From: David Laight <David.Laight@ACULAB.COM>
To: 'Juergen Gross' <jgross@suse.com>, 'Joerg Roedel' <joro@8bytes.org>
Cc: "x86@kernel.org" <x86@kernel.org>,
Hyunwook Baek <baekhw@google.com>, Joerg Roedel <jroedel@suse.de>,
"stable@vger.kernel.org" <stable@vger.kernel.org>,
"hpa@zytor.com" <hpa@zytor.com>,
Andy Lutomirski <luto@kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Jiri Slaby <jslaby@suse.cz>,
Dan Williams <dan.j.williams@intel.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
Kees Cook <keescook@chromium.org>,
David Rientjes <rientjes@google.com>,
Cfir Cohen <cfir@google.com>, Erdem Aktas <erdemaktas@google.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Mike Stunes <mstunes@vmware.com>,
Sean Christopherson <seanjc@google.com>,
Martin Radev <martin.b.radev@gmail.com>,
Arvind Sankar <nivedita@alum.mit.edu>,
"linux-coco@lists.linux.dev" <linux-coco@lists.linux.dev>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"virtualization@lists.linux-foundation.org"
<virtualization@lists.linux-foundation.org>
Subject: RE: [PATCH 3/6] x86/sev-es: Use __put_user()/__get_user
Date: Wed, 12 May 2021 09:31:10 +0000 [thread overview]
Message-ID: <8cdbb6928c7144c6b065c3ff68f03aee@AcuMS.aculab.com> (raw)
In-Reply-To: <92244e37-4443-98bd-24aa-bf59548aab47@suse.com>
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
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Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
next prev parent reply other threads:[~2021-05-12 9:31 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-12 7:54 [PATCH 0/6] x86/sev-es: Fixes for SEV-ES guest support Joerg Roedel
2021-05-12 7:54 ` [PATCH 1/6] x86/sev-es: Don't return NULL from sev_es_get_ghcb() Joerg Roedel
2021-05-12 7:54 ` [PATCH 2/6] x86/sev-es: Forward page-faults which happen during emulation Joerg Roedel
2021-05-12 17:31 ` Sean Christopherson
2021-05-19 13:16 ` Joerg Roedel
2021-05-12 7:54 ` [PATCH 3/6] x86/sev-es: Use __put_user()/__get_user Joerg Roedel
2021-05-12 8:04 ` David Laight
2021-05-12 8:16 ` Juergen Gross
2021-05-12 8:50 ` 'Joerg Roedel'
2021-05-12 8:58 ` Juergen Gross
2021-05-12 9:31 ` David Laight [this message]
2021-05-12 9:32 ` Joerg Roedel
2021-05-19 11:33 ` 'Joerg Roedel'
2021-05-12 8:37 ` 'Joerg Roedel'
2021-05-12 15:59 ` Dave Hansen
2021-05-12 15:57 ` Dave Hansen
2021-05-12 16:00 ` Joerg Roedel
2021-05-12 7:54 ` [PATCH 4/6] Revert "x86/sev-es: Handle string port IO to kernel memory properly" Joerg Roedel
2021-05-12 17:38 ` Sean Christopherson
2021-05-19 12:22 ` Joerg Roedel
2021-05-12 7:54 ` [PATCH 5/6] x86/sev-es: Fix error message in runtime #VC handler Joerg Roedel
2021-05-12 7:54 ` [PATCH 6/6] x86/sev-es: Leave NMI-mode before sending signals Joerg Roedel
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