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2023-06-06x86/sev: Add SNP-specific unaccepted memory supportTom Lendacky
Add SNP-specific hooks to the unaccepted memory support in the boot path (__accept_memory()) and the core kernel (accept_memory()) in order to support booting SNP guests when unaccepted memory is present. Without this support, SNP guests will fail to boot and/or panic() when unaccepted memory is present in the EFI memory map. The process of accepting memory under SNP involves invoking the hypervisor to perform a page state change for the page to private memory and then issuing a PVALIDATE instruction to accept the page. Since the boot path and the core kernel paths perform similar operations, move the pvalidate_pages() and vmgexit_psc() functions into sev-shared.c to avoid code duplication. Create the new header file arch/x86/boot/compressed/sev.h because adding the function declaration to any of the existing SEV related header files pulls in too many other header files, causing the build to fail. Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/r/a52fa69f460fd1876d70074b20ad68210dfc31dd.1686063086.git.thomas.lendacky@amd.com
2022-07-27Revert "x86/sev: Expose sev_es_ghcb_hv_call() for use by HyperV"Borislav Petkov
This reverts commit 007faec014cb5d26983c1f86fd08c6539b41392e. Now that hyperv does its own protocol negotiation: 49d6a3c062a1 ("x86/Hyper-V: Add SEV negotiate protocol support in Isolation VM") revert this exposure of the sev_es_ghcb_hv_call() helper. Cc: Wei Liu <wei.liu@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by：Tianyu Lan <tiala@microsoft.com> Link: https://lore.kernel.org/r/20220614014553.1915929-1-ltykernel@gmail.com
2022-05-17x86/sev: Remove duplicated assignment to variable infoColin Ian King
Variable info is being assigned the same value twice, remove the redundant assignment. Also assign variable v in the declaration. Cleans up clang scan warning: warning: Value stored to 'info' during its initialization is never read [deadcode.DeadStores] No code changed: # arch/x86/kernel/sev.o: text data bss dec hex filename 19878 4487 4112 28477 6f3d sev.o.before 19878 4487 4112 28477 6f3d sev.o.after md5: bfbaa515af818615fd01fea91e7eba1b sev.o.before.asm bfbaa515af818615fd01fea91e7eba1b sev.o.after.asm [ bp: Running the before/after check on sev.c because sev-shared.c gets included into it. ] Fixes: 597cfe48212a ("x86/boot/compressed/64: Setup a GHCB-based VC Exception handler") Signed-off-by: Colin Ian King <colin.i.king@gmail.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20220516184215.51841-1-colin.i.king@gmail.com
2022-04-07x86/sev: Use firmware-validated CPUID for SEV-SNP guestsMichael Roth
SEV-SNP guests will be provided the location of special 'secrets' and 'CPUID' pages via the Confidential Computing blob. This blob is provided to the run-time kernel either through a boot_params field that was initialized by the boot/compressed kernel, or via a setup_data structure as defined by the Linux Boot Protocol. Locate the Confidential Computing blob from these sources and, if found, use the provided CPUID page/table address to create a copy that the run-time kernel will use when servicing CPUID instructions via a #VC handler. Signed-off-by: Michael Roth <michael.roth@amd.com> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20220307213356.2797205-40-brijesh.singh@amd.com
2022-04-07x86/sev: Add SEV-SNP feature detection/setupMichael Roth
Initial/preliminary detection of SEV-SNP is done via the Confidential Computing blob. Check for it prior to the normal SEV/SME feature initialization, and add some sanity checks to confirm it agrees with SEV-SNP CPUID/MSR bits. Signed-off-by: Michael Roth <michael.roth@amd.com> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20220307213356.2797205-39-brijesh.singh@amd.com
2022-04-07x86/compressed/64: Add support for SEV-SNP CPUID table in #VC handlersMichael Roth
CPUID instructions generate a #VC exception for SEV-ES/SEV-SNP guests, for which early handlers are currently set up to handle. In the case of SEV-SNP, guests can use a configurable location in guest memory that has been pre-populated with a firmware-validated CPUID table to look up the relevant CPUID values rather than requesting them from hypervisor via a VMGEXIT. Add the various hooks in the #VC handlers to allow CPUID instructions to be handled via the table. The code to actually configure/enable the table will be added in a subsequent commit. Signed-off-by: Michael Roth <michael.roth@amd.com> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20220307213356.2797205-33-brijesh.singh@amd.com
2022-04-07x86/sev: Move MSR-based VMGEXITs for CPUID to helperMichael Roth
This code will also be used later for SEV-SNP-validated CPUID code in some cases, so move it to a common helper. While here, also add a check to terminate in cases where the CPUID function/subfunction is indexed and the subfunction is non-zero, since the GHCB MSR protocol does not support non-zero subfunctions. Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Michael Roth <michael.roth@amd.com> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20220307213356.2797205-32-brijesh.singh@amd.com
2022-04-06x86/sev: Register GHCB memory when SEV-SNP is activeBrijesh Singh
The SEV-SNP guest is required by the GHCB spec to register the GHCB's Guest Physical Address (GPA). This is because the hypervisor may prefer that a guest uses a consistent and/or specific GPA for the GHCB associated with a vCPU. For more information, see the GHCB specification section "GHCB GPA Registration". [ bp: Cleanup comments. ] Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20220307213356.2797205-18-brijesh.singh@amd.com
