From: Christoph Hellwig <hch@infradead.org>
To: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Christoph Hellwig <hch@infradead.org>,
linux-kernel@vger.kernel.org, x86@kernel.org,
linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org,
iommu@lists.linux-foundation.org, kvm@vger.kernel.org,
linux-efi@vger.kernel.org, platform-driver-x86@vger.kernel.org,
linux-graphics-maintainer@vmware.com,
amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
kexec@lists.infradead.org, linux-fsdevel@vger.kernel.org,
Borislav Petkov <bp@alien8.de>,
Brijesh Singh <brijesh.singh@amd.com>,
Joerg Roedel <joro@8bytes.org>, Andi Kleen <ak@linux.intel.com>,
Sathyanarayanan Kuppuswamy
<sathyanarayanan.kuppuswamy@linux.intel.com>,
Tianyu Lan <Tianyu.Lan@microsoft.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Joerg Roedel <jroedel@suse.de>
Subject: Re: [PATCH v2 03/12] x86/sev: Add an x86 version of prot_guest_has()
Date: Tue, 24 Aug 2021 08:14:34 +0100 [thread overview]
Message-ID: <YSScWvpXeVXw/ed5@infradead.org> (raw)
In-Reply-To: <4272eaf5-b654-2669-62ac-ba768acd6b91@amd.com>
On Thu, Aug 19, 2021 at 01:33:09PM -0500, Tom Lendacky wrote:
> I did it as inline originally because the presence of the function will be
> decided based on the ARCH_HAS_PROTECTED_GUEST config. For now, that is
> only selected by the AMD memory encryption support, so if I went out of
> line I could put in mem_encrypt.c. But with TDX wanting to also use it, it
> would have to be in an always built file with some #ifdefs or in its own
> file that is conditionally built based on the ARCH_HAS_PROTECTED_GUEST
> setting (they've already tried building with ARCH_HAS_PROTECTED_GUEST=y
> and AMD_MEM_ENCRYPT not set).
>
> To take it out of line, I'm leaning towards the latter, creating a new
> file that is built based on the ARCH_HAS_PROTECTED_GUEST setting.
Yes. In general everytime architectures have to provide the prototype
and not just the implementation of something we end up with a giant mess
sooner or later. In a few cases that is still warranted due to
performance concerns, but i don't think that is the case here.
>
> >
> >> +/* 0x800 - 0x8ff reserved for AMD */
> >> +#define PATTR_SME 0x800
> >> +#define PATTR_SEV 0x801
> >> +#define PATTR_SEV_ES 0x802
> >
> > Why do we need reservations for a purely in-kernel namespace?
> >
> > And why are you overoading a brand new generic API with weird details
> > of a specific implementation like this?
>
> There was some talk about this on the mailing list where TDX and SEV may
> need to be differentiated, so we wanted to reserve a range of values per
> technology. I guess I can remove them until they are actually needed.
In that case add a flag for the differing behavior. And only add them
when actually needed. And either way there is absolutely no need to
reserve ranges.
next prev parent reply other threads:[~2021-08-24 7:16 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-13 16:59 [PATCH v2 00/12] Implement generic prot_guest_has() helper function Tom Lendacky
2021-08-13 16:59 ` [PATCH v2 01/12] x86/ioremap: Selectively build arch override encryption functions Tom Lendacky
2021-08-14 15:25 ` Borislav Petkov
2021-08-13 16:59 ` [PATCH v2 02/12] mm: Introduce a function to check for virtualization protection features Tom Lendacky
2021-08-13 17:19 ` Kuppuswamy, Sathyanarayanan
2021-08-14 18:32 ` Borislav Petkov
2021-08-14 18:49 ` Tom Lendacky
2021-08-19 9:46 ` Christoph Hellwig
2021-08-19 16:39 ` Tom Lendacky
2021-08-13 16:59 ` [PATCH v2 03/12] x86/sev: Add an x86 version of prot_guest_has() Tom Lendacky
2021-08-14 19:08 ` Borislav Petkov
2021-08-15 13:53 ` Tom Lendacky
2021-08-15 14:39 ` Borislav Petkov
2021-08-17 15:22 ` Tom Lendacky
2021-08-17 18:39 ` Borislav Petkov
2021-08-19 9:52 ` Christoph Hellwig
2021-08-19 17:26 ` Borislav Petkov
2021-08-19 18:33 ` Tom Lendacky
2021-08-19 19:57 ` Kuppuswamy, Sathyanarayanan
2021-08-24 7:14 ` Christoph Hellwig [this message]
2021-08-13 16:59 ` [PATCH v2 04/12] powerpc/pseries/svm: Add a powerpc " Tom Lendacky
2021-08-17 8:35 ` Borislav Petkov
2021-08-17 14:11 ` Tom Lendacky
2021-08-17 12:38 ` Michael Ellerman
2021-08-19 9:55 ` Christoph Hellwig
2021-08-19 18:34 ` Tom Lendacky
2021-08-13 16:59 ` [PATCH v2 05/12] x86/sme: Replace occurrences of sme_active() with prot_guest_has() Tom Lendacky
2021-08-17 9:00 ` Borislav Petkov
2021-08-17 14:46 ` Tom Lendacky
2021-08-17 18:41 ` Borislav Petkov
2021-08-13 16:59 ` [PATCH v2 06/12] x86/sev: Replace occurrences of sev_active() " Tom Lendacky
2021-08-17 10:02 ` Borislav Petkov
2021-08-17 15:26 ` Tom Lendacky
2021-08-17 18:43 ` Borislav Petkov
2021-08-13 16:59 ` [PATCH v2 07/12] x86/sev: Replace occurrences of sev_es_active() " Tom Lendacky
2021-08-17 10:06 ` Borislav Petkov
2021-08-13 16:59 ` [PATCH v2 08/12] treewide: Replace the use of mem_encrypt_active() " Tom Lendacky
2021-08-13 16:59 ` [PATCH v2 09/12] mm: Remove the now unused mem_encrypt_active() function Tom Lendacky
2021-08-17 10:22 ` Borislav Petkov
2021-08-17 10:24 ` Borislav Petkov
2021-08-17 15:30 ` Tom Lendacky
2021-08-13 16:59 ` [PATCH v2 10/12] x86/sev: " Tom Lendacky
2021-08-13 16:59 ` [PATCH v2 11/12] powerpc/pseries/svm: " Tom Lendacky
2021-08-13 16:59 ` [PATCH v2 12/12] s390/mm: " Tom Lendacky
2021-08-13 17:22 ` [PATCH v2 00/12] Implement generic prot_guest_has() helper function Tom Lendacky
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