From: Sean Christopherson <seanjc@google.com>
To: Borislav Petkov <bp@alien8.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>,
Michael Roth <michael.roth@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>,
"H. Peter Anvin" <hpa@zytor.com>,
Ard Biesheuvel <ardb@kernel.org>,
Paolo Bonzini <pbonzini@redhat.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@linux.intel.com>,
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 v12 19/46] x86/kernel: Make the .bss..decrypted section shared in RMP table
Date: Thu, 7 Jul 2022 20:43:40 +0000 [thread overview]
Message-ID: <YsdFfL231NXvYOXu@google.com> (raw)
In-Reply-To: <Yr8mARnQT+VZK0iy@zn.tnic>
On Fri, Jul 01, 2022, Borislav Petkov wrote:
> On Thu, Jun 16, 2022 at 04:41:05PM +0000, Sean Christopherson wrote:
> > > I worry that another use of cc_platform_has() could creep in at some point
> > > and cause the same issue. Not sure how bad it would be, performance-wise, to
> > > remove the jump table optimization for arch/x86/coco/core.c.
>
> Is there a gcc switch for that?
I believe -fno-jump-tables will do the trick. That also reminds me exactly why
CONFIG_RETPOLINE=y isn't broken, jump tables are disabled when retpolines are enabled[*].
[*] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86952
> > One thought would be to initialize "vendor" to a bogus value, disallow calls to
> > cc_set_vendor() until after the kernel as gotten to a safe point, and then WARN
> > (or panic?) if cc_platform_has() is called before "vendor" is explicitly set.
> > New calls can still get in, but they'll be much easier to detect and less likely
> > to escape initial testing.
>
> The invalid vendor thing makes sense but I don't think it'll help in
> this case.
>
> We set vendor in sme_enable() which comes before the
>
> __startup_64 -> sme_postprocess_startup
>
> path you're hitting.
Right, but that's easily solved, no? E.g.
diff --git a/arch/x86/mm/mem_encrypt_amd.c b/arch/x86/mm/mem_encrypt_amd.c
index e8f7953fda83..ed3118f5bf62 100644
--- a/arch/x86/mm/mem_encrypt_amd.c
+++ b/arch/x86/mm/mem_encrypt_amd.c
@@ -487,6 +487,8 @@ void __init sme_early_init(void)
if (!sme_me_mask)
return;
+ cc_set_vendor(CC_VENDOR_AMD);
+
early_pmd_flags = __sme_set(early_pmd_flags);
__supported_pte_mask = __sme_set(__supported_pte_mask);
diff --git a/arch/x86/mm/mem_encrypt_identity.c b/arch/x86/mm/mem_encrypt_identity.c
index f415498d3175..6b1c60032400 100644
--- a/arch/x86/mm/mem_encrypt_identity.c
+++ b/arch/x86/mm/mem_encrypt_identity.c
@@ -611,7 +611,6 @@ void __init sme_enable(struct boot_params *bp)
out:
if (sme_me_mask) {
physical_mask &= ~sme_me_mask;
- cc_set_vendor(CC_VENDOR_AMD);
cc_set_mask(sme_me_mask);
}
}
And disallow cc_set_vendor() before x86_64_start_kernel(), then fix any fallout.
> We could do only the aspect of checking whether it hasn't been set yet
> and warn then, in order to make the usage more robust...
>
> --
> Regards/Gruss,
> Boris.
