From: Michael Roth <michael.roth@amd.com>
To: Borislav Petkov <bp@alien8.de>
Cc: Brijesh Singh <brijesh.singh@amd.com>, <x86@kernel.org>,
<linux-kernel@vger.kernel.org>, <kvm@vger.kernel.org>,
<linux-efi@vger.kernel.org>,
<platform-driver-x86@vger.kernel.org>,
<linux-coco@lists.linux.dev>, <linux-mm@kvack.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Joerg Roedel <jroedel@suse.de>,
Tom Lendacky <thomas.lendacky@amd.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Ard Biesheuvel <ardb@kernel.org>,
Paolo Bonzini <pbonzini@redhat.com>,
Sean Christopherson <seanjc@google.com>,
"Vitaly Kuznetsov" <vkuznets@redhat.com>,
Jim Mattson <jmattson@google.com>,
"Andy Lutomirski" <luto@kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Sergio Lopez <slp@redhat.com>, Peter Gonda <pgonda@google.com>,
"Peter Zijlstra" <peterz@infradead.org>,
Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
David Rientjes <rientjes@google.com>,
Dov Murik <dovmurik@linux.ibm.com>,
Tobin Feldman-Fitzthum <tobin@ibm.com>,
Vlastimil Babka <vbabka@suse.cz>,
"Kirill A . Shutemov" <kirill@shutemov.name>,
Andi Kleen <ak@linux.intel.com>,
"Dr . David Alan Gilbert" <dgilbert@redhat.com>,
<brijesh.ksingh@gmail.com>, <tony.luck@intel.com>,
<marcorr@google.com>,
<sathyanarayanan.kuppuswamy@linux.intel.com>
Subject: Re: [PATCH v9 05/43] x86/compressed/64: Detect/setup SEV/SME features earlier in boot
Date: Tue, 1 Feb 2022 18:52:12 -0600 [thread overview]
Message-ID: <20220202005212.a3fnn6i76ko6u6t5@amd.com> (raw)
In-Reply-To: <YfmmBykN2s0HsiAJ@zn.tnic>
On Tue, Feb 01, 2022 at 10:28:39PM +0100, Borislav Petkov wrote:
> On Tue, Feb 01, 2022 at 02:35:07PM -0600, Michael Roth wrote:
> > Unfortunately rdmsr()/wrmsr()/__rdmsr()/__wrmsr() etc. definitions are all
> > already getting pulled in via:
> >
> > misc.h:
> > #include linux/elf.h
> > #include linux/thread_info.h
> > #include linux/cpufeature.h
> > #include linux/processor.h
> > #include linux/msr.h
> >
> > Those definitions aren't usable in boot/compressed because of __ex_table
> > and possibly some other dependency hellishness.
>
> And they should not be. Mixing kernel proper and decompressor code needs
> to stop and untangling that is a multi-year effort, unfortunately. ;-\
>
> > Would read_msr()/write_msr() be reasonable alternative names for these new
> > helpers, or something else that better distinguishes them from the
> > kernel proper definitions?
>
> Nah, just call them rdmsr/wrmsr(). There is already {read,write}_msr()
> tracepoint symbols in kernel proper and there's no point in keeping them
> apart using different names - that ship has long sailed.
Since the kernel proper rdmsr()/wrmsr() definitions are getting pulled in via
misc.h, I have to use a different name to avoid compiler errors. For now I've
gone with rd_msr()/wr_msr(), but no problem changing those if needed.
> > Should we introduce something like this as well for cpucheck.c? Or
> > re-write cpucheck.c to make use of the u64 versions? Or just set the
> > cpucheck.c rework aside for now? (but still introduce the above helpers
> > as boot/msr.h in preparation)?
>
> How about you model it after
>
> static int msr_read(u32 msr, struct msr *m)
>
> from arch/x86/lib/msr.c which takes struct msr from which you can return
> either u32s or a u64?
