diff options
Diffstat (limited to 'arch/x86/coco/sev/core.c')
| -rw-r--r-- | arch/x86/coco/sev/core.c | 276 |
1 files changed, 240 insertions, 36 deletions
diff --git a/arch/x86/coco/sev/core.c b/arch/x86/coco/sev/core.c index 14ef5908fb27..9ae3b11754e6 100644 --- a/arch/x86/coco/sev/core.c +++ b/arch/x86/coco/sev/core.c @@ -46,6 +46,48 @@ #include <asm/cmdline.h> #include <asm/msr.h> +/* Bitmap of SEV features supported by the hypervisor */ +u64 sev_hv_features __ro_after_init; +SYM_PIC_ALIAS(sev_hv_features); + +/* Secrets page physical address from the CC blob */ +u64 sev_secrets_pa __ro_after_init; +SYM_PIC_ALIAS(sev_secrets_pa); + +/* For early boot SVSM communication */ +struct svsm_ca boot_svsm_ca_page __aligned(PAGE_SIZE); +SYM_PIC_ALIAS(boot_svsm_ca_page); + +/* + * SVSM related information: + * During boot, the page tables are set up as identity mapped and later + * changed to use kernel virtual addresses. Maintain separate virtual and + * physical addresses for the CAA to allow SVSM functions to be used during + * early boot, both with identity mapped virtual addresses and proper kernel + * virtual addresses. + */ +u64 boot_svsm_caa_pa __ro_after_init; +SYM_PIC_ALIAS(boot_svsm_caa_pa); + +DEFINE_PER_CPU(struct svsm_ca *, svsm_caa); +DEFINE_PER_CPU(u64, svsm_caa_pa); + +static inline struct svsm_ca *svsm_get_caa(void) +{ + if (sev_cfg.use_cas) + return this_cpu_read(svsm_caa); + else + return rip_rel_ptr(&boot_svsm_ca_page); +} + +static inline u64 svsm_get_caa_pa(void) +{ + if (sev_cfg.use_cas) + return this_cpu_read(svsm_caa_pa); + else + return boot_svsm_caa_pa; +} + /* AP INIT values as documented in the APM2 section "Processor Initialization State" */ #define AP_INIT_CS_LIMIT 0xffff #define AP_INIT_DS_LIMIT 0xffff @@ -79,6 +121,7 @@ static const char * const sev_status_feat_names[] = { [MSR_AMD64_SNP_IBS_VIRT_BIT] = "IBSVirt", [MSR_AMD64_SNP_VMSA_REG_PROT_BIT] = "VMSARegProt", [MSR_AMD64_SNP_SMT_PROT_BIT] = "SMTProt", + [MSR_AMD64_SNP_SECURE_AVIC_BIT] = "SecureAVIC", }; /* @@ -100,6 +143,26 @@ DEFINE_PER_CPU(struct sev_es_save_area *, sev_vmsa); */ u8 snp_vmpl __ro_after_init; EXPORT_SYMBOL_GPL(snp_vmpl); +SYM_PIC_ALIAS(snp_vmpl); + +/* + * Since feature negotiation related variables are set early in the boot + * process they must reside in the .data section so as not to be zeroed + * out when the .bss section is later cleared. + * + * GHCB protocol version negotiated with the hypervisor. + */ +u16 ghcb_version __ro_after_init; +SYM_PIC_ALIAS(ghcb_version); + +/* 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 + */ +struct ghcb *boot_ghcb __section(".data"); static u64 __init get_snp_jump_table_addr(void) { @@ -154,6 +217,73 @@ static u64 __init get_jump_table_addr(void) return ret; } +static int svsm_perform_ghcb_protocol(struct ghcb *ghcb, struct svsm_call *call) +{ + struct es_em_ctxt ctxt; + u8 pending = 0; + + vc_ghcb_invalidate(ghcb); + + /* + * Fill in protocol and format specifiers. This can