| // 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 <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 |
| |
| /* 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); |
| DEFINE_STATIC_KEY_FALSE(sev_es_enable_key); |
| |
| static DEFINE_PER_CPU(struct sev_es_save_area *, sev_vmsa); |
| |
| struct sev_config { |
| __u64 debug : 1, |
| __reserved : 63; |
| }; |
| |
| 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; |
| } |
| |
| /* 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 pvalidate_pages(unsigned long vaddr, unsigned int npages, bool validate) |
| { |
| unsigned long vaddr_end; |
| int rc; |
| |
| vaddr = vaddr & PAGE_MASK; |
| vaddr_end = vaddr + (npages << PAGE_SHIFT); |
| |
| while (vaddr < vaddr_end) { |
| rc = pvalidate(vaddr, RMP_PG_SIZE_4K, validate); |
| if (WARN(rc, "Failed to validate address 0x%lx ret %d", vaddr, rc)) |
| sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_PVALIDATE); |
| |
| vaddr = vaddr + PAGE_SIZE; |
| } |
| } |
| |
| static void __init early_set_pages_state(unsigned long paddr, unsigned int npages, enum psc_op op) |
| { |
| unsigned long paddr_end; |
| u64 val; |
| |
| paddr = paddr & PAGE_MASK; |
| paddr_end = paddr + (npages << PAGE_SHIFT); |
| |
| while (paddr < paddr_end) { |
| /* |
| * 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; |
| |
| paddr = paddr + PAGE_SIZE; |
| } |
| |
| return; |
| |
| e_term: |
| sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_PSC); |
| } |
| |
| void __init early_snp_set_memory_private(unsigned long vaddr, unsigned long paddr, |
| unsigned int npages) |
| { |
| if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) |
| return; |
| |
| /* |
| * Ask the hypervisor to mark the memory pages as private in the RMP |
| * table. |
| */ |
| early_set_pages_state(paddr, npages, SNP_PAGE_STATE_PRIVATE); |
| |
| /* Validate the memory pages after they've been added in the RMP table. */ |
| pvalidate_pages(vaddr, npages, true); |
| } |
| |
| void __init early_snp_set_memory_shared(unsigned long vaddr, unsigned long paddr, |
| unsigned int npages) |
| { |
| if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) |
| return; |
| |
| /* Invalidate the memory pages before they are marked shared in the RMP table. */ |
| pvalidate_pages(vaddr, npages, false); |
| |
| /* Ask hypervisor to mark the memory pages shared in the RMP table. */ |
| early_set_pages_state(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 int vmgexit_psc(struct snp_psc_desc *desc) |
| { |
| int cur_entry, end_entry, ret = 0; |
| struct snp_psc_desc *data; |
| struct ghcb_state state; |
| struct es_em_ctxt ctxt; |
| unsigned long flags; |
| struct ghcb *ghcb; |
| |
| /* |
| * __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 = 1; |
| goto out_unlock; |
| } |
| |
| /* Copy the input desc into GHCB shared buffer */ |
| data = (struct snp_psc_desc *)ghcb->shared_buffer; |
| memcpy(ghcb->shared_buffer, desc, min_t(int, GHCB_SHARED_BUF_SIZE, sizeof(*desc))); |
| |
| /* |
| * As per the GHCB specification, the hypervisor can resume the guest |
| * before processing all the entries. Check whether all the entries |
| * are processed. If not, then keep retrying. Note, the hypervisor |
| * will update the data memory directly to indicate the status, so |
| * reference the data->hdr everywhere. |
| * |
| * The strategy here is to wait for the hypervisor to change the page |
| * state in the RMP table before guest accesses the memory pages. If the |
| * page state change was not successful, then later memory access will |
| * result in a crash. |
| */ |
| cur_entry = data->hdr.cur_entry; |
| end_entry = data->hdr.end_entry; |
| |
| while (data->hdr.cur_entry <= data->hdr.end_entry) { |
| ghcb_set_sw_scratch(ghcb, (u64)__pa(data)); |
| |
| /* This will advance the shared buffer data points to. */ |
| ret = sev_es_ghcb_hv_call(ghcb, true, &ctxt, SVM_VMGEXIT_PSC, 0, 0); |
| |
| /* |
| * Page State Change VMGEXIT can pass error code through |
| * exit_info_2. |
| */ |
| if (WARN(ret || ghcb->save.sw_exit_info_2, |
| "SNP: PSC failed ret=%d exit_info_2=%llx\n", |
| ret, ghcb->save.sw_exit_info_2)) { |
| ret = 1; |
| goto out; |
| } |
| |
| /* Verify that reserved bit is not set */ |
| if (WARN(data->hdr.reserved, "Reserved bit is set in the PSC header\n")) { |
| ret = 1; |
| goto out; |
| } |
| |
| /* |
| * Sanity check that entry processing is not going backwards. |
| * This will happen only if hypervisor is tricking us. |
| */ |
| if (WARN(data->hdr.end_entry > end_entry || cur_entry > data->hdr.cur_entry, |
| "SNP: PSC processing going backward, end_entry %d (got %d) cur_entry %d (got %d)\n", |
| end_entry, data->hdr.end_entry, cur_entry, data->hdr.cur_entry)) { |
| ret = 1; |
| goto out; |
| } |
| } |
| |
| out: |
| __sev_put_ghcb(&state); |
| |
| out_unlock: |
| local_irq_restore(flags); |
| |
| return ret; |
| } |
| |
| static void __set_pages_state(struct snp_psc_desc *data, unsigned long vaddr, |
| unsigned long vaddr_end, int op) |
| { |
| struct psc_hdr *hdr; |
| struct psc_entry *e; |
| unsigned long pfn; |
| int i; |
| |
| hdr = &data->hdr; |
| e = data->entries; |
| |
| memset(data, 0, sizeof(*data)); |