>
> The stuff you share between the decompressor and kernel proper you put
> in a arch/x86/include/asm/shared/ folder, for an example, see what we do
> there in the TDX patchset:
>
> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Fr%2F20220124150215.36893-11-kirill.shutemov%40linux.intel.com&data=04%7C01%7Cmichael.roth%40amd.com%7C1662b963f1c54f3663df08d9e5c9d6bd%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637793477399827883%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=rtdo9ci3XjOHn2HphvNE7ciFR6tKh1pVclFuNhXkNGs%3D&reserved=0
>
> I.e., you move struct msr in such a shared header and then you include
> it everywhere needed.
>
> The arch/x86/boot/ msr helpers are then plain and simple, without
> tracepoints and exception fixups and you define them in ...boot/msr.c or
> so.
>
> If the patch gets too big, make sure to split it in a couple so that it
> is clear what happens at each step.
>
> How does that sound?
Thanks for the suggestions, this works out nicely, but as far as defining
them in boot/msr.c, it looks like the Makefile in boot/compressed doesn't
currently have any instances of linking to objects in boot/, and the status
quo seems to be #include'ing the whole C file in cases where boot/ code is
needed in boot/compressed.
Since the rd_msr/wr_msr are oneliners, it seemed like it might be a
little cleaner to just define them in boot/msr.h as static inline and
include them directly as part of the header.
Here's what it looks like on top of this tree, and roughly how I plan to
split the patches for v10:
- define the rd_msr/wr_msr helpers
https://github.com/mdroth/linux/commit/982c6c5741478c8f634db8ac0ba36575b5eff946
- use the helpers in boot/compressed/sev.c and boot/cpucheck.c
https://github.com/mdroth/linux/commit/a16e11f727c01fc478d3b741e1bdd2fd44975d7c
For v10 though I'll likely just drop rd_sev_status_msr() completely and use
rd_msr() directly.
Let me know if I should make any changes and I'll make sure to get those in for
the next spin.
>
> Thx.
>
> --
> Regards/Gruss,
> Boris.
>
> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpeople.kernel.org%2Ftglx%2Fnotes-about-netiquette&data=04%7C01%7Cmichael.roth%40amd.com%7C1662b963f1c54f3663df08d9e5c9d6bd%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637793477399827883%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=njDai06MS2mcyMLZ5YvLMcgXSXwfoO01U2c0D%2BE3HG4%3D&reserved=0
next prev parent reply other threads:[~2022-02-02 0:52 UTC|newest]
Thread overview: 79+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-28 17:17 [PATCH v9 00/43] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
2022-01-28 17:17 ` [PATCH v9 01/43] KVM: SVM: Define sev_features and vmpl field in the VMSA Brijesh Singh
2022-01-28 17:17 ` [PATCH v9 02/43] KVM: SVM: Create a separate mapping for the SEV-ES save area Brijesh Singh
[not found] ` <YfkvchuxmkHgnPWT@zn.tnic>
2022-02-09 15:02 ` Brijesh Singh
2022-01-28 17:17 ` [PATCH v9 03/43] KVM: SVM: Create a separate mapping for the GHCB " Brijesh Singh
2022-01-28 17:17 ` [PATCH v9 04/43] KVM: SVM: Update the SEV-ES save area mapping Brijesh Singh
2022-01-28 17:17 ` [PATCH v9 05/43] x86/compressed/64: Detect/setup SEV/SME features earlier in boot Brijesh Singh
[not found] ` <Yfl3FaTGPxE7qMCq@zn.tnic>
2022-02-01 20:35 ` Michael Roth
[not found] ` <YfmmBykN2s0HsiAJ@zn.tnic>
2022-02-02 0:52 ` Michael Roth [this message]
[not found] ` <YfogFFOoHvCV+/2Y@zn.tnic>
2022-02-02 17:28 ` Michael Roth
2022-01-28 17:17 ` [PATCH v9 06/43] x86/sev: " Brijesh Singh
2022-01-28 17:17 ` [PATCH v9 07/43] x86/mm: Extend cc_attr to include AMD SEV-SNP Brijesh Singh
2022-01-28 17:17 ` [PATCH v9 08/43] x86/sev: Define the Linux specific guest termination reasons Brijesh Singh
2022-01-28 17:17 ` [PATCH v9 09/43] x86/sev: Save the negotiated GHCB version Brijesh Singh
2022-01-28 17:17 ` [PATCH v9 10/43] x86/sev: Check SEV-SNP features support Brijesh Singh
[not found] ` <YfmRBUtoWNb9BkuL@zn.tnic>
2022-02-02 14:28 ` Brijesh Singh
2022-01-28 17:17 ` [PATCH v9 11/43] x86/sev: Add a helper for the PVALIDATE instruction Brijesh Singh
2022-01-28 17:17 ` [PATCH v9 12/43] x86/sev: Check the vmpl level Brijesh Singh
2022-01-28 17:17 ` [PATCH v9 13/43] x86/compressed: Add helper for validating pages in the decompression stage Brijesh Singh
2022-01-28 17:17 ` [PATCH v9 14/43] x86/compressed: Register GHCB memory when SEV-SNP is active Brijesh Singh
2022-01-28 17:17 ` [PATCH v9 15/43] x86/sev: " Brijesh Singh
[not found] ` <YfpeSErxB9KHOd7m@zn.tnic>
2022-02-02 14:29 ` Brijesh Singh
2022-01-28 17:17 ` [PATCH v9 16/43] x86/sev: Add helper for validating pages in early enc attribute changes Brijesh Singh
2022-01-28 17:17 ` [PATCH v9 17/43] x86/kernel: Make the .bss..decrypted section shared in RMP table Brijesh Singh
2022-01-28 17:17 ` [PATCH v9 18/43] x86/kernel: Validate ROM memory before accessing when SEV-SNP is active Brijesh Singh
2022-01-28 17:17 ` [PATCH v9 19/43] x86/mm: Add support to validate memory when changing C-bit Brijesh Singh
2022-01-28 17:17 ` [PATCH v9 20/43] x86/sev: Use SEV-SNP AP creation to start secondary CPUs Brijesh Singh
2022-01-28 17:17 ` [PATCH v9 21/43] x86/head/64: Re-enable stack protection Brijesh Singh
2022-01-28 17:17 ` [PATCH v9 22/43] x86/sev: Move MSR-based VMGEXITs for CPUID to helper Brijesh Singh
2022-01-28 17:17 ` [PATCH v9 23/43] KVM: x86: Move lookup of indexed CPUID leafs " Brijesh Singh
[not found] ` <Yfvx0Rq8Tydyr/RO@zn.tnic>
2022-02-03 16:44 ` Michael Roth
2022-01-28 17:17 ` [PATCH v9 24/43] x86/compressed/acpi: Move EFI detection " Brijesh Singh
2022-01-28 17:17 ` [PATCH v9 25/43] x86/compressed/acpi: Move EFI system table lookup " Brijesh Singh
2022-01-28 17:17 ` [PATCH v9 26/43] x86/compressed/acpi: Move EFI config " Brijesh Singh
2022-01-28 17:17 ` [PATCH v9 27/43] x86/compressed/acpi: Move EFI vendor " Brijesh Singh