2022-04-06x86/compressed: Register GHCB memory when SEV-SNP is activeBrijesh Singh
The SEV-SNP guest is required by the GHCB spec to register the GHCB's Guest Physical Address (GPA). This is because the hypervisor may prefer that a guest use a consistent and/or specific GPA for the GHCB associated with a vCPU. For more information, see the GHCB specification section "GHCB GPA Registration". If hypervisor can not work with the guest provided GPA then terminate the guest boot. Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Venu Busireddy <venu.busireddy@oracle.com> Link: https://lore.kernel.org/r/20220307213356.2797205-17-brijesh.singh@amd.com
2022-04-06x86/sev: Check SEV-SNP features supportBrijesh Singh
Version 2 of the GHCB specification added the advertisement of features that are supported by the hypervisor. If the hypervisor supports SEV-SNP then it must set the SEV-SNP features bit to indicate that the base functionality is supported. Check that feature bit while establishing the GHCB; if failed, terminate the guest. Version 2 of the GHCB specification adds several new Non-Automatic Exits (NAEs), most of them are optional except the hypervisor feature. Now that the hypervisor feature NAE is implemented, bump the GHCB maximum supported protocol version. While at it, move the GHCB protocol negotiation check from the #VC exception handler to sev_enable() so that all feature detection happens before the first #VC exception. While at it, document why the GHCB page cannot be setup from load_stage2_idt(). [ bp: Massage commit message. ] Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20220307213356.2797205-13-brijesh.singh@amd.com
2022-04-06x86/sev: Save the negotiated GHCB versionBrijesh Singh
The SEV-ES guest calls sev_es_negotiate_protocol() to negotiate the GHCB protocol version before establishing the GHCB. Cache the negotiated GHCB version so that it can be used later. Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Venu Busireddy <venu.busireddy@oracle.com> Link: https://lore.kernel.org/r/20220307213356.2797205-12-brijesh.singh@amd.com
2022-04-06x86/sev: Define the Linux-specific guest termination reasonsBrijesh Singh
The GHCB specification defines the reason code for reason set 0. The reason codes defined in the set 0 do not cover all possible causes for a guest to request termination. The reason sets 1 to 255 are reserved for the vendor-specific codes. Reserve the reason set 1 for the Linux guest. Define the error codes for reason set 1 so that one can have meaningful termination reasons and thus better guest failure diagnosis. While at it, change sev_es_terminate() to accept a reason set parameter. [ bp: Massage commit message. ] Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Venu Busireddy <venu.busireddy@oracle.com> Link: https://lore.kernel.org/r/20220307213356.2797205-11-brijesh.singh@amd.com
2021-11-15x86/sev: Shorten GHCB terminate macro namesBrijesh Singh
Shorten macro names for improved readability. Suggested-by: Borislav Petkov <bp@suse.de> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Venu Busireddy <venu.busireddy@oracle.com> Link: https://lkml.kernel.org/r/20211110220731.2396491-5-brijesh.singh@amd.com
2021-11-01Merge tag 'x86_sev_for_v5.16_rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 SEV updates from Borislav Petkov: - Export sev_es_ghcb_hv_call() so that HyperV Isolation VMs can use it too - Non-urgent fixes and cleanups * tag 'x86_sev_for_v5.16_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/sev: Expose sev_es_ghcb_hv_call() for use by HyperV x86/sev: Allow #VC exceptions on the VC2 stack x86/sev: Fix stack type check in vc_switch_off_ist() x86/sme: Use #define USE_EARLY_PGTABLE_L5 in mem_encrypt_identity.c x86/sev: Carve out HV call's return value verification
2021-11-01Merge tag 'objtool-core-2021-10-31' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull objtool updates from Thomas Gleixner: - Improve retpoline code patching by separating it from alternatives which reduces memory footprint and allows to do better optimizations in the actual runtime patching. - Add proper retpoline support for x86/BPF - Address noinstr warnings in x86/kvm, lockdep and paravirtualization code - Add support to handle pv_opsindirect calls in the noinstr analysis - Classify symbols upfront and cache the result to avoid redundant str*cmp() invocations. - Add a CFI hash to reduce memory consumption which also reduces runtime on a allyesconfig by ~50% - Adjust XEN code to make objtool handling more robust and as a side effect to prevent text fragmentation due to placement of the hypercall page. * tag 'objtool-core-2021-10-31' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (41 commits) bpf,x86: Respect X86_FEATURE_RETPOLINE* bpf,x86: Simplify computing label offsets x86,bugs: Unconditionally allow spectre_v2=retpoline,amd x86/alternative: Add debug prints to apply_retpolines() x86/alternative: Try inline spectre_v2=retpoline,amd x86/alternative: Handle Jcc __x86_indirect_thunk_\reg x86/alternative: Implement .retpoline_sites support x86/retpoline: Create a retpoline thunk array x86/retpoline: Move the retpoline thunk declarations to nospec-branch.h x86/asm: Fixup odd GEN-for-each-reg.h usage x86/asm: Fix register order x86/retpoline: Remove unused replacement symbols objtool,x86: Replace alternatives with .retpoline_sites objtool: Shrink struct instruction objtool: Explicitly avoid self modifying code in .altinstr_replacement objtool: Classify symbols objtool: Support pv_opsindirect calls for noinstr x86/xen: Rework the xen_{cpu,irq,mmu}_opsarrays x86/xen: Mark xen_force_evtchn_callback() noinstr x86/xen: Make irq_disable() noinstr ...
