acrn-hypervisor/hypervisor/arch/x86/guest/trusty.c

/*
 * Copyright (C) 2018 Intel Corporation. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#include <types.h>
#include <bits.h>
#include <crypto_api.h>
#include <trusty.h>
#include <page.h>
#include <pgtable.h>
#include <mmu.h>
#include <ept.h>
#include <vm.h>
#include <vmx.h>
#include <security.h>
#include <logmsg.h>
#include <seed.h>

#define TRUSTY_VERSION   1U
#define TRUSTY_VERSION_2 2U

struct trusty_mem {
	/* The first page of trusty memory is reserved for key_info and trusty_startup_param. */
	struct {
		struct trusty_key_info key_info;
		struct trusty_startup_param startup_param;
	} first_page;

	/* The left memory is for trusty's code/data/heap/stack */
} __aligned(PAGE_SIZE);

/**
 * @defgroup trusty_apis Trusty APIs
 *
 * This is a special group that includes all APIs
 * related to Trusty
 *
 * @{
 */

/**
 * @brief Create Secure World EPT hierarchy
 *
 * Create Secure World EPT hierarchy, construct new PML4/PDPT, reuse PD/PT parse from
 * vm->arch_vm->ept
 *
 * @param vm pointer to a VM with 2 Worlds
 * @param gpa_orig original gpa allocated from vSBL
 * @param size LK size (16M by default)
 * @param gpa_rebased gpa rebased to offset xxx (511G_OFFSET)
 *
 */
static void create_secure_world_ept(struct acrn_vm *vm, uint64_t gpa_orig,
		uint64_t size, uint64_t gpa_rebased)
{
	uint64_t nworld_pml4e;
	uint64_t sworld_pml4e;
	/* Check the HPA of parameter gpa_orig when invoking check_continuos_hpa */
	uint64_t hpa;
	uint64_t table_present = EPT_RWX;
	uint64_t pdpte, *dest_pdpte_p, *src_pdpte_p;
	void *sub_table_addr, *pml4_base;
	uint16_t i;

	hpa = gpa2hpa(vm, gpa_orig);

	/* Unmap gpa_orig~gpa_orig+size from guest normal world ept mapping */
	ept_mr_del(vm, (uint64_t *)vm->arch_vm.nworld_eptp, gpa_orig, size);

	/* Copy PDPT entries from Normal world to Secure world
	 * Secure world can access Normal World's memory,
	 * but Normal World can not access Secure World's memory.
	 * The PML4/PDPT for Secure world are separated from
	 * Normal World.PD/PT are shared in both Secure world's EPT
	 * and Normal World's EPT
	 */
	pml4_base = vm->arch_vm.ept_mem_ops.info->ept.sworld_pgtable_base;
	(void)memset(pml4_base, 0U, PAGE_SIZE);
	vm->arch_vm.sworld_eptp = pml4_base;
	sanitize_pte((uint64_t *)vm->arch_vm.sworld_eptp, &vm->arch_vm.ept_mem_ops);

	/* The trusty memory is remapped to guest physical address
	 * of gpa_rebased to gpa_rebased + size
	 */
	sub_table_addr = vm->arch_vm.ept_mem_ops.info->ept.sworld_pgtable_base +
									TRUSTY_PML4_PAGE_NUM(TRUSTY_EPT_REBASE_GPA);
	(void)memset(sub_table_addr, 0U, PAGE_SIZE);
	sworld_pml4e = hva2hpa(sub_table_addr) | table_present;
	set_pgentry((uint64_t *)pml4_base, sworld_pml4e, &vm->arch_vm.ept_mem_ops);

	nworld_pml4e = get_pgentry((uint64_t *)vm->arch_vm.nworld_eptp);

	/*
	 * copy PTPDEs from normal world EPT to secure world EPT,
	 * and remove execute access attribute in these entries
	 */
	dest_pdpte_p = pml4e_page_vaddr(sworld_pml4e);
	src_pdpte_p = pml4e_page_vaddr(nworld_pml4e);
	for (i = 0U; i < (uint16_t)(PTRS_PER_PDPTE - 1UL); i++) {
		pdpte = get_pgentry(src_pdpte_p);
		if ((pdpte & table_present) != 0UL) {
			pdpte &= ~EPT_EXE;
			set_pgentry(dest_pdpte_p, pdpte, &vm->arch_vm.ept_mem_ops);
		}
		src_pdpte_p++;
		dest_pdpte_p++;
	}

	/* Map [gpa_rebased, gpa_rebased + size) to secure ept mapping */
	ept_mr_add(vm, (uint64_t *)vm->arch_vm.sworld_eptp, hpa, gpa_rebased, size, EPT_RWX | EPT_WB);

	/* Backup secure world info, will be used when destroy secure world and suspend UOS */
	vm->sworld_control.sworld_memory.base_gpa_in_uos = gpa_orig;
	vm->sworld_control.sworld_memory.base_hpa = hpa;
	vm->sworld_control.sworld_memory.length = size;
}

void destroy_secure_world(struct acrn_vm *vm, bool need_clr_mem)
{
	uint64_t hpa = vm->sworld_control.sworld_memory.base_hpa;
	uint64_t gpa_uos = vm->sworld_control.sworld_memory.base_gpa_in_uos;
	uint64_t size = vm->sworld_control.sworld_memory.length;

	if (vm->arch_vm.sworld_eptp != NULL) {
		if (need_clr_mem) {
			/* clear trusty memory space */
			stac();
			(void)memset(hpa2hva(hpa), 0U, (size_t)size);
			clac();
		}

		ept_mr_del(vm, vm->arch_vm.sworld_eptp, gpa_uos, size);
		/* sanitize trusty ept page-structures */
		sanitize_pte((uint64_t *)vm->arch_vm.sworld_eptp, &vm->arch_vm.ept_mem_ops);
		vm->arch_vm.sworld_eptp = NULL;

		/* Restore memory to guest normal world */
		ept_mr_add(vm, vm->arch_vm.nworld_eptp, hpa, gpa_uos, size, EPT_RWX | EPT_WB);
	} else {
		pr_err("sworld eptp is NULL, it's not created");
	}
}

static inline void save_fxstore_guest_area(struct ext_context *ext_ctx)
{
	asm volatile("fxsave (%0)"
			: : "r" (ext_ctx->fxstore_guest_area) : "memory");
}

static inline void rstor_fxstore_guest_area(const struct ext_context *ext_ctx)
{
	asm volatile("fxrstor (%0)" : : "r" (ext_ctx->fxstore_guest_area));
}

static void save_world_ctx(struct acrn_vcpu *vcpu, struct ext_context *ext_ctx)
{
	uint32_t i;

	/* cache on-demand run_context for efer/rflags/rsp/rip/cr0/cr4 */
	(void)vcpu_get_efer(vcpu);
	(void)vcpu_get_rflags(vcpu);
	(void)vcpu_get_rsp(vcpu);
	(void)vcpu_get_rip(vcpu);
	(void)vcpu_get_cr0(vcpu);
	(void)vcpu_get_cr4(vcpu);

	/* VMCS GUEST field */
	ext_ctx->tsc_offset = exec_vmread(VMX_TSC_OFFSET_FULL);
	ext_ctx->cr3 = exec_vmread(VMX_GUEST_CR3);
	ext_ctx->dr7 = exec_vmread(VMX_GUEST_DR7);
	ext_ctx->ia32_debugctl = exec_vmread64(VMX_GUEST_IA32_DEBUGCTL_FULL);

	/*
	 * Similar to CR0 and CR4, the actual value of guest's IA32_PAT MSR
	 * (represented by ext_ctx->ia32_pat) could be different from the
	 * value that guest reads (guest_msrs[IA32_PAT]).
	 *
	 * the wrmsr handler keeps track of 'guest_msrs', and we only
	 * need to save/load 'ext_ctx->ia32_pat' in world switch.
	 */
	ext_ctx->ia32_pat = exec_vmread64(VMX_GUEST_IA32_PAT_FULL);
	ext_ctx->ia32_sysenter_esp = exec_vmread(VMX_GUEST_IA32_SYSENTER_ESP);
	ext_ctx->ia32_sysenter_eip = exec_vmread(VMX_GUEST_IA32_SYSENTER_EIP);
	ext_ctx->ia32_sysenter_cs = exec_vmread32(VMX_GUEST_IA32_SYSENTER_CS);
	save_segment(ext_ctx->cs, VMX_GUEST_CS);
	save_segment(ext_ctx->ss, VMX_GUEST_SS);
	save_segment(ext_ctx->ds, VMX_GUEST_DS);
	save_segment(ext_ctx->es, VMX_GUEST_ES);
	save_segment(ext_ctx->fs, VMX_GUEST_FS);
	save_segment(ext_ctx->gs, VMX_GUEST_GS);
	save_segment(ext_ctx->tr, VMX_GUEST_TR);
	save_segment(ext_ctx->ldtr, VMX_GUEST_LDTR);
	/* Only base and limit for IDTR and GDTR */
	ext_ctx->idtr.base = exec_vmread(VMX_GUEST_IDTR_BASE);
	ext_ctx->gdtr.base = exec_vmread(VMX_GUEST_GDTR_BASE);
	ext_ctx->idtr.limit = exec_vmread32(VMX_GUEST_IDTR_LIMIT);
	ext_ctx->gdtr.limit = exec_vmread32(VMX_GUEST_GDTR_LIMIT);

	/* MSRs which not in the VMCS */
	ext_ctx->ia32_star = msr_read(MSR_IA32_STAR);
	ext_ctx->ia32_lstar = msr_read(MSR_IA32_LSTAR);
	ext_ctx->ia32_fmask = msr_read(MSR_IA32_FMASK);
	ext_ctx->ia32_kernel_gs_base = msr_read(MSR_IA32_KERNEL_GS_BASE);

	/* FX area */
	save_fxstore_guest_area(ext_ctx);

	/* For MSRs need isolation between worlds */
	for (i = 0U; i < NUM_WORLD_MSRS; i++) {
		vcpu->arch.contexts[vcpu->arch.cur_context].world_msrs[i] = vcpu->arch.guest_msrs[i];
	}
}

static void load_world_ctx(struct acrn_vcpu *vcpu, const struct ext_context *ext_ctx)
{
	uint32_t i;

	/* mark to update on-demand run_context for efer/rflags/rsp/rip/cr0/cr4 */
	bitmap_set_lock(CPU_REG_EFER, &vcpu->reg_updated);
	bitmap_set_lock(CPU_REG_RFLAGS, &vcpu->reg_updated);
	bitmap_