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[82.30.61.225]) by smtp.gmail.com with ESMTPSA id c79sm14527579wme.43.2021.11.15.08.32.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 15 Nov 2021 08:32:41 -0800 (PST) Date: Mon, 15 Nov 2021 16:32:38 +0000 From: "Dr. David Alan Gilbert" To: Joerg Roedel 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> MIME-Version: 1.0 In-Reply-To: User-Agent: Mutt/2.0.7 (2021-05-04) X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 0C86650000BC X-Stat-Signature: y684g886pj8zpdpsnkfapqpaqm8qyzd1 Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=cvRjN1uJ; spf=none (imf04.hostedemail.com: domain of dgilbert@redhat.com has no SPF policy when checking 170.10.133.124) smtp.mailfrom=dgilbert@redhat.com; dmarc=pass (policy=none) header.from=redhat.com X-HE-Tag: 1636993952-968068 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: * Joerg Roedel (jroedel@suse.de) wrote: > 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? >=20 > The host needs to log the access in some way (trace-event, pr_err) with > relevant information. Yeh OK that makes sense if the host-owner could then enable some type of debugging based on that event for the unfortunate guest owner. > 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). >=20 > (Guest and host owner need to work together for debugging, of course). Yeh. Dave > Regards, >=20 > --=20 > J=F6rg R=F6del > jroedel@suse.de >=20 > SUSE Software Solutions Germany GmbH > Maxfeldstr. 5 > 90409 N=FCrnberg > Germany > =20 > (HRB 36809, AG N=FCrnberg) > Gesch=E4ftsf=FChrer: Ivo Totev >=20 --=20 Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK