diff options
Diffstat (limited to 'arch/x86/kernel/sev.c')
| -rw-r--r-- | arch/x86/kernel/sev.c | 2314 |
1 files changed, 0 insertions, 2314 deletions
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c deleted file mode 100644 index b59b09c2f284..000000000000 --- a/arch/x86/kernel/sev.c +++ /dev/null @@ -1,2314 +0,0 @@ -// 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/sched/debug.h> /* For show_regs() */ -#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/platform_device.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/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.h> -#include <asm/cmdline.h> - -#define DR7_RESET_VALUE 0x400 - -/* AP INIT values as documented in the APM2 section "Processor Initialization State" */ -#define AP_INIT_CS_LIMIT 0xffff -#define AP_INIT_DS_LIMIT 0xffff -#define AP_INIT_LDTR_LIMIT 0xffff -#define AP_INIT_GDTR_LIMIT 0xffff -#define AP_INIT_IDTR_LIMIT 0xffff -#define AP_INIT_TR_LIMIT 0xffff -#define AP_INIT_RFLAGS_DEFAULT 0x2 -#define AP_INIT_DR6_DEFAULT 0xffff0ff0 -#define AP_INIT_GPAT_DEFAULT 0x0007040600070406ULL -#define AP_INIT_XCR0_DEFAULT 0x1 -#define AP_INIT_X87_FTW_DEFAULT 0x5555 -#define AP_INIT_X87_FCW_DEFAULT 0x0040 -#define AP_INIT_CR0_DEFAULT 0x60000010 -#define AP_INIT_MXCSR_DEFAULT 0x1f80 - -static const char * const sev_status_feat_names[] = { - [MSR_AMD64_SEV_ENABLED_BIT] = "SEV", - [MSR_AMD64_SEV_ES_ENABLED_BIT] = "SEV-ES", - [MSR_AMD64_SEV_SNP_ENABLED_BIT] = "SEV-SNP", - [MSR_AMD64_SNP_VTOM_BIT] = "vTom", - [MSR_AMD64_SNP_REFLECT_VC_BIT] = "ReflectVC", - [MSR_AMD64_SNP_RESTRICTED_INJ_BIT] = "RI", - [MSR_AMD64_SNP_ALT_INJ_BIT] = "AI", - [MSR_AMD64_SNP_DEBUG_SWAP_BIT] = "DebugSwap", - [MSR_AMD64_SNP_PREVENT_HOST_IBS_BIT] = "NoHostIBS", - [MSR_AMD64_SNP_BTB_ISOLATION_BIT] = "BTBIsol", - [MSR_AMD64_SNP_VMPL_SSS_BIT] = "VmplSSS", - [MSR_AMD64_SNP_SECURE_TSC_BIT] = "SecureTSC", - [MSR_AMD64_SNP_VMGEXIT_PARAM_BIT] = "VMGExitParam", - [MSR_AMD64_SNP_IBS_VIRT_BIT] = "IBSVirt", - [MSR_AMD64_SNP_VMSA_REG_PROT_BIT] = "VMSARegProt", - [MSR_AMD64_SNP_SMT_PROT_BIT] = "SMTProt", -}; - -/* For early boot hypervisor communication in SEV-ES enabled guests */ -static struct ghcb boot_ghcb_page __bss_decrypted __aligned(PAGE_SIZE); - -/* - * Needs to be in the .data section because we need it NULL before bss is - * cleared - */ -static struct ghcb *boot_ghcb __section(".data"); - -/* Bitmap of SEV features supported by the hypervisor */ -static u64 sev_hv_features __ro_after_init; - -/* #VC handler runtime per-CPU data */ -struct sev_es_runtime_data { - struct ghcb ghcb_page; - - /* - * Reserve one page per CPU as backup storage for the unencrypted GHCB. - * It is needed when an NMI happens while the #VC handler uses the real - * GHCB, and the NMI handler itself is causing another #VC exception. In - * that case the GHCB content of the first handler needs to be backed up - * and restored. - */ - struct ghcb backup_ghcb; - - /* - * Mark the per-cpu GHCBs as in-use to detect nested #VC exceptions. - * There is no need for it to be atomic, because nothing is written to - * the GHCB between the read and the write of ghcb_active. So it is safe - * to use it when a nested #VC exception happens before the write. - * - * This is necessary for example in the #VC->NMI->#VC case when the NMI - * happens while the first #VC handler uses the GHCB. When the NMI code - * raises a second #VC handler it might overwrite the contents of the - * GHCB written by the first handler. To avoid this the content of the - * GHCB is saved and restored when the GHCB is detected to be in use - * already. - */ - bool ghcb_active; - bool backup_ghcb_active; - - /* - * Cached DR7 value - write it on DR7 writes and return it on reads. - * That value will never make it to the real hardware DR7 as debugging - * is currently unsupported in SEV-ES guests. - */ - unsigned long dr7; -}; - -struct ghcb_state { - struct ghcb *ghcb; -}; - -static DEFINE_PER_CPU(struct sev_es_runtime_data*, runtime_data); -static DEFINE_PER_CPU(struct sev_es_save_area *, sev_vmsa); - -struct sev_config { - __u64 debug : 1, - - /* - * A flag used by __set_pages_state() that indicates when the - * per-CPU GHCB has been created and registered and thus can be - * used by the BSP instead of the early boot GHCB. - * - * For APs, the per-CPU GHCB is created before they are started - * and registered upon startup, so this flag can be used globally - * for the BSP and APs. - */ - ghcbs_initialized : 1, - - __reserved : 62; -}; - -static struct sev_config sev_cfg __read_mostly; - -static __always_inline bool on_vc_stack(struct pt_regs *regs) -{ - unsigned long sp = regs->sp; - - /* User-mode RSP is not trusted */ - if (user_mode(regs)) - return false; - - /* SYSCALL gap still has user-mode RSP */ - if (ip_within_syscall_gap(regs)) - return false; - - return ((sp >= __this_cpu_ist_bottom_va(VC)) && (sp < __this_cpu_ist_top_va(VC))); -} - -/* - * This function handles the case when an NMI is raised in the #VC - * exception handler entry code, before the #VC handler has switched off - * its IST stack. In this case, the IST entry for #VC must be adjusted, - * so that any nested #VC exception will not overwrite the stack - * contents of the interrupted #VC handler. - * - * The IST entry is adjusted unconditionally so that it can be also be - * unconditionally adjusted back in __sev_es_ist_exit(). Otherwise a - * nested sev_es_ist_exit() call may adjust back the IST entry too - * early. - * - * The __sev_es_ist_enter() and __sev_es_ist_exit() functions always run - * on the NMI IST stack, as they are only called from NMI handling code - * right now. - */ -void noinstr __sev_es_ist_enter(struct pt_regs *regs) -{ - unsigned long old_ist, new_ist; - - /* Read old IST entry */ - new_ist = old_ist = __this_cpu_read(cpu_tss_rw.x86_tss.ist[IST_INDEX_VC]); - - /* - * If NMI happened while on the #VC IST stack, set the new IST - * value below regs->sp, so that the interrupted stack frame is - * not overwritten by subsequent #VC exceptions. - */ - if (on_vc_stack(regs)) - new_ist = regs->sp; - - /* - * Reserve additional 8 bytes and store old IST value so this - * adjustment can be unrolled in __sev_es_ist_exit(). - */ - new_ist -= sizeof(old_ist); - *(unsigned long *)new_ist = old_ist; - - /* Set new IST entry */ - this_cpu_write(cpu_tss_rw.x86_tss.ist[IST_INDEX_VC], new_ist); -} - -void noinstr __sev_es_ist_exit(void) -{ - unsigned long ist; - - /* Read IST entry */ - ist = __this_cpu_read(cpu_tss_rw.x86_tss.ist[IST_INDEX_VC]); - - if (WARN_ON(ist == __this_cpu_ist_top_va(VC))) - return; - - /* Read back old IST entry and write it to the TSS */ - this_cpu_write(cpu_tss_rw.x86_tss.ist[IST_INDEX_VC], *(unsigned long *)ist); -} - -/* - * Nothing shall interrupt this code path while holding the per-CPU - * GHCB. The backup GHCB is only for NMIs interrupting this path. - * - * Callers must disable local interrupts around it. - */ -static noinstr struct ghcb *__sev_get_ghcb(struct ghcb_state *state) -{ - struct sev_es_runtime_data *data; - struct ghcb *ghcb; - - WARN_ON(!irqs_disabled()); - - data = this_cpu_read(runtime_data); - ghcb = &data->ghcb_page; - - if (unlikely(data->ghcb_active)) { - /* GHCB is already in use - save its contents */ - - if (unlikely(data->backup_ghcb_active)) { - /* - * Backup-GHCB is also already in use. There is no way - * to continue here so just kill the machine. To make - * panic() work, mark GHCBs inactive so that messages - * can be printed out. - */ - data->ghcb_active = false; - data->backup_ghcb_active = false; - - instrumentation_begin(); - panic("Unable to handle #VC exception! GHCB and Backup GHCB are already in use"); - instrumentation_end(); - } - - /* Mark backup_ghcb active before writing to it */ - data->backup_ghcb_active = true; - - state->ghcb = &data->backup_ghcb; - - /* Backup GHCB content */ - *state->ghcb = *ghcb; - } else { - state->ghcb = NULL; - data->ghcb_active = true; - } - - return ghcb; -} - -static inline u64 sev_es_rd_ghcb_msr(void) -{ - return __rdmsr(MSR_AMD64_SEV_ES_GHCB); -} - -static __always_inline void sev_es_wr_ghcb_msr(u64 val) -{ - u32 low, high; - - low = (u32)(val); - high = (u32)(val >> 32); - - native_wrmsr(MSR_AMD64_SEV_ES_GHCB, low, high); -} - -static int vc_fetch_insn_kernel(struct es_em_ctxt *ctxt, - unsigned char *buffer) -{ - return copy_from_kernel_nofault(buffer, (unsigned char *)ctxt->regs->ip, MAX_INSN_SIZE); -} - -static enum es_result __vc_decode_user_insn(struct es_em_ctxt *ctxt) -{ - char buffer[MAX_INSN_SIZE]; - int insn_bytes; - - insn_bytes = insn_fetch_from_user_inatomic(ctxt->regs, buffer); - if (insn_bytes == 0) { - /* Nothing could be copied */ - ctxt->fi.vector = X86_TRAP_PF; - ctxt->fi.error_code = X86_PF_INSTR | X86_PF_USER; - ctxt->fi.cr2 = ctxt->regs->ip; - return ES_EXCEPTION; - } else if (insn_bytes == -EINVAL) { - /* Effective RIP could not be calculated */ - ctxt->fi.vector = X86_TRAP_GP; - ctxt->fi.error_code = 0; - ctxt->fi.cr2 = 0; - return ES_EXCEPTION; - } - - if (!insn_decode_from_regs(&ctxt->insn, ctxt->regs, buffer, insn_bytes)) - return ES_DECODE_FAILED; - - if (ctxt->insn.immediate.got) - return ES_OK; - else - return ES_DECODE_FAILED; -} - -static enum es_result __vc_decode_kern_insn(struct es_em_ctxt *ctxt) -{ - char buffer[MAX_INSN_SIZE]; - int res, ret; - - res = vc_fetch_insn_kernel(ctxt, buffer); - if (res) { - ctxt->fi.vector = X86_TRAP_PF; - ctxt->fi.error_code = X86_PF_INSTR; - ctxt->fi.cr2 = ctxt->regs->ip; - return ES_EXCEPTION; - } - - ret = insn_decode(&ctxt->insn, buffer, MAX_INSN_SIZE, INSN_MODE_64); - if (ret < 0) - return ES_DECODE_FAILED; - else - return ES_OK; -} - -static enum es_result vc_decode_insn(struct es_em_ctxt *ctxt) -{ - if (user_mode(ctxt->regs)) - return __vc_decode_user_insn(ctxt); - else - return __vc_decode_kern_insn(ctxt); -} - -static enum es_result vc_write_mem(struct es_em_ctxt *ctxt, - char *dst, char *buf, size_t size) -{ - unsigned long error_code = X86_PF_PROT | X86_PF_WRITE; - - /* - * This function uses __put_user() independent of whether kernel or user - * memory is accessed. This works fine because __put_user() does no - * sanity checks of the pointer being accessed. All that it does is - * to report when the access failed. - * - * Also, this function runs in atomic context, so __put_user() is not - * allowed to sleep. The page-fault handler detects that it is running - * in atomic context and will not try to take mmap_sem and handle the - * fault, so additional pagefault_enable()/disable() calls are not - * needed. - * - * The access can't be done via copy_to_user() here because - * vc_write_mem() must not use string instructions to access unsafe - * memory. The reason is that MOVS is emulated by the #VC handler by - * splitting the move up into a read and a write and taking a nested #VC - * exception on whatever of them is the MMIO access. Using string - * instructions here would cause infinite nesting. - */ - switch (size) { - case 1: { - u8 d1; - u8 __user *target = (u8 __user *)dst; - - memcpy(&d1, buf, 1); - if (__put_user(d1, target)) - goto fault; - break; - } - case 2: { - u16 d2; - u16 __user *target = (u16 __user *)dst; - - memcpy(&d2, buf, 2); - if (__put_user(d2, target)) - goto fault; - break; - } - case 4: { - u32 d4; - u32 __user *target = (u32 __user *)dst; - - memcpy(&d4, buf, 4); - if (__put_user(d4, target)) - goto fault; - break; - } - case 8: { - u64 d8; - u64 __user *target = (u64 __user *)dst; - - memcpy(&d8, buf, 8); - if (__put_user(d8, target)) - goto fault; - break; - } - default: - WARN_ONCE(1, "%s: Invalid size: %zu\n", __func__, size); - return ES_UNSUPPORTED; - } - - return ES_OK; - -fault: - if (user_mode(ctxt->regs)) - error_code |= X86_PF_USER; - - ctxt->fi.vector = X86_TRAP_PF; - ctxt->fi.error_code = error_code; - ctxt->fi.cr2 = (unsigned long)dst; - - return ES_EXCEPTION; -} - -static enum es_result vc_read_mem(struct es_em_ctxt *ctxt, - char *src, char *buf, size_t size) -{ - unsigned long error_code = X86_PF_PROT; - - /* - * This function uses __get_user() independent of whether kernel or user - * memory is accessed. This works fine because __get_user() does no - * sanity checks of the pointer being accessed. All that it does is - * to report when the access failed. - * - * Also, this function runs in atomic context, so __get_user() is not - * allowed to sleep. The page-fault handler detects that it is running - * in atomic context and will not try to take mmap_sem and handle the - * fault, so additional pagefault_enable()/disable() calls are not - * needed. - * - * The access can't be done via copy_from_user() here because - * vc_read_mem() must not use string instructions to access unsafe - * memory. The reason is that MOVS is emulated by the #VC handler by - * splitting the move up into a read and a write and taking a nested #VC - * exception on whatever of them is the MMIO access. Using string - * instructions here would cause infinite nesting. - */ - switch (size) { - case 1: { - u8 d1; - u8 __user *s = (u8 __user *)src; - - if (__get_user(d1, s)) - goto fault; - memcpy(buf, &d1, 1); - break; - } - case 2: { - u16 d2; - u16 __user *s = (u16 __user *)src; - - if (__get_user(d2, s)) - goto fault; - memcpy(buf, &d2, 2); - break; - } - case 4: { - u32 d4; - u32 __user *s = (u32 __user *)src; - - if (__get_user(d4, s)) - goto fault; - memcpy(buf, &d4, 4); - break; - } - case 8: { - u64 d8; - u64 __user *s = (u64 __user *)src; - if (__get_user(d8, s)) - goto fault; - memcpy(buf, &d8, 8); - break; - } - default: - WARN_ONCE(1, "%s: Invalid size: %zu\n", __func__, size); - return ES_UNSUPPORTED; - } - - return ES_OK; - -fault: - if (user_mode(ctxt->regs)) - error_code |= X86_PF_USER; - - ctxt->fi.vector = X86_TRAP_PF; - ctxt->fi.error_code = error_code; - ctxt->fi.cr2 = (unsigned long)src; - - return ES_EXCEPTION; -} - -static enum es_result vc_slow_virt_to_phys(struct ghcb *ghcb, struct es_em_ctxt *ctxt, - unsigned long vaddr, phys_addr_t *paddr) -{ - unsigned long va = (unsigned long)vaddr; - unsigned int level; - phys_addr_t pa; - pgd_t *pgd; - pte_t *pte; - - pgd = __va(read_cr3_pa()); - pgd = &pgd[pgd_index(va)]; - pte = lookup_address_in_pgd(pgd, va, &level); - if (!pte) { - ctxt->fi.vector = X86_TRAP_PF; - ctxt->fi.cr2 = vaddr; - ctxt->fi.error_code = 0; - - if (user_mode(ctxt->regs)) - ctxt->fi.error_code |= X86_PF_USER; - - return ES_EXCEPTION; - } - - if (WARN_ON_ONCE(pte_val(*pte) & _PAGE_ENC)) - /* Emulated MMIO to/from encrypted memory not supported */ - return ES_UNSUPPORTED; - - pa = (phys_addr_t)pte_pfn(*pte) << PAGE_SHIFT; - pa |= va & ~page_level_mask(level); - - *paddr = pa; - - return ES_OK; -} - -static enum es_result vc_ioio_check(struct es_em_ctxt *ctxt, u16 port, size_t size) -{ - BUG_ON(size > 4); - - if (user_mode(ctxt->regs)) { - struct thread_struct *t = ¤t->thread; - struct io_bitmap *iobm = t->io_bitmap; - size_t idx; - - if (!iobm) - goto fault; - - for (idx = port; idx < port + size; ++idx) { - if (test_bit(idx, iobm->bitmap)) - goto fault; - } - } - - return ES_OK; - -fault: - ctxt->fi.vector = X86_TRAP_GP; - ctxt->fi.error_code = 0; - - return ES_EXCEPTION; -} - -/* Include code shared with pre-decompression boot stage */ -#include "sev-shared.c" - -static noinstr void __sev_put_ghcb(struct ghcb_state *state) -{ - struct sev_es_runtime_data *data; - struct ghcb *ghcb; - - WARN_ON(!irqs_disabled()); - - data = this_cpu_read(runtime_data); - ghcb = &data->ghcb_page; - - if (state->ghcb) { - /* Restore GHCB from Backup */ - *ghcb = *state->ghcb; - data->backup_ghcb_active = false; - state->ghcb = NULL; - } else { - /* - * Invalidate the GHCB so a VMGEXIT instruction issued - * from userspace won't appear to be valid. - */ - vc_ghcb_invalidate(ghcb); - data->ghcb_active = false; - } -} - -void noinstr __sev_es_nmi_complete(void) -{ - struct ghcb_state state; - struct ghcb *ghcb; - - ghcb = __sev_get_ghcb(&state); - - vc_ghcb_invalidate(ghcb); - ghcb_set_sw_exit_code(ghcb, SVM_VMGEXIT_NMI_COMPLETE); - ghcb_set_sw_exit_info_1(ghcb, 0); - ghcb_set_sw_exit_info_2(ghcb, 0); - - sev_es_wr_ghcb_msr(__pa_nodebug(ghcb)); - VMGEXIT(); - - __sev_put_ghcb(&state); -} - -static u64 __init get_secrets_page(void) -{ - u64 pa_data = boot_params.cc_blob_address; - struct cc_blob_sev_info info; - void *map; - - /* - * The CC blob contains the address of the secrets page, check if the - * blob is present. - */ - if (!pa_data) - return 0; - - map = early_memremap(pa_data, sizeof(info)); - if (!map) { - pr_err("Unable to locate SNP secrets page: failed to map the Confidential Computing blob.\n"); - return 0; - } - memcpy(&info, map, sizeof(info)); - early_memunmap(map, sizeof(info)); - - /* smoke-test the secrets page passed */ - if (!info.secrets_phys || info.secrets_len != PAGE_SIZE) - return 0; - - return info.secrets_phys; -} - -static u64 __init get_snp_jump_table_addr(void) -{ - struct snp_secrets_page_layout *layout; - void __iomem *mem; - u64 pa, addr; - - pa = get_secrets_page(); - if (!pa) - return 0; - - mem = ioremap_encrypted(pa, PAGE_SIZE); - if (!mem) { - pr_err("Unable to locate AP jump table address: failed to map the SNP secrets page.\n"); - return 0; - } - - layout = (__force struct snp_secrets_page_layout *)mem; - - addr = layout->os_area.ap_jump_table_pa; - iounmap(mem); - - return addr; -} - -static u64 __init get_jump_table_addr(void) -{ - struct ghcb_state state; - unsigned long flags; - struct ghcb *ghcb; - u64 ret = 0; - - if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) - return get_snp_jump_table_addr(); - - local_irq_save(flags); - - ghcb = __sev_get_ghcb(&state); - - vc_ghcb_invalidate(ghcb); - ghcb_set_sw_exit_code(ghcb, SVM_VMGEXIT_AP_JUMP_TABLE); - ghcb_set_sw_exit_info_1(ghcb, SVM_VMGEXIT_GET_AP_JUMP_TABLE); - ghcb_set_sw_exit_info_2(ghcb, 0); - - sev_es_wr_ghcb_msr(__pa(ghcb)); - VMGEXIT(); - - if (ghcb_sw_exit_info_1_is_valid(ghcb) && - ghcb_sw_exit_info_2_is_valid(ghcb)) - ret = ghcb->save.sw_exit_info_2; - - __sev_put_ghcb(&state); - - local_irq_restore(flags); - - return ret; -} - -static void __head -early_set_pages_state(unsigned long vaddr, unsigned long paddr, - unsigned long npages, enum psc_op op) -{ - unsigned long paddr_end; - u64 val; - int ret; - - vaddr = vaddr & PAGE_MASK; - - paddr = paddr & PAGE_MASK; - paddr_end = paddr + (npages << PAGE_SHIFT); - - while (paddr < paddr_end) { - if (op == SNP_PAGE_STATE_SHARED) { - /* Page validation must be rescinded before changing to shared */ - ret = pvalidate(vaddr, RMP_PG_SIZE_4K, false); - if (WARN(ret, "Failed to validate address 0x%lx ret %d", paddr, ret)) - goto e_term; - } - - /* - * Use the MSR protocol because this function can be called before - * the GHCB is established. - */ - sev_es_wr_ghcb_msr(GHCB_MSR_PSC_REQ_GFN(paddr >> PAGE_SHIFT, op)); - VMGEXIT(); - - val = sev_es_rd_ghcb_msr(); - - if (WARN(GHCB_RESP_CODE(val) != GHCB_MSR_PSC_RESP, - "Wrong PSC response code: 0x%x\n", - (unsigned int)GHCB_RESP_CODE(val))) - goto e_term; - - if (WARN(GHCB_MSR_PSC_RESP_VAL(val), - "Failed to change page state to '%s' paddr 0x%lx error 0x%llx\n", - op == SNP_PAGE_STATE_PRIVATE ? "private" : "shared", - paddr, GHCB_MSR_PSC_RESP_VAL(val))) - goto e_term; - - if (op == SNP_PAGE_STATE_PRIVATE) { - /* Page validation must be performed after changing to private */ - ret = pvalidate(vaddr, RMP_PG_SIZE_4K, true); - if (WARN(ret, "Failed to validate address 0x%lx ret %d", paddr, ret)) - goto e_term; - } - - vaddr += PAGE_SIZE; - paddr += PAGE_SIZE; - } - - return; - -e_term: - sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_PSC); -} - -void __head early_snp_set_memory_private(unsigned long vaddr, unsigned long paddr, - unsigned long npages) -{ - /* - * 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 (!(RIP_REL_REF(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, SNP_PAGE_STATE_PRIVATE); -} - -void __init early_snp_set_memory_shared(unsigned long vaddr, unsigned long paddr, - unsigned long npages) -{ - /* - * 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 (!(RIP_REL_REF(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, SNP_PAGE_STATE_SHARED); -} - -void __init snp_prep_memory(unsigned long paddr, unsigned int sz, enum psc_op op) -{ - unsigned long vaddr, npages; - - vaddr = (unsigned long)__va(paddr); - npages = PAGE_ALIGN(sz) >> PAGE_SHIFT; - - if (op == SNP_PAGE_STATE_PRIVATE) - early_snp_set_memory_private(vaddr, paddr, npages); - else if (op == SNP_PAGE_STATE_SHARED) - early_snp_set_memory_shared(vaddr, paddr, npages); - else - WARN(1, "invalid memory op %d\n", op); -} - -static unsigned long __set_pages_state(struct snp_psc_desc *data, unsigned long vaddr, - unsigned long vaddr_end, int op) -{ - struct ghcb_state state; - bool use_large_entry; - struct psc_hdr *hdr; - struct psc_entry *e; - unsigned long flags; - unsigned long pfn; - struct ghcb *ghcb; - int i; - - hdr = &data->hdr; - e = data->entries; - - memset(data, 0, sizeof(*data)); - i = 0; - - while (vaddr < vaddr_end && i < ARRAY_SIZE(data->entries)) { - hdr->end_entry = i; - - if (is_vmalloc_addr((void *)vaddr)) { - pfn = vmalloc_to_pfn((void *)vaddr); - use_large_entry = false; - } else { - pfn = __pa(vaddr) >> PAGE_SHIFT; - use_large_entry = true; - } - - e->gfn = pfn; - e->operation = op; - - if (use_large_entry && IS_ALIGNED(vaddr, PMD_SIZE) && - (vaddr_end - vaddr) >= PMD_SIZE) { - e->pagesize = RMP_PG_SIZE_2M; - vaddr += PMD_SIZE; - } else { - e->pagesize = RMP_PG_SIZE_4K; - vaddr += PAGE_SIZE; - } - - e++; - i++; - } - - /* Page validation must be rescinded before changing to shared */ - if (op == SNP_PAGE_STATE_SHARED) - pvalidate_pages(data); - - local_irq_save(flags); - - if (sev_cfg.ghcbs_initialized) - ghcb = __sev_get_ghcb(&state); - else - ghcb = boot_ghcb; - - /* Invoke the hypervisor to perform the page state changes */ - if (!ghcb || vmgexit_psc(ghcb, data)) - sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_PSC); - - if (sev_cfg.ghcbs_initialized) - __sev_put_ghcb(&state); - - local_irq_restore(flags); - - /* Page validation must be performed after changing to private */ - if (op == SNP_PAGE_STATE_PRIVATE) - pvalidate_pages(data); - - return vaddr; -} - -static void set_pages_state(unsigned long vaddr, unsigned long npages, int op) -{ - struct snp_psc_desc desc; - unsigned long vaddr_end; - - /* Use the MSR protocol when a GHCB is not available. */ - if (!boot_ghcb) - return early_set_pages_state(vaddr, __pa(vaddr), npages, op); - - vaddr = vaddr & PAGE_MASK; - vaddr_end = vaddr + (npages << PAGE_SHIFT); - - while (vaddr < vaddr_end) - vaddr = __set_pages_state(&desc, vaddr, vaddr_end, op); -} - -void snp_set_memory_shared(unsigned long vaddr, unsigned long npages) -{ - if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) - return; - - set_pages_state(vaddr, npages, SNP_PAGE_STATE_SHARED); -} - -void snp_set_memory_private(unsigned long vaddr, unsigned long npages) -{ - if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) - return; - - set_pages_state(vaddr, npages, SNP_PAGE_STATE_PRIVATE); -} - -void snp_accept_memory(phys_addr_t start, phys_addr_t end) -{ - unsigned long vaddr, npages; - - if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) - return; - - vaddr = (unsigned long)__va(start); - npages = (end - start) >> PAGE_SHIFT; - - set_pages_state(vaddr, npages, SNP_PAGE_STATE_PRIVATE); -} - -static int snp_set_vmsa(void *va, bool vmsa) -{ - u64 attrs; - - /* - * Running at VMPL0 allows the kernel to change the VMSA bit for a page - * using the RMPADJUST instruction. However, for the instruction to - * succeed it must target the permissions of a lesser privileged - * (higher numbered) VMPL level, so use VMPL1 (refer to the RMPADJUST - * instruction in the AMD64 APM Volume 3). - */ - attrs = 1; - if (vmsa) - attrs |= RMPADJUST_VMSA_PAGE_BIT; - - return rmpadjust((unsigned long)va, RMP_PG_SIZE_4K, attrs); -} - -#define __ATTR_BASE (SVM_SELECTOR_P_MASK | SVM_SELECTOR_S_MASK) -#define INIT_CS_ATTRIBS (__ATTR_BASE | SVM_SELECTOR_READ_MASK | SVM_SELECTOR_CODE_MASK) -#define INIT_DS_ATTRIBS (__ATTR_BASE | SVM_SELECTOR_WRITE_MASK) - -#define INIT_LDTR_ATTRIBS (SVM_SELECTOR_P_MASK | 2) -#define INIT_TR_ATTRIBS (SVM_SELECTOR_P_MASK | 3) - -static void *snp_alloc_vmsa_page(void) -{ - struct page *p; - - /* - * Allocate VMSA page to work around the SNP erratum where the CPU will - * incorrectly signal an RMP violation #PF if a large page (2MB or 1GB) - * collides with the RMP entry of VMSA page. The recommended workaround - * is to not use a large page. - * - * Allocate an 8k page which is also 8k-aligned. - */ - p = alloc_pages(GFP_KERNEL_ACCOUNT | __GFP_ZERO, 1); - if (!p) - return NULL; - - split_page(p, 1); - - /* Free the first 4k. This page may be 2M/1G aligned and cannot be used. */ - __free_page(p); - - return page_address(p + 1); -} - -static void snp_cleanup_vmsa(struct sev_es_save_area *vmsa) -{ - int err; - - err = snp_set_vmsa(vmsa, false); - if (err) - pr_err("clear VMSA page failed (%u), leaking page\n", err); - else - free_page((unsigned long)vmsa); -} - -static int wakeup_cpu_via_vmgexit(u32 apic_id, unsigned long start_ip) -{ - struct sev_es_save_area *cur_vmsa, *vmsa; - struct ghcb_state state; - unsigned long flags; - struct ghcb *ghcb; - u8 sipi_vector; - int cpu, ret; - u64 cr4; - - /* - * The hypervisor SNP feature support check has happened earlier, just check - * the AP_CREATION one here. - */ - if (!(sev_hv_features & GHCB_HV_FT_SNP_AP_CREATION)) - return -EOPNOTSUPP; - - /* - * Verify the desired start IP against the known trampoline start IP - * to catch any future new trampolines that may be introduced that - * would require a new protected guest entry point. - */ - if (WARN_ONCE(start_ip != real_mode_header->trampoline_start, - "Unsupported SNP start_ip: %lx\n", start_ip)) - return -EINVAL; - - /* Override start_ip with known protected guest start IP */ - start_ip = real_mode_header->sev_es_trampoline_start; - - /* Find the logical CPU for the APIC ID */ - for_each_present_cpu(cpu) { - if (arch_match_cpu_phys_id(cpu, apic_id)) - break; - } - if (cpu >= nr_cpu_ids) - return -EINVAL; - - cur_vmsa = per_cpu(sev_vmsa, cpu); - - /* - * A new VMSA is created each time because there is no guarantee that - * the current VMSA is the kernels or that the vCPU is not running. If - * an attempt was done to use the current VMSA with a running vCPU, a - * #VMEXIT of that vCPU would wipe out all of the settings being done - * here. - */ - vmsa = (struct sev_es_save_area *)snp_alloc_vmsa_page(); - if (!vmsa) - return -ENOMEM; - - /* CR4 should maintain the MCE value */ - cr4 = native_read_cr4() & X86_CR4_MCE; - - /* Set the CS value based on the start_ip converted to a SIPI vector */ - sipi_vector = (start_ip >> 12); - vmsa->cs.base = sipi_vector << 12; - vmsa->cs.limit = AP_INIT_CS_LIMIT; - vmsa->cs.attrib = INIT_CS_ATTRIBS; - vmsa->cs.selector = sipi_vector << 8; - - /* Set the RIP value based on start_ip */ - vmsa->rip = start_ip & 0xfff; - - /* Set AP INIT defaults as documented in the APM */ - vmsa->ds.limit = AP_INIT_DS_LIMIT; - vmsa->ds.attrib = INIT_DS_ATTRIBS; - vmsa->es = vmsa->ds; - vmsa->fs = vmsa->ds; - vmsa->gs = vmsa->ds; - vmsa->ss = vmsa->ds; - - vmsa->gdtr.limit = AP_INIT_GDTR_LIMIT; - vmsa->ldtr.limit = AP_INIT_LDTR_LIMIT; - vmsa->ldtr.attrib = INIT_LDTR_ATTRIBS; - vmsa->idtr.limit = AP_INIT_IDTR_LIMIT; - vmsa->tr.limit = AP_INIT_TR_LIMIT; - vmsa->tr.attrib = INIT_TR_ATTRIBS; - - vmsa->cr4 = cr4; - vmsa->cr0 = AP_INIT_CR0_DEFAULT; - vmsa->dr7 = DR7_RESET_VALUE; - vmsa->dr6 = AP_INIT_DR6_DEFAULT; - vmsa->rflags = AP_INIT_RFLAGS_DEFAULT; - vmsa->g_pat = AP_INIT_GPAT_DEFAULT; - vmsa->xcr0 = AP_INIT_XCR0_DEFAULT; - vmsa->mxcsr = AP_INIT_MXCSR_DEFAULT; - vmsa->x87_ftw = AP_INIT_X87_FTW_DEFAULT; - vmsa->x87_fcw = AP_INIT_X87_FCW_DEFAULT; - - /* SVME must be set. */ - vmsa->efer = EFER_SVME; - - /* - * Set the SNP-specific fields for this VMSA: - * VMPL level - * SEV_FEATURES (matches the SEV STATUS MSR right shifted 2 bits) - */ - vmsa->vmpl = 0; - vmsa->sev_features = sev_status >> 2; - - /* Switch the page over to a VMSA page now that it is initialized */ - ret = snp_set_vmsa(vmsa, true); - if (ret) { - pr_err("set VMSA page failed (%u)\n", ret); - free_page((unsigned long)vmsa); - - return -EINVAL; - } - - /* Issue VMGEXIT AP Creation NAE event */ - local_irq_save(flags); - - ghcb = __sev_get_ghcb(&state); - - vc_ghcb_invalidate(ghcb); - ghcb_set_rax(ghcb, vmsa->sev_features); - ghcb_set_sw_exit_code(ghcb, SVM_VMGEXIT_AP_CREATION); - ghcb_set_sw_exit_info_1(ghcb, ((u64)apic_id << 32) | SVM_VMGEXIT_AP_CREATE); - ghcb_set_sw_exit_info_2(ghcb, __pa(vmsa)); - - sev_es_wr_ghcb_msr(__pa(ghcb)); - VMGEXIT(); - - if (!ghcb_sw_exit_info_1_is_valid(ghcb) || - lower_32_bits(ghcb->save.sw_exit_info_1)) { - pr_err("SNP AP Creation error\n"); - ret = -EINVAL; - } - - __sev_put_ghcb(&state); - - local_irq_restore(flags); - - /* Perform cleanup if there was an error */ - if (ret) { - snp_cleanup_vmsa(vmsa); - vmsa = NULL; - } - - /* Free up any previous VMSA page */ - if (cur_vmsa) - snp_cleanup_vmsa(cur_vmsa); - - /* Record the current VMSA page */ - per_cpu(sev_vmsa, cpu) = vmsa; - - return ret; -} - -void __init snp_set_wakeup_secondary_cpu(void) -{ - if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) - return; - - /* - * Always set this override if SNP is enabled. This makes it the - * required method to start APs under SNP. If the hypervisor does - * not support AP creation, then no APs will be started. - */ - apic_update_callback(wakeup_secondary_cpu, wakeup_cpu_via_vmgexit); -} - -int __init sev_es_setup_ap_jump_table(struct real_mode_header *rmh) -{ - u16 startup_cs, startup_ip; - phys_addr_t jump_table_pa; - u64 jump_table_addr; - u16 __iomem *jump_table; - - jump_table_addr = get_jump_table_addr(); - - /* On UP guests there is no jump table so this is not a failure */ - if (!jump_table_addr) - return 0; - - /* Check if AP Jump Table is page-aligned */ - if (jump_table_addr & ~PAGE_MASK) - return -EINVAL; - - jump_table_pa = jump_table_addr & PAGE_MASK; - - startup_cs = (u16)(rmh->trampoline_start >> 4); - startup_ip = (u16)(rmh->sev_es_trampoline_start - - rmh->trampoline_start); - - jump_table = ioremap_encrypted(jump_table_pa, PAGE_SIZE); - if (!jump_table) - return -EIO; - - writew(startup_ip, &jump_table[0]); - writew(startup_cs, &jump_table[1]); - - iounmap(jump_table); - - return 0; -} - -/* - * This is needed by the OVMF UEFI firmware which will use whatever it finds in - * the GHCB MSR as its GHCB to talk to the hypervisor. So make sure the per-cpu - * runtime GHCBs used by the kernel are also mapped in the EFI page-table. - */ -int __init sev_es_efi_map_ghcbs(pgd_t *pgd) -{ - struct sev_es_runtime_data *data; - unsigned long address, pflags; - int cpu; - u64 pfn; - - if (!cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT)) - return 0; - - pflags = _PAGE_NX | _PAGE_RW; - - for_each_possible_cpu(cpu) { - data = per_cpu(runtime_data, cpu); - - address = __pa(&data->ghcb_page); - pfn = address >> PAGE_SHIFT; - - if (kernel_map_pages_in_pgd(pgd, pfn, address, 1, pflags)) - return 1; - } - - return 0; -} - -static enum es_result vc_handle_msr(struct ghcb *ghcb, struct es_em_ctxt *ctxt) -{ - struct pt_regs *regs = ctxt->regs; - enum es_result ret; - u64 exit_info_1; - - /* Is it a WRMSR? */ - exit_info_1 = (ctxt->insn.opcode.bytes[1] == 0x30) ? 1 : 0; - - ghcb_set_rcx(ghcb, regs->cx); - if (exit_info_1) { - ghcb_set_rax(ghcb, regs->ax); - ghcb_set_rdx(ghcb, regs->dx); - } - - ret = sev_es_ghcb_hv_call(ghcb, ctxt, SVM_EXIT_MSR, exit_info_1, 0); - - if ((ret == ES_OK) && (!exit_info_1)) { - regs->ax = ghcb->save.rax; - regs->dx = ghcb->save.rdx; - } - - return ret; -} - -static void snp_register_per_cpu_ghcb(void) -{ - struct sev_es_runtime_data *data; - struct ghcb *ghcb; - - data = this_cpu_read(runtime_data); - ghcb = &data->ghcb_page; - - snp_register_ghcb_early(__pa(ghcb)); -} - -void setup_ghcb(void) -{ - if (!cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT)) - return; - - /* - * Check whether the runtime #VC exception handler is active. It uses - * the per-CPU GHCB page which is set up by sev_es_init_vc_handling(). - * - * If SNP is active, register the per-CPU GHCB page so that the runtime - * exception handler can use it. - */ - if (initial_vc_handler == (unsigned long)kernel_exc_vmm_communication) { - if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) - snp_register_per_cpu_ghcb(); - - sev_cfg.ghcbs_initialized = true; - - return; - } - - /* - * Make sure the hypervisor talks a supported protocol. - * This gets called only in the BSP boot phase. - */ - if (!sev_es_negotiate_protocol()) - sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ); - - /* - * Clear the boot_ghcb. The first exception comes in before the bss - * section is cleared. - */ - memset(&boot_ghcb_page, 0, PAGE_SIZE); - - /* Alright - Make the boot-ghcb public */ - boot_ghcb = &boot_ghcb_page; - - /* SNP guest requires that GHCB GPA must be registered. */ - if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) - snp_register_ghcb_early(__pa(&boot_ghcb_page)); -} - -#ifdef CONFIG_HOTPLUG_CPU -static void sev_es_ap_hlt_loop(void) -{ - struct ghcb_state state; - struct ghcb *ghcb; - - ghcb = __sev_get_ghcb(&state); - - while (true) { - vc_ghcb_invalidate(ghcb); - ghcb_set_sw_exit_code(ghcb, SVM_VMGEXIT_AP_HLT_LOOP); - ghcb_set_sw_exit_info_1(ghcb, 0); - ghcb_set_sw_exit_info_2(ghcb, 0); - - sev_es_wr_ghcb_msr(__pa(ghcb)); - VMGEXIT(); - - /* Wakeup signal? */ - if (ghcb_sw_exit_info_2_is_valid(ghcb) && - ghcb->save.sw_exit_info_2) - break; - } - - __sev_put_ghcb(&state); -} - -/* - * Play_dead handler when running under SEV-ES. This is needed because - * the hypervisor can't deliver an SIPI request to restart the AP. - * Instead the kernel has to issue a VMGEXIT to halt the VCPU until the - * hypervisor wakes it up again. - */ -static void sev_es_play_dead(void) -{ - play_dead_common(); - - /* IRQs now disabled */ - - sev_es_ap_hlt_loop(); - - /* - * If we get here, the VCPU was woken up again. Jump to CPU - * startup code to get it back online. - */ - soft_restart_cpu(); -} -#else /* CONFIG_HOTPLUG_CPU */ -#define sev_es_play_dead native_play_dead -#endif /* CONFIG_HOTPLUG_CPU */ - -#ifdef CONFIG_SMP -static void __init sev_es_setup_play_dead(void) -{ - smp_ops.play_dead = sev_es_play_dead; -} -#else -static inline void sev_es_setup_play_dead(void) { } -#endif - -static void __init alloc_runtime_data(int cpu) -{ - struct sev_es_runtime_data *data; - - data = memblock_alloc(sizeof(*data), PAGE_SIZE); - if (!data) - panic("Can't allocate SEV-ES runtime data"); - - per_cpu(runtime_data, cpu) = data; -} - -static void __init init_ghcb(int cpu) -{ - struct sev_es_runtime_data *data; - int err; - - data = per_cpu(runtime_data, cpu); - - err = early_set_memory_decrypted((unsigned long)&data->ghcb_page, - sizeof(data->ghcb_page)); - if (err) - panic("Can't map GHCBs unencrypted"); - - memset(&data->ghcb_page, 0, sizeof(data->ghcb_page)); - - data->ghcb_active = false; - data->backup_ghcb_active = false; -} - -void __init sev_es_init_vc_handling(void) -{ - int cpu; - - BUILD_BUG_ON(offsetof(struct sev_es_runtime_data, ghcb_page) % PAGE_SIZE); - - if (!cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT)) - return; - - if (!sev_es_check_cpu_features()) - panic("SEV-ES CPU Features missing"); - - /* - * SNP is supported in v2 of the GHCB spec which mandates support for HV - * features. - */ - if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) { - sev_hv_features = get_hv_features(); - - if (!(sev_hv_features & GHCB_HV_FT_SNP)) - sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED); - } - - /* Initialize per-cpu GHCB pages */ - for_each_possible_cpu(cpu) { - alloc_runtime_data(cpu); - init_ghcb(cpu); - } - - sev_es_setup_play_dead(); - - /* Secondary CPUs use the runtime #VC handler */ - initial_vc_handler = (unsigned long)kernel_exc_vmm_communication; -} - -static void __init vc_early_forward_exception(struct es_em_ctxt *ctxt) -{ - int trapnr = ctxt->fi.vector; - - if (trapnr == X86_TRAP_PF) - native_write_cr2(ctxt->fi.cr2); - - ctxt->regs->orig_ax = ctxt->fi.error_code; - do_early_exception(ctxt->regs, trapnr); -} - -static long *vc_insn_get_rm(struct es_em_ctxt *ctxt) -{ - long *reg_array; - int offset; - - reg_array = (long *)ctxt->regs; - offset = insn_get_modrm_rm_off(&ctxt->insn, ctxt->regs); - - if (offset < 0) - return NULL; - - offset /= sizeof(long); - - return reg_array + offset; -} -static enum es_result vc_do_mmio(struct ghcb *ghcb, struct es_em_ctxt *ctxt, - unsigned int bytes, bool read) -{ - u64 exit_code, exit_info_1, exit_info_2; - unsigned long ghcb_pa = __pa(ghcb); - enum es_result res; - phys_addr_t paddr; - void __user *ref; - - ref = insn_get_addr_ref(&ctxt->insn, ctxt->regs); - if (ref == (void __user *)-1L) - return ES_UNSUPPORTED; - - exit_code = read ? SVM_VMGEXIT_MMIO_READ : SVM_VMGEXIT_MMIO_WRITE; - - res = vc_slow_virt_to_phys(ghcb, ctxt, (unsigned long)ref, &paddr); - if (res != ES_OK) { - if (res == ES_EXCEPTION && !read) - ctxt->fi.error_code |= X86_PF_WRITE; - - return res; - } - - exit_info_1 = paddr; - /* Can never be greater than 8 */ - exit_info_2 = bytes; - - ghcb_set_sw_scratch(ghcb, ghcb_pa + offsetof(struct ghcb, shared_buffer)); - - return sev_es_ghcb_hv_call(ghcb, ctxt, exit_code, exit_info_1, exit_info_2); -} - -/* - * The MOVS instruction has two memory operands, which raises the - * problem that it is not known whether the access to the source or the - * destination caused the #VC exception (and hence whether an MMIO read - * or write operation needs to be emulated). - * - * Instead of playing games with walking page-tables and trying to guess - * whether the source or destination is an MMIO range, split the move - * into two operations, a read and a write with only one memory operand. - * This will cause a nested #VC exception on the MMIO address which can - * then be handled. - * - * This implementation has the benefit that it also supports MOVS where - * source _and_ destination are MMIO regions. - * - * It will slow MOVS on MMIO down a lot, but in SEV-ES guests it is a - * rare operation. If it turns out to be a performance problem the split - * operations can be moved to memcpy_fromio() and memcpy_toio(). - */ -static enum es_result vc_handle_mmio_movs(struct es_em_ctxt *ctxt, - unsigned int bytes) -{ - unsigned long ds_base, es_base; - unsigned char *src, *dst; - unsigned char buffer[8]; - enum es_result ret; - bool rep; - int off; - - ds_base = insn_get_seg_base(ctxt->regs, INAT_SEG_REG_DS); - es_base = insn_get_seg_base(ctxt->regs, INAT_SEG_REG_ES); - - if (ds_base == -1L || es_base == -1L) { - ctxt->fi.vector = X86_TRAP_GP; - ctxt->fi.error_code = 0; - return ES_EXCEPTION; - } - - src = ds_base + (unsigned char *)ctxt->regs->si; - dst = es_base + (unsigned char *)ctxt->regs->di; - - ret = vc_read_mem(ctxt, src, buffer, bytes); - if (ret != ES_OK) - return ret; - - ret = vc_write_mem(ctxt, dst, buffer, bytes); - if (ret != ES_OK) - return ret; - - if (ctxt->regs->flags & X86_EFLAGS_DF) - off = -bytes; - else - off = bytes; - - ctxt->regs->si += off; - ctxt->regs->di += off; - - rep = insn_has_rep_prefix(&ctxt->insn); - if (rep) - ctxt->regs->cx -= 1; - - if (!rep || ctxt->regs->cx == 0) - return ES_OK; - else - return ES_RETRY; -} - -static enum es_result vc_handle_mmio(struct ghcb *ghcb, struct es_em_ctxt *ctxt) -{ - struct insn *insn = &ctxt->insn; - enum insn_mmio_type mmio; - unsigned int bytes = 0; - enum es_result ret; - u8 sign_byte; - long *reg_data; - - mmio = insn_decode_mmio(insn, &bytes); - if (mmio == INSN_MMIO_DECODE_FAILED) - return ES_DECODE_FAILED; - - if (mmio != INSN_MMIO_WRITE_IMM && mmio != INSN_MMIO_MOVS) { - reg_data = insn_get_modrm_reg_ptr(insn, ctxt->regs); - if (!reg_data) - return ES_DECODE_FAILED; - } - - if (user_mode(ctxt->regs)) - return ES_UNSUPPORTED; - - switch (mmio) { - case INSN_MMIO_WRITE: - memcpy(ghcb->shared_buffer, reg_data, bytes); - ret = vc_do_mmio(ghcb, ctxt, bytes, false); - break; - case INSN_MMIO_WRITE_IMM: - memcpy(ghcb->shared_buffer, insn->immediate1.bytes, bytes); - ret = vc_do_mmio(ghcb, ctxt, bytes, false); - break; - case INSN_MMIO_READ: - ret = vc_do_mmio(ghcb, ctxt, bytes, true); - if (ret) - break; - - /* Zero-extend for 32-bit operation */ - if (bytes == 4) - *reg_data = 0; - - memcpy(reg_data, ghcb->shared_buffer, bytes); - break; - case INSN_MMIO_READ_ZERO_EXTEND: - ret = vc_do_mmio(ghcb, ctxt, bytes, true); - if (ret) - break; - - /* Zero extend based on operand size */ - memset(reg_data, 0, insn->opnd_bytes); - memcpy(reg_data, ghcb->shared_buffer, bytes); - break; - case INSN_MMIO_READ_SIGN_EXTEND: - ret = vc_do_mmio(ghcb, ctxt, bytes, true); - if (ret) - break; - - if (bytes == 1) { - u8 *val = (u8 *)ghcb->shared_buffer; - - sign_byte = (*val & 0x80) ? 0xff : 0x00; - } else { - u16 *val = (u16 *)ghcb->shared_buffer; - - sign_byte = (*val & 0x8000) ? 0xff : 0x00; - } - - /* Sign extend based on operand size */ - memset(reg_data, sign_byte, insn->opnd_bytes); - memcpy(reg_data, ghcb->shared_buffer, bytes); - break; - case INSN_MMIO_MOVS: - ret = vc_handle_mmio_movs(ctxt, bytes); - break; - default: - ret = ES_UNSUPPORTED; - break; - } - - return ret; -} - -static enum es_result vc_handle_dr7_write(struct ghcb *ghcb, - struct es_em_ctxt *ctxt) -{ - struct sev_es_runtime_data *data = this_cpu_read(runtime_data); - long val, *reg = vc_insn_get_rm(ctxt); - enum es_result ret; - - if (sev_status & MSR_AMD64_SNP_DEBUG_SWAP) - return ES_VMM_ERROR; - - if (!reg) - return ES_DECODE_FAILED; - - val = *reg; - - /* Upper 32 bits must be written as zeroes */ - if (val >> 32) { - ctxt->fi.vector = X86_TRAP_GP; - ctxt->fi.error_code = 0; - return ES_EXCEPTION; - } - - /* Clear out other reserved bits and set bit 10 */ - val = (val & 0xffff23ffL) | BIT(10); - - /* Early non-zero writes to DR7 are not supported */ - if (!data && (val & ~DR7_RESET_VALUE)) - return ES_UNSUPPORTED; - - /* Using a value of 0 for ExitInfo1 means RAX holds the value */ - ghcb_set_rax(ghcb, val); - ret = sev_es_ghcb_hv_call(ghcb, ctxt, SVM_EXIT_WRITE_DR7, 0, 0); - if (ret != ES_OK) - return ret; - - if (data) - data->dr7 = val; - - return ES_OK; -} - -static enum es_result vc_handle_dr7_read(struct ghcb *ghcb, - struct es_em_ctxt *ctxt) -{ - struct sev_es_runtime_data *data = this_cpu_read(runtime_data); - long *reg = vc_insn_get_rm(ctxt); - - if (sev_status & MSR_AMD64_SNP_DEBUG_SWAP) - return ES_VMM_ERROR; - - if (!reg) - return ES_DECODE_FAILED; - - if (data) - *reg = data->dr7; - else - *reg = DR7_RESET_VALUE; - - return ES_OK; -} - -static enum es_result vc_handle_wbinvd(struct ghcb *ghcb, - struct es_em_ctxt *ctxt) -{ - return sev_es_ghcb_hv_call(ghcb, ctxt, SVM_EXIT_WBINVD, 0, 0); -} - -static enum es_result vc_handle_rdpmc(struct ghcb *ghcb, struct es_em_ctxt *ctxt) -{ - enum es_result ret; - - ghcb_set_rcx(ghcb, ctxt->regs->cx); - - ret = sev_es_ghcb_hv_call(ghcb, ctxt, SVM_EXIT_RDPMC, 0, 0); - if (ret != ES_OK) - return ret; - - if (!(ghcb_rax_is_valid(ghcb) && ghcb_rdx_is_valid(ghcb))) - return ES_VMM_ERROR; - - ctxt->regs->ax = ghcb->save.rax; - ctxt->regs->dx = ghcb->save.rdx; - - return ES_OK; -} - -static enum es_result vc_handle_monitor(struct ghcb *ghcb, - struct es_em_ctxt *ctxt) -{ - /* - * Treat it as a NOP and do not leak a physical address to the - * hypervisor. - */ - return ES_OK; -} - -static enum es_result vc_handle_mwait(struct ghcb *ghcb, - struct es_em_ctxt *ctxt) -{ - /* Treat the same as MONITOR/MONITORX */ - return ES_OK; -} - -static enum es_result vc_handle_vmmcall(struct ghcb *ghcb, - struct es_em_ctxt *ctxt) -{ - enum es_result ret; - - ghcb_set_rax(ghcb, ctxt->regs->ax); - ghcb_set_cpl(ghcb, user_mode(ctxt->regs) ? 3 : 0); - - if (x86_platform.hyper.sev_es_hcall_prepare) - x86_platform.hyper.sev_es_hcall_prepare(ghcb, ctxt->regs); - - ret = sev_es_ghcb_hv_call(ghcb, ctxt, SVM_EXIT_VMMCALL, 0, 0); - if (ret != ES_OK) - return ret; - - if (!ghcb_rax_is_valid(ghcb)) - return ES_VMM_ERROR; - - ctxt->regs->ax = ghcb->save.rax; - - /* - * Call sev_es_hcall_finish() after regs->ax is already set. - * This allows the hypervisor handler to overwrite it again if - * necessary. - */ - if (x86_platform.hyper.sev_es_hcall_finish && - !x86_platform.hyper.sev_es_hcall_finish(ghcb, ctxt->regs)) - return ES_VMM_ERROR; - - return ES_OK; -} - -static enum es_result vc_handle_trap_ac(struct ghcb *ghcb, - struct es_em_ctxt *ctxt) -{ - /* - * Calling ecx_alignment_check() directly does not work, because it - * enables IRQs and the GHCB is active. Forward the exception and call - * it later from vc_forward_exception(). - */ - ctxt->fi.vector = X86_TRAP_AC; - ctxt->fi.error_code = 0; - return ES_EXCEPTION; -} - -static enum es_result vc_handle_exitcode(struct es_em_ctxt *ctxt, - struct ghcb *ghcb, - unsigned long exit_code) -{ - enum es_result result = vc_check_opcode_bytes(ctxt, exit_code); - - if (result != ES_OK) - return result; - - switch (exit_code) { - case SVM_EXIT_READ_DR7: - result = vc_handle_dr7_read(ghcb, ctxt); - break; - case SVM_EXIT_WRITE_DR7: - result = vc_handle_dr7_write(ghcb, ctxt); - break; - case SVM_EXIT_EXCP_BASE + X86_TRAP_AC: - result = vc_handle_trap_ac(ghcb, ctxt); - break; - case SVM_EXIT_RDTSC: - case SVM_EXIT_RDTSCP: - result = vc_handle_rdtsc(ghcb, ctxt, exit_code); - break; - case SVM_EXIT_RDPMC: - result = vc_handle_rdpmc(ghcb, ctxt); - break; - case SVM_EXIT_INVD: - pr_err_ratelimited("#VC exception for INVD??? Seriously???\n"); - result = ES_UNSUPPORTED; - break; - case SVM_EXIT_CPUID: - result = vc_handle_cpuid(ghcb, ctxt); - break; - case SVM_EXIT_IOIO: - result = vc_handle_ioio(ghcb, ctxt); - break; - case SVM_EXIT_MSR: - result = vc_handle_msr(ghcb, ctxt); - break; - case SVM_EXIT_VMMCALL: - result = vc_handle_vmmcall(ghcb, ctxt); - break; - case SVM_EXIT_WBINVD: - result = vc_handle_wbinvd(ghcb, ctxt); - break; - case SVM_EXIT_MONITOR: - result = vc_handle_monitor(ghcb, ctxt); - break; - case SVM_EXIT_MWAIT: - result = vc_handle_mwait(ghcb, ctxt); - break; - case SVM_EXIT_NPF: - result = vc_handle_mmio(ghcb, ctxt); - break; - default: - /* - * Unexpected #VC exception - */ - result = ES_UNSUPPORTED; - } - - return result; -} - -static __always_inline void vc_forward_exception(struct es_em_ctxt *ctxt) -{ - long error_code = ctxt->fi.error_code; - int trapnr = ctxt->fi.vector; - - ctxt->regs->orig_ax = ctxt->fi.error_code; - - switch (trapnr) { - case X86_TRAP_GP: - exc_general_protection(ctxt->regs, error_code); - break; - case X86_TRAP_UD: - exc_invalid_op(ctxt->regs); - break; - case X86_TRAP_PF: - write_cr2(ctxt->fi.cr2); - exc_page_fault(ctxt->regs, error_code); - break; - case X86_TRAP_AC: - exc_alignment_check(ctxt->regs, error_code); - break; - default: - pr_emerg("Unsupported exception in #VC instruction emulation - can't continue\n"); - BUG(); - } -} - -static __always_inline bool is_vc2_stack(unsigned long sp) -{ - return (sp >= __this_cpu_ist_bottom_va(VC2) && sp < __this_cpu_ist_top_va(VC2)); -} - -static __always_inline bool vc_from_invalid_context(struct pt_regs *regs) -{ - unsigned long sp, prev_sp; - - sp = (unsigned long)regs; - prev_sp = regs->sp; - - /* - * If the code was already executing on the VC2 stack when the #VC - * happened, let it proceed to the normal handling routine. This way the - * code executing on the VC2 stack can cause #VC exceptions to get handled. - */ - return is_vc2_stack(sp) && !is_vc2_stack(prev_sp); -} - -static bool vc_raw_handle_exception(struct pt_regs *regs, unsigned long error_code) -{ - struct ghcb_state state; - struct es_em_ctxt ctxt; - enum es_result result; - struct ghcb *ghcb; - bool ret = true; - - ghcb = __sev_get_ghcb(&state); - - vc_ghcb_invalidate(ghcb); - result = vc_init_em_ctxt(&ctxt, regs, error_code); - - if (result == ES_OK) - result = vc_handle_exitcode(&ctxt, ghcb, error_code); - - __sev_put_ghcb(&state); - - /* Done - now check the result */ - switch (result) { - case ES_OK: - vc_finish_insn(&ctxt); - break; - case ES_UNSUPPORTED: - pr_err_ratelimited("Unsupported exit-code 0x%02lx in #VC exception (IP: 0x%lx)\n", - error_code, regs->ip); - ret = false; - break; - case ES_VMM_ERROR: - pr_err_ratelimited("Failure in communication with VMM (exit-code 0x%02lx IP: 0x%lx)\n", - error_code, regs->ip); - ret = false; - break; - case ES_DECODE_FAILED: - pr_err_ratelimited("Failed to decode instruction (exit-code 0x%02lx IP: 0x%lx)\n", - error_code, regs->ip); - ret = false; - break; - case ES_EXCEPTION: - vc_forward_exception(&ctxt); - break; - case ES_RETRY: - /* Nothing to do */ - break; - default: - pr_emerg("Unknown result in %s():%d\n", __func__, result); - /* - * Emulating the instruction which caused the #VC exception - * failed - can't continue so print debug information - */ - BUG(); - } - - return ret; -} - -static __always_inline bool vc_is_db(unsigned long error_code) -{ - return error_code == SVM_EXIT_EXCP_BASE + X86_TRAP_DB; -} - -/* - * Runtime #VC exception handler when raised from kernel mode. Runs in NMI mode - * and will panic when an error happens. - */ -DEFINE_IDTENTRY_VC_KERNEL(exc_vmm_communication) -{ - irqentry_state_t irq_state; - - /* - * With the current implementation it is always possible to switch to a - * safe stack because #VC exceptions only happen at known places, like - * intercepted instructions or accesses to MMIO areas/IO ports. They can - * also happen with code instrumentation when the hypervisor intercepts - * #DB, but the critical paths are forbidden to be instrumented, so #DB - * exceptions currently also only happen in safe places. - * - * But keep this here in case the noinstr annotations are violated due - * to bug elsewhere. - */ - if (unlikely(vc_from_invalid_context(regs))) { - instrumentation_begin(); - panic("Can't handle #VC