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 67905149C6A; Mon, 5 Aug 2024 22:15:38 +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=1722896139; cv=none; b=BSMiJybkVXdju52biWapT2xqQeLTuX0hj4XehrbTuuGvvgpDkh/lLgyGcnTELO3YXDRYLfEt/sBIIO877dvIxwsbj4iUeQKgEfNKOhqLZHDo44H+yI/Z4QC5/LqJL6nRc3ZRYtZJbbB8Qh15sgezjGqjOanrvMQTb0rIlfIERiE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722896139; c=relaxed/simple; bh=Qd9QtJL78qy4DZtivGdD9JK7nN9GwbtazNpwHPFdXFA=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=VP2UIjvOnme68PvzPBnV2EFH4u+iP8h4d/n4TGyYHf8MbaGeVZGj+nAkiCmNSOKLVe4bFwgzd/E2xJvuFHJThLxFgn9q0uhHMcUACS40i7wLweCQvJsQLCOzra80odSG0BmztmzdhMf0Ez2k+xjx+eWNvJZVrD3SEDN3yE+wmOQ= 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=ExG996eQ; 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="ExG996eQ" Received: from romank-3650.corp.microsoft.com (unknown [131.107.159.62]) by linux.microsoft.com (Postfix) with ESMTPSA id A133720B7165; Mon, 5 Aug 2024 15:15:37 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com A133720B7165 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1722896137; bh=G3dgLn42s1ul+udyzzDEMMSWft6zAfZ2rlnkvyFt+OI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ExG996eQVxnp55uEL3uhRAoHERbEJIYfxjRemCmsgZGiUBoZxjRCPZpKL5WD9jWyQ TSCGCpbSaUQLk3irbv0+SlRckxO/veFeFezDOCoQjrlAllSgRy5KT9xycRWAvauccK ibdf2bXQpbmQCqGbWC6LteHxJDIvJ+KUW+qKSSXk= From: Roman Kisel To: mhklinux@outlook.com Cc: apais@microsoft.com, arnd@arndb.de, benhill@microsoft.com, bhelgaas@google.com, bp@alien8.de, catalin.marinas@arm.com, dave.hansen@linux.intel.com, decui@microsoft.com, haiyangz@microsoft.com, hpa@zytor.com, kw@linux.com, kys@microsoft.com, lenb@kernel.org, linux-acpi@vger.kernel.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, lpieralisi@kernel.org, mingo@redhat.com, rafael@kernel.org, robh@kernel.org, romank@linux.microsoft.com, ssengar@linux.microsoft.com, ssengar@microsoft.com, sunilmut@microsoft.com, tglx@linutronix.de, vdso@hexbites.dev, wei.liu@kernel.org, will@kernel.org, x86@kernel.org Subject: RE: [PATCH v3 2/7] Drivers: hv: Enable VTL mode for arm64 Date: Mon, 5 Aug 2024 15:15:37 -0700 Message-Id: <20240805221537.383265-1-romank@linux.microsoft.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-hyperv@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit > > > > On 8/4/2024 9:05 PM, Saurabh Singh Sengar wrote: > > > On Mon, Aug 05, 2024 at 03:01:58AM +0000, Michael Kelley wrote: > > >> From: Roman Kisel Sent: Friday, July 26, 2024 3:59 > > PM > > >>> > > >>> Kconfig dependencies for arm64 guests on Hyper-V require that be ACPI enabled, > > >>> and limit VTL mode to x86/x64. To enable VTL mode on arm64 as well, update the > > >>> dependencies. Since VTL mode requires DeviceTree instead of ACPI, don't require > > >>> arm64 guests on Hyper-V to have ACPI. > > >>> > > >>> Signed-off-by: Roman Kisel > > >>> --- > > >>> drivers/hv/Kconfig | 6 +++--- > > >>> 1 file changed, 3 insertions(+), 3 deletions(-) > > >>> > > >>> diff --git a/drivers/hv/Kconfig b/drivers/hv/Kconfig > > >>> index 862c47b191af..a5cd1365e248 100644 > > >>> --- a/drivers/hv/Kconfig > > >>> +++ b/drivers/hv/Kconfig > > >>> @@ -5,7 +5,7 @@ menu "Microsoft Hyper-V guest support" > > >>> config HYPERV > > >>> tristate "Microsoft Hyper-V client