// SPDX-License-Identifier: GPL-2.0-only /* * AMD Memory Encryption Support * * Copyright (C) 2019 SUSE * * Author: Joerg Roedel */ #define pr_fmt(fmt) "SEV: " fmt #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* Include code shared with pre-decompression boot stage */ #include "sev-shared.c" void early_set_pages_state(unsigned long vaddr, unsigned long paddr, unsigned long npages, const struct psc_desc *desc) { unsigned long paddr_end; vaddr = vaddr & PAGE_MASK; paddr = paddr & PAGE_MASK; paddr_end = paddr + (npages << PAGE_SHIFT); while (paddr < paddr_end) { __page_state_change(vaddr, paddr, desc); vaddr += PAGE_SIZE; paddr += PAGE_SIZE; } } void __init early_snp_set_memory_private(unsigned long vaddr, unsigned long paddr, unsigned long npages) { struct psc_desc d = { SNP_PAGE_STATE_PRIVATE, rip_rel_ptr(&boot_svsm_ca_page), boot_svsm_caa_pa }; /* * This can be invoked in early boot while running identity mapped, so * use an open coded check for SNP instead of using cc_platform_has(). * This eliminates worries about jump tables or checking boot_cpu_data * in the cc_platform_has() function. */ if (!(sev_status & MSR_AMD64_SEV_SNP_ENABLED)) return; /* * Ask the hypervisor to mark the memory pages as private in the RMP * table. */ early_set_pages_state(vaddr, paddr, npages, &d); } void __init early_snp_set_memory_shared(unsigned long vaddr, unsigned long paddr, unsigned long npages) { struct psc_desc d = { SNP_PAGE_STATE_SHARED, rip_rel_ptr(&boot_svsm_ca_page), boot_svsm_caa_pa }; /* * This can be invoked in early boot while running identity mapped, so * use an open coded check for SNP instead of using cc_platform_has(). * This eliminates worries about jump tables or checking boot_cpu_data * in the cc_platform_has() function. */ if (!(sev_status & MSR_AMD64_SEV_SNP_ENABLED)) return; /* Ask hypervisor to mark the memory pages shared in the RMP table. */ early_set_pages_state(vaddr, paddr, npages, &d); } /* * Initial set up of SNP relies on information provided by the * Confidential Computing blob, which can be passed to the kernel * in the following ways, depending on how it is booted: * * - when booted via the boot/decompress kernel: * - via boot_params * * - when booted directly by firmware/bootloader (e.g. CONFIG_PVH): * - via a setup_data entry, as defined by the Linux Boot Protocol * * Scan for the blob in that order. */ static struct cc_blob_sev_info *__init find_cc_blob(struct boot_params *bp) { struct cc_blob_sev_info *cc_info; /* Boot kernel would have passed the CC blob via boot_params. */ if (bp->cc_blob_address) { cc_info = (struct cc_blob_sev_info *)(unsigned long)bp->cc_blob_address; goto found_cc_info; } /* * If kernel was booted directly, without the use of the * boot/decompression kernel, the CC blob may have been passed via * setup_data instead. */ cc_info = find_cc_blob_setup_data(bp); if (!cc_info) return NULL; found_cc_info: if (cc_info->magic != CC_BLOB_SEV_HDR_MAGIC) sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED); return cc_info; } static void __init svsm_setup(struct cc_blob_sev_info *cc_info) { struct snp_secrets_page *secrets = (void *)cc_info->secrets_phys; struct svsm_call call = {}; u64 pa; /* * Record the SVSM Calling Area address (CAA) if the guest is not * running at VMPL0. The CA will be used to communicate with the * SVSM to perform the SVSM services. */ if (!svsm_setup_ca(cc_info, rip_rel_ptr(&boot_svsm_ca_page))) return; /* * It is very early in the boot and the kernel is running identity * mapped but without having adjusted the pagetables to where the * kernel was loaded (physbase), so the get the CA address using * RIP-relative addressing. */ pa = (u64)rip_rel_ptr(&boot_svsm_ca_page); /* * Switch over to the boot SVSM CA while the current CA is still 1:1 * mapped and thus addressable with VA == PA. There is no GHCB at this * point so use the MSR protocol. * * SVSM_CORE_REMAP_CA call: * RAX = 0 (Protocol=0, CallID=0) * RCX = New CA GPA */ call.caa = (struct svsm_ca *)secrets->svsm_caa; call.rax = SVSM_CORE_CALL(SVSM_CORE_REMAP_CA); call.rcx = pa; if (svsm_call_msr_protocol(&call)) sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_SVSM_CA_REMAP_FAIL); boot_svsm_caa_pa = pa; } bool __init snp_init(struct boot_params *bp) { struct cc_blob_sev_info *cc_info; if (!bp) return false; cc_info = find_cc_blob(bp); if (!cc_info) return false; if (cc_info->secrets_phys && cc_info->secrets_len == PAGE_SIZE) sev_secrets_pa = cc_info->secrets_phys; else return false; setup_cpuid_table(cc_info); svsm_setup(cc_info); /* * The CC blob will be used later to access the secrets page. Cache * it here like the boot kernel does. */ bp->cc_blob_address = (u32)(unsigned long)cc_info; return true; }