From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id BB1B52594B7 for ; Fri, 28 Feb 2025 09:56:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740736580; cv=none; b=JGEWWAjC081mlJmPHnqIjIIrSJYUcd+xb0R0QfR7J0DwABZrUJgO/O+PmgQJg5APnp18+bpcStCe5BCIhv8OWWXOzumMCbTFws2Husj4v1TTC7oeszkiGhpyo1y0QrXi5XzRgpJAFeiZRJeFZhl5Ii+zaQcIu7o/SQTSHw/1qlI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740736580; c=relaxed/simple; bh=sxEMEK/fLAyGnNxuTuhzNWuMZmb8rbboe40TJW456hU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Qh/HPlHyu0j9L2yxW1Rrg0CgAcaw+8RTZXHvtSqXOKafRsvBWpSeVwtJLNxgcAkbh3ajJuLDKTj31aHOyS4TaKUukokvLMdJwbsEc4Uf4hl0X9axF6W+IvCNZR5hipNbsdtBXaOFokzhCnzrQOeaK45nycmtzQP2UDS6ZQTUc2g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 43BE11515; Fri, 28 Feb 2025 01:56:33 -0800 (PST) Received: from localhost (e132581.arm.com [10.2.76.71]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 98CA03F6A8; Fri, 28 Feb 2025 01:56:17 -0800 (PST) Date: Fri, 28 Feb 2025 09:56:13 +0000 From: Leo Yan To: Mark Rutland Cc: linux-arm-kernel@lists.infradead.org, ahmed.genidi@arm.com, ben.horgan@arm.com, catalin.marinas@arm.com, kvmarm@lists.linux.dev, maz@kernel.org, oliver.upton@linux.dev, will@kernel.org Subject: Re: [PATCH 2/2] KVM: arm64: Initialize SCTLR_EL1 in __kvm_hyp_init_cpu() Message-ID: <20250228095613.GD2157064@e132581.arm.com> References: <20250227180526.1204723-1-mark.rutland@arm.com> <20250227180526.1204723-3-mark.rutland@arm.com> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250227180526.1204723-3-mark.rutland@arm.com> On Thu, Feb 27, 2025 at 06:05:26PM +0000, Mark Rutland wrote: > From: Ahmed Genidi > > When KVM is in protected mode, host calls to PSCI are proxied via EL2, > and cold entries from CPU_ON, CPU_SUSPEND, and SYSTEM_SUSPEND bounce > through __kvm_hyp_init_cpu() at EL2 before entering the host kernel's > entry point at EL1. While __kvm_hyp_init_cpu() initializes SPSR_EL2 for > the exception return to EL1, it does not initialize SCTLR_EL1. > > Due to this, it's possible to enter EL1 with SCTLR_EL1 in an UNKNOWN > state. In practice this has been seen to result in kernel crashes after > CPU_ON as a result of SCTLR_EL1.M being 1 in violation of the initial > core configuration specified by PSCI. > > Fix this by initializing SCTLR_EL1 for cold entry to the host kernel. > As it's necessary to write to SCTLR_EL12 in VHE mode, this > initialization is moved into __kvm_host_psci_cpu_entry() where we can > use write_sysreg_el1(). > > The remnants of the '__init_el2_nvhe_prepare_eret' macro are folded into > its only caller, as this is clearer than having the macro. > > Fixes: cdf367192766ad11 ("KVM: arm64: Intercept host's CPU_ON SMCs") > Reported-by: Leo Yan > Signed-off-by: Ahmed Genidi > [ Mark: clarify commit message, handle E2H, move to C, remove macro ] > Signed-off-by: Mark Rutland Reviewed-by: Leo Yan > Cc: Ahmed Genidi > Cc: Ben Horgan > Cc: Catalin Marinas > Cc: Leo Yan > Cc: Marc Zyngier > Cc: Oliver Upton > Cc: Will Deacon > --- > arch/arm64/include/asm/el2_setup.h | 5 ----- > arch/arm64/kernel/head.S | 3 ++- > arch/arm64/kvm/hyp/nvhe/hyp-init.S | 2 -- > arch/arm64/kvm/hyp/nvhe/psci-relay.c | 3 +++ > 4 files changed, 5 insertions(+), 8 deletions(-) > > diff --git a/arch/arm64/include/asm/el2_setup.h b/arch/arm64/include/asm/el2_setup.h > index bc8ebd55788ac..7774aec91027e 100644 > --- a/arch/arm64/include/asm/el2_setup.h > +++ b/arch/arm64/include/asm/el2_setup.h > @@ -270,11 +270,6 @@ > .Lskip_gcs_\@: > .endm > > -.macro __init_el2_nvhe_prepare_eret > - mov x0, #INIT_PSTATE_EL1 > - msr spsr_el2, x0 > -.endm > - > .macro __init_el2_mpam > /* Memory Partitioning And Monitoring: disable EL2 traps */ > mrs x1, id_aa64pfr0_el1 > diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S > index 2d56459d6c94c..2ce73525de2c9 100644 > --- a/arch/arm64/kernel/head.S > +++ b/arch/arm64/kernel/head.S > @@ -322,7 +322,8 @@ SYM_INNER_LABEL(init_el2, SYM_L_LOCAL) > msr sctlr_el1, x1 > mov x2, xzr > 3: > - __init_el2_nvhe_prepare_eret > + mov x0, #INIT_PSTATE_EL1 > + msr spsr_el2, x0 > > mov w0, #BOOT_CPU_MODE_EL2 > orr x0, x0, x2 > diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-init.S b/arch/arm64/kvm/hyp/nvhe/hyp-init.S > index 3fb5504a7d7fc..f8af11189572f 100644 > --- a/arch/arm64/kvm/hyp/nvhe/hyp-init.S > +++ b/arch/arm64/kvm/hyp/nvhe/hyp-init.S > @@ -214,8 +214,6 @@ SYM_CODE_START_LOCAL(__kvm_hyp_init_cpu) > > bl __kvm_init_el2_state > > - __init_el2_nvhe_prepare_eret > - > /* Enable MMU, set vectors and stack. */ > mov x0, x28 > bl ___kvm_hyp_init // Clobbers x0..x2 > diff --git a/arch/arm64/kvm/hyp/nvhe/psci-relay.c b/arch/arm64/kvm/hyp/nvhe/psci-relay.c > index 9c2ce1e0e99a5..c3e196fb8b18f 100644 > --- a/arch/arm64/kvm/hyp/nvhe/psci-relay.c > +++ b/arch/arm64/kvm/hyp/nvhe/psci-relay.c > @@ -218,6 +218,9 @@ asmlinkage void __noreturn __kvm_host_psci_cpu_entry(bool is_cpu_on) > if (is_cpu_on) > release_boot_args(boot_args); > > + write_sysreg_el1(INIT_SCTLR_EL1_MMU_OFF, SYS_SCTLR); > + write_sysreg(INIT_PSTATE_EL1, SPSR_EL2); > + > __host_enter(host_ctxt); > } > > -- > 2.30.2 >