>
> https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2022-07-07 20:43 UTC|newest]
Thread overview: 129+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-07 21:33 [PATCH v12 00/46] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
2022-03-07 21:33 ` [PATCH v12 01/46] KVM: SVM: Define sev_features and vmpl field in the VMSA Brijesh Singh
2022-04-08 9:09 ` [tip: x86/sev] KVM: SVM: Define sev_features and VMPL " tip-bot2 for Brijesh Singh
2022-03-07 21:33 ` [PATCH v12 02/46] KVM: SVM: Create a separate mapping for the SEV-ES save area Brijesh Singh
2022-04-05 18:27 ` [PATCH v12 2.1/46] " Brijesh Singh
2022-04-05 18:55 ` Borislav Petkov
2022-04-08 9:09 ` [tip: x86/sev] " tip-bot2 for Tom Lendacky
2022-03-07 21:33 ` [PATCH v12 03/46] KVM: SVM: Create a separate mapping for the GHCB " Brijesh Singh
2022-04-08 9:09 ` [tip: x86/sev] " tip-bot2 for Tom Lendacky
2022-03-07 21:33 ` [PATCH v12 04/46] KVM: SVM: Update the SEV-ES save area mapping Brijesh Singh
2022-04-08 9:09 ` [tip: x86/sev] " tip-bot2 for Tom Lendacky
2022-03-07 21:33 ` [PATCH v12 05/46] x86/boot: Introduce helpers for MSR reads/writes Brijesh Singh
2022-04-08 9:09 ` [tip: x86/sev] " tip-bot2 for Michael Roth
2022-03-07 21:33 ` [PATCH v12 06/46] x86/boot: Use MSR read/write helpers instead of inline assembly Brijesh Singh
2022-04-08 9:09 ` [tip: x86/sev] " tip-bot2 for Michael Roth
2022-03-07 21:33 ` [PATCH v12 07/46] x86/compressed/64: Detect/setup SEV/SME features earlier in boot Brijesh Singh
2022-04-08 9:09 ` [tip: x86/sev] x86/compressed/64: Detect/setup SEV/SME features earlier during boot tip-bot2 for Michael Roth
2022-03-07 21:33 ` [PATCH v12 08/46] x86/sev: Detect/setup SEV/SME features earlier in boot Brijesh Singh
2022-04-08 9:09 ` [tip: x86/sev] " tip-bot2 for Michael Roth
2022-03-07 21:33 ` [PATCH v12 09/46] x86/mm: Extend cc_attr to include AMD SEV-SNP Brijesh Singh
2022-04-08 9:09 ` [tip: x86/sev] " tip-bot2 for Brijesh Singh
2022-03-07 21:33 ` [PATCH v12 10/46] x86/sev: Define the Linux specific guest termination reasons Brijesh Singh
2022-04-08 9:09 ` [tip: x86/sev] x86/sev: Define the Linux-specific " tip-bot2 for Brijesh Singh
2022-03-07 21:33 ` [PATCH v12 11/46] x86/sev: Save the negotiated GHCB version Brijesh Singh
2022-04-08 9:09 ` [tip: x86/sev] " tip-bot2 for Brijesh Singh
2022-03-07 21:33 ` [PATCH v12 12/46] x86/sev: Check SEV-SNP features support Brijesh Singh
2022-04-08 9:09 ` [tip: x86/sev] " tip-bot2 for Brijesh Singh
2022-03-07 21:33 ` [PATCH v12 13/46] x86/sev: Add a helper for the PVALIDATE instruction Brijesh Singh
2022-04-08 9:09 ` [tip: x86/sev] " tip-bot2 for Brijesh Singh
2022-03-07 21:33 ` [PATCH v12 14/46] x86/sev: Check the vmpl level Brijesh Singh
2022-04-08 9:09 ` [tip: x86/sev] x86/sev: Check the VMPL level tip-bot2 for Brijesh Singh
2022-03-07 21:33 ` [PATCH v12 15/46] x86/compressed: Add helper for validating pages in the decompression stage Brijesh Singh
2022-04-08 9:09 ` [tip: x86/sev] " tip-bot2 for Brijesh Singh
2022-03-07 21:33 ` [PATCH v12 16/46] x86/compressed: Register GHCB memory when SEV-SNP is active Brijesh Singh
2022-04-08 9:09 ` [tip: x86/sev] " tip-bot2 for Brijesh Singh
2022-03-07 21:33 ` [PATCH v12 17/46] x86/sev: " Brijesh Singh
