linux-kernel - Re: [PATCH v2 05/15] KVM: vmx/pmu: Emulate MSR_ARCH_LBR

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Thu, 22 Dec 2022 19:15:33 +0800
From:   Like Xu <like.xu.linux@...il.com>
To:     Yang Weijiang <weijiang.yang@...el.com>
Cc:     kan.liang@...ux.intel.com, wei.w.wang@...el.com, seanjc@...gle.com,
        pbonzini@...hat.com, jmattson@...gle.com, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 05/15] KVM: vmx/pmu: Emulate MSR_ARCH_LBR_DEPTH for
 guest Arch LBR

On 25/11/2022 12:05 pm, Yang Weijiang wrote:
> +static bool cpuid_enable_lbr(struct kvm_vcpu *vcpu)
> +{
> +	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
> +	struct kvm_cpuid_entry2 *entry;
> +	int depth_bit;
> +
> +	if (!kvm_cpu_cap_has(X86_FEATURE_ARCH_LBR))
> +		return !static_cpu_has(X86_FEATURE_ARCH_LBR) &&
> +			cpuid_model_is_consistent(vcpu);

Please add selftests to cover this incompatibility.

And running the SPR vcpu model on a GNR host, the guest arch lbr
should be fully supported as long as both hosts have the same lbr_depth.