diff options
Diffstat (limited to 'arch/x86/hyperv/ivm.c')
| -rw-r--r-- | arch/x86/hyperv/ivm.c | 289 |
1 files changed, 289 insertions, 0 deletions
diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c new file mode 100644 index 000000000000..69c7a57f3307 --- /dev/null +++ b/arch/x86/hyperv/ivm.c @@ -0,0 +1,289 @@ +// 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/mshyperv.h> +#include <asm/hypervisor.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); + +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; +} + +void hv_ghcb_msr_write(u64 msr, u64 value) +{ + union hv_ghcb *hv_ghcb; + void **ghcb_base; + unsigned long flags; + struct es_em_ctxt ctxt; + + 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 (sev_es_ghcb_hv_call(&hv_ghcb->ghcb, false, &ctxt, + SVM_EXIT_MSR, 1, 0)) + pr_warn("Fail to write msr via ghcb %llx.\n", msr); + + local_irq_restore(flags); +} +EXPORT_SYMBOL_GPL(hv_ghcb_msr_write); + +void hv_ghcb_msr_read(u64 msr, u64 *value) +{ + union hv_ghcb *hv_ghcb; + void **ghcb_base; + unsigned long flags; + struct es_em_ctxt ctxt; + + /* 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 (sev_es_ghcb_hv_call(&hv_ghcb->ghcb, false, &ctxt, + 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); +} +EXPORT_SYMBOL_GPL(hv_ghcb_msr_read); +#endif + +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 system runs in the AMD SEV-SNP based + * isolation VM. + */ +bool hv_isolation_type_snp(void) +{ + return static_branch_unlikely(&isolation_type_snp); +} + +/* + * 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_pcpu, *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_pcpu = (struct hv_gpa_range_for_visibility **) + this_cpu_ptr(hyperv_pcpu_input_arg); + input = *input_pcpu; + 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_set_mem_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. + */ +int hv_set_mem_host_visibility(unsigned long kbuffer, int pagecount, bool visible) +{ + enum hv_mem_host_visibility visibility = visible ? + VMBUS_PAGE_VISIBLE_READ_WRITE : VMBUS_PAGE_NOT_VISIBLE; + u64 *pfn_array; + int ret = 0; + int i, pfn; + + if (!hv_is_isolation_supported() || !hv_hypercall_pg) + return 0; + + pfn_array = kmalloc(HV_HYP_PAGE_SIZE, GFP_KERNEL); + if (!pfn_array) + return -ENOMEM; + + 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) + goto err_free_pfn_array; + pfn = 0; + } + } + + err_free_pfn_array: + kfree(pfn_array); + return ret; +} |