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* x86/sev: Mark snp_abort() noreturnBorislav Petkov2022-08-251-1/+1
| | | | | | | | | | | | | | | | | | Mark both the function prototype and definition as noreturn in order to prevent the compiler from doing transformations which confuse objtool like so: vmlinux.o: warning: objtool: sme_enable+0x71: unreachable instruction This triggers with gcc-12. Add it and sev_es_terminate() to the objtool noreturn tracking array too. Sort it while at it. Suggested-by: Michael Matz <matz@suse.de> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/20220824152420.20547-1-bp@alien8.de
* Revert "x86/sev: Expose sev_es_ghcb_hv_call() for use by HyperV"Borislav Petkov2022-07-271-6/+1
| | | | | | | | | | | | | | | 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
* x86/sev: Get the AP jump table address from secrets pageBrijesh Singh2022-04-271-0/+35
| | | | | | | | | | | | | | | | | | | | | | | | The GHCB specification section 2.7 states that when SEV-SNP is enabled, a guest should not rely on the hypervisor to provide the address of the AP jump table. Instead, if a guest BIOS wants to provide an AP jump table, it should record the address in the SNP secrets page so the guest operating system can obtain it directly from there. Fix this on the guest kernel side by having SNP guests use the AP jump table address published in the secrets page rather than issuing a GHCB request to get it. [ mroth: - Improve error handling when ioremap()/memremap() return NULL - Don't mix function calls with declarations - Add missing __init - Tweak commit message ] Fixes: 0afb6b660a6b ("x86/sev: Use SEV-SNP AP creation to start secondary CPUs") Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> Signed-off-by: Michael Roth <michael.roth@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20220422135624.114172-3-michael.roth@amd.com
* virt: sevguest: Change driver name to reflect generic SEV supportTom Lendacky2022-04-211-1/+1
| | | | | | | | | | | | | | | | During patch review, it was decided the SNP guest driver name should not be SEV-SNP specific, but should be generic for use with anything SEV. However, this feedback was missed and the driver name, and many of the driver functions and structures, are SEV-SNP name specific. Rename the driver to "sev-guest" (to match the misc device that is created) and update some of the function and structure names, too. While in the file, adjust the one pr_err() message to be a dev_err() message so that the message, if issued, uses the driver name. Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/307710bb5515c9088a19fd0b930268c7300479b2.1650464054.git.thomas.lendacky@amd.com
* x86/sev: Register SEV-SNP guest request platform deviceBrijesh Singh2022-04-071-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | Version 2 of the GHCB specification provides a Non Automatic Exit (NAE) event type that can be used by the SEV-SNP guest to communicate with the PSP without risk from a malicious hypervisor who wishes to read, alter, drop or replay the messages sent. SNP_LAUNCH_UPDATE can insert two special pages into the guest’s memory: the secrets page and the CPUID page. The PSP firmware populates the contents of the secrets page. The secrets page contains encryption keys used by the guest to interact with the firmware. Because the secrets page is encrypted with the guest’s memory encryption key, the hypervisor cannot read the keys. See SEV-SNP firmware spec for further details on the secrets page format. Create a platform device that the SEV-SNP guest driver can bind to get the platform resources such as encryption key and message id to use to communicate with the PSP. The SEV-SNP guest driver provides a userspace interface to get the attestation report, key derivation, extended attestation report etc. Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20220307213356.2797205-43-brijesh.singh@amd.com
* x86/sev: Provide support for SNP guest request NAEsBrijesh Singh2022-04-071-0/+14
| | | | | | | | | | | | | | | Version 2 of GHCB specification provides SNP_GUEST_REQUEST and SNP_EXT_GUEST_REQUEST NAE that can be used by the SNP guest to communicate with the PSP. While at it, add a snp_issue_guest_request() helper that will be used by driver or other subsystem to issue the request to PSP. See SEV-SNP firmware and GHCB spec for more details. Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20220307213356.2797205-42-brijesh.singh@amd.com
* x86/sev: Add SEV-SNP feature detection/setupMichael Roth2022-04-071-0/+2
| | | | | | | | | | | | 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
* x86/compressed: Add SEV-SNP feature detection/setupMichael Roth2022-04-071-0/+3
| | | | | | | | | | | | 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/20220307213356.2797205-35-brijesh.singh@amd.com
* x86/boot: Add Confidential Computing type to setup_dataBrijesh Singh2022-04-071-0/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | While launching encrypted guests, the hypervisor may need to provide some additional information during the guest boot. When booting under an EFI-based BIOS, the EFI configuration table contains an entry for the confidential computing blob that contains the required information. To support booting encrypted guests on non-EFI VMs, the hypervisor needs to pass this additional information to the guest kernel using a different method. For this purpose, introduce SETUP_CC_BLOB type in setup_data to hold the physical address of the confidential computing blob location. The boot loader or hypervisor may choose to use this method instead of an EFI configuration table. The CC blob location scanning should give preference to a setup_data blob over an EFI configuration table. In AMD SEV-SNP, the CC blob contains the address of the secrets and CPUID pages. The secrets page includes information such as a VM to PSP communication key and the CPUID page contains PSP-filtered CPUID values. Define the AMD SEV confidential computing blob structure. While at it, define the EFI GUID for the confidential computing blob. [ bp: Massage commit message, mark struct __packed. ] Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Ard Biesheuvel <ardb@kernel.org> Link: https://lore.kernel.org/r/20220307213356.2797205-30-brijesh.singh@amd.com
