Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752602AbdIER1G (ORCPT ); Tue, 5 Sep 2017 13:27:06 -0400 Received: from mail-wm0-f46.google.com ([74.125.82.46]:34984 "EHLO mail-wm0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752108AbdIER1D (ORCPT ); Tue, 5 Sep 2017 13:27:03 -0400 X-Google-Smtp-Source: ADKCNb4aops2Eq4i7iwgirvBaCLizSESyyX5emxEmxy1+9JdTZLN2S6a6SPOF8yFrsqEAqe8neArXXAEaMfxFVvKaDk= MIME-Version: 1.0 In-Reply-To: <1503066227-18251-5-git-send-email-gengdongjiu@huawei.com> References: <1503066227-18251-1-git-send-email-gengdongjiu@huawei.com> <1503066227-18251-5-git-send-email-gengdongjiu@huawei.com> From: Peter Maydell Date: Tue, 5 Sep 2017 18:26:41 +0100 Message-ID: Subject: Re: [PATCH v11 4/6] target-arm: kvm64: detect guest RAS EXTENSION feature To: Dongjiu Geng Cc: "Michael S. Tsirkin" , Igor Mammedov , Shannon Zhao , Paolo Bonzini , QEMU Developers , qemu-arm , kvm-devel , "edk2-devel@lists.01.org" , Christoffer Dall , Marc Zyngier , Will Deacon , James Morse , Tyler Baicar , Ard Biesheuvel , Ingo Molnar , bp@suse.de, shiju.jose@huawei.com, zjzhang@codeaurora.org, arm-mail-list , "kvmarm@lists.cs.columbia.edu" , lkml - Kernel Mailing List , linux-acpi@vger.kernel.org, devel@acpica.org, john.garry@huawei.com, jonathan.cameron@huawei.com, shameerali.kolothum.thodi@huawei.com, huangdaode@hisilicon.com, wangzhou1@hisilicon.com, Huangshaoyu , wuquanming , Linuxarm , zhengqiang10@huawei.com Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3027 Lines: 85 On 18 August 2017 at 15:23, Dongjiu Geng wrote: > check if kvm supports guest RAS EXTENSION. if so, set > corresponding feature bit for vcpu. > > Signed-off-by: Dongjiu Geng > --- > linux-headers/linux/kvm.h | 1 + > target/arm/cpu.h | 3 +++ > target/arm/kvm64.c | 8 ++++++++ > 3 files changed, 12 insertions(+) > > diff --git a/linux-headers/linux/kvm.h b/linux-headers/linux/kvm.h > index 7971a4f..2aa176e 100644 > --- a/linux-headers/linux/kvm.h > +++ b/linux-headers/linux/kvm.h > @@ -929,6 +929,7 @@ struct kvm_ppc_resize_hpt { > #define KVM_CAP_PPC_SMT_POSSIBLE 147 > #define KVM_CAP_HYPERV_SYNIC2 148 > #define KVM_CAP_HYPERV_VP_INDEX 149 > +#define KVM_CAP_ARM_RAS_EXTENSION 150 > > #ifdef KVM_CAP_IRQ_ROUTING > Hi. Changes to linux-headers need to be done as a patch of their own created using scripts/update-linux-headers.sh run against a mainline kernel tree (and with a commit message that quotes the kernel commit hash used). This ensures that we have a consistent set of headers that don't diverge from the kernel copy. > diff --git a/target/arm/cpu.h b/target/arm/cpu.h > index b39d64a..6b0961b 100644 > --- a/target/arm/cpu.h > +++ b/target/arm/cpu.h > @@ -611,6 +611,8 @@ struct ARMCPU { > > /* CPU has memory protection unit */ > bool has_mpu; > + /* CPU has ras extension unit */ > + bool has_ras_extension; > /* PMSAv7 MPU number of supported regions */ > uint32_t pmsav7_dregion; > > @@ -1229,6 +1231,7 @@ enum arm_features { > ARM_FEATURE_THUMB_DSP, /* DSP insns supported in the Thumb encodings */ > ARM_FEATURE_PMU, /* has PMU support */ > ARM_FEATURE_VBAR, /* has cp15 VBAR */ > + ARM_FEATURE_RAS_EXTENSION, /*has RAS extension support */ Missing space after '/*' ? > }; > > static inline int arm_feature(CPUARMState *env, int feature) > diff --git a/target/arm/kvm64.c b/target/arm/kvm64.c > index a16abc8..0781367 100644 > --- a/target/arm/kvm64.c > +++ b/target/arm/kvm64.c > @@ -518,6 +518,14 @@ int kvm_arch_init_vcpu(CPUState *cs) > unset_feature(&env->features, ARM_FEATURE_PMU); > } > > + if (kvm_check_extension(cs->kvm_state, KVM_CAP_ARM_RAS_EXTENSION)) { > + cpu->has_ras_extension = true; > + set_feature(&env->features, ARM_FEATURE_RAS_EXTENSION); > + } else { > + cpu->has_ras_extension = false; > + unset_feature(&env->features, ARM_FEATURE_RAS_EXTENSION); > + } > + Shouldn't we need to also tell the kernel that we actually want it to expose RAS to the guest? Compare the PMU code in this function, where we set a kvm_init_features bit to do this. (This suggests that your ABI for the kernel part of this feature may not be correct?) You should also not be calling set_feature() here -- if the CPU features bit doesn't say "this CPU should have the RAS extensions" we shouldn't create a CPU with them. Instead you should set it in kvm_arm_get_host_cpu_features() (again, compare the PMU code). thanks -- PMM