exception from unsupported context\n"); - instrumentation_end(); - } - - /* - * Handle #DB before calling into !noinstr code to avoid recursive #DB. - */ - if (vc_is_db(error_code)) { - exc_debug(regs); - return; - } - - irq_state = irqentry_nmi_enter(regs); - - instrumentation_begin(); - - if (!vc_raw_handle_exception(regs, error_code)) { - /* Show some debug info */ - show_regs(regs); - - /* Ask hypervisor to sev_es_terminate */ - sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ); - - /* If that fails and we get here - just panic */ - panic("Returned from Terminate-Request to Hypervisor\n"); - } - - instrumentation_end(); - irqentry_nmi_exit(regs, irq_state); -} - -/* - * Runtime #VC exception handler when raised from user mode. Runs in IRQ mode - * and will kill the current task with SIGBUS when an error happens. - */ -DEFINE_IDTENTRY_VC_USER(exc_vmm_communication) -{ - /* - * Handle #DB before calling into !noinstr code to avoid recursive #DB. - */ - if (vc_is_db(error_code)) { - noist_exc_debug(regs); - return; - } - - irqentry_enter_from_user_mode(regs); - instrumentation_begin(); - - if (!vc_raw_handle_exception(regs, error_code)) { - /* - * Do not kill the machine if user-space triggered the - * exception. Send SIGBUS instead and let user-space deal with - * it. - */ - force_sig_fault(SIGBUS, BUS_OBJERR, (void __user *)0); - } - - instrumentation_end(); - irqentry_exit_to_user_mode(regs); -} - -bool __init handle_vc_boot_ghcb(struct pt_regs *regs) -{ - unsigned long exit_code = regs->orig_ax; - struct es_em_ctxt ctxt; - enum es_result result; - - vc_ghcb_invalidate(boot_ghcb); - - result = vc_init_em_ctxt(&ctxt, regs, exit_code); - if (result == ES_OK) - result = vc_handle_exitcode(&ctxt, boot_ghcb, exit_code); - - /* Done - now check the result */ - switch (result) { - case ES_OK: - vc_finish_insn(&ctxt); - break; - case ES_UNSUPPORTED: - early_printk("PANIC: Unsupported exit-code 0x%02lx in early #VC exception (IP: 0x%lx)\n", - exit_code, regs->ip); - goto fail; - case ES_VMM_ERROR: - early_printk("PANIC: Failure in communication with VMM (exit-code 0x%02lx IP: 0x%lx)\n", - exit_code, regs->ip); - goto fail; - case ES_DECODE_FAILED: - early_printk("PANIC: Failed to decode instruction (exit-code 0x%02lx IP: 0x%lx)\n", - exit_code, regs->ip); - goto fail; - case ES_EXCEPTION: - vc_early_forward_exception(&ctxt); - break; - case ES_RETRY: - /* Nothing to do */ - break; - default: - BUG(); - } - - return true; - -fail: - show_regs(regs); - - sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ); -} - -/* - * 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 __head struct cc_blob_sev_info *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) - snp_abort(); - - return cc_info; -} - -bool __head 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; - - setup_cpuid_table(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; -} - -void __head __noreturn snp_abort(void) -{ - sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED); -} - -static void dump_cpuid_table(void) -{ - const struct snp_cpuid_table *cpuid_table = snp_cpuid_get_table(); - int i = 0; - - pr_info("count=%d reserved=0x%x reserved2=0x%llx\n", - cpuid_table->count, cpuid_table->__reserved1, cpuid_table->__reserved2); - - for (i = 0; i < SNP_CPUID_COUNT_MAX; i++) { - const struct snp_cpuid_fn *fn = &cpuid_table->fn[i]; - - pr_info("index=%3d fn=0x%08x subfn=0x%08x: eax=0x%08x ebx=0x%08x ecx=0x%08x edx=0x%08x xcr0_in=0x%016llx xss_in=0x%016llx reserved=0x%016llx\n", - i, fn->eax_in, fn->ecx_in, fn->eax, fn->ebx, fn->ecx, - fn->edx, fn->xcr0_in, fn->xss_in, fn->__reserved); - } -} - -/* - * It is useful from an auditing/testing perspective to provide an easy way - * for the guest owner to know that the CPUID table has been initialized as - * expected, but that initialization happens too early in boot to print any - * sort of indicator, and there's not really any other good place to do it, - * so do it here. - */ -static int __init report_cpuid_table(void) -{ - const struct snp_cpuid_table *cpuid_table = snp_cpuid_get_table(); - - if (!cpuid_table->count) - return 0; - - pr_info("Using SNP CPUID table, %d entries present.\n", - cpuid_table->count); - - if (sev_cfg.debug) - dump_cpuid_table(); - - return 0; -} -arch_initcall(report_cpuid_table); - -static int __init init_sev_config(char *str) -{ - char *s; - - while ((s = strsep(&str, ","))) { - if (!strcmp(s, "debug")) { - sev_cfg.debug = true; - continue; - } - - pr_info("SEV command-line option '%s' was not recognized\n", s); - } - - return 1; -} -__setup("sev=", init_sev_config); - -int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, struct snp_guest_request_ioctl *rio) -{ - struct ghcb_state state; - struct es_em_ctxt ctxt; - unsigned long flags; - struct ghcb *ghcb; - int ret; - - rio->exitinfo2 = SEV_RET_NO_FW_CALL; - - /* - * __sev_get_ghcb() needs to run with IRQs disabled because it is using - * a per-CPU GHCB. - */ - local_irq_save(flags); - - ghcb = __sev_get_ghcb(&state); - if (!ghcb) { - ret = -EIO; - goto e_restore_irq; - } - - vc_ghcb_invalidate(ghcb); - - if (exit_code == SVM_VMGEXIT_EXT_GUEST_REQUEST) { - ghcb_set_rax(ghcb, input->data_gpa); - ghcb_set_rbx(ghcb, input->data_npages); - } - - ret = sev_es_ghcb_hv_call(ghcb, &ctxt, exit_code, input->req_gpa, input->resp_gpa); - if (ret) - goto e_put; - - rio->exitinfo2 = ghcb->save.sw_exit_info_2; - switch (rio->exitinfo2) { - case 0: - break; - - case SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_BUSY): - ret = -EAGAIN; - break; - - case SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_INVALID_LEN): - /* Number of expected pages are returned in RBX */ - if (exit_code == SVM_VMGEXIT_EXT_GUEST_REQUEST) { - input->data_npages = ghcb_get_rbx(ghcb); - ret = -ENOSPC; - break; - } - fallthrough; - default: - ret = -EIO; - break; - } - -e_put: - __sev_put_ghcb(&state); -e_restore_irq: - local_irq_restore(flags); - - return ret; -} -EXPORT_SYMBOL_GPL(snp_issue_guest_request); - -static struct platform_device sev_guest_device = { - .name = "sev-guest", - .id = -1, -}; - -static int __init snp_init_platform_device(void) -{ - struct sev_guest_platform_data data; - u64 gpa; - - if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) - return -ENODEV; - - gpa = get_secrets_page(); - if (!gpa) - return -ENODEV; - - data.secrets_gpa = gpa; - if (platform_device_add_data(&sev_guest_device, &data, sizeof(data))) - return -ENODEV; - - if (platform_device_register(&sev_guest_device)) - return -ENODEV; - - pr_info("SNP guest platform device initialized.\n"); - return 0; -} -device_initcall(snp_init_platform_device); - -void kdump_sev_callback(void) -{ - /* - * Do wbinvd() on remote CPUs when SNP is enabled in order to - * safely do SNP_SHUTDOWN on the local CPU. - */ - if (cpu_feature_enabled(X86_FEATURE_SEV_SNP)) - wbinvd(); -} - -void sev_show_status(void) -{ - int i; - - pr_info("Status: "); - for (i = 0; i < MSR_AMD64_SNP_RESV_BIT; i++) { - if (sev_status & BIT_ULL(i)) { - if (!sev_status_feat_names[i]) - continue; - - pr_cont("%s ", sev_status_feat_names[i]); - } - } - pr_cont("\n"); -} |