From: Joerg Roedel <jroedel@suse.de>
To: Juergen Gross <jgross@suse.com>
Cc: "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
"virtualization@lists.linux-foundation.org"
<virtualization@lists.linux-foundation.org>,
Arvind Sankar <nivedita@alum.mit.edu>,
"hpa@zytor.com" <hpa@zytor.com>, Jiri Slaby <jslaby@suse.cz>,
'Joerg Roedel' <joro@8bytes.org>,
"x86@kernel.org" <x86@kernel.org>,
David Rientjes <rientjes@google.com>,
Martin Radev <martin.b.radev@gmail.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
Kees Cook <keescook@chromium.org>, Cfir Cohen <cfir@google.com>,
Hyunwook Baek <baekhw@google.com>,
"linux-coco@lists.linux.dev" <linux-coco@lists.linux.dev>,
Andy Lutomirski <luto@kernel.org>,
Dan Williams <dan.j.williams@intel.com>,
Mike Stunes <mstunes@vmware.com>,
Sean Christopherson <seanjc@google.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"stable@vger.kernel.org" <stable@vger.kernel.org>,
David Laight <David.Laight@aculab.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Erdem Aktas <erdemaktas@google.com>
Subject: Re: [PATCH 3/6] x86/sev-es: Use __put_user()/__get_user
Date: Wed, 12 May 2021 11:32:35 +0200 [thread overview]
Message-ID: <YJugs0CdiNo0/Gbd@suse.de> (raw)
In-Reply-To: <92244e37-4443-98bd-24aa-bf59548aab47@suse.com>
On Wed, May 12, 2021 at 10:58:20AM +0200, Juergen Gross wrote:
> No, those were used before, but commit 9da3f2b7405440 broke Xen's use
> case. That is why I did commit 1457d8cf7664f.
I see, thanks for the heads-up. So here this is not a big issue, because
when an access to kernel space faults under SEV-ES, its a kernel bug
anyway. The issue is that it is not reported correctly.
I think I need to re-work the helper and use probe_kernel_read/write()
when the address is in kernel space. This distinction is already made
when fetching instruction bytes in the #VC handler, but I thought I
could get around it for data accesses.
Having the distinction between user and kernel memory accesses
explicitly in the code seems to be the most robust solution.
Regards,
Joerg
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next prev parent reply other threads:[~2021-05-12 9:32 UTC|newest]
Thread overview: 20+ 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
[not found] ` <YJwQ1xsiDtv3LkBe@google.com>
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 via Virtualization
2021-05-12 8:50 ` 'Joerg Roedel'
2021-05-12 8:58 ` Juergen Gross via Virtualization
2021-05-12 9:31 ` David Laight
2021-05-12 9:32 ` Joerg Roedel [this message]
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
[not found] ` <YJwSlVnHb0SZTSrG@google.com>
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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