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From: Wei Liu <wei.liu@kernel.org>
To: Michael Kelley <mhklinux@outlook.com>
Cc: "wei.liu@kernel.org" <wei.liu@kernel.org>,
	"haiyangz@microsoft.com" <haiyangz@microsoft.com>,
	"decui@microsoft.com" <decui@microsoft.com>,
	"tglx@linutronix.de" <tglx@linutronix.de>,
	"mingo@redhat.com" <mingo@redhat.com>,
	"bp@alien8.de" <bp@alien8.de>,
	"dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>,
	"hpa@zytor.com" <hpa@zytor.com>, "arnd@arndb.de" <arnd@arndb.de>,
	"tytso@mit.edu" <tytso@mit.edu>,
	"Jason@zx2c4.com" <Jason@zx2c4.com>,
	"x86@kernel.org" <x86@kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
	"linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
	Saurabh Singh Sengar <ssengar@microsoft.com>,
	Long Li <longli@microsoft.com>
Subject: Re: [PATCH 1/1] x86/hyperv: Use Hyper-V entropy to seed guest random number generator
Date: Fri, 8 Mar 2024 23:53:02 +0000	[thread overview]
Message-ID: <Zeuk3ixlvMFg1CDo@liuwe-devbox-debian-v2> (raw)
In-Reply-To: <SN6PR02MB4157B61CA09C0DAF0BB994E1D4212@SN6PR02MB4157.namprd02.prod.outlook.com>

On Wed, Mar 06, 2024 at 05:43:41PM +0000, Michael Kelley wrote:
> From: wei.liu@kernel.org @ 2024-03-04  6:57 UTC
> > 
> > > +void __init ms_hyperv_late_init(void)
> > > +{
> > > +	struct acpi_table_header *header;
> > > +	acpi_status status;
> > > +	u8 *randomdata;
> > > +	u32 length, i;
> > > +
> > > +	/*
> > > +	 * Seed the Linux random number generator with entropy provided by
> > > +	 * the Hyper-V host in ACPI table OEM0.  It would be nice to do this
> > > +	 * even earlier in ms_hyperv_init_platform(), but the ACPI subsystem
> > > +	 * isn't set up at that point. Skip if booted via EFI as generic EFI
> > > +	 * code has already done some seeding using the EFI RNG protocol.
> > > +	 */
> > > +	if (!IS_ENABLED(CONFIG_ACPI) || efi_enabled(EFI_BOOT))
> > > +		return;
> > > +
> > > +	status = acpi_get_table("OEM0", 0, &header);
> > > +	if (ACPI_FAILURE(status) || !header) {
> > > +		pr_info("Hyper-V: ACPI table OEM0 not found\n");
> > 
> > I would like this to be a pr_debug() instead of pr_info(), considering
> > using the negative case may cause users to think not having this table
> > can be problematic.
> > 
> > Alternatively, we can remove this message here, and then ...
> > 
> > > +		return;
> > > +	}
> > > +
> > 
> > ... add a pr_debug() here to indicate that the table was found.
> > 
> > 	pr_info("Hyper-V: Seeding randomness with data from ACPI table OEM0\n");
> 
> You wrote the code as "pr_info()" but your comment suggests "pr_debug()".
> I'm assuming pr_debug() is better because we don't really need any output

Yes, I meant to use pr_debug() here. Sorry for the confusion. The
pr_info() was a c&p error.

Thanks,
Wei.

      reply	other threads:[~2024-03-08 23:53 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-01-22 16:00 [PATCH 1/1] x86/hyperv: Use Hyper-V entropy to seed guest random number generator mhkelley58
2024-03-04  6:57 ` Wei Liu
2024-03-06 17:43 ` Michael Kelley
2024-03-08 23:53   ` Wei Liu [this message]

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