be called very early + * in the boot, so use rip-relative references as needed. + */ + ghcb->protocol_version = ghcb_version; + ghcb->ghcb_usage = GHCB_DEFAULT_USAGE; + + ghcb_set_sw_exit_code(ghcb, SVM_VMGEXIT_SNP_RUN_VMPL); + ghcb_set_sw_exit_info_1(ghcb, 0); + ghcb_set_sw_exit_info_2(ghcb, 0); + + sev_es_wr_ghcb_msr(__pa(ghcb)); + + svsm_issue_call(call, &pending); + + if (pending) + return -EINVAL; + + switch (verify_exception_info(ghcb, &ctxt)) { + case ES_OK: + break; + case ES_EXCEPTION: + vc_forward_exception(&ctxt); + fallthrough; + default: + return -EINVAL; + } + + return svsm_process_result_codes(call); +} + +static int svsm_perform_call_protocol(struct svsm_call *call) +{ + struct ghcb_state state; + unsigned long flags; + struct ghcb *ghcb; + int ret; + + flags = native_local_irq_save(); + + if (sev_cfg.ghcbs_initialized) + ghcb = __sev_get_ghcb(&state); + else if (boot_ghcb) + ghcb = boot_ghcb; + else + ghcb = NULL; + + do { + ret = ghcb ? svsm_perform_ghcb_protocol(ghcb, call) + : __pi_svsm_perform_msr_protocol(call); + } while (ret == -EAGAIN); + + if (sev_cfg.ghcbs_initialized) + __sev_put_ghcb(&state); + + native_local_irq_restore(flags); + + return ret; +} + static inline void __pval_terminate(u64 pfn, bool action, unsigned int page_size, int ret, u64 svsm_ret) { @@ -531,8 +661,11 @@ static void set_pages_state(unsigned long vaddr, unsigned long npages, int op) 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); + if (!boot_ghcb) { + struct psc_desc d = { op, svsm_get_caa(), svsm_get_caa_pa() }; + + return early_set_pages_state(vaddr, __pa(vaddr), npages, &d); + } vaddr = vaddr & PAGE_MASK; vaddr_end = vaddr + (npages << PAGE_SHIFT); @@ -973,6 +1106,9 @@ static int wakeup_cpu_via_vmgexit(u32 apic_id, unsigned long start_ip, unsigned vmsa->x87_ftw = AP_INIT_X87_FTW_DEFAULT; vmsa->x87_fcw = AP_INIT_X87_FCW_DEFAULT; + if (cc_platform_has(CC_ATTR_SNP_SECURE_AVIC)) + vmsa->vintr_ctrl |= V_GIF_MASK | V_NMI_ENABLE_MASK; + /* SVME must be set. */ vmsa->efer = EFER_SVME; @@ -1107,6 +1243,105 @@ int __init sev_es_efi_map_ghcbs_cas(pgd_t *pgd) return 0; } +u64 savic_ghcb_msr_read(u32 reg) +{ + u64 msr = APIC_BASE_MSR + (reg >> 4); + struct pt_regs regs = { .cx = msr }; + struct es_em_ctxt ctxt = { .regs = ®s }; + struct ghcb_state state; + enum es_result res; + struct ghcb *ghcb; + + guard(irqsave)(); + + ghcb = __sev_get_ghcb(&state); + vc_ghcb_invalidate(ghcb); + + res = sev_es_ghcb_handle_msr(ghcb, &ctxt, false); + if (res != ES_OK) { + pr_err("Secure AVIC MSR (0x%llx) read returned error (%d)\n", msr, res); + /* MSR read failures are treated as fatal errors */ + sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_SAVIC_FAIL); + } + + __sev_put_ghcb(&state); + + return regs.ax | regs.dx << 32; +} + +void savic_ghcb_msr_write(u32 reg, u64 value) +{ + u64 msr = APIC_BASE_MSR + (reg >> 4); + struct pt_regs regs = { + .cx = msr, + .ax = lower_32_bits(value), + .dx = upper_32_bits(value) + }; + struct es_em_ctxt