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Co-developed-by: Lendacky Thomas Co-developed-by: Kalra Ashish Signed-off-by: Tianyu Lan --- Change since RFC V3: * Check NMI event when irq is disabled. * Remove redundant variable --- arch/x86/include/asm/mem_encrypt.h | 2 + arch/x86/include/uapi/asm/svm.h | 4 + arch/x86/kernel/sev.c | 314 ++++++++++++++++++++++++----- arch/x86/kernel/traps.c | 2 + 4 files changed, 266 insertions(+), 56 deletions(-) diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h index b7126701574c..9299caeca69f 100644 --- a/arch/x86/include/asm/mem_encrypt.h +++ b/arch/x86/include/asm/mem_encrypt.h @@ -50,6 +50,7 @@ void __init early_set_mem_enc_dec_hypercall(unsigned long vaddr, int npages, void __init mem_encrypt_free_decrypted_mem(void); void __init sev_es_init_vc_handling(void); +void __init sev_snp_init_hv_handling(void); #define __bss_decrypted __section(".bss..decrypted") @@ -73,6 +74,7 @@ static inline void __init sme_encrypt_kernel(struct boot_params *bp) { } static inline void __init sme_enable(struct boot_params *bp) { } static inline void sev_es_init_vc_handling(void) { } +static inline void sev_snp_init_hv_handling(void) { } static inline int __init early_set_memory_decrypted(unsigned long vaddr, unsigned long size) { return 0; } diff --git a/arch/x86/include/uapi/asm/svm.h b/arch/x86/include/uapi/asm/svm.h index 80e1df482337..828d624a38cf 100644 --- a/arch/x86/include/uapi/asm/svm.h +++ b/arch/x86/include/uapi/asm/svm.h @@ -115,6 +115,10 @@ #define SVM_VMGEXIT_AP_CREATE_ON_INIT 0 #define SVM_VMGEXIT_AP_CREATE 1 #define SVM_VMGEXIT_AP_DESTROY 2 +#define SVM_VMGEXIT_HV_DOORBELL_PAGE 0x80000014 +#define SVM_VMGEXIT_GET_PREFERRED_HV_DOORBELL_PAGE 0 +#define SVM_VMGEXIT_SET_HV_DOORBELL_PAGE 1 +#define SVM_VMGEXIT_QUERY_HV_DOORBELL_PAGE 2 #define SVM_VMGEXIT_HV_FEATURES 0x8000fffd #define SVM_VMGEXIT_TERM_REQUEST 0x8000fffe #define SVM_VMGEXIT_TERM_REASON(reason_set, reason_code) \ diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c index e2bb19605a46..b6dafeb0edbe 100644 --- a/arch/x86/kernel/sev.c +++ b/arch/x86/kernel/sev.c @@ -124,6 +124,152 @@ struct sev_config { static struct sev_config sev_cfg __read_mostly; +static noinstr struct ghcb *__sev_get_ghcb(struct ghcb_state *state); +static noinstr void __sev_put_ghcb(struct ghcb_state *state); +static int vmgexit_hv_doorbell_page(struct ghcb *ghcb, u64 op, u64 pa); +static void sev_snp_setup_hv_doorbell_page(struct ghcb *ghcb); + +union hv_pending_events { + u16 events; + struct { + u8 vector; + u8 nmi : 1; + u8 mc : 1; + u8 reserved1 : 5; + u8 no_further_signal : 1; + }; +}; + +struct sev_hv_doorbell_page { + union hv_pending_events pending_events; + u8 no_eoi_required; + u8 reserved2[61]; + u8 padding[4032]; +}; + +struct sev_snp_runtime_data { + struct sev_hv_doorbell_page hv_doorbell_page; +}; + +static DEFINE_PER_CPU(struct sev_snp_runtime_data*, snp_runtime_data); + +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); +} + +struct sev_hv_doorbell_page *sev_snp_current_doorbell_page(void) +{ + return &this_cpu_read(snp_runtime_data)->hv_doorbell_page; +} + +static u8 sev_hv_pending(void) +{ + return sev_snp_current_doorbell_page()->pending_events.events; +} + +#define sev_hv_pending_nmi \ + sev_snp_current_doorbell_page()->pending_events.nmi + +static void hv_doorbell_apic_eoi_write(u32 reg, u32 val) +{ + if (xchg(&sev_snp_current_doorbell_page()->no_eoi_required, 0) & 0x1) + return; + + BUG_ON(reg != APIC_EOI); + apic->write(reg, val); +} + +static void do_exc_hv(struct pt_regs *regs) +{ + union hv_pending_events pending_events; + + while (sev_hv_pending()) { + pending_events.events = xchg( + &sev_snp_current_doorbell_page()->pending_events.events, + 0); + + if (pending_events.nmi) + exc_nmi(regs); + +#ifdef CONFIG_X86_MCE + if (pending_events.mc) + exc_machine_check(regs); +#endif + + if (!pending_events.vector) + return; + + if (pending_events.vector < FIRST_EXTERNAL_VECTOR) { + /* Exception vectors */ + WARN(1, "exception shouldn't happen\n"); + } else if (pending_events.vector == FIRST_EXTERNAL_VECTOR) { + sysvec_irq_move_cleanup(regs); + } else if (pending_events.vector == IA32_SYSCALL_VECTOR) { + WARN(1, "syscall shouldn't happen\n"); + } else if (pending_events.vector >= FIRST_SYSTEM_VECTOR) { + switch (pending_events.vector) { +#if IS_ENABLED(CONFIG_HYPERV) + case HYPERV_STIMER0_VECTOR: + sysvec_hyperv_stimer0(regs); + break; + case HYPERVISOR_CALLBACK_VECTOR: + sysvec_hyperv_callback(regs); + break; +#endif +#ifdef CONFIG_SMP + case RESCHEDULE_VECTOR: + sysvec_reschedule_ipi(regs); + break; + case IRQ_MOVE_CLEANUP_VECTOR: + sysvec_irq_move_cleanup(regs); + break; + case REBOOT_VECTOR: + sysvec_reboot(regs); + break; + case CALL_FUNCTION_SINGLE_VECTOR: + sysvec_call_function_single(regs); + break; + case CALL_FUNCTION_VECTOR: + sysvec_call_function(regs); + break; +#endif +#ifdef CONFIG_X86_LOCAL_APIC + case ERROR_APIC_VECTOR: + sysvec_error_interrupt(regs); + break; + case SPURIOUS_APIC_VECTOR: + sysvec_spurious_apic_interrupt(regs); + break; + case LOCAL_TIMER_VECTOR: + sysvec_apic_timer_interrupt(regs); + break; + case X86_PLATFORM_IPI_VECTOR: + sysvec_x86_platform_ipi(regs); + break; +#endif + case 0x0: + break; + default: + panic("Unexpected vector %d\n", vector); + unreachable(); + } + } else { + common_interrupt(regs, pending_events.vector); + } + } +} + static __always_inline bool on_vc_stack(struct pt_regs *regs) { unsigned long sp = regs->sp; @@ -181,18 +327,19 @@ void noinstr __sev_es_ist_enter(struct pt_regs *regs) this_cpu_write(cpu_tss_rw.x86_tss.ist[IST_INDEX_VC], new_ist); } -static void do_exc_hv(struct pt_regs *regs) -{ - /* Handle #HV exception. */ -} - void check_hv_pending(struct pt_regs *regs) { if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) return; - if ((regs->flags & X86_EFLAGS_IF) == 0) + /* Handle NMI when irq is disabled. */ + if ((regs->flags & X86_EFLAGS_IF) == 0) { + if (sev_hv_pending_nmi) { + exc_nmi(regs); + sev_hv_pending_nmi = 0; + } return; + } do_exc_hv(regs); } @@ -233,68 +380,35 @@ void noinstr __sev_es_ist_exit(void) 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) +static bool sev_restricted_injection_enabled(void) +{ + return sev_status & MSR_AMD64_SNP_RESTRICTED_INJ; +} + +void __init sev_snp_init_hv_handling(void) { struct sev_es_runtime_data *data; + struct ghcb_state state; struct ghcb *ghcb; + unsigned long flags; WARN_ON(!irqs_disabled()); + if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP) || !sev_restricted_injection_enabled()) + return; 