diff options
Diffstat (limited to 'arch/x86/boot/startup/sev-startup.c')
| -rw-r--r-- | arch/x86/boot/startup/sev-startup.c | 220 |
1 files changed, 220 insertions, 0 deletions
diff --git a/arch/x86/boot/startup/sev-startup.c b/arch/x86/boot/startup/sev-startup.c new file mode 100644 index 000000000000..09725428d3e6 --- /dev/null +++ b/arch/x86/boot/startup/sev-startup.c @@ -0,0 +1,220 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * AMD Memory Encryption Support + * + * Copyright (C) 2019 SUSE + * + * Author: Joerg Roedel <jroedel@suse.de> + */ + +#define pr_fmt(fmt) "SEV: " fmt + +#include <linux/percpu-defs.h> +#include <linux/cc_platform.h> +#include <linux/printk.h> +#include <linux/mm_types.h> +#include <linux/set_memory.h> +#include <linux/memblock.h> +#include <linux/kernel.h> +#include <linux/mm.h> +#include <linux/cpumask.h> +#include <linux/efi.h> +#include <linux/io.h> +#include <linux/psp-sev.h> +#include <uapi/linux/sev-guest.h> + +#include <asm/init.h> +#include <asm/cpu_entry_area.h> +#include <asm/stacktrace.h> +#include <asm/sev.h> +#include <asm/sev-internal.h> +#include <asm/insn-eval.h> +#include <asm/fpu/xcr.h> +#include <asm/processor.h> +#include <asm/realmode.h> +#include <asm/setup.h> +#include <asm/traps.h> +#include <asm/svm.h> +#include <asm/smp.h> +#include <asm/cpu.h> +#include <asm/apic.h> +#include <asm/cpuid/api.h> +#include <asm/cmdline.h> + +/* 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; +} |