ctxt = { .regs = ®s }; + struct ghcb_state state; + enum es_result res; + struct ghcb *ghcb; + + guard(irqsave)(); + + ghcb = __sev_get_ghcb(&state); + vc_ghcb_invalidate(ghcb); + + res = sev_es_ghcb_handle_msr(ghcb, &ctxt, true); + if (res != ES_OK) { + pr_err("Secure AVIC MSR (0x%llx) write returned error (%d)\n", msr, res); + /* MSR writes should never fail. Any failure is fatal error for SNP guest */ + sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_SAVIC_FAIL); + } + + __sev_put_ghcb(&state); +} + +enum es_result savic_register_gpa(u64 gpa) +{ + struct ghcb_state state; + struct es_em_ctxt ctxt; + enum es_result res; + struct ghcb *ghcb; + + guard(irqsave)(); + + ghcb = __sev_get_ghcb(&state); + vc_ghcb_invalidate(ghcb); + + ghcb_set_rax(ghcb, SVM_VMGEXIT_SAVIC_SELF_GPA); + ghcb_set_rbx(ghcb, gpa); + res = sev_es_ghcb_hv_call(ghcb, &ctxt, SVM_VMGEXIT_SAVIC, + SVM_VMGEXIT_SAVIC_REGISTER_GPA, 0); + + __sev_put_ghcb(&state); + + return res; +} + +enum es_result savic_unregister_gpa(u64 *gpa) +{ + struct ghcb_state state; + struct es_em_ctxt ctxt; + enum es_result res; + struct ghcb *ghcb; + + guard(irqsave)(); + + ghcb = __sev_get_ghcb(&state); + vc_ghcb_invalidate(ghcb); + + ghcb_set_rax(ghcb, SVM_VMGEXIT_SAVIC_SELF_GPA); + res = sev_es_ghcb_hv_call(ghcb, &ctxt, SVM_VMGEXIT_SAVIC, + SVM_VMGEXIT_SAVIC_UNREGISTER_GPA, 0); + if (gpa && res == ES_OK) + *gpa = ghcb->save.rbx; + + __sev_put_ghcb(&state); + + return res; +} + static void snp_register_per_cpu_ghcb(void) { struct sev_es_runtime_data *data; @@ -1233,7 +1468,8 @@ static void __init alloc_runtime_data(int cpu) struct svsm_ca *caa; /* Allocate the SVSM CA page if an SVSM is present */ - caa = memblock_alloc_or_panic(sizeof(*caa), PAGE_SIZE); + caa = cpu ? memblock_alloc_or_panic(sizeof(*caa), PAGE_SIZE) + : &boot_svsm_ca_page; per_cpu(svsm_caa, cpu) = caa; per_cpu(svsm_caa_pa, cpu) = __pa(caa); @@ -1287,32 +1523,9 @@ void __init sev_es_init_vc_handling(void) init_ghcb(cpu); } - /* If running under an SVSM, switch to the per-cpu CA */ - if (snp_vmpl) { - struct svsm_call call = {}; - unsigned long flags; - int ret; - - local_irq_save(flags); - - /* - * SVSM_CORE_REMAP_CA call: - * RAX = 0 (Protocol=0, CallID=0) - * RCX = New CA GPA - */ - call.caa = svsm_get_caa(); - call.rax = SVSM_CORE_CALL(SVSM_CORE_REMAP_CA); - call.rcx = this_cpu_read(svsm_caa_pa); - ret = svsm_perform_call_protocol(&call); - if (ret) - panic("Can't remap the SVSM CA, ret=%d, rax_out=0x%llx\n", - ret, call.rax_out); - + if (snp_vmpl) sev_cfg.use_cas = true; - local_irq_restore(flags); - } - sev_es_setup_play_dead(); /* Secondary CPUs use the runtime #VC handler */ @@ -1590,15 +1803,6 @@ void sev_show_status(void) pr_cont("\n"); } -void __init snp_update_svsm_ca(void) -{ - if (!snp_vmpl) - return; - - /* Update the CAA to a proper kernel address */ - boot_svsm_caa = &boot_svsm_ca_page; -} - #ifdef CONFIG_SYSFS static ssize_t vmpl_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) |