Message-ID: <524C6A14.40905@zytor.com>
Date: Wed, 02 Oct 2013 11:46:44 -0700
From: "H. Peter Anvin" <hpa@zytor.com>
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To: Borislav Petkov <bp@alien8.de>
CC: Dave Young <dyoung@redhat.com>, X86 ML <x86@kernel.org>,
        LKML <linux-kernel@vger.kernel.org>, Borislav Petkov <bp@suse.de>,
        Matt Fleming <matt@console-pimps.org>,
        Matthew Garrett <mjg59@srcf.ucam.org>,
        James Bottomley <James.Bottomley@HansenPartnership.com>,
        Vivek Goyal <vgoyal@redhat.com>, linux-efi@vger.kernel.org
Subject: Re: [PATCH -v2] EFI: Runtime services virtual mapping
References: <20130921113929.GB1587@pd.tnic> <20130922123515.GA7476@dhcp-16-126.nay.redhat.com> <20130922133722.GC28718@pd.tnic> <1ba7eca6-419c-4181-9927-9ba0927a6abf@email.android.com> <20130924025209.GA5561@dhcp-16-126.nay.redhat.com> <2d27a1bc-eabf-4d45-8303-27ae58511b11@email.android.com> <20131002100426.GB20568@pd.tnic> <524C3F38.6050507@zytor.com> <20131002170522.GA20647@pd.tnic> <524C58A3.4090704@zytor.com> <20131002184229.GE20568@pd.tnic>
In-Reply-To: <20131002184229.GE20568@pd.tnic>
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On 10/02/2013 11:42 AM, Borislav Petkov wrote:
> 
> Yes, so the alignment has to be such that both PA and VA are the same
> amount of 4K pages away from the next 2M boundary, to put it bluntly.
> 
> I have a couple of ideas on how to do that.
> 

It's pretty straightforward - just drop the starting address to proper
alignment after you subtract the size.

	-hpa


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