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; + local_irq_save(flags); - /* Backup GHCB content */ - *state->ghcb = *ghcb; - } else { - state->ghcb = NULL; - data->ghcb_active = true; - } + ghcb = __sev_get_ghcb(&state); - return ghcb; -} + sev_snp_setup_hv_doorbell_page(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; + __sev_put_ghcb(&state); - low = (u32)(val); - high = (u32)(val >> 32); + apic_set_eoi_write(hv_doorbell_apic_eoi_write); - native_wrmsr(MSR_AMD64_SEV_ES_GHCB, low, high); + local_irq_restore(flags); } static int vc_fetch_insn_kernel(struct es_em_ctxt *ctxt, @@ -555,6 +669,69 @@ static enum es_result vc_slow_virt_to_phys(struct ghcb *ghcb, struct es_em_ctxt /* Include code shared with pre-decompression boot stage */ #include "sev-shared.c" +/* + * 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 void sev_snp_setup_hv_doorbell_page(struct ghcb *ghcb) +{ + u64 pa; + enum es_result ret; + + pa = __pa(sev_snp_current_doorbell_page()); + vc_ghcb_invalidate(ghcb); + ret = vmgexit_hv_doorbell_page(ghcb, + SVM_VMGEXIT_SET_HV_DOORBELL_PAGE, + pa); + if (ret != ES_OK) + panic("SEV-SNP: failed to set up #HV doorbell page"); +} + static noinstr void __sev_put_ghcb(struct ghcb_state *state) { struct sev_es_runtime_data *data; @@ -1283,6 +1460,7 @@ static void snp_register_per_cpu_ghcb(void) ghcb = &data->ghcb_page; snp_register_ghcb_early(__pa(ghcb)); + sev_snp_setup_hv_doorbell_page(ghcb); } void setup_ghcb(void) @@ -1322,6 +1500,11 @@ void setup_ghcb(void) snp_register_ghcb_early(__pa(&boot_ghcb_page)); } +int vmgexit_hv_doorbell_page(struct ghcb *ghcb, u64 op, u64 pa) +{ + return sev_es_ghcb_hv_call(ghcb, NULL, SVM_VMGEXIT_HV_DOORBELL_PAGE, op, pa); +} + #ifdef CONFIG_HOTPLUG_CPU static void sev_es_ap_hlt_loop(void) { @@ -1395,6 +1578,7 @@ static void __init alloc_runtime_data(int cpu) static void __init init_ghcb(int cpu) { struct sev_es_runtime_data *data; + struct sev_snp_runtime_data *snp_data; int err; data = per_cpu(runtime_data, cpu); @@ -1406,6 +1590,19 @@ static void __init init_ghcb(int cpu) memset(&data->ghcb_page, 0, sizeof(data->ghcb_page)); + snp_data = memblock_alloc(sizeof(*snp_data), PAGE_SIZE); + if (!snp_data) + panic("Can't allocate SEV-SNP runtime data"); + + err = early_set_memory_decrypted((unsigned long)&snp_data->hv_doorbell_page, + sizeof(snp_data->hv_doorbell_page)); + if (err) + panic("Can't map #HV doorbell pages unencrypted"); + + memset(&snp_data->hv_doorbell_page, 0, sizeof(snp_data->hv_doorbell_page)); + + per_cpu(snp_runtime_data, cpu) = snp_data; + data->ghcb_active = false; data->backup_ghcb_active = false; } @@ -2046,7 +2243,12 @@ DEFINE_IDTENTRY_VC_USER(exc_vmm_communication) static bool hv_raw_handle_exception(struct pt_regs *regs) { - return false; + /* Clear the no_further_signal bit */ + sev_snp_current_doorbell_page()->pending_events.events &= 0x7fff; + + check_hv_pending(regs); + + return true; } static __always_inline bool on_hv_fallback_stack(struct pt_regs *regs) diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index d29debec8134..1aa6cab2394b 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -1503,5 +1503,7 @@ void __init trap_init(void) cpu_init_exception_handling(); /* Setup traps as cpu_init() might #GP */ idt_setup_traps(); + sev_snp_init_hv_handling(); + cpu_init(); }