From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 06CE63FD0 for ; Mon, 13 Sep 2021 16:02:52 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10105"; a="285411180" X-IronPort-AV: E=Sophos;i="5.85,290,1624345200"; d="scan'208";a="285411180" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Sep 2021 09:02:42 -0700 X-IronPort-AV: E=Sophos;i="5.85,290,1624345200"; d="scan'208";a="551736777" Received: from holdensm-mobl.amr.corp.intel.com (HELO [10.212.147.16]) ([10.212.147.16]) by fmsmga002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Sep 2021 09:02:40 -0700 Subject: Re: [PATCH v2 00/12] x86/sev: KEXEC/KDUMP support for SEV-ES guests To: Joerg Roedel , x86@kernel.org Cc: Eric Biederman , kexec@lists.infradead.org, Joerg Roedel , hpa@zytor.com, Andy Lutomirski , Dave Hansen , Peter Zijlstra , Jiri Slaby , Dan Williams , Tom Lendacky , Juergen Gross , Kees Cook , David Rientjes , Cfir Cohen , Erdem Aktas , Masami Hiramatsu , Mike Stunes , Sean Christopherson , Martin Radev , Arvind Sankar , linux-coco@lists.linux.dev, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org References: <20210913155603.28383-1-joro@8bytes.org> From: Dave Hansen Autocrypt: addr=dave.hansen@intel.com; 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Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: <20210913155603.28383-1-joro@8bytes.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit On 9/13/21 8:55 AM, Joerg Roedel wrote: > This does not work under SEV-ES, because the hypervisor has no access > to the vCPU registers and can't make modifications to them. So an > SEV-ES guest needs to reset the vCPU itself and park it using the > AP-reset-hold protocol. Upon wakeup the guest needs to jump to > real-mode and to the reset-vector configured in the AP-Jump-Table. How does this end up looking to an end user that tries to kexec() from a an SEV-ES kernel? Does it just hang?