From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8F674C43381 for ; Mon, 11 Mar 2019 19:56:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 60DE3214AF for ; Mon, 11 Mar 2019 19:56:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1552334166; bh=JH6fIgRyDCa3XCU7IDhlqsOf6U0MIvsnBFMn8CYfdYQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=G2634PpAIyAYPVZweRoFnVZQjVoyqBnrfk5a+wU/3yMzEPh0jDHtUwl8sD5zxpCa4 6L4arltBJWfhLcBYFMx8PIO06d/g7DXsGrEnTKVF/ic/WwFhLywzM/pySa2Xny42ZX qptOVYqyLRXZ8n4I9Hty4/27qgMlVtZptbi10UNI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728486AbfCKT4E (ORCPT ); Mon, 11 Mar 2019 15:56:04 -0400 Received: from mail.kernel.org ([198.145.29.99]:33266 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728419AbfCKT4C (ORCPT ); Mon, 11 Mar 2019 15:56:02 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5F28F2173C; Mon, 11 Mar 2019 19:56:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1552334161; bh=JH6fIgRyDCa3XCU7IDhlqsOf6U0MIvsnBFMn8CYfdYQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wow0O9pVbCbdOT/oVgayPaRdmY1+PD7Nq5j9/EzQuNXgHtst0F0glt58GlLDCOKoS ImzpoEKMCHVogCsbdZTjR00VNFv17PSCGzNCDj7uD3N7APCOeNTDPvEkxPTQGj6rBc QzJmFk4+rMAeEwtvVrOPDCrFOJ41BIgERTtkVSUQ= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: James Morse , Marc Zyngier , Sasha Levin , kvmarm@lists.cs.columbia.edu Subject: [PATCH AUTOSEL 4.20 22/52] KVM: arm64: Forbid kprobing of the VHE world-switch code Date: Mon, 11 Mar 2019 15:54:46 -0400 Message-Id: <20190311195516.137772-22-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190311195516.137772-1-sashal@kernel.org> References: <20190311195516.137772-1-sashal@kernel.org> MIME-Version: 1.0 X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: James Morse [ Upstream commit 7d82602909ed9c73b34ad26f05d10db4850a4f8c ] On systems with VHE the kernel and KVM's world-switch code run at the same exception level. Code that is only used on a VHE system does not need to be annotated as __hyp_text as it can reside anywhere in the kernel text. __hyp_text was also used to prevent kprobes from patching breakpoint instructions into this region, as this code runs at a different exception level. While this is no longer true with VHE, KVM still switches VBAR_EL1, meaning a kprobe's breakpoint executed in the world-switch code will cause a hyp-panic. echo "p:weasel sysreg_save_guest_state_vhe" > /sys/kernel/debug/tracing/kprobe_events echo 1 > /sys/kernel/debug/tracing/events/kprobes/weasel/enable lkvm run -k /boot/Image --console serial -p "console=ttyS0 earlycon=uart,mmio,0x3f8" # lkvm run -k /boot/Image -m 384 -c 3 --name guest-1474 Info: Placing fdt at 0x8fe00000 - 0x8fffffff Info: virtio-mmio.devices=0x200@0x10000:36 Info: virtio-mmio.devices=0x200@0x10200:37 Info: virtio-mmio.devices=0x200@0x10400:38 [ 614.178186] Kernel panic - not syncing: HYP panic: [ 614.178186] PS:404003c9 PC:ffff0000100d70e0 ESR:f2000004 [ 614.178186] FAR:0000000080080000 HPFAR:0000000000800800 PAR:1d00007edbadc0de [ 614.178186] VCPU:00000000f8de32f1 [ 614.178383] CPU: 2 PID: 1482 Comm: kvm-vcpu-0 Not tainted 5.0.0-rc2 #10799 [ 614.178446] Call trace: [ 614.178480] dump_backtrace+0x0/0x148 [ 614.178567] show_stack+0x24/0x30 [ 614.178658] dump_stack+0x90/0xb4 [ 614.178710] panic+0x13c/0x2d8 [ 614.178793] hyp_panic+0xac/0xd8 [ 614.178880] kvm_vcpu_run_vhe+0x9c/0xe0 [ 614.178958] kvm_arch_vcpu_ioctl_run+0x454/0x798 [ 614.179038] kvm_vcpu_ioctl+0x360/0x898 [ 614.179087] do_vfs_ioctl+0xc4/0x858 [ 614.179174] ksys_ioctl+0x84/0xb8 [ 614.179261] __arm64_sys_ioctl+0x28/0x38 [ 614.179348] el0_svc_common+0x94/0x108 [ 614.179401] el0_svc_handler+0x38/0x78 [ 614.179487] el0_svc+0x8/0xc [ 614.179558] SMP: stopping secondary CPUs [ 614.179661] Kernel Offset: disabled [ 614.179695] CPU features: 0x003,2a80aa38 [ 614.179758] Memory Limit: none [ 614.179858] ---[ end Kernel panic - not syncing: HYP panic: [ 614.179858] PS:404003c9 PC:ffff0000100d70e0 ESR:f2000004 [ 614.179858] FAR:0000000080080000 HPFAR:0000000000800800 PAR:1d00007edbadc0de [ 614.179858] VCPU:00000000f8de32f1 ]--- Annotate the VHE world-switch functions that aren't marked __hyp_text using NOKPROBE_SYMBOL(). Signed-off-by: James Morse Fixes: 3f5c90b890ac ("KVM: arm64: Introduce VHE-specific kvm_vcpu_run") Acked-by: Masami Hiramatsu Signed-off-by: Marc Zyngier Signed-off-by: Sasha Levin --- arch/arm64/kvm/hyp/switch.c | 5 +++++ arch/arm64/kvm/hyp/sysreg-sr.c | 5 +++++ 2 files changed, 10 insertions(+) diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c index f6e02cc4d856..c9f4b25f67d9 100644 --- a/arch/arm64/kvm/hyp/switch.c +++ b/arch/arm64/kvm/hyp/switch.c @@ -23,6 +23,7 @@ #include #include +#include #include #include #include @@ -107,6 +108,7 @@ static void activate_traps_vhe(struct kvm_vcpu *vcpu) write_sysreg(kvm_get_hyp_vector(), vbar_el1); } +NOKPROBE_SYMBOL(activate_traps_vhe); static void __hyp_text __activate_traps_nvhe(struct kvm_vcpu *vcpu) { @@ -146,6 +148,7 @@ static void deactivate_traps_vhe(void) write_sysreg(CPACR_EL1_DEFAULT, cpacr_el1); write_sysreg(vectors, vbar_el1); } +NOKPROBE_SYMBOL(deactivate_traps_vhe); static void __hyp_text __deactivate_traps_nvhe(void) { @@ -529,6 +532,7 @@ int kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu) return exit_code; } +NOKPROBE_SYMBOL(kvm_vcpu_run_vhe); /* Switch to the guest for legacy non-VHE systems */ int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu) @@ -636,6 +640,7 @@ static void __hyp_call_panic_vhe(u64 spsr, u64 elr, u64 par, read_sysreg_el2(esr), read_sysreg_el2(far), read_sysreg(hpfar_el2), par, vcpu); } +NOKPROBE_SYMBOL(__hyp_call_panic_vhe); void __hyp_text __noreturn hyp_panic(struct kvm_cpu_context *host_ctxt) { diff --git a/arch/arm64/kvm/hyp/sysreg-sr.c b/arch/arm64/kvm/hyp/sysreg-sr.c index 68d6f7c3b237..b426e2cf973c 100644 --- a/arch/arm64/kvm/hyp/sysreg-sr.c +++ b/arch/arm64/kvm/hyp/sysreg-sr.c @@ -18,6 +18,7 @@ #include #include +#include #include #include #include @@ -98,12 +99,14 @@ void sysreg_save_host_state_vhe(struct kvm_cpu_context *ctxt) { __sysreg_save_common_state(ctxt); } +NOKPROBE_SYMBOL(sysreg_save_host_state_vhe); void sysreg_save_guest_state_vhe(struct kvm_cpu_context *ctxt) { __sysreg_save_common_state(ctxt); __sysreg_save_el2_return_state(ctxt); } +NOKPROBE_SYMBOL(sysreg_save_guest_state_vhe); static void __hyp_text __sysreg_restore_common_state(struct kvm_cpu_context *ctxt) { @@ -188,12 +191,14 @@ void sysreg_restore_host_state_vhe(struct kvm_cpu_context *ctxt) { __sysreg_restore_common_state(ctxt); } +NOKPROBE_SYMBOL(sysreg_restore_host_state_vhe); void sysreg_restore_guest_state_vhe(struct kvm_cpu_context *ctxt) { __sysreg_restore_common_state(ctxt); __sysreg_restore_el2_return_state(ctxt); } +NOKPROBE_SYMBOL(sysreg_restore_guest_state_vhe); void __hyp_text __sysreg32_save_state(struct kvm_vcpu *vcpu) { -- 2.19.1