* x86/sev: Use SEV-SNP AP creation to start secondary CPUsTom Lendacky2022-04-061-0/+4
| | | | | | | | | | | | | | | | | | | | | | To provide a more secure way to start APs under SEV-SNP, use the SEV-SNP AP Creation NAE event. This allows for guest control over the AP register state rather than trusting the hypervisor with the SEV-ES Jump Table address. During native_smp_prepare_cpus(), invoke an SEV-SNP function that, if SEV-SNP is active, will set/override apic->wakeup_secondary_cpu. This will allow the SEV-SNP AP Creation NAE event method to be used to boot the APs. As a result of installing the override when SEV-SNP is active, this method of starting the APs becomes the required method. The override function will fail to start the AP if the hypervisor does not have support for AP creation. [ bp: Work in forgotten review comments. ] Signed-off-by: Tom Lendacky <thomas.lendacky@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/20220307213356.2797205-23-brijesh.singh@amd.com
* x86/mm: Validate memory when changing the C-bitBrijesh Singh2022-04-061-0/+4
| | | | | | | | | | Add the needed functionality to change pages state from shared to private and vice-versa using the Page State Change VMGEXIT as documented in the GHCB spec. Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20220307213356.2797205-22-brijesh.singh@amd.com
* x86/sev: Add helper for validating pages in early enc attribute changesBrijesh Singh2022-04-061-0/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | early_set_memory_{encrypted,decrypted}() are used for changing the page state from decrypted (shared) to encrypted (private) and vice versa. When SEV-SNP is active, the page state transition needs to go through additional steps. If the page is transitioned from shared to private, then perform the following after the encryption attribute is set in the page table: 1. Issue the page state change VMGEXIT to add the page as a private in the RMP table. 2. Validate the page after its successfully added in the RMP table. To maintain the security guarantees, if the page is transitioned from private to shared, then perform the following before clearing the encryption attribute from the page table. 1. Invalidate the page. 2. Issue the page state change VMGEXIT to make the page shared in the RMP table. early_set_memory_{encrypted,decrypted}() can be called before the GHCB is setup so use the SNP page state MSR protocol VMGEXIT defined in the GHCB specification to request the page state change in the RMP table. While at it, add a helper snp_prep_memory() which will be used in probe_roms(), in a later patch. [ 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/20220307213356.2797205-19-brijesh.singh@amd.com
* x86/sev: Register GHCB memory when SEV-SNP is activeBrijesh Singh2022-04-061-0/+2
| | | | | | | | | | | | | | 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
* x86/sev: Check the VMPL levelBrijesh Singh2022-04-061-0/+16
| | | | | | | | | | | | | | | | | | | | | | | | The Virtual Machine Privilege Level (VMPL) feature in the SEV-SNP architecture allows a guest VM to divide its address space into four levels. The level can be used to provide hardware isolated abstraction layers within a VM. VMPL0 is the highest privilege level, and VMPL3 is the least privilege level. Certain operations must be done by the VMPL0 software, such as: * Validate or invalidate memory range (PVALIDATE instruction) * Allocate VMSA page (RMPADJUST instruction when VMSA=1) The initial SNP support requires that the guest kernel is running at VMPL0. Add such a check to verify the guest is running at level 0 before continuing the boot. There is no easy method to query the current VMPL level, so use the RMPADJUST instruction to determine whether the guest is running at the VMPL0. [ 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/20220307213356.2797205-15-brijesh.singh@amd.com
* x86/sev: Add a helper for the PVALIDATE instructionBrijesh Singh2022-04-061-0/+21
| | | | | | | | | | | | | | | An SNP-active guest uses the PVALIDATE instruction to validate or rescind the validation of a guest page’s RMP entry. Upon completion, a return code is stored in EAX and rFLAGS bits are set based on the return code. If the instruction completed successfully, the carry flag (CF) indicates if the content of the RMP were changed or not. See AMD APM Volume 3 for additional details. 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/20220307213356.2797205-14-brijesh.singh@amd.com
* x86/sev: Check SEV-SNP features supportBrijesh Singh2022-04-061-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* x86/sev: Save the negotiated GHCB versionBrijesh Singh2022-04-061-1/+1
| | | | | | | | | | | 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
* x86/sev: Expose sev_es_ghcb_hv_call() for use by HyperVTianyu Lan2021-10-251-0/+6
| | | | | | | | | | | | | | | | | | | | | | 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
* x86/sev: Move GHCB MSR protocol and NAE definitions in a common headerBrijesh Singh2021-05-101-26/+4
| | | | | | | | | | | | | | | | | 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
* x86/sev-es: Rename sev-es.{ch} to sev.{ch}Brijesh Singh2021-05-101-0/+114
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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