diff options
Diffstat (limited to 'arch/x86/hyperv/ivm.c')
| -rw-r--r-- | arch/x86/hyperv/ivm.c | 661 |
1 files changed, 661 insertions, 0 deletions
diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c new file mode 100644 index 0000000000..8c6bf07f7d --- /dev/null +++ b/arch/x86/hyperv/ivm.c @@ -0,0 +1,661 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Hyper-V Isolation VM interface with paravisor and hypervisor + * + * Author: + * Tianyu Lan <Tianyu.Lan@microsoft.com> + */ + +#include <linux/bitfield.h> +#include <linux/hyperv.h> +#include <linux/types.h> +#include <linux/slab.h> +#include <asm/svm.h> +#include <asm/sev.h> +#include <asm/io.h> +#include <asm/coco.h> +#include <asm/mem_encrypt.h> +#include <asm/mshyperv.h> +#include <asm/hypervisor.h> +#include <asm/mtrr.h> +#include <asm/io_apic.h> +#include <asm/realmode.h> +#include <asm/e820/api.h> +#include <asm/desc.h> +#include <uapi/asm/vmx.h> + +#ifdef CONFIG_AMD_MEM_ENCRYPT + +#define GHCB_USAGE_HYPERV_CALL 1 + +union hv_ghcb { + struct ghcb ghcb; + struct { + u64 hypercalldata[509]; + u64 outputgpa; + union { + union { + struct { + u32 callcode : 16; + u32 isfast : 1; + u32 reserved1 : 14; + u32 isnested : 1; + u32 countofelements : 12; + u32 reserved2 : 4; + u32 repstartindex : 12; + u32 reserved3 : 4; + }; + u64 asuint64; + } hypercallinput; + union { + struct { + u16 callstatus; + u16 reserved1; + u32 elementsprocessed : 12; + u32 reserved2 : 20; + }; + u64 asunit64; + } hypercalloutput; + }; + u64 reserved2; + } hypercall; +} __packed __aligned(HV_HYP_PAGE_SIZE); + +/* Only used in an SNP VM with the paravisor */ +static u16 hv_ghcb_version __ro_after_init; + +/* Functions only used in an SNP VM with the paravisor go here. */ +u64 hv_ghcb_hypercall(u64 control, void *input, void *output, u32 input_size) +{ + union hv_ghcb *hv_ghcb; + void **ghcb_base; + unsigned long flags; + u64 status; + + if (!hv_ghcb_pg) + return -EFAULT; + + WARN_ON(in_nmi()); + + local_irq_save(flags); + ghcb_base = (void **)this_cpu_ptr(hv_ghcb_pg); + hv_ghcb = (union hv_ghcb *)*ghcb_base; + if (!hv_ghcb) { + local_irq_restore(flags); + return -EFAULT; + } + + hv_ghcb->ghcb.protocol_version = GHCB_PROTOCOL_MAX; + hv_ghcb->ghcb.ghcb_usage = GHCB_USAGE_HYPERV_CALL; + + hv_ghcb->hypercall.outputgpa = (u64)output; + hv_ghcb->hypercall.hypercallinput.asuint64 = 0; + hv_ghcb->hypercall.hypercallinput.callcode = control; + + if (input_size) + memcpy(hv_ghcb->hypercall.hypercalldata, input, input_size); + + VMGEXIT(); + + hv_ghcb->ghcb.ghcb_usage = 0xffffffff; + memset(hv_ghcb->ghcb.save.valid_bitmap, 0, + sizeof(hv_ghcb->ghcb.save.valid_bitmap)); + + status = hv_ghcb->hypercall.hypercalloutput.callstatus; + + local_irq_restore(flags); + + return status; +} + +static inline u64 rd_ghcb_msr(void) +{ + return __rdmsr(MSR_AMD64_SEV_ES_GHCB); +} + +static inline void wr_ghcb_msr(u64 val) +{ + native_wrmsrl(MSR_AMD64_SEV_ES_GHCB, val); +} + +static enum es_result hv_ghcb_hv_call(struct ghcb *ghcb, u64 exit_code, + u64 exit_info_1, u64 exit_info_2) +{ + /* Fill in protocol and format specifiers */ + ghcb->protocol_version = hv_ghcb_version; + ghcb->ghcb_usage = GHCB_DEFAULT_USAGE; + + ghcb_set_sw_exit_code(ghcb, exit_code); + ghcb_set_sw_exit_info_1(ghcb, exit_info_1); + ghcb_set_sw_exit_info_2(ghcb, exit_info_2); + + VMGEXIT(); + + if (ghcb->save.sw_exit_info_1 & GENMASK_ULL(31, 0)) + return ES_VMM_ERROR; + else + return ES_OK; +} + +void __noreturn hv_ghcb_terminate(unsigned int set, unsigned int reason) +{ + u64 val = GHCB_MSR_TERM_REQ; + + /* Tell the hypervisor what went wrong. */ + val |= GHCB_SEV_TERM_REASON(set, reason); + + /* Request Guest Termination from Hypvervisor */ + wr_ghcb_msr(val); + VMGEXIT(); + + while (true) + asm volatile("hlt\n" : : : "memory"); +} + +bool hv_ghcb_negotiate_protocol(void) +{ + u64 ghcb_gpa; + u64 val; + + /* Save ghcb page gpa. */ + ghcb_gpa = rd_ghcb_msr(); + + /* Do the GHCB protocol version negotiation */ + wr_ghcb_msr(GHCB_MSR_SEV_INFO_REQ); + VMGEXIT(); + val = rd_ghcb_msr(); + + if (GHCB_MSR_INFO(val) != GHCB_MSR_SEV_INFO_RESP) + return false; + + if (GHCB_MSR_PROTO_MAX(val) < GHCB_PROTOCOL_MIN || + GHCB_MSR_PROTO_MIN(val) > GHCB_PROTOCOL_MAX) + return false; + + hv_ghcb_version = min_t(size_t, GHCB_MSR_PROTO_MAX(val), + GHCB_PROTOCOL_MAX); + + /* Write ghcb page back after negotiating protocol. */ + wr_ghcb_msr(ghcb_gpa); + VMGEXIT(); + + return true; +} + +static void hv_ghcb_msr_write(u64 msr, u64 value) +{ + union hv_ghcb *hv_ghcb; + void **ghcb_base; + unsigned long flags; + + if (!hv_ghcb_pg) + return; + + WARN_ON(in_nmi()); + + local_irq_save(flags); + ghcb_base = (void **)this_cpu_ptr(hv_ghcb_pg); + hv_ghcb = (union hv_ghcb *)*ghcb_base; + if (!hv_ghcb) { + local_irq_restore(flags); + return; + } + + ghcb_set_rcx(&hv_ghcb->ghcb, msr); + ghcb_set_rax(&hv_ghcb->ghcb, lower_32_bits(value)); + ghcb_set_rdx(&hv_ghcb->ghcb, upper_32_bits(value)); + + if (hv_ghcb_hv_call(&hv_ghcb->ghcb, SVM_EXIT_MSR, 1, 0)) + pr_warn("Fail to write msr via ghcb %llx.\n", msr); + + local_irq_restore(flags); +} + +static void hv_ghcb_msr_read(u64 msr, u64 *value) +{ + union hv_ghcb *hv_ghcb; + void **ghcb_base; + unsigned long flags; + + /* Check size of union hv_ghcb here. */ + BUILD_BUG_ON(sizeof(union hv_ghcb) != HV_HYP_PAGE_SIZE); + + if (!hv_ghcb_pg) + return; + + WARN_ON(in_nmi()); + + local_irq_save(flags); + ghcb_base = (void **)this_cpu_ptr(hv_ghcb_pg); + hv_ghcb = (union hv_ghcb *)*ghcb_base; + if (!hv_ghcb) { + local_irq_restore(flags); + return; + } + + ghcb_set_rcx(&hv_ghcb->ghcb, msr); + if (hv_ghcb_hv_call(&hv_ghcb->ghcb, SVM_EXIT_MSR, 0, 0)) + pr_warn("Fail to read msr via ghcb %llx.\n", msr); + else + *value = (u64)lower_32_bits(hv_ghcb->ghcb.save.rax) + | ((u64)lower_32_bits(hv_ghcb->ghcb.save.rdx) << 32); + local_irq_restore(flags); +} + +/* Only used in a fully enlightened SNP VM, i.e. without the paravisor */ +static u8 ap_start_input_arg[PAGE_SIZE] __bss_decrypted __aligned(PAGE_SIZE); +static u8 ap_start_stack[PAGE_SIZE] __aligned(PAGE_SIZE); +static DEFINE_PER_CPU(struct sev_es_save_area *, hv_sev_vmsa); + +/* Functions only used in an SNP VM without the paravisor go here. */ + +#define hv_populate_vmcb_seg(seg, gdtr_base) \ +do { \ + if (seg.selector) { \ + seg.base = 0; \ + seg.limit = HV_AP_SEGMENT_LIMIT; \ + seg.attrib = *(u16 *)(gdtr_base + seg.selector + 5); \ + seg.attrib = (seg.attrib & 0xFF) | ((seg.attrib >> 4) & 0xF00); \ + } \ +} while (0) \ + +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); +} + +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); +} + +int hv_snp_boot_ap(int cpu, unsigned long start_ip) +{ + struct sev_es_save_area *vmsa = (struct sev_es_save_area *) + __get_free_page(GFP_KERNEL | __GFP_ZERO); + struct sev_es_save_area *cur_vmsa; + struct desc_ptr gdtr; + u64 ret, retry = 5; + struct hv_enable_vp_vtl *start_vp_input; + unsigned long flags; + + if (!vmsa) + return -ENOMEM; + + native_store_gdt(&gdtr); + + vmsa->gdtr.base = gdtr.address; + vmsa->gdtr.limit = gdtr.size; + + asm volatile("movl %%es, %%eax;" : "=a" (vmsa->es.selector)); + hv_populate_vmcb_seg(vmsa->es, vmsa->gdtr.base); + + asm volatile("movl %%cs, %%eax;" : "=a" (vmsa->cs.selector)); + hv_populate_vmcb_seg(vmsa->cs, vmsa->gdtr.base); + + asm volatile("movl %%ss, %%eax;" : "=a" (vmsa->ss.selector)); + hv_populate_vmcb_seg(vmsa->ss, vmsa->gdtr.base); + + asm volatile("movl %%ds, %%eax;" : "=a" (vmsa->ds.selector)); + hv_populate_vmcb_seg(vmsa->ds, vmsa->gdtr.base); + + vmsa->efer = native_read_msr(MSR_EFER); + + asm volatile("movq %%cr4, %%rax;" : "=a" (vmsa->cr4)); + asm volatile("movq %%cr3, %%rax;" : "=a" (vmsa->cr3)); + asm volatile("movq %%cr0, %%rax;" : "=a" (vmsa->cr0)); + + vmsa->xcr0 = 1; + vmsa->g_pat = HV_AP_INIT_GPAT_DEFAULT; + vmsa->rip = (u64)secondary_startup_64_no_verify; + vmsa->rsp = (u64)&ap_start_stack[PAGE_SIZE]; + + /* + * 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; + + ret = snp_set_vmsa(vmsa, true); + if (!ret) { + pr_err("RMPADJUST(%llx) failed: %llx\n", (u64)vmsa, ret); + free_page((u64)vmsa); + return ret; + } + + local_irq_save(flags); + start_vp_input = (struct hv_enable_vp_vtl *)ap_start_input_arg; + memset(start_vp_input, 0, sizeof(*start_vp_input)); + start_vp_input->partition_id = -1; + start_vp_input->vp_index = cpu; + start_vp_input->target_vtl.target_vtl = ms_hyperv.vtl; + *(u64 *)&start_vp_input->vp_context = __pa(vmsa) | 1; + + do { + ret = hv_do_hypercall(HVCALL_START_VP, + start_vp_input, NULL); + } while (hv_result(ret) == HV_STATUS_TIME_OUT && retry--); + + local_irq_restore(flags); + + if (!hv_result_success(ret)) { + pr_err("HvCallStartVirtualProcessor failed: %llx\n", ret); + snp_cleanup_vmsa(vmsa); + vmsa = NULL; + } + + cur_vmsa = per_cpu(hv_sev_vmsa, cpu); + /* Free up any previous VMSA page */ + if (cur_vmsa) + snp_cleanup_vmsa(cur_vmsa); + + /* Record the current VMSA page */ + per_cpu(hv_sev_vmsa, cpu) = vmsa; + + return ret; +} + +#else +static inline void hv_ghcb_msr_write(u64 msr, u64 value) {} +static inline void hv_ghcb_msr_read(u64 msr, u64 *value) {} +#endif /* CONFIG_AMD_MEM_ENCRYPT */ + +#ifdef CONFIG_INTEL_TDX_GUEST +static void hv_tdx_msr_write(u64 msr, u64 val) +{ + struct tdx_hypercall_args args = { + .r10 = TDX_HYPERCALL_STANDARD, + .r11 = EXIT_REASON_MSR_WRITE, + .r12 = msr, + .r13 = val, + }; + + u64 ret = __tdx_hypercall(&args); + + WARN_ONCE(ret, "Failed to emulate MSR write: %lld\n", ret); +} + +static void hv_tdx_msr_read(u64 msr, u64 *val) +{ + struct tdx_hypercall_args args = { + .r10 = TDX_HYPERCALL_STANDARD, + .r11 = EXIT_REASON_MSR_READ, + .r12 = msr, + }; + + u64 ret = __tdx_hypercall_ret(&args); + + if (WARN_ONCE(ret, "Failed to emulate MSR read: %lld\n", ret)) + *val = 0; + else + *val = args.r11; +} + +u64 hv_tdx_hypercall(u64 control, u64 param1, u64 param2) +{ + struct tdx_hypercall_args args = { }; + + args.r10 = control; + args.rdx = param1; + args.r8 = param2; + + (void)__tdx_hypercall_ret(&args); + + return args.r11; +} + +#else +static inline void hv_tdx_msr_write(u64 msr, u64 value) {} +static inline void hv_tdx_msr_read(u64 msr, u64 *value) {} +#endif /* CONFIG_INTEL_TDX_GUEST */ + +#if defined(CONFIG_AMD_MEM_ENCRYPT) || defined(CONFIG_INTEL_TDX_GUEST) +void hv_ivm_msr_write(u64 msr, u64 value) +{ + if (!ms_hyperv.paravisor_present) + return; + + if (hv_isolation_type_tdx()) + hv_tdx_msr_write(msr, value); + else if (hv_isolation_type_snp()) + hv_ghcb_msr_write(msr, value); +} + +void hv_ivm_msr_read(u64 msr, u64 *value) +{ + if (!ms_hyperv.paravisor_present) + return; + + if (hv_isolation_type_tdx()) + hv_tdx_msr_read(msr, value); + else if (hv_isolation_type_snp()) + hv_ghcb_msr_read(msr, value); +} + +/* + * hv_mark_gpa_visibility - Set pages visible to host via hvcall. + * + * In Isolation VM, all guest memory is encrypted from host and guest + * needs to set memory visible to host via hvcall before sharing memory + * with host. + */ +static int hv_mark_gpa_visibility(u16 count, const u64 pfn[], + enum hv_mem_host_visibility visibility) +{ + struct hv_gpa_range_for_visibility *input; + u16 pages_processed; + u64 hv_status; + unsigned long flags; + + /* no-op if partition isolation is not enabled */ + if (!hv_is_isolation_supported()) + return 0; + + if (count > HV_MAX_MODIFY_GPA_REP_COUNT) { + pr_err("Hyper-V: GPA count:%d exceeds supported:%lu\n", count, + HV_MAX_MODIFY_GPA_REP_COUNT); + return -EINVAL; + } + + local_irq_save(flags); + input = *this_cpu_ptr(hyperv_pcpu_input_arg); + + if (unlikely(!input)) { + local_irq_restore(flags); + return -EINVAL; + } + + input->partition_id = HV_PARTITION_ID_SELF; + input->host_visibility = visibility; + input->reserved0 = 0; + input->reserved1 = 0; + memcpy((void *)input->gpa_page_list, pfn, count * sizeof(*pfn)); + hv_status = hv_do_rep_hypercall( + HVCALL_MODIFY_SPARSE_GPA_PAGE_HOST_VISIBILITY, count, + 0, input, &pages_processed); + local_irq_restore(flags); + + if (hv_result_success(hv_status)) + return 0; + else + return -EFAULT; +} + +/* + * hv_vtom_set_host_visibility - Set specified memory visible to host. + * + * In Isolation VM, all guest memory is encrypted from host and guest + * needs to set memory visible to host via hvcall before sharing memory + * with host. This function works as wrap of hv_mark_gpa_visibility() + * with memory base and size. + */ +static bool hv_vtom_set_host_visibility(unsigned long kbuffer, int pagecount, bool enc) +{ + enum hv_mem_host_visibility visibility = enc ? + VMBUS_PAGE_NOT_VISIBLE : VMBUS_PAGE_VISIBLE_READ_WRITE; + u64 *pfn_array; + int ret = 0; + bool result = true; + int i, pfn; + + pfn_array = kmalloc(HV_HYP_PAGE_SIZE, GFP_KERNEL); + if (!pfn_array) + return false; + + for (i = 0, pfn = 0; i < pagecount; i++) { + pfn_array[pfn] = virt_to_hvpfn((void *)kbuffer + i * HV_HYP_PAGE_SIZE); + pfn++; + + if (pfn == HV_MAX_MODIFY_GPA_REP_COUNT || i == pagecount - 1) { + ret = hv_mark_gpa_visibility(pfn, pfn_array, + visibility); + if (ret) { + result = false; + goto err_free_pfn_array; + } + pfn = 0; + } + } + + err_free_pfn_array: + kfree(pfn_array); + return result; +} + +static bool hv_vtom_tlb_flush_required(bool private) +{ + return true; +} + +static bool hv_vtom_cache_flush_required(void) +{ + return false; +} + +static bool hv_is_private_mmio(u64 addr) +{ + /* + * Hyper-V always provides a single IO-APIC in a guest VM. + * When a paravisor is used, it is emulated by the paravisor + * in the guest context and must be mapped private. + */ + if (addr >= HV_IOAPIC_BASE_ADDRESS && + addr < (HV_IOAPIC_BASE_ADDRESS + PAGE_SIZE)) + return true; + + /* Same with a vTPM */ + if (addr >= VTPM_BASE_ADDRESS && + addr < (VTPM_BASE_ADDRESS + PAGE_SIZE)) + return true; + + return false; +} + +void __init hv_vtom_init(void) +{ + enum hv_isolation_type type = hv_get_isolation_type(); + + switch (type) { + case HV_ISOLATION_TYPE_VBS: + fallthrough; + /* + * By design, a VM using vTOM doesn't see the SEV setting, + * so SEV initialization is bypassed and sev_status isn't set. + * Set it here to indicate a vTOM VM. + * + * Note: if CONFIG_AMD_MEM_ENCRYPT is not set, sev_status is + * defined as 0ULL, to which we can't assigned a value. + */ +#ifdef CONFIG_AMD_MEM_ENCRYPT + case HV_ISOLATION_TYPE_SNP: + sev_status = MSR_AMD64_SNP_VTOM; + cc_vendor = CC_VENDOR_AMD; + break; +#endif + + case HV_ISOLATION_TYPE_TDX: + cc_vendor = CC_VENDOR_INTEL; + break; + + default: + panic("hv_vtom_init: unsupported isolation type %d\n", type); + } + + cc_set_mask(ms_hyperv.shared_gpa_boundary); + physical_mask &= ms_hyperv.shared_gpa_boundary - 1; + + x86_platform.hyper.is_private_mmio = hv_is_private_mmio; + x86_platform.guest.enc_cache_flush_required = hv_vtom_cache_flush_required; + x86_platform.guest.enc_tlb_flush_required = hv_vtom_tlb_flush_required; + x86_platform.guest.enc_status_change_finish = hv_vtom_set_host_visibility; + + /* Set WB as the default cache mode. */ + mtrr_overwrite_state(NULL, 0, MTRR_TYPE_WRBACK); +} + +#endif /* defined(CONFIG_AMD_MEM_ENCRYPT) || defined(CONFIG_INTEL_TDX_GUEST) */ + +enum hv_isolation_type hv_get_isolation_type(void) +{ + if (!(ms_hyperv.priv_high & HV_ISOLATION)) + return HV_ISOLATION_TYPE_NONE; + return FIELD_GET(HV_ISOLATION_TYPE, ms_hyperv.isolation_config_b); +} +EXPORT_SYMBOL_GPL(hv_get_isolation_type); + +/* + * hv_is_isolation_supported - Check system runs in the Hyper-V + * isolation VM. + */ +bool hv_is_isolation_supported(void) +{ + if (!cpu_feature_enabled(X86_FEATURE_HYPERVISOR)) + return false; + + if (!hypervisor_is_type(X86_HYPER_MS_HYPERV)) + return false; + + return hv_get_isolation_type() != HV_ISOLATION_TYPE_NONE; +} + +DEFINE_STATIC_KEY_FALSE(isolation_type_snp); + +/* + * hv_isolation_type_snp - Check if the system runs in an AMD SEV-SNP based + * isolation VM. + */ +bool hv_isolation_type_snp(void) +{ + return static_branch_unlikely(&isolation_type_snp); +} + +DEFINE_STATIC_KEY_FALSE(isolation_type_tdx); +/* + * hv_isolation_type_tdx - Check if the system runs in an Intel TDX based + * isolated VM. + */ +bool hv_isolation_type_tdx(void) +{ + return static_branch_unlikely(&isolation_type_tdx); +} |