linux-kernel - Re: [PATCH V2 1/1] X86: Hyper-V: Get the local APIC timer frequency from the hypervisor

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: <5226FA9702000078000F0387@nat28.tlf.novell.com>
Date:	Wed, 04 Sep 2013 08:17:11 +0100
From:	"Jan Beulich" <JBeulich@...e.com>
To:	"K. Y. Srinivasan" <kys@...rosoft.com>
Cc:	<olaf@...fle.de>, <bp@...en8.de>, <apw@...onical.com>,
	<x86@...nel.org>, <tglx@...utronix.de>,
	<devel@...uxdriverproject.org>, <gregkh@...uxfoundation.org>,
	<jasowang@...hat.com>, <linux-kernel@...r.kernel.org>,
	<hpa@...or.com>
Subject: Re: [PATCH V2 1/1] X86: Hyper-V: Get the local APIC timer
 frequency from the hypervisor

>>> On 03.09.13 at 20:30, "K. Y. Srinivasan" <kys@...rosoft.com> wrote:
> @@ -76,6 +80,26 @@ static void __init ms_hyperv_init_platform(void)
>  	printk(KERN_INFO "HyperV: features 0x%x, hints 0x%x\n",
>  	       ms_hyperv.features, ms_hyperv.hints);
>  
> +	if (ms_hyperv.features & HV_X64_MSR_APIC_FREQUENCY_AVAILABLE) {
> +		/*
> +		 * Get the APIC frequency.
> +		 */
> +		rdmsrl(HV_X64_MSR_APIC_FREQUENCY, hv_lapic_frequency);
> +		hv_lapic_frequency /= HZ;
> +		lapic_timer_frequency = hv_lapic_frequency;
> +		printk(KERN_INFO "HyperV: LAPIC Timer Frequency: %#x\n",
> +				lapic_timer_frequency);
> +
> +		/*
> +		 * On Hyper-V, when we are booting off an EFI firmware stack,
> +		 * we do not have many legacy devices including PIC, PIT etc.
> +		 */
> +		if (efi_enabled(EFI_BOOT)) {
> +			printk(KERN_INFO "HyperV: Using null_legacy_pic\n");
> +			legacy_pic = &null_legacy_pic;
> +		}

And this check is really connected to the feature check around the
whole block, rather than being independent? (I'd also think that
this latter message would suffice to be KERN_DEBUG).

Jan

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/