diff options
| -rw-r--r-- | arch/x86/include/asm/sev-common.h | 1 | ||||
| -rw-r--r-- | arch/x86/include/asm/sev.h | 4 | ||||
| -rw-r--r-- | arch/x86/include/uapi/asm/svm.h | 5 | ||||
| -rw-r--r-- | arch/x86/kernel/sev.c | 242 | ||||
| -rw-r--r-- | arch/x86/kernel/smpboot.c | 3 |
5 files changed, 255 insertions, 0 deletions
diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h index 1aa72b5c2490..e9b6815b3b3d 100644 --- a/arch/x86/include/asm/sev-common.h +++ b/arch/x86/include/asm/sev-common.h @@ -104,6 +104,7 @@ enum psc_op { (((u64)(v) & GENMASK_ULL(63, 12)) >> 12) #define GHCB_HV_FT_SNP BIT_ULL(0) +#define GHCB_HV_FT_SNP_AP_CREATION BIT_ULL(1) /* SNP Page State Change NAE event */ #define VMGEXIT_PSC_MAX_ENTRY 253 diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h index feeb93e6ec97..a3203b2caaca 100644 --- a/arch/x86/include/asm/sev.h +++ b/arch/x86/include/asm/sev.h @@ -66,6 +66,8 @@ extern bool handle_vc_boot_ghcb(struct pt_regs *regs); /* RMP page size */ #define RMP_PG_SIZE_4K 0 +#define RMPADJUST_VMSA_PAGE_BIT BIT(16) + #ifdef CONFIG_AMD_MEM_ENCRYPT extern struct static_key_false sev_es_enable_key; extern void __sev_es_ist_enter(struct pt_regs *regs); @@ -130,6 +132,7 @@ void __init early_snp_set_memory_shared(unsigned long vaddr, unsigned long paddr void __init snp_prep_memory(unsigned long paddr, unsigned int sz, enum psc_op op); void snp_set_memory_shared(unsigned long vaddr, unsigned int npages); void snp_set_memory_private(unsigned long vaddr, unsigned int npages); +void snp_set_wakeup_secondary_cpu(void); #else static inline void sev_es_ist_enter(struct pt_regs *regs) { } static inline void sev_es_ist_exit(void) { } @@ -146,6 +149,7 @@ early_snp_set_memory_shared(unsigned long vaddr, unsigned long paddr, unsigned i static inline void __init snp_prep_memory(unsigned long paddr, unsigned int sz, enum psc_op op) { } static inline void snp_set_memory_shared(unsigned long vaddr, unsigned int npages) { } static inline void snp_set_memory_private(unsigned long vaddr, unsigned int npages) { } +static inline void snp_set_wakeup_secondary_cpu(void) { } #endif #endif diff --git a/arch/x86/include/uapi/asm/svm.h b/arch/x86/include/uapi/asm/svm.h index 64404b47b773..cfea5e875088 100644 --- a/arch/x86/include/uapi/asm/svm.h +++ b/arch/x86/include/uapi/asm/svm.h @@ -109,6 +109,10 @@ #define SVM_VMGEXIT_SET_AP_JUMP_TABLE 0 #define SVM_VMGEXIT_GET_AP_JUMP_TABLE 1 #define SVM_VMGEXIT_PSC 0x80000010 +#define SVM_VMGEXIT_AP_CREATION 0x80000013 +#define SVM_VMGEXIT_AP_CREATE_ON_INIT 0 +#define SVM_VMGEXIT_AP_CREATE 1 +#define SVM_VMGEXIT_AP_DESTROY 2 #define SVM_VMGEXIT_HV_FEATURES 0x8000fffd #define SVM_VMGEXIT_UNSUPPORTED_EVENT 0x8000ffff @@ -221,6 +225,7 @@ { SVM_VMGEXIT_AP_HLT_LOOP, "vmgexit_ap_hlt_loop" }, \ { SVM_VMGEXIT_AP_JUMP_TABLE, "vmgexit_ap_jump_table" }, \ { SVM_VMGEXIT_PSC, "vmgexit_page_state_change" }, \ + { SVM_VMGEXIT_AP_CREATION, "vmgexit_ap_creation" }, \ { SVM_VMGEXIT_HV_FEATURES, "vmgexit_hypervisor_feature" }, \ { SVM_EXIT_ERR, "invalid_guest_state" } diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c index bf4b57835694..d7915ae7729d 100644 --- a/arch/x86/kernel/sev.c +++ b/arch/x86/kernel/sev.c @@ -18,6 +18,7 @@ #include <linux/memblock.h> #include <linux/kernel.h> #include <linux/mm.h> +#include <linux/cpumask.h> #include <asm/cpu_entry_area.h> #include <asm/stacktrace.h> @@ -31,9 +32,26 @@ #include <asm/svm.h> #include <asm/smp.h> #include <asm/cpu.h> +#include <asm/apic.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); @@ -90,6 +108,8 @@ struct ghcb_state { 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); + static __always_inline bool on_vc_stack(struct pt_regs *regs) { unsigned long sp = regs->sp; @@ -823,6 +843,228 @@ void snp_set_memory_private(unsigned long vaddr, unsigned int npages) 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 sev_es_setup_ap_jump_table(struct real_mode_header *rmh) { u16 startup_cs, startup_ip; diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 2ef14772dc04..85d7b1c5eb70 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -82,6 +82,7 @@ #include <asm/spec-ctrl.h> #include <asm/hw_irq.h> #include <asm/stackprotector.h> +#include <asm/sev.h> /* representing HT siblings of each logical CPU */ DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_sibling_map); @@ -1430,6 +1431,8 @@ void __init native_smp_prepare_cpus(unsigned int max_cpus) smp_quirk_init_udelay(); speculative_store_bypass_ht_init(); + + snp_set_wakeup_secondary_cpu(); } void arch_thaw_secondary_cpus_begin(void) |