From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eu-smtp-delivery-151.mimecast.com (eu-smtp-delivery-151.mimecast.com [185.58.86.151]) (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 047A571 for ; Wed, 12 May 2021 09:31:18 +0000 (UTC) Received: from AcuMS.aculab.com (156.67.243.121 [156.67.243.121]) (Using TLS) by relay.mimecast.com with ESMTP id uk-mta-79-oLFw4AwlPEex5jOXqlFBlw-1; Wed, 12 May 2021 10:31:12 +0100 X-MC-Unique: oLFw4AwlPEex5jOXqlFBlw-1 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b:0:994c:f5c2:35d6:9b65) by AcuMS.aculab.com (fd9f:af1c:a25b:0:994c:f5c2:35d6:9b65) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Wed, 12 May 2021 10:31:10 +0100 Received: from AcuMS.Aculab.com ([fe80::994c:f5c2:35d6:9b65]) by AcuMS.aculab.com ([fe80::994c:f5c2:35d6:9b65%12]) with mapi id 15.00.1497.015; Wed, 12 May 2021 10:31:10 +0100 From: David Laight To: 'Juergen Gross' , 'Joerg Roedel' CC: "x86@kernel.org" , Hyunwook Baek , Joerg Roedel , "stable@vger.kernel.org" , "hpa@zytor.com" , Andy Lutomirski , Dave Hansen , Peter Zijlstra , Jiri Slaby , Dan Williams , Tom Lendacky , 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" Subject: RE: [PATCH 3/6] x86/sev-es: Use __put_user()/__get_user Thread-Topic: [PATCH 3/6] x86/sev-es: Use __put_user()/__get_user Thread-Index: AQHXRwQswpicLJM6a0eoGXhfP+3kQqrfe29ggAAQd36AAAai8A== Date: Wed, 12 May 2021 09:31:10 +0000 Message-ID: <8cdbb6928c7144c6b065c3ff68f03aee@AcuMS.aculab.com> References: <20210512075445.18935-1-joro@8bytes.org> <20210512075445.18935-4-joro@8bytes.org> <0496626f018d4d27a8034a4822170222@AcuMS.aculab.com> <92244e37-4443-98bd-24aa-bf59548aab47@suse.com> In-Reply-To: <92244e37-4443-98bd-24aa-bf59548aab47@suse.com> Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Authentication-Results: relay.mimecast.com; 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Wed, 12 May 2021 10:31:10 +0100 From: David Laight To: 'Juergen Gross' , 'Joerg Roedel' CC: "x86@kernel.org" , Hyunwook Baek , Joerg Roedel , "stable@vger.kernel.org" , "hpa@zytor.com" , Andy Lutomirski , Dave Hansen , Peter Zijlstra , Jiri Slaby , Dan Williams , Tom Lendacky , 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" Subject: RE: [PATCH 3/6] x86/sev-es: Use __put_user()/__get_user Thread-Topic: [PATCH 3/6] x86/sev-es: Use __put_user()/__get_user Thread-Index: AQHXRwQswpicLJM6a0eoGXhfP+3kQqrfe29ggAAQd36AAAai8A== Date: Wed, 12 May 2021 09:31:10 +0000 Message-ID: <8cdbb6928c7144c6b065c3ff68f03aee@AcuMS.aculab.com> References: <20210512075445.18935-1-joro@8bytes.org> <20210512075445.18935-4-joro@8bytes.org> <0496626f018d4d27a8034a4822170222@AcuMS.aculab.com> <92244e37-4443-98bd-24aa-bf59548aab47@suse.com> In-Reply-To: <92244e37-4443-98bd-24aa-bf59548aab47@suse.com> Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 Authentication-Results: relay.mimecast.com; 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Wed, 12 May 2021 10:31:12 +0100 X-MC-Unique: oLFw4AwlPEex5jOXqlFBlw-1 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b:0:994c:f5c2:35d6:9b65) by AcuMS.aculab.com (fd9f:af1c:a25b:0:994c:f5c2:35d6:9b65) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Wed, 12 May 2021 10:31:10 +0100 Received: from AcuMS.Aculab.com ([fe80::994c:f5c2:35d6:9b65]) by AcuMS.aculab.com ([fe80::994c:f5c2:35d6:9b65%12]) with mapi id 15.00.1497.015; Wed, 12 May 2021 10:31:10 +0100 From: David Laight To: 'Juergen Gross' , 'Joerg Roedel' Subject: RE: [PATCH 3/6] x86/sev-es: Use __put_user()/__get_user Thread-Topic: [PATCH 3/6] x86/sev-es: Use __put_user()/__get_user Thread-Index: AQHXRwQswpicLJM6a0eoGXhfP+3kQqrfe29ggAAQd36AAAai8A== Date: Wed, 12 May 2021 09:31:10 +0000 Message-ID: <8cdbb6928c7144c6b065c3ff68f03aee@AcuMS.aculab.com> References: <20210512075445.18935-1-joro@8bytes.org> <20210512075445.18935-4-joro@8bytes.org> <0496626f018d4d27a8034a4822170222@AcuMS.aculab.com> <92244e37-4443-98bd-24aa-bf59548aab47@suse.com> In-Reply-To: <92244e37-4443-98bd-24aa-bf59548aab47@suse.com> Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=C51A453 smtp.mailfrom=david.laight@aculab.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Language: en-US Cc: "kvm@vger.kernel.org" , Peter Zijlstra , Dave Hansen , "virtualization@lists.linux-foundation.org" , Arvind Sankar , "hpa@zytor.com" , Jiri Slaby , "x86@kernel.org" , David Rientjes , Martin Radev , Tom Lendacky , Joerg Roedel , Kees Cook , Cfir Cohen , Hyunwook Baek , "linux-coco@lists.linux.dev" , Andy Lutomirski , Dan Williams , Mike Stunes , Sean Christopherson , "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" , Masami Hiramatsu , Erdem Aktas X-BeenThere: virtualization@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux virtualization List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" From: Juergen Gross > Sent: 12 May 2021 09:58 > > On 12.05.21 10:50, 'Joerg Roedel' wrote: > > On Wed, May 12, 2021 at 10:16:12AM +0200, Juergen Gross wrote: > >> You want something like xen_safe_[read|write]_ulong(). > > > > From a first glance I can't see it, what is the difference between the > > xen_safe_*_ulong() functions and __get_user()/__put_user()? The only > > difference I can see is that __get/__put_user() support different access > > sizes, but neither of those disables page-faults by itself, for example. > > > > Couldn't these xen-specific functions not also be replaces by > > __get_user()/__put_user()? > > No, those were used before, but commit 9da3f2b7405440 broke Xen's use > case. That is why I did commit 1457d8cf7664f. I've just looked at 9da3f2b7405440. It doesn't look right to me - wrong return value for a lot of cases. OTOH it isn't in my newest tree at all. If bogus_uaccess() is now elsewhere I can't see how (without changes) it would allow through these faults. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales) _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization