From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ed1-f73.google.com (mail-ed1-f73.google.com [209.85.208.73]) (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 8B129364A4 for ; Mon, 10 Jun 2024 06:33:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.73 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718001203; cv=none; b=R+wlucsRO7oOAsvFlSQQXZ1aK96+a0cuM6JGMuWF352UvMBd5crAYlferV1fgI7SrodJyqWNenrSdV1bGcTS8hQf7CAH4U4XXRkTwpnR9mazu019OvqYJ+B7I4MUmA56EzvkjpAmoGh/WaWP7iXPV/hYv5JXCVPExRdaAwMVcUg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718001203; c=relaxed/simple; bh=qfv6I1jjnDAU1Imno9iVu5bVjsuWAXtM6J7EWpc+Pus=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=HB0hYTehiEBg3FBfa7AKWE/XJqkCVrteuDYlPH7a+BGSoYcBExKY01rih1+pPDruKXlVN7iCi+CYk6zpgGiMyZvKMmVEge2HsjlxtI2XDfBCzyC3i1Zmo8tvRyibJFwv0B1IpFL0sAoqiYYaOvSMtDXQXxbxCJaPCsQyxESdqNM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--ptosi.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=bFlk5eBH; arc=none smtp.client-ip=209.85.208.73 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--ptosi.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="bFlk5eBH" Received: by mail-ed1-f73.google.com with SMTP id 4fb4d7f45d1cf-57c748dd112so677875a12.0 for ; Sun, 09 Jun 2024 23:33:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1718001200; x=1718606000; darn=lists.linux.dev; h=content-transfer-encoding:cc:to:from:subject:message-id:references :mime-version:in-reply-to:date:from:to:cc:subject:date:message-id :reply-to; bh=/3Fqo6uZ6WACSXr1SiKgfaQUsW+tD2BveY2g61YybgU=; b=bFlk5eBHM53eik4xMc4jzgxTZIrmo6x3ChjQOApdVICdHiGtz8Tk0moHoYHa+BZHOV D1BuwJmBqj73w1Z1f44jvlmNG15xr+zGaJNzGmA+KgbP/PctuEfV6Sb3IVQ2LZOHNE3i gYlpM7g8VGgYTNIytlYLaYDguCwXzhKE6v1DkQG/RnQ1S/GMU266BzidNCWTESpayRxj UBAjxIIMwtFj2jzb1EMqhg/rb1+PeMNjctv2M1Tm/gHy3Y+hPUZfL9JtTBOG3NPRCh4Y n+EyoUDxaYiI9uzGVTU6Niky83NtDepFGLYG75yALlxOv7f87y/4/OHzaIDfuF1jze3s 0LwA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1718001200; x=1718606000; h=content-transfer-encoding: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=/3Fqo6uZ6WACSXr1SiKgfaQUsW+tD2BveY2g61YybgU=; b=gvvtTWBb/5ld2tGK7yZ4f0Bp0HxADZwAR1U656CYEIwaMd2CB4nFiBaQNXipEBBIxX pWYXfIjWh9NjuUm9mYByXGR37eOcCOllQ5577djSIT6CSS8u55WorCSLO2q+Ni7DfANf zNTdR6ihlGF7Vfr/UDTINF3EBNG87S4nTAtvikmYNv5RP555Bje5Wn6tJZEH0W0dTXqT 8gEm/1lQzW9eNrkQOdiG7J2Kp6GtUUoQ83KXV1+5LrxX0rwR3l6DP4k4XVetCDA5jnks ZdTNGMpY6sM+02nwvH0TrTZ0/zvwdIDFQ79565/LToyzigkgW9uXCqeVs22ayXQLqcv6 7o2g== X-Gm-Message-State: AOJu0Ywhbgt/Nx1g3ayD5CkVLeFl/uSMTCAWePLggf19Q5SmNLljqWsD wjh25+yIwEzw+icPIaGaIEno2qH5c6R5Mv+B5lj7iur52y2/LaKLzyIzA4eNe3CGCIu5l/qxzuZ MPgYpWRrHWpcna1NVbLexU98ioGZQG6eU8yDvnA+2BBT0qgHGL8X5cZYUqzubatPjXbnMH4aeVr 20/xCie3jQxtSGxxu/2afYjfMtcfs= X-Google-Smtp-Source: AGHT+IGl14UbfzJFzP5FVcOdHdoo6VR8VgccIp2YuEQvM8uJdIjgJCFM5cwo5OdJoioDTQ1NLN2OfjF80w== X-Received: from ptosi.c.googlers.com ([fda3:e722:ac3:cc00:31:98fb:c0a8:11ec]) (user=ptosi job=sendgmr) by 2002:a05:6402:381b:b0:57c:803e:3a57 with SMTP id 4fb4d7f45d1cf-57c803e3c99mr3092a12.2.1718001200147; Sun, 09 Jun 2024 23:33:20 -0700 (PDT) Date: Mon, 10 Jun 2024 07:32:37 +0100 In-Reply-To: <20240610063244.2828978-1-ptosi@google.com> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240610063244.2828978-1-ptosi@google.com> X-Mailer: git-send-email 2.45.2.505.gda0bf45e8d-goog Message-ID: <20240610063244.2828978-9-ptosi@google.com> Subject: [PATCH v5 8/8] KVM: arm64: nVHE: Support CONFIG_CFI_CLANG at EL2 From: "=?UTF-8?q?Pierre-Cl=C3=A9ment=20Tosi?=" To: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org Cc: "=?UTF-8?q?Pierre-Cl=C3=A9ment=20Tosi?