-VHE KVM EL2 object. - Failure reports will BUG() in the hypervisor. This is intended for - local EL2 hypervisor development. + Failure reports will BUG() in the hypervisor; and panics will print + the hypervisor call stack. This is intended for local EL2 hypervisor + development. =20 If unsure, say N. =20 diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 7a23630c4a7f..66c07c04eb52 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -49,7 +49,7 @@ DEFINE_STATIC_KEY_FALSE(kvm_protected_mode_initialized); =20 DECLARE_KVM_HYP_PER_CPU(unsigned long, kvm_hyp_vector); =20 -static DEFINE_PER_CPU(unsigned long, kvm_arm_hyp_stack_page); +DEFINE_PER_CPU(unsigned long, kvm_arm_hyp_stack_page); unsigned long kvm_arm_hyp_percpu_base[NR_CPUS]; DECLARE_KVM_NVHE_PER_CPU(struct kvm_nvhe_init_params, kvm_init_params); =20 diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c index e3140abd2e2e..ff69dff33700 100644 --- a/arch/arm64/kvm/handle_exit.c +++ b/arch/arm64/kvm/handle_exit.c @@ -17,6 +17,7 @@ #include #include #include +#include #include =20 #include @@ -326,6 +327,8 @@ void __noreturn __cold nvhe_hyp_panic_handler(u64 esr, = u64 spsr, kvm_err("nVHE hyp panic at: %016llx!\n", elr_virt + hyp_offset); } =20 + kvm_nvhe_dump_backtrace(hyp_offset); + /* * Hyp has panicked and we're going to handle that by panicking the * kernel. The kernel offset will be revealed in the panic so we're diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/swi= tch.c index efc20273a352..b8ecffc47424 100644 --- a/arch/arm64/kvm/hyp/nvhe/switch.c +++ b/arch/arm64/kvm/hyp/nvhe/switch.c @@ -37,6 +37,22 @@ DEFINE_PER_CPU(unsigned long, kvm_hyp_vector); #ifdef CONFIG_NVHE_EL2_DEBUG DEFINE_PER_CPU(unsigned long [PAGE_SIZE/sizeof(long)], hyp_overflow_stack) __aligned(16); +DEFINE_PER_CPU(struct kvm_nvhe_panic_info, kvm_panic_info); + +static inline void cpu_prepare_nvhe_panic_info(void) +{ + struct kvm_nvhe_panic_info *panic_info =3D this_cpu_ptr(&kvm_panic_info); + struct kvm_nvhe_init_params *params =3D this_cpu_ptr(&kvm_init_params); + + panic_info->hyp_stack_base =3D (unsigned long)(params->stack_hyp_va - PAG= E_SIZE); + panic_info->hyp_overflow_stack_base =3D (unsigned long)this_cpu_ptr(hyp_o= verflow_stack); + panic_info->fp =3D (unsigned long)__builtin_frame_address(0); + panic_info->pc =3D _THIS_IP_; +} + #else +static inline void cpu_prepare_nvhe_panic_info(void) +{ +} #endif =20 static void __activate_traps(struct kvm_vcpu *vcpu) @@ -360,6 +376,8 @@ asmlinkage void __noreturn hyp_panic(void) struct kvm_cpu_context *host_ctxt; struct kvm_vcpu *vcpu; =20 + cpu_prepare_nvhe_panic_info(); + host_ctxt =3D &this_cpu_ptr(&kvm_host_data)->host_ctxt; vcpu =3D host_ctxt->__hyp_running_vcpu; =20 --=20 2.35.1.473.g83b2b277ed-goog From nobody Tue Jun 23 23:42:13 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E15A4C433EF for ; Thu, 24 Feb 2022 05:23:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230176AbiBXFYN (ORCPT ); Thu, 24 Feb 2022 00:24:13 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56570 