| i = 0; |
| |
| while (vaddr < vaddr_end) { |
| if (is_vmalloc_addr((void *)vaddr)) |
| pfn = vmalloc_to_pfn((void *)vaddr); |
| else |
| pfn = __pa(vaddr) >> PAGE_SHIFT; |
| |
| e->gfn = pfn; |
| e->operation = op; |
| hdr->end_entry = i; |
| |
| /* |
| * Current SNP implementation doesn't keep track of the RMP page |
| * size so use 4K for simplicity. |
| */ |
| e->pagesize = RMP_PG_SIZE_4K; |
| |
| vaddr = vaddr + PAGE_SIZE; |
| e++; |
| i++; |
| } |
| |
| if (vmgexit_psc(data)) |
| sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_PSC); |
| } |
| |
| static void set_pages_state(unsigned long vaddr, unsigned int npages, int op) |
| { |
| unsigned long vaddr_end, next_vaddr; |
| struct snp_psc_desc *desc; |
| |
| desc = kmalloc(sizeof(*desc), GFP_KERNEL_ACCOUNT); |
| if (!desc) |
| panic("SNP: failed to allocate memory for PSC descriptor\n"); |
| |
| vaddr = vaddr & PAGE_MASK; |
| vaddr_end = vaddr + (npages << PAGE_SHIFT); |
| |
| while (vaddr < vaddr_end) { |
| /* Calculate the last vaddr that fits in one struct snp_psc_desc. */ |
| next_vaddr = min_t(unsigned long, vaddr_end, |
| (VMGEXIT_PSC_MAX_ENTRY * PAGE_SIZE) + vaddr); |
| |
| __set_pages_state(desc, vaddr, next_vaddr, op); |
| |
| vaddr = next_vaddr; |
| } |
| |
| kfree(desc); |
| } |
| |
| void snp_set_memory_shared(unsigned long vaddr, unsigned int npages) |
| { |
| if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) |
| return; |
| |
| pvalidate_pages(vaddr, npages, false); |
| |
| set_pages_state(vaddr, npages, SNP_PAGE_STATE_SHARED); |
| } |
| |
| void snp_set_memory_private(unsigned long vaddr, unsigned int npages) |
| { |
| if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) |
| return; |
| |
| set_pages_state(vaddr, npages, SNP_PAGE_STATE_PRIVATE); |
| |
| pvalidate_pages(vaddr, npages, true); |
| } |
| |
| 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(int 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 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->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, true, 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; |
| |
| /* First make sure the hypervisor talks a supported protocol. */ |
| if (!sev_es_negotiate_protocol()) |
| sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ); |
| |
| /* |
| * 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(); |
| |
| return; |
| } |
| |
| /* |
| * 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. |
| */ |
| start_cpu0(); |
| } |
| #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); |
| } |
| |
| /* Enable SEV-ES special handling */ |
| static_branch_enable(&sev_es_enable_key); |
| |
| /* 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, true, 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; |
| unsigned int bytes = 0; |
| enum mmio_type mmio; |
| enum es_result ret; |
| u8 sign_byte; |
| long *reg_data; |
| |
| mmio = insn_decode_mmio(insn, &bytes); |
| if (mmio == MMIO_DECODE_FAILED) |
| return ES_DECODE_FAILED; |
| |
| if (mmio != MMIO_WRITE_IMM && mmio != MMIO_MOVS) { |
| reg_data = insn_get_modrm_reg_ptr(insn, ctxt->regs); |
| if (!reg_data) |
| return ES_DECODE_FAILED; |
| } |
| |
| switch (mmio) { |
| case MMIO_WRITE: |
| memcpy(ghcb->shared_buffer, reg_data, bytes); |
| ret = vc_do_mmio(ghcb, ctxt, bytes, false); |
| break; |
| case MMIO_WRITE_IMM: |
| memcpy(ghcb->shared_buffer, insn->immediate1.bytes, bytes); |
| ret = vc_do_mmio(ghcb, ctxt, bytes, false); |
| break; |
| case 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 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 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 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 (!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, true, 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 (!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, true, 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, true, 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, true, 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; |
| |
| 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 __init 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 __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; |
| |
| 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 __init 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, unsigned long *fw_err) |
| { |
| struct ghcb_state state; |
| struct es_em_ctxt ctxt; |
| unsigned long flags; |
| struct ghcb *ghcb; |
| int ret; |
| |
| if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) |
| return -ENODEV; |
| |
| if (!fw_err) |
| return -EINVAL; |
| |
| /* |
| * __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, true, &ctxt, exit_code, input->req_gpa, input->resp_gpa); |
| if (ret) |
| goto e_put; |
| |
| if (ghcb->save.sw_exit_info_2) { |
| /* Number of expected pages are returned in RBX */ |
| if (exit_code == SVM_VMGEXIT_EXT_GUEST_REQUEST && |
| ghcb->save.sw_exit_info_2 == SNP_GUEST_REQ_INVALID_LEN) |
| input->data_npages = ghcb_get_rbx(ghcb); |
| |
| *fw_err = ghcb->save.sw_exit_info_2; |
| |
| ret = -EIO; |
| } |
| |
| 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); |