From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Morse Subject: Re: [PATCH] arm64: vgic-v2: Fix proxying of cpuif access Date: Fri, 4 May 2018 16:19:16 +0100 Message-ID: References: <20180427145102.5645-1-marc.zyngier@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org To: Marc Zyngier Return-path: In-Reply-To: <20180427145102.5645-1-marc.zyngier@arm.com> Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu List-Id: kvm.vger.kernel.org Hi Marc, On 27/04/18 15:51, Marc Zyngier wrote: > Proxying the cpuif accesses at EL2 makes use of vcpu_data_guest_to_host > and co, which check the endianness, which call into vcpu_read_sys_reg... > which isn't mapped at EL2 (it was inlined before, and got moved OoL > with the VHE optimizations). > > The result is of course a nice panic. Let's add some specialized > cruft to keep the broken platforms that require this hack alive. > I'd rather kill BE support, but hey, just in case... I have this a spin on Juno with a big-endian host and 64K pages: Trying to boot a BE guest hangs. Trying to boot a LE guest hangs. > @@ -64,14 +88,11 @@ int __hyp_text __vgic_v2_perform_cpuif_access(struct kvm_vcpu *vcpu) > addr += fault_ipa - vgic->vgic_cpu_base; > > if (kvm_vcpu_dabt_iswrite(vcpu)) { > - u32 data = vcpu_data_guest_to_host(vcpu, > - vcpu_get_reg(vcpu, rd), > - sizeof(u32)); > + u32 data = __guest_to_host_u32(vcpu, vcpu_get_reg(vcpu, rd)); > writel_relaxed(data, addr); > } else { > - u32 data = readl_relaxed(addr); > - vcpu_set_reg(vcpu, rd, vcpu_data_host_to_guest(vcpu, data, > - sizeof(u32))); > + u32 data = __host_to_guest_u32(vcpu, readl_relaxed(addr)); > + vcpu_set_reg(vcpu, rd, data); > } This happens because readl()/writel() are doing their own swabbing on big-endian, even if the guest had already done this. As I've trampled all over this patch, I'll post a v2... Thanks, James