From: Venu Busireddy <venu.busireddy@oracle.com>
To: Michael Roth <michael.roth@amd.com>
Cc: Borislav Petkov <bp@alien8.de>,
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>,
tony.luck@intel.com, marcorr@google.com,
sathyanarayanan.kuppuswamy@linux.intel.com
Subject: Re: [PATCH v7 01/45] x86/compressed/64: detect/setup SEV/SME features earlier in boot
Date: Tue, 23 Nov 2021 15:55:54 -0600 [thread overview]
Message-ID: <YZ1jaiavtDTHVVD+@dt> (raw)
In-Reply-To: <20211112203001.kdzhpgp3uqcr2dy5@amd.com>
On 2021-11-12 14:30:01 -0600, Michael Roth wrote:
> On Fri, Nov 12, 2021 at 05:52:51PM +0100, Borislav Petkov wrote:
> > On Wed, Nov 10, 2021 at 04:06:47PM -0600, Brijesh Singh wrote:
> > > +void sev_enable(struct boot_params *bp)
> > > +{
> > > + unsigned int eax, ebx, ecx, edx;
> > > +
> > > + /* Check for the SME/SEV support leaf */
> > > + eax = 0x80000000;
> > > + ecx = 0;
> > > + native_cpuid(&eax, &ebx, &ecx, &edx);
> > > + if (eax < 0x8000001f)
> > > + return;
> > > +
> > > + /*
> > > + * Check for the SME/SEV feature:
> > > + * CPUID Fn8000_001F[EAX]
> > > + * - Bit 0 - Secure Memory Encryption support
> > > + * - Bit 1 - Secure Encrypted Virtualization support
> > > + * CPUID Fn8000_001F[EBX]
> > > + * - Bits 5:0 - Pagetable bit position used to indicate encryption
> > > + */
> > > + eax = 0x8000001f;
> > > + ecx = 0;
> > > + native_cpuid(&eax, &ebx, &ecx, &edx);
> > > + /* Check whether SEV is supported */
> > > + if (!(eax & BIT(1)))
> > > + return;
> > > +
> > > + /* Check the SEV MSR whether SEV or SME is enabled */
> > > + sev_status = rd_sev_status_msr();
> > > +
> > > + if (!(sev_status & MSR_AMD64_SEV_ENABLED))
> > > + error("SEV support indicated by CPUID, but not SEV status MSR.");
> >
> > What is the practical purpose of this test?
>
> In the current QEMU/KVM implementation the SEV* CPUID bits are only
> exposed for SEV guests, so this was more of a sanity check on that. But
> looking at things more closely: that's more of a VMM-specific behavior
> and isn't necessarily an invalid guest configuration as far as the spec
> is concerned, so I think this check should be dropped.
>
> >
> > > + sme_me_mask = 1UL << (ebx & 0x3f);
> >
> > sme_me_mask = BIT_ULL(ebx & 0x3f);
>
> Will do.
Also, could you please remove the references to set_sev_encryption_mask()
at lines 195 and 572? And perhaps reword those comments too?
Thanks,
Venu
> Thanks,
>
> Mike
>
> >
> > 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%7Ca6bf3479fffa4b5eee8b08d9a5fce2e2%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637723327924654730%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=SRy8YSe8a2njNc6IT8CGKv0hUefSOW55DJV%2Fi2Lhkic%3D&reserved=0
next prev parent reply other threads:[~2021-11-23 21:56 UTC|newest]
Thread overview: 80+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
2021-11-10 22:06 ` [PATCH v7 01/45] x86/compressed/64: detect/setup SEV/SME features earlier in boot Brijesh Singh
2021-11-12 16:52 ` Borislav Petkov
2021-11-12 20:30 ` Michael Roth
2021-11-23 21:55 ` Venu Busireddy [this message]
2021-11-10 22:06 ` [PATCH v7 02/45] x86/sev: " Brijesh Singh
2021-11-15 19:12 ` Borislav Petkov
2021-11-15 20:17 ` Michael Roth
2021-11-17 13:11 ` Borislav Petkov
2021-12-06 23:47 ` Venu Busireddy
2021-11-10 22:06 ` [PATCH v7 03/45] x86/mm: Extend cc_attr to include AMD SEV-SNP Brijesh Singh
2021-11-10 22:06 ` [PATCH v7 04/45] x86/sev: Shorten GHCB terminate macro names Brijesh Singh
2021-11-10 22:06 ` [PATCH v7 05/45] x86/sev: Get rid of excessive use of defines Brijesh Singh
2021-11-10 22:06 ` [PATCH v7 06/45] x86/head64: Carve out the guest encryption postprocessing into a helper Brijesh Singh
2021-11-10 22:06 ` [PATCH v7 07/45] x86/sev: Remove do_early_exception() forward declarations Brijesh Singh
2021-11-10 22:06 ` [PATCH v7 08/45] x86/sev: Define the Linux specific guest termination reasons Brijesh Singh
2021-11-10 22:06 ` [PATCH v7 09/45] x86/sev: Save the negotiated GHCB version Brijesh Singh
2021-12-07 12:51 ` Tianyu Lan
2021-12-07 13:17 ` Borislav Petkov
2021-12-07 16:58 ` Brijesh Singh
2021-11-10 22:06 ` [PATCH v7 10/45] x86/sev: Add support for hypervisor feature VMGEXIT Brijesh Singh
2021-12-02 17:52 ` Borislav Petkov
2021-12-06 15:15 ` Brijesh Singh
2021-11-10 22:06 ` [PATCH v7 11/45] x86/sev: Check SEV-SNP features support Brijesh Singh
2021-11-10 22:06 ` [PATCH v7 12/45] x86/sev: Add a helper for the PVALIDATE instruction Brijesh Singh
2021-11-10 22:06 ` [PATCH v7 13/45] x86/sev: Check the vmpl level Brijesh Singh