2022-04-08 9:09 ` [tip: x86/sev] " tip-bot2 for Brijesh Singh
2022-03-07 21:33 ` [PATCH v12 18/46] x86/sev: Add helper for validating pages in early enc attribute changes Brijesh Singh
2022-04-08 9:09 ` [tip: x86/sev] " tip-bot2 for Brijesh Singh
2022-03-07 21:33 ` [PATCH v12 19/46] x86/kernel: Make the .bss..decrypted section shared in RMP table Brijesh Singh
2022-04-08 9:09 ` [tip: x86/sev] x86/kernel: Mark the .bss..decrypted section as shared in the " tip-bot2 for Brijesh Singh
2022-06-14 0:46 ` [PATCH v12 19/46] x86/kernel: Make the .bss..decrypted section shared in " Sean Christopherson
2022-06-14 15:43 ` Sean Christopherson
2022-06-14 16:01 ` Tom Lendacky
2022-06-14 16:13 ` Sean Christopherson
2022-06-14 19:00 ` Tom Lendacky
2022-06-14 19:52 ` Sean Christopherson
2022-06-16 16:17 ` Tom Lendacky
2022-06-16 16:41 ` Sean Christopherson
2022-07-01 16:51 ` Borislav Petkov
2022-07-07 20:43 ` Sean Christopherson [this message]
2022-03-07 21:33 ` [PATCH v12 20/46] x86/kernel: Validate ROM memory before accessing when SEV-SNP is active Brijesh Singh
2022-04-08 9:09 ` [tip: x86/sev] " tip-bot2 for Brijesh Singh
2022-03-07 21:33 ` [PATCH v12 21/46] x86/mm: Validate memory when changing the C-bit Brijesh Singh
2022-04-08 9:09 ` [tip: x86/sev] " tip-bot2 for Brijesh Singh
2022-03-07 21:33 ` [PATCH v12 22/46] x86/sev: Use SEV-SNP AP creation to start secondary CPUs Brijesh Singh
2022-04-05 0:24 ` Sean Christopherson
2022-04-05 16:20 ` Brijesh Singh
2022-04-05 19:41 ` Sean Christopherson
2022-04-08 9:09 ` [tip: x86/sev] " tip-bot2 for Tom Lendacky
2022-03-07 21:33 ` [PATCH v12 23/46] x86/head/64: Re-enable stack protection Brijesh Singh
2022-04-08 9:08 ` [tip: x86/sev] " tip-bot2 for Michael Roth
2022-03-07 21:33 ` [PATCH v12 24/46] x86/compressed/acpi: Move EFI detection to helper Brijesh Singh
2022-04-08 9:08 ` [tip: x86/sev] " tip-bot2 for Michael Roth
2022-03-07 21:33 ` [PATCH v12 25/46] x86/compressed/acpi: Move EFI system table lookup " Brijesh Singh
2022-04-08 9:08 ` [tip: x86/sev] " tip-bot2 for Michael Roth
2022-03-07 21:33 ` [PATCH v12 26/46] x86/compressed/acpi: Move EFI config " Brijesh Singh
2022-04-08 9:08 ` [tip: x86/sev] " tip-bot2 for Michael Roth
2022-03-07 21:33 ` [PATCH v12 27/46] x86/compressed/acpi: Move EFI vendor " Brijesh Singh
2022-04-08 9:08 ` [tip: x86/sev] " tip-bot2 for Michael Roth
2022-03-07 21:33 ` [PATCH v12 28/46] x86/compressed/acpi: Move EFI kexec handling into common code Brijesh Singh
2022-04-08 9:08 ` [tip: x86/sev] " tip-bot2 for Michael Roth
2022-03-07 21:33 ` [PATCH v12 29/46] x86/boot: Add Confidential Computing type to setup_data Brijesh Singh
2022-04-06 21:19 ` Thomas Gleixner
2022-04-07 14:47 ` Borislav Petkov
2022-04-07 14:57 ` Brijesh Singh
2022-07-17 5:08 ` H. Peter Anvin
2022-04-08 9:08 ` [tip: x86/sev] " tip-bot2 for Brijesh Singh
2022-03-07 21:33 ` [PATCH v12 30/46] KVM: x86: Move lookup of indexed CPUID leafs to helper Brijesh Singh
2022-04-08 9:08 ` [tip: x86/sev] " tip-bot2 for Michael Roth
2022-03-07 21:33 ` [PATCH v12 31/46] x86/sev: Move MSR-based VMGEXITs for CPUID " Brijesh Singh
2022-04-08 9:08 ` [tip: x86/sev] " tip-bot2 for Michael Roth