drivers" > > >>> depends on (X86 && X86_LOCAL_APIC && HYPERVISOR_GUEST) \ > > >>> - || (ACPI && ARM64 && !CPU_BIG_ENDIAN) > > >>> + || (ARM64 && !CPU_BIG_ENDIAN) > > >>> select PARAVIRT > > >>> select X86_HV_CALLBACK_VECTOR if X86 > > >>> select OF_EARLY_FLATTREE if OF > > >>> @@ -15,7 +15,7 @@ config HYPERV > > >>> > > >>> config HYPERV_VTL_MODE > > >>> bool "Enable Linux to boot in VTL context" > > >>> - depends on X86_64 && HYPERV > > >>> + depends on HYPERV > > >>> depends on SMP > > >>> default n > > >>> help > > >>> @@ -31,7 +31,7 @@ config HYPERV_VTL_MODE > > >>> > > >>> Select this option to build a Linux kernel to run at a VTL other than > > >>> the normal VTL0, which currently is only VTL2. This option > > >>> - initializes the x86 platform for VTL2, and adds the ability to boot > > >>> + initializes the kernel to run in VTL2, and adds the ability to boot > > >>> secondary CPUs directly into 64-bit context as required for VTLs other > > >>> than 0. A kernel built with this option must run at VTL2, and will > > >>> not run as a normal guest. > > >>> -- > > >>> 2.34.1 > > >>> > > >> > > >> In v2 of this patch, I suggested [1] making a couple additional minor changes > > >> so that kernels built *without* HYPER_VTL_MODE would still require > > >> ACPI. Did that suggestion not work out? If that's the case, I'm curious > > >> about what goes wrong. > > > > > > Hi Michael/Roman, > > > I was considering making HYPERV_VTL_MODE depend on CONFIG_OF. That should > > address > > > above concern as well. Do you see any potential issue with it. > > > > > Michael, > > > > I ran into a pretty gnarly recursive dependencies which in all fairness > > might stem from not being fluent enough in the Kconfig language. Any > > help of how to approach implementing your idea would be greatly appreciated! > > > > This is what I had in mind: > > --- a/drivers/hv/Kconfig > +++ b/drivers/hv/Kconfig > @@ -5,7 +5,8 @@ menu "Microsoft Hyper-V guest support" > config HYPERV > tristate "Microsoft Hyper-V client drivers" > depends on (X86 && X86_LOCAL_APIC && HYPERVISOR_GUEST) \ > - || (ACPI && ARM64 && !CPU_BIG_ENDIAN) > + || (ARM64 && !CPU_BIG_ENDIAN) > + depends on (ACPI || HYPERV_VTL_MODE) > select PARAVIRT > select X86_HV_CALLBACK_VECTOR if X86 > select OF_EARLY_FLATTREE if OF > @@ -15,7 +16,7 @@ config HYPERV > > config HYPERV_VTL_MODE > bool "Enable Linux to boot in VTL context" > - depends on X86_64 && HYPERV > + depends on X86_64 > depends on SMP > default n > help > > HYPERV_VTL_MODE can now be selected independently of HYPERV. > The existing code should be such that even if someone is building a > random config and gets HYPERV_VTL_MODE without HYPERV, the > kernel will build and run in a non-Hyper-V environment and isn't > broken somehow. > > For HYPERV to be selected, either ACPI must already be selected, or > HYPERV_VTL_MODE must already be selected. So "normal" kernels are > still enforced to require ACPI. But if building with HYPERV_VTL_MODE, > then ACPI is optional. > Thanks a ton! Let me try this out for the (arch; VTL) build matrix :) > Saurabh's idea of adding "depends on OF" to HYPERV_VTL_MODE > should also work with these changes. > > I haven't fully tested the above with all the relevant combinations > on both x86 and arm64, but I think the logic makes sense.