From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A0F632C83 for ; Mon, 15 Nov 2021 16:21:02 +0000 (UTC) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 09E4A21963; Mon, 15 Nov 2021 16:21:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1636993261; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=xH1er7OqSuuJ5YTdhzCxckYbwTk4iNtOoSLu5zThNBY=; b=S5RPaaB1ynsBS3DtRqe2QXTsGVjRPAB0B9fxhPlXQ1LQsrK9f7BrlX0VvTSp5u4hN+U8cz owzKFOCHRg12QkIWDcR3qGCQDfkT4u0p/GHbX5eWDc+5TVMirmzjSSqK2ENK+xciFKbxby Dh6+rnm+Bqz73Od3odCqo7W7cRqZnbU= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1636993261; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=xH1er7OqSuuJ5YTdhzCxckYbwTk4iNtOoSLu5zThNBY=; b=piTY591ks928erotECYDOBiRDTI3QXoOluqRnvqLQly4R+1GAVPZCX+fbQFPXQ1srJrWuG mNKIq//T9UhiqqBQ== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id CE0EC139EC; Mon, 15 Nov 2021 16:20:59 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id h8oXMOuIkmEbfAAAMHmgww (envelope-from ); Mon, 15 Nov 2021 16:20:59 +0000 Date: Mon, 15 Nov 2021 17:20:58 +0100 From: Joerg Roedel To: "Dr. David Alan Gilbert" Cc: Sean Christopherson , Borislav Petkov , Dave Hansen , Peter Gonda , Brijesh Singh , x86@kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-coco@lists.linux.dev, linux-mm@kvack.org, linux-crypto@vger.kernel.org, Thomas Gleixner , Ingo Molnar , Tom Lendacky , "H. Peter Anvin" , Ard Biesheuvel , Paolo Bonzini , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Andy Lutomirski , Dave Hansen , Sergio Lopez , Peter Zijlstra , Srinivas Pandruvada , David Rientjes , Dov Murik , Tobin Feldman-Fitzthum , Michael Roth , Vlastimil Babka , "Kirill A . Shutemov" , Andi Kleen , tony.luck@intel.com, marcorr@google.com, sathyanarayanan.kuppuswamy@linux.intel.com Subject: Re: [PATCH Part2 v5 00/45] Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support Message-ID: References: <20210820155918.7518-1-brijesh.singh@amd.com> <061ccd49-3b9f-d603-bafd-61a067c3f6fa@intel.com> Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Mon, Nov 15, 2021 at 03:33:03PM +0000, Dr. David Alan Gilbert wrote: > How would you debug an unexpected access by the host kernel using a > guests kdump? The host needs to log the access in some way (trace-event, pr_err) with relevant information. And with the guest-side kdump you can rule out that it was a guest bug which triggered the access. And you learn what the guest was trying to do when it triggered the access. This also helps finding the issue on the host side (if it is a host-side issue). (Guest and host owner need to work together for debugging, of course). Regards, -- Jörg Rödel jroedel@suse.de SUSE Software Solutions Germany GmbH Maxfeldstr. 5 90409 Nürnberg Germany (HRB 36809, AG Nürnberg) Geschäftsführer: Ivo Totev