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230165AbiBXFYK (ORCPT ); Thu, 24 Feb 2022 00:24:10 -0500 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A5E4B238918 for ; Wed, 23 Feb 2022 21:23:40 -0800 (PST) Received: by mail-yb1-xb49.google.com with SMTP id a12-20020a056902056c00b0061dc0f2a94aso934993ybt.6 for ; Wed, 23 Feb 2022 21:23:40 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:cc; bh=fcCfTEScaMgjegsqAtCFQCUUlnf7S421rxV5/DLFNa4=; b=K2UkLk6KH0WGprg1Tt3b/YISPTEbGJ5NwL75GWwwQRifJr+Ia78r3xJ74AmzAn6des +RpW5F9uvgZ9sJ1fT5i6np+KQN4qKRmZSJJLm2W9x5SYPYx8og6F3yLGsatCWV6FzEDf 673NAhqpRqg9eTDgS3UnApqhvX/5GRHjopLIWxweU9YOKdQpVxRnTDNuOFv5bZKbiXBW 6zpPdP2dAFKxHQAsD8SNy1C39D6al0+AgBC+DSjUXheYoiIBU/1Kmxx/wpNbXRnyHlFP d6Mi3V5tWu+SiyXcU2q1ve1zdVP5SR3nN7kl8jsFPLZhM2l3A8Uk9bYysuSZ57PN/rxz s+uA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:cc; bh=fcCfTEScaMgjegsqAtCFQCUUlnf7S421rxV5/DLFNa4=; b=b/tkrb6QKOEez39/nIf6DaE72rCvTX/0ImXGkazl0Yb7SVziE+mEAvhTJRKhRvbYul JMuVtWzf4yQXdBwnSX6tDanK8LSuO1gdR25J3lBbmtbZ/UcOgPFEfbfs7IngozU92c5m 2OKIr4J1pv8ac3Wmo+DNjTbZwu0KIG7Dz1w18xcII2yUftqj+1u8QCB7Zrbhttoerr50 zbPp4jeYgsrUlYjJGtnzUrRfCozhAZb4YrWkcz3n2vcq2dJ13qXhYvFlG99vihSY9p7m CqYcOd0mY265FE+VOsTxiQhC4EEP8qmLs4SCYqkH0F9RmQ00QDzBYgeajga4hYv16QfA Cxrg== X-Gm-Message-State: AOAM530BRpRc4CQp1R0iqpAW7yN6ZheekXJ8LLpfqpfkCFPTNzogICAp g6TNprupJIpbTG29DrKPJulIeiKRR7ncKSUMog== X-Google-Smtp-Source: ABdhPJwr5WYU+mcvUrEVYhYcHNbWEi05aKeybW8uxmEUPY7QeTHeRrUuULjEo5RNfVU+of1dj3HUHZ68vUNHlphVAQ== X-Received: from kaleshsingh.mtv.corp.google.com ([2620:15c:211:200:415c:9be0:c461:440a]) (user=kaleshsingh job=sendgmr) by 2002:a25:30d6:0:b0:624:cd97:b907 with SMTP id w205-20020a2530d6000000b00624cd97b907mr981062ybw.542.1645680219922; Wed, 23 Feb 2022 21:23:39 -0800 (PST) Date: Wed, 23 Feb 2022 21:13:43 -0800 In-Reply-To: <20220224051439.640768-1-kaleshsingh@google.com> Message-Id: <20220224051439.640768-9-kaleshsingh@google.com> Mime-Version: 1.0 References: <20220224051439.640768-1-kaleshsingh@google.com> X-Mailer: git-send-email 2.35.1.473.g83b2b277ed-goog Subject: [PATCH v3 8/8] KVM: arm64: Symbolize the nVHE HYP backtrace From: Kalesh Singh Cc: will@kernel.org, maz@kernel.org, qperret@google.com, tabba@google.com, surenb@google.com, kernel-team@android.com, Kalesh Singh , James Morse , Alexandru Elisei , Suzuki K Poulose , Catalin Marinas , Mark Rutland , Mark Brown , Masami Hiramatsu , Peter Collingbourne , "Madhavan T. Venkataraman" , Andrew Walbran , Andrew Scull , linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org To: unlisted-recipients:; (no To-header on input) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Reintroduce the __kvm_nvhe_ symbols in kallsyms, ignoring the local symbols in this namespace. The local symbols are not informative and can cause aliasing issues when symbolizing the addresses. With the necessary symbols now in kallsyms we can symbolize nVHE stacktrace addresses using the %pB print format specifier. Example call trace: [ 98.916444][ T426] kvm [426]: nVHE hyp panic at: [] _= _kvm_nvhe_overflow_stack+0x8/0x34! [ 98.918360][ T426] nVHE HYP call trace: [ 98.918692][ T426] kvm [426]: [] __kvm_nvhe_cpu_prepa= re_nvhe_panic_info+0x4c/0x68 [ 98.919545][ T426] kvm [426]: [] __kvm_nvhe_hyp_panic= +0x2c/0xe8 [ 98.920107][ T426] kvm [426]: [] __kvm_nvhe_hyp_panic= _bad_stack+0x10/0x10 [ 98.920665][ T426] kvm [426]: [] __kvm_nvhe___kvm_hyp= _host_vector+0x24c/0x794 [ 98.921292][ T426] kvm [426]: [] __kvm_nvhe_overflow_= stack+0x24/0x34 . . . [ 98.973382][ T426] kvm [426]: [] __kvm_nvhe_overflow_= stack+0x24/0x34 [ 98.973816][ T426] kvm [426]: [] __kvm_nvhe___kvm_vcp= u_run+0x38/0x438 [ 98.974255][ T426] kvm [426]: [] __kvm_nvhe_handle___= kvm_vcpu_run+0x1c4/0x364 [ 98.974719][ T426] kvm [426]: [] __kvm_nvhe_handle_tr= ap+0xa8/0x130 [ 98.975152][ T426] kvm [426]: [] __kvm_nvhe___host_ex= it+0x64/0x64 [ 98.975588][ T426] ---- end of nVHE HYP call trace ---- Signed-off-by: Kalesh Singh --- Changes in v2: - Fix printk warnings - %p expects (void *) arch/arm64/kvm/handle_exit.c | 13 +++++-------- scripts/kallsyms.c | 2 +- 2 files changed, 6 insertions(+), 9 deletions(-) diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c index ff69dff33700..3a5c32017c6b 100644 --- a/arch/arm64/kvm/handle_exit.c +++ b/arch/arm64/kvm/handle_exit.c @@ -296,13 +296,8 @@ void __noreturn __cold nvhe_hyp_panic_handler(u64 esr,= u64 spsr, u64 elr_in_kimg =3D __phys_to_kimg(elr_phys); u64 hyp_offset =3D elr_in_kimg - kaslr_offset() - elr_virt; u64 mode =3D spsr & PSR_MODE_MASK; + u64 panic_addr =3D elr_virt + hyp_offset; =20 - /* - * The nVHE hyp symbols are not included by kallsyms to avoid issues - * with aliasing. That means that the symbols cannot be printed with the - * "%pS" format specifier, so fall back to the vmlinux address if - * there's no better option. - */ if (mode !=3D PSR_MODE_EL2t && mode !=3D PSR_MODE_EL2h) { kvm_err("Invalid host exception to nVHE hyp!\n"); } else if (ESR_ELx_EC(esr) =3D=3D ESR_ELx_EC_BRK64 && @@ -322,9 +317,11 @@ void __noreturn __cold nvhe_hyp_panic_handler(u64 esr,= u64 spsr, if (file) kvm_err("nVHE hyp BUG at: %s:%u!\n", file, line); else - kvm_err("nVHE hyp BUG at: %016llx!\n", elr_virt + hyp_offset); + kvm_err("nVHE hyp BUG at: [<%016llx>] %pB!\n", panic_addr, + (void *)panic_addr); } else { - kvm_err("nVHE hyp panic at: %016llx!\n", elr_virt + hyp_offset); + kvm_err("nVHE hyp panic at: [<%016llx>] %pB!\n", panic_addr, + (void *)panic_addr); } =20 kvm_nvhe_dump_backtrace(hyp_offset); diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c index 54ad86d13784..19aba43d9da4 100644 --- a/scripts/kallsyms.c +++ b/scripts/kallsyms.c @@ -111,7 +111,7 @@ static bool is_ignored_symbol(const char *name, char ty= pe) ".LASANPC", /* s390 kasan local symbols */ "__crc_", /* modversions */ "__efistub_", /* arm64 EFI stub namespace */ - "__kvm_nvhe_", /* arm64 non-VHE KVM namespace */ + "__kvm_nvhe_$", /* arm64 local symbols in non-VHE KVM namespace */ "__AArch64ADRPThunk_", /* arm64 lld */ "__ARMV5PILongThunk_", /* arm lld */ "__ARMV7PILongThunk_", --=20 2.35.1.473.g83b2b277ed-goog