linux-kernel - Re: [PATCH v1 1/4] KVM/vmx: re-write the msr auto switch feature

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]

Message-ID: <7f9d54dd-546a-548f-5425-e4151e09fbdc@redhat.com>
Date:   Mon, 25 Sep 2017 13:54:37 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Wei Wang <wei.w.wang@...el.com>,
        virtualization@...ts.linux-foundation.org, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, mst@...hat.com, rkrcmar@...hat.com,
        ak@...ux.intel.com, mingo@...hat.com
Subject: Re: [PATCH v1 1/4] KVM/vmx: re-write the msr auto switch feature

On 25/09/2017 06:44, Wei Wang wrote:
>  
> +static void update_msr_autoload_count_max(void)
> +{
> +	u64 vmx_msr;
> +	int n;
> +
> +	/*
> +	 * According to the Intel SDM, if Bits 27:25 of MSR_IA32_VMX_MISC is
> +	 * n, then (n + 1) * 512 is the recommended max number of MSRs to be
> +	 * included in the VMExit and VMEntry MSR auto switch list.
> +	 */
> +	rdmsrl(MSR_IA32_VMX_MISC, vmx_msr);
> +	n = ((vmx_msr & 0xe000000) >> 25) + 1;
> +	msr_autoload_count_max = n * KVM_VMX_DEFAULT_MSR_AUTO_LOAD_COUNT;
> +}
> +


Any reasons to do this if it's unlikely that we'll ever update more than
512 MSRs?

Paolo