From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id B73DE387364; Tue, 5 May 2026 11:35:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=13.77.154.182 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777980950; cv=none; b=gtxiHV3cl+ND5yeXuGEfDbdxfjFWE6XyTXxQRs937l91XVgAY9kDSLuQLE7iSyioriZY8Ao6RRwkHS+NPmD7W6KV7cwmxI/BSfztQy8ZmJKbuk1l9cIb3wejRZJNKyVECbQtnIL4iP4Gtu7yonZta+5WNO9p08cBqMiqE6cuIpQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777980950; c=relaxed/simple; bh=at19uvxNcHMfcG+vd2NFqn/Rp/ZQnuYgva4Zq0bYUg4=; h=Date:From:To:cc:Subject:In-Reply-To:Message-ID:References: MIME-Version:Content-Type; b=njdTLr//DcqIldHfpfp2dIVfC2lY0+JC7lXeJa+cEEwbGzZ08bbDUUHO8N6aETUZoofd51jejTIUx1kgpPm43Zl51O9QId5ltynhV+S+aJ1Y5XeZu8yzHxVF1rehVPBI5smxesswrrfXr1kwPyuHmSJTSphGNzCSjcLL9fLdgE8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com; spf=pass smtp.mailfrom=linux.microsoft.com; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b=OYTAspS4; arc=none smtp.client-ip=13.77.154.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="OYTAspS4" Received: by linux.microsoft.com (Postfix, from userid 1241) id 2C94820B7168; Tue, 5 May 2026 04:35:46 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 2C94820B7168 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1777980946; bh=I4klsKzTXH34c/6RkK2WQi9jxixheunHFgfWXjXIHIk=; h=Date:From:To:cc:Subject:In-Reply-To:References:From; b=OYTAspS4xGyg/MRyaMAAWFEcDxi2hRjko1QnVvfe/d7s6tdxoWlXkL9rBrBmk4XlA 64i7Cnk2/Jo+G2c/nseUdPntKzM5IUpcU7NcYaSqjbPdaK8Fh+C+c2sHp8KhlxBFsf SP0OdePFhHmpi8kDIA59gm7AmoFoxmyxQIpmD3HQ= Received: from localhost (localhost [127.0.0.1]) by linux.microsoft.com (Postfix) with ESMTP id 2A8ED30705A3; Tue, 5 May 2026 04:35:46 -0700 (PDT) Date: Tue, 5 May 2026 04:35:46 -0700 (PDT) From: Jork Loeser To: Michael Kelley cc: "linux-hyperv@vger.kernel.org" , "x86@kernel.org" , "K . Y . Srinivasan" , Haiyang Zhang , Wei Liu , Dexuan Cui , Long Li , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H . Peter Anvin" , Arnd Bergmann , Anirudh Rayabharam , "linux-kernel@vger.kernel.org" , "linux-arch@vger.kernel.org" Subject: RE: [PATCH v4 1/3] mshv: limit SynIC management to MSHV-owned resources In-Reply-To: Message-ID: <91faacb-d16-8540-4713-dad25bacf695@linux.microsoft.com> References: <20260427213855.1675044-1-jloeser@linux.microsoft.com> <20260427213855.1675044-2-jloeser@linux.microsoft.com> Precedence: bulk X-Mailing-List: linux-arch@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed On Mon, 4 May 2026, Michael Kelley wrote: > From: Jork Loeser Sent: Monday, April 27, 2026 2:39 PM >> >> While here, fix the SIEFP and SIRBP memremap() and virt_to_phys() >> calls to use HV_HYP_PAGE_SHIFT/HV_HYP_PAGE_SIZE instead of >> PAGE_SHIFT/PAGE_SIZE. The hypervisor always uses 4K pages for SynIC >> register GPAs regardless of the kernel page size, so using PAGE_SHIFT >> produces wrong addresses on ARM64 with 64K pages. > > I agree that this is a good change. But any kernel image built with > CONFIG_MSHV_ROOT set must use only 4KiB pages, as enforced > by the dependency in drivers/hv/Kconfig. The change makes the > code explicitly match the SynIC register layout, which is good, > but it doesn't actually fix a problem since root MSHV code can't > run on ARM64 with 64KiB pages. My only concern is that this > commit message should not imply that an ARM64/64KiB > configuration is possible for the root. Agree for root. For L1VH, I think it theoretically could (likely with other changes needing to happen elsewhere). Best, Jork