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Shutemov" , Andi Kleen , Tony Luck , Sathyanarayanan Kuppuswamy Subject: Re: [PATCH Part2 v5 00/45] Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support Message-ID: References: <2cb3217b-8af5-4349-b59f-ca4a3703a01a@www.fastmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: CF9D54002088 X-Stat-Signature: ibx1cj471j3u6t4hm96t7rgf9ukx6bp1 Authentication-Results: imf18.hostedemail.com; dkim=pass header.d=suse.de header.s=susede2_rsa header.b=2KJORy1s; dkim=pass header.d=suse.de header.s=susede2_ed25519 header.b=3+c573I9; dmarc=pass (policy=none) header.from=suse.de; spf=pass (imf18.hostedemail.com: domain of jroedel@suse.de designates 195.135.220.29 as permitted sender) smtp.mailfrom=jroedel@suse.de X-HE-Tag: 1636995126-564889 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: On Sat, Nov 13, 2021 at 06:28:16PM +0000, Sean Christopherson wrote: > Another issue is that the host kernel, which despite being "untrusted",= absolutely > should be acting in the best interests of the guest. Allowing userspac= e to inject > #VC, e.g. to attempt to attack the guest by triggering a spurious PVALI= DATE, means > the kernel is failing miserably on that front. Well, no. The kernel is only a part of the hypervisor, KVM userspace is another. It is possible today for the userspace part(s) to interact in ba= d ways with the guest and trick or kill it. Allowing user-space to cause a #VC in the guest is no different from that. Regards, --=20 J=F6rg R=F6del jroedel@suse.de SUSE Software Solutions Germany GmbH Maxfeldstr. 5 90409 N=FCrnberg Germany =20 (HRB 36809, AG N=FCrnberg) Gesch=E4ftsf=FChrer: Ivo Totev