=" , Will Deacon , Marc Zyngier , Oliver Upton , Suzuki K Poulose , Vincent Donnefort Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable The compiler implements kCFI by adding type information (u32) above every function that might be indirectly called and, whenever a function pointer is called, injects a read-and-compare of that u32 against the value corresponding to the expected type. In case of a mismatch, a BRK instruction gets executed. When the hypervisor triggers such an exception in nVHE, it panics and triggers and exception return to EL1. Therefore, teach nvhe_hyp_panic_handler() to detect kCFI errors from the ESR and report them. If necessary, remind the user that EL2 kCFI is not affected by CONFIG_CFI_PERMISSIVE. Pass $(CC_FLAGS_CFI) to the compiler when building the nVHE hyp code. Use SYM_TYPED_FUNC_START() for __pkvm_init_switch_pgd, as nVHE can't call it directly and must use a PA function pointer from C (because it is part of the idmap page), which would trigger a kCFI failure if the type ID wasn't present. Signed-off-by: Pierre-Cl=C3=A9ment Tosi Acked-by: Will Deacon --- arch/arm64/kvm/handle_exit.c | 10 ++++++++++ arch/arm64/kvm/hyp/nvhe/Makefile | 6 +++--- arch/arm64/kvm/hyp/nvhe/hyp-init.S | 6 +++++- 3 files changed, 18 insertions(+), 4 deletions(-) diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c index b3d6657a259d..69b08ac7322d 100644 --- a/arch/arm64/kvm/handle_exit.c +++ b/arch/arm64/kvm/handle_exit.c @@ -417,6 +417,14 @@ static void print_nvhe_hyp_panic(const char *name, u64= panic_addr) (void *)(panic_addr + kaslr_offset())); } =20 +static void kvm_nvhe_report_cfi_failure(u64 panic_addr) +{ + print_nvhe_hyp_panic("CFI failure", panic_addr); + + if (IS_ENABLED(CONFIG_CFI_PERMISSIVE)) + kvm_err(" (CONFIG_CFI_PERMISSIVE ignored for hyp failures)\n"); +} + void __noreturn __cold nvhe_hyp_panic_handler(u64 esr, u64 spsr, u64 elr_virt, u64 elr_phys, u64 par, uintptr_t vcpu, @@ -446,6 +454,8 @@ void __noreturn __cold nvhe_hyp_panic_handler(u64 esr, = u64 spsr, kvm_err("nVHE hyp BUG at: %s:%u!\n", file, line); else print_nvhe_hyp_panic("BUG", panic_addr); + } else if (IS_ENABLED(CONFIG_CFI_CLANG) && esr_is_cfi_brk(esr)) { + kvm_nvhe_report_cfi_failure(panic_addr); } else { print_nvhe_hyp_panic("panic", panic_addr); } diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Mak= efile index 50fa0ffb6b7e..782b34b004be 100644 --- a/arch/arm64/kvm/hyp/nvhe/Makefile +++ b/arch/arm64/kvm/hyp/nvhe/Makefile @@ -89,9 +89,9 @@ quiet_cmd_hyprel =3D HYPREL $@ quiet_cmd_hypcopy =3D HYPCOPY $@ cmd_hypcopy =3D $(OBJCOPY) --prefix-symbols=3D__kvm_nvhe_ $< $@ =20 -# Remove ftrace, Shadow Call Stack, and CFI CFLAGS. -# This is equivalent to the 'notrace', '__noscs', and '__nocfi' annotation= s. -KBUILD_CFLAGS :=3D $(filter-out $(CC_FLAGS_FTRACE) $(CC_FLAGS_SCS) $(CC_FL= AGS_CFI), $(KBUILD_CFLAGS)) +# Remove ftrace and Shadow Call Stack CFLAGS. +# This is equivalent to the 'notrace' and '__noscs' annotations. +KBUILD_CFLAGS :=3D $(filter-out $(CC_FLAGS_FTRACE) $(CC_FLAGS_SCS), $(KBUI= LD_CFLAGS)) # Starting from 13.0.0 llvm emits SHT_REL section '.llvm.call-graph-profil= e' # when profile optimization is applied. gen-hyprel does not support SHT_RE= L and # causes a build failure. Remove profile optimization flags. diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-init.S b/arch/arm64/kvm/hyp/nvhe/h= yp-init.S index 3a2836a52e85..07120b37da35 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-init.S +++ b/arch/arm64/kvm/hyp/nvhe/hyp-init.S @@ -5,6 +5,7 @@ */ =20 #include +#include #include =20 #include @@ -268,8 +269,11 @@ SYM_CODE_END(__kvm_handle_stub_hvc) /* * void __pkvm_init_switch_pgd(phys_addr_t pgd, unsigned long sp, * void (*fn)(void)); + * + * SYM_TYPED_FUNC_START() allows C to call this ID-mapped function indirec= tly + * using a physical pointer without triggering a kCFI failure. */ -SYM_FUNC_START(__pkvm_init_switch_pgd) +SYM_TYPED_FUNC_START(__pkvm_init_switch_pgd) /* Turn the MMU off */ pre_disable_mmu_workaround mrs x3, sctlr_el2 --=20 2.45.2.505.gda0bf45e8d-goog