2022-01-28 17:17 ` [PATCH v9 28/43] x86/compressed/acpi: Move EFI kexec handling into common code Brijesh Singh
2022-01-28 17:17 ` [PATCH v9 29/43] x86/boot: Add Confidential Computing type to setup_data Brijesh Singh
[not found] ` <Yf1Sn4AdPgIzpih9@zn.tnic>
2022-02-04 17:41 ` Brijesh Singh
2022-01-28 17:17 ` [PATCH v9 30/43] KVM: SEV: Add documentation for SEV-SNP CPUID Enforcement Brijesh Singh
2022-02-07 23:48 ` Sean Christopherson
2022-02-08 14:54 ` Michael Roth
2022-02-08 15:11 ` Borislav Petkov
2022-01-28 17:17 ` [PATCH v9 31/43] x86/compressed/64: Add support for SEV-SNP CPUID table in #VC handlers Brijesh Singh
[not found] ` <Yf5XScto3mDXnl9u@zn.tnic>
2022-02-05 15:42 ` Michael Roth
2022-02-05 16:22 ` Michael Roth
[not found] ` <Yf/PN8rBy3m5seU9@zn.tnic>
2022-02-07 15:37 ` Michael Roth
2022-01-28 17:17 ` [PATCH v9 32/43] x86/boot: Add a pointer to Confidential Computing blob in bootparams Brijesh Singh
2022-01-28 17:17 ` [PATCH v9 33/43] x86/compressed: Add SEV-SNP feature detection/setup Brijesh Singh
[not found] ` <Yf/6NhnS50UDv4xV@zn.tnic>
2022-02-08 13:50 ` Michael Roth
2022-02-08 15:02 ` Borislav Petkov
2022-01-28 17:17 ` [PATCH v9 34/43] x86/compressed: Use firmware-validated CPUID leaves for SEV-SNP guests Brijesh Singh
2022-01-28 17:17 ` [PATCH v9 35/43] x86/compressed: Export and rename add_identity_map() Brijesh Singh
2022-01-28 17:17 ` [PATCH v9 36/43] x86/compressed/64: Add identity mapping for Confidential Computing blob Brijesh Singh
2022-01-28 17:17 ` [PATCH v9 37/43] x86/sev: Add SEV-SNP feature detection/setup Brijesh Singh
[not found] ` <YgAjq3mSudt+G+6Y@zn.tnic>
2022-02-08 5:25 ` Michael Roth
2022-01-28 17:17 ` [PATCH v9 38/43] x86/sev: Use firmware-validated CPUID for SEV-SNP guests Brijesh Singh
2022-02-05 17:19 ` Michael Roth
[not found] ` <Yf/tQPqbP97lrVpg@zn.tnic>
2022-02-07 17:00 ` Michael Roth
2022-01-28 17:18 ` [PATCH v9 39/43] x86/sev: Provide support for SNP guest request NAEs Brijesh Singh
2022-02-01 20:17 ` Peter Gonda
2022-03-03 14:53 ` Brijesh Singh
2022-01-28 17:18 ` [PATCH v9 40/43] x86/sev: Register SEV-SNP guest request platform device Brijesh Singh
2022-02-01 20:21 ` Peter Gonda
2022-02-02 16:27 ` Brijesh Singh
2022-01-28 17:18 ` [PATCH v9 41/43] virt: Add SEV-SNP guest driver Brijesh Singh
2022-02-01 20:33 ` Peter Gonda
2022-02-06 22:39 ` Borislav Petkov
2022-02-07 14:41 ` Brijesh Singh
2022-01-28 17:18 ` [PATCH v9 42/43] virt: sevguest: Add support to derive key Brijesh Singh
2022-02-01 20:39 ` Peter Gonda
2022-02-02 22:31 ` Brijesh Singh
[not found] ` <YgDduR0mrptX5arB@zn.tnic>
2022-02-07 16:23 ` Brijesh Singh
2022-02-07 19:09 ` Dov Murik
2022-02-07 20:08 ` Brijesh Singh
2022-02-08 7:56 ` Dov Murik
2022-02-08 10:51 ` Borislav Petkov
2022-02-08 14:14 ` Brijesh Singh
2022-01-28 17:18 ` [PATCH v9 43/43] virt: sevguest: Add support to get extended report Brijesh Singh
2022-02-01 20:43 ` Peter Gonda
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