2021-10-25x86/sev: Expose sev_es_ghcb_hv_call() for use by HyperVTianyu Lan
Hyper-V needs to issue the GHCB HV call in order to read/write MSRs in Isolation VMs. For that, expose sev_es_ghcb_hv_call(). The Hyper-V Isolation VMs are unenlightened guests and run a paravisor at VMPL0 for communicating. GHCB pages are being allocated and set up by that paravisor. Linux gets the GHCB page's physical address via MSR_AMD64_SEV_ES_GHCB from the paravisor and should not change it. Add a @set_ghcb_msr parameter to sev_es_ghcb_hv_call() to control whether the function should set the GHCB's address prior to the call or not and export that function for use by HyperV. [ bp: - Massage commit message - add a struct ghcb forward declaration to fix randconfig builds. ] Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/20211025122116.264793-6-ltykernel@gmail.com
2021-10-19x86/sev: Carve out HV call's return value verificationBorislav Petkov
Carve out the verification of the HV call return value into a separate helper and make it more readable. No functional changes. Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/YVbYWz%2B8J7iMTJjc@zn.tnic
2021-10-01x86/sev: Return an error on a returned non-zero SW_EXITINFO1[31:0]Tom Lendacky
After returning from a VMGEXIT NAE event, SW_EXITINFO1[31:0] is checked for a value of 1, which indicates an error and that SW_EXITINFO2 contains exception information. However, future versions of the GHCB specification may define new values for SW_EXITINFO1[31:0], so really any non-zero value should be treated as an error. Fixes: 597cfe48212a ("x86/boot/compressed/64: Setup a GHCB-based VC Exception handler") Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: <stable@vger.kernel.org> # 5.10+ Link: https://lkml.kernel.org/r/efc772af831e9e7f517f0439b13b41f56bad8784.1633063321.git.thomas.lendacky@amd.com
2021-09-15x86/sev: Fix noinstr for vc_ghcb_invalidate()Peter Zijlstra
vmlinux.o: warning: objtool: __sev_put_ghcb()+0x88: call to __memset() leaves .noinstr.text section vmlinux.o: warning: objtool: __sev_es_nmi_complete()+0x39: call to __memset() leaves .noinstr.text section Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20210624095148.250770465@infradead.org
2021-05-18x86/sev-es: Invalidate the GHCB after completing VMGEXITTom Lendacky
Since the VMGEXIT instruction can be issued from userspace, invalidate the GHCB after performing VMGEXIT processing in the kernel. Invalidation is only required after userspace is available, so call vc_ghcb_invalidate() from sev_es_put_ghcb(). Update vc_ghcb_invalidate() to additionally clear the GHCB exit code so that it is always presented as 0 when VMGEXIT has been issued by anything else besides the kernel. Fixes: 0786138c78e79 ("x86/sev-es: Add a Runtime #VC Exception Handler") Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/5a8130462e4f0057ee1184509cd056eedd78742b.1621273353.git.thomas.lendacky@amd.com
2021-05-10x86/sev: Move GHCB MSR protocol and NAE definitions in a common headerBrijesh Singh
The guest and the hypervisor contain separate macros to get and set the GHCB MSR protocol and NAE event fields. Consolidate the GHCB protocol definitions and helper macros in one place. Leave the supported protocol version define in separate files to keep the guest and hypervisor flexibility to support different GHCB version in the same release. There is no functional change intended. Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Joerg Roedel <jroedel@suse.de> Link: https://lkml.kernel.org/r/20210427111636.1207-3-brijesh.singh@amd.com
2021-05-10x86/sev-es: Rename sev-es.{ch} to sev.{ch}Brijesh Singh
SEV-SNP builds upon the SEV-ES functionality while adding new hardware protection. Version 2 of the GHCB specification adds new NAE events that are SEV-SNP specific. Rename the sev-es.{ch} to sev.{ch} so that all SEV* functionality can be consolidated in one place. Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Joerg Roedel <jroedel@suse.de> Link: https://lkml.kernel.org/r/20210427111636.1207-2-brijesh.singh@amd.com
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