2022-03-07 21:33 ` [PATCH v12 32/46] x86/compressed/64: Add support for SEV-SNP CPUID table in #VC handlers Brijesh Singh
2022-03-10 14:51 ` Peter Gonda
2022-03-10 21:25 ` Michael Roth
2022-03-11 17:06 ` Joerg Roedel
2022-03-14 17:34 ` Peter Gonda
2022-03-17 13:11 ` Boris Petkov
2022-03-17 20:20 ` Peter Gonda
2022-04-08 9:08 ` [tip: x86/sev] " tip-bot2 for Michael Roth
2022-03-07 21:33 ` [PATCH v12 33/46] x86/boot: Add a pointer to Confidential Computing blob in bootparams Brijesh Singh
2022-04-08 9:08 ` [tip: x86/sev] " tip-bot2 for Michael Roth
2022-03-07 21:33 ` [PATCH v12 34/46] x86/compressed: Add SEV-SNP feature detection/setup Brijesh Singh
2022-04-08 9:08 ` [tip: x86/sev] " tip-bot2 for Michael Roth
2022-03-07 21:33 ` [PATCH v12 35/46] x86/compressed: Use firmware-validated CPUID leaves for SEV-SNP guests Brijesh Singh
2022-04-08 9:08 ` [tip: x86/sev] " tip-bot2 for Michael Roth
2022-03-07 21:33 ` [PATCH v12 36/46] x86/compressed: Export and rename add_identity_map() Brijesh Singh
2022-04-08 9:08 ` [tip: x86/sev] " tip-bot2 for Michael Roth
2022-03-07 21:33 ` [PATCH v12 37/46] x86/compressed/64: Add identity mapping for Confidential Computing blob Brijesh Singh
2022-04-08 9:08 ` [tip: x86/sev] " tip-bot2 for Michael Roth
2022-03-07 21:33 ` [PATCH v12 38/46] x86/sev: Add SEV-SNP feature detection/setup Brijesh Singh
2022-04-08 9:08 ` [tip: x86/sev] " tip-bot2 for Michael Roth
2022-03-07 21:33 ` [PATCH v12 39/46] x86/sev: Use firmware-validated CPUID for SEV-SNP guests Brijesh Singh
2022-04-08 9:08 ` [tip: x86/sev] " tip-bot2 for Michael Roth
2022-03-07 21:33 ` [PATCH v12 40/46] x86/sev: add sev=debug cmdline option to dump SNP CPUID table Brijesh Singh
2022-03-25 9:24 ` Borislav Petkov
2022-04-08 9:08 ` [tip: x86/sev] x86/sev: Add a sev= cmdline option tip-bot2 for Michael Roth
2022-03-07 21:33 ` [PATCH v12 41/46] x86/sev: Provide support for SNP guest request NAEs Brijesh Singh
2022-04-08 9:08 ` [tip: x86/sev] " tip-bot2 for Brijesh Singh
2022-03-07 21:33 ` [PATCH v12 42/46] x86/sev: Register SEV-SNP guest request platform device Brijesh Singh
2022-04-08 9:08 ` [tip: x86/sev] " tip-bot2 for Brijesh Singh
2022-03-07 21:33 ` [PATCH v12 43/46] virt: Add SEV-SNP guest driver Brijesh Singh
2022-04-08 9:08 ` [tip: x86/sev] " tip-bot2 for Brijesh Singh
2022-04-18 16:42 ` Dionna Amalie Glaze
2022-04-18 17:14 ` Borislav Petkov
2022-04-18 17:40 ` Tom Lendacky
2022-04-18 21:18 ` Borislav Petkov
2022-08-24 18:01 ` [PATCH v12 43/46] " Dionna Amalie Glaze
2022-08-24 19:28 ` Peter Gonda
2022-08-25 18:54 ` Tom Lendacky
2022-08-25 20:09 ` Peter Gonda
2022-03-07 21:33 ` [PATCH v12 44/46] virt: sevguest: Add support to derive key Brijesh Singh
2022-04-08 9:08 ` [tip: x86/sev] " tip-bot2 for Brijesh Singh
2022-03-07 21:33 ` [PATCH v12 45/46] virt: sevguest: Add support to get extended report Brijesh Singh
2022-04-08 9:08 ` [tip: x86/sev] " tip-bot2 for Brijesh Singh
2022-03-07 21:33 ` [PATCH v12 46/46] virt: sevguest: Add documentation for SEV-SNP CPUID Enforcement Brijesh Singh
2022-03-14 15:37 ` Peter Gonda
2022-04-08 9:08 ` [tip: x86/sev] " tip-bot2 for Michael Roth
2022-03-07 21:53 ` [PATCH v12 43.1/46] virt: Add SEV-SNP guest driver Brijesh Singh
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