2021-12-06 18:25 ` Borislav Petkov
2021-11-10 22:07 ` [PATCH v7 14/45] x86/compressed: Add helper for validating pages in the decompression stage Brijesh Singh
2021-12-07 11:48 ` Borislav Petkov
2021-12-07 19:21 ` Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 15/45] x86/compressed: Register GHCB memory when SEV-SNP is active Brijesh Singh
2021-11-15 14:05 ` Jörg Rödel
2021-11-10 22:07 ` [PATCH v7 16/45] x86/sev: " Brijesh Singh
2021-12-08 17:41 ` Borislav Petkov
2021-11-10 22:07 ` [PATCH v7 17/45] x86/sev: Add helper for validating pages in early enc attribute changes Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 18/45] x86/kernel: Make the bss.decrypted section shared in RMP table Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 19/45] x86/kernel: Validate rom memory before accessing when SEV-SNP is active Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 20/45] x86/mm: Add support to validate memory when changing C-bit Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 21/45] KVM: SVM: Define sev_features and vmpl field in the VMSA Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 22/45] KVM: SVM: Create a separate mapping for the SEV-ES save area Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 23/45] KVM: SVM: Create a separate mapping for the GHCB " Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 24/45] KVM: SVM: Update the SEV-ES save area mapping Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 25/45] x86/sev: Use SEV-SNP AP creation to start secondary CPUs Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 26/45] x86/head: re-enable stack protection for 32/64-bit builds Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 27/45] x86/sev: move MSR-based VMGEXITs for CPUID to helper Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 28/45] KVM: x86: move lookup of indexed CPUID leafs " Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 29/45] x86/compressed/acpi: move EFI system table lookup " Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 30/45] x86/compressed/acpi: move EFI config " Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 31/45] x86/compressed/acpi: move EFI vendor " Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 32/45] x86/boot: Add Confidential Computing type to setup_data Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 33/45] KVM: SEV: Add documentation for SEV-SNP CPUID Enforcement Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 34/45] x86/compressed/64: add support for SEV-SNP CPUID table in #VC handlers Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 35/45] x86/boot: add a pointer to Confidential Computing blob in bootparams Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 36/45] x86/compressed: add SEV-SNP feature detection/setup Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 37/45] x86/compressed: use firmware-validated CPUID for SEV-SNP guests Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 38/45] x86/compressed/64: add identity mapping for Confidential Computing blob Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 39/45] x86/sev: add SEV-SNP feature detection/setup Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 40/45] x86/sev: use firmware-validated CPUID for SEV-SNP guests Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 41/45] x86/sev: Provide support for SNP guest request NAEs Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 42/45] x86/sev: Register SNP guest request platform device Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 43/45] virt: Add SEV-SNP guest driver Brijesh Singh
2021-11-10 22:27 ` Randy Dunlap
2021-11-11 19:27 ` Brijesh Singh
2021-11-11 22:57 ` Randy Dunlap
2021-11-17 23:34 ` Peter Gonda
2021-11-18 17:08 ` Peter Gonda
2021-11-18 17:32 ` Brijesh Singh
2021-11-19 16:16 ` Peter Gonda
2021-11-20 0:28 ` Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 44/45] virt: sevguest: Add support to derive key Brijesh Singh
2021-11-18 16:43 ` Peter Gonda
2021-11-18 17:43 ` Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 45/45] virt: sevguest: Add support to get extended report Brijesh Singh
2021-11-15 15:56 ` [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Venu Busireddy
2021-11-15 16:02 ` Brijesh Singh
2021-11-15 16:37 ` Venu Busireddy
2021-11-15 16:45 ` Brijesh Singh
2021-11-15 16:55 ` Venu Busireddy
2021-11-16 15:45 ` Venu Busireddy
2021-11-16 16:03 ` Brijesh Singh
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