From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DE230C74A5B for ; Thu, 23 Mar 2023 16:36:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231649AbjCWQgo (ORCPT ); Thu, 23 Mar 2023 12:36:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53434 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232313AbjCWQgY (ORCPT ); Thu, 23 Mar 2023 12:36:24 -0400 Received: from mail.skyhub.de (mail.skyhub.de [IPv6:2a01:4f8:190:11c2::b:1457]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 674C436448; Thu, 23 Mar 2023 09:34:59 -0700 (PDT) Received: from zn.tnic (p5de8e687.dip0.t-ipconnect.de [93.232.230.135]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 809A61EC0666; Thu, 23 Mar 2023 17:34:55 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1679589295; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=4sg0gkB9DRPOhlMDZ3zP/dpFav3wNu5TRPV6O3JS84Q=; b=FyrzPcj0DL33qZdewBbLEPpJ1DHFdxbWP3v7Wcce+2+bLo4VhNzy7gZuttjXvFk7hZBOCS ecsQYvzGAW+GdThqAEiKjSgEyu7kLtpNulEsxpV4BP5pH+8qhkKW+Wkp7UdWzULXSTsFwb Y4qa5WnyTodkPt4/nRMIX5Ka24ZQZJI= Date: Thu, 23 Mar 2023 17:34:50 +0100 From: Borislav Petkov To: Jeremi Piotrowski Cc: linux-kernel@vger.kernel.org, Brijesh Singh , Tom Lendacky , "Kalra, Ashish" , linux-crypto@vger.kernel.org, "Rafael J. Wysocki" , Len Brown , linux-acpi@vger.kernel.org, Thomas Gleixner , Ingo Molnar , Dave Hansen , x86@kernel.org Subject: Re: [PATCH v3 0/8] Support ACPI PSP on Hyper-V Message-ID: <20230323163450.GGZBx/qpnclFnMaf7e@fat_crate.local> References: <20230320191956.1354602-1-jpiotrowski@linux.microsoft.com> <20230322154655.GDZBsi75f6LnQStxSp@fat_crate.local> <1d25221c-eaab-0f97-83aa-8b4fbe3a53ed@linux.microsoft.com> <20230322181541.GEZBtFzRAMcH9BAzUe@fat_crate.local> <20230323152342.GFZBxu/m3u6aFUDY/7@fat_crate.local> <105d019c-2249-5dfd-e032-95944ea6dc8c@linux.microsoft.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <105d019c-2249-5dfd-e032-95944ea6dc8c@linux.microsoft.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 23, 2023 at 05:11:26PM +0100, Jeremi Piotrowski wrote: > That same interface is exposed by physical hardware+firmware to the underlying > Hyper-V. Let me see if I understand it correctly: Hyper-V *baremetal* is using the same ASPT spec to to talk to the *physical* PSP device? Is that ASPT interface to talk to the PSP used by the L0 hypervisor? Or does the L0 HV have a normal driver, similar to the Linux one, without the functionality this ASPT spec provides? > So it wasn't a matter of Microsoft architects coming up with a > guest-host interface but rather exposing the virtual hardware in the same > way as on a physical server. So if you want to expose the same interface to the L1 guest, why isn't Hyper-V emulating an ACPI device just like any other functionality? Why does it need to reach into the interrupt handling internals? I'd expect that the L0 HV would emulate a PSP device, the L1 would simply load the Linux PSP device driver and everything should just work. What's the point of that alternate access at all? But I might still be missing something... -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette