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 66EB619993B; Fri, 17 Jan 2025 21:07:09 +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=1737148030; cv=none; b=hRRyqc/RdYFiL2wSPy4kofAcIzWRujoMcUHGXKimBnJdggFrI2+XNEw6nAQLKb1STWuki3zKnqm4V8WVCAT8NDvbv7Cosd/J8g00McK7216mFQ/6JYqxZdPgTWIaPeY1822gaJuD0/cS5iGJctND38NCiNdYiBtZvVjYESbbcPs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737148030; c=relaxed/simple; bh=xrvNzagBDqrQ9BUdnh4LrSE95mjUaFh9DDBy3prWIKo=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=m1AH/D15r5SqPalqEdTHdO0l+ookF7J3IIUOvc6ApZ0erIiN2UNaEfukiCd6RpBnxPXzH+AQqS38mDr/0kbNWWFC5ihHtbH17sRVJjrDEIFOWs8r/SXM7adTx2IIZXuc7PKMQs2WjSLeqxU8nj2rdlRGg44rSBM6fzHoRkTZ3Jo= 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=gzOXF5oA; 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="gzOXF5oA" Received: from romank-3650.corp.microsoft.com (unknown [131.107.160.188]) by linux.microsoft.com (Postfix) with ESMTPSA id 9589120591BB; Fri, 17 Jan 2025 13:07:03 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 9589120591BB DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1737148023; bh=/Uzvh8YJhJBStfh25f7oVgVnZZ+0NfuKAjLsMf09uMQ=; h=From:To:Cc:Subject:Date:From; b=gzOXF5oAdb1OatFZ1zfPMofqHO5XWPtbAymkWBh+FyLm9C8W4HlOFmvpHbhBqAEAc VNCU+x4dEPbt8jFJKP7j13Z2p/J6Ad9HA+0klxOWAbttZwgYcHR/6npNuWGrZMNZjT 59LlZuXJwYiRPscKGn1wNdaUhKuLUNFITDvLzvGw= From: Roman Kisel To: bp@alien8.de, dave.hansen@linux.intel.com, decui@microsoft.com, haiyangz@microsoft.com, hpa@zytor.com, kys@microsoft.com, mingo@redhat.com, ssengar@linux.microsoft.com, tglx@linutronix.de, wei.liu@kernel.org, linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, x86@kernel.org Cc: apais@microsoft.com, benhill@microsoft.com, sunilmut@microsoft.com, vdso@hexbites.dev Subject: [PATCH hyperv-next 0/2] x86/hyperv: VTL mode reboot fixes Date: Fri, 17 Jan 2025 13:07:00 -0800 Message-Id: <20250117210702.1529580-1-romank@linux.microsoft.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-hyperv@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The first patch defines a specialized machine emergency restart callback not to write to the physical address of 0x472 which is what the native_machine_emergency_restart() does unconditionally. I first wanted to tweak that function[1], and in the course of the discussion it looked as the risks of doing that would outweigh the benefit: the bare-metal systems have likely adopted that behavior as a standard although I could not find any mentions of that magic address in the UEFI+ACPI specification. The second patch removes the need to always supply "reboot=t" to the kernel command line in the OpenHCL bootloader [2]. There is no other option at the moment; when/if it appears the newly added callback's code can be adjusted as required. It would be great to apply this to the stable tree if no concerns, should apply cleanly. [1] https://lore.kernel.org/all/20250109204352.1720337-1-romank@linux.microsoft.com/ [2] https://github.com/microsoft/openvmm/blob/7a9d0e0a00461be6e5f3267af9ea54cc7157c900/openhcl/openhcl_boot/src/main.rs#L139 Roman Kisel (2): x86/hyperv: VTL mode emergency restart callback x86/hyperv: VTL mode callback for restarting the system arch/x86/hyperv/hv_vtl.c | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) base-commit: 2e03358be78b65d28b66e17aca9e0c8700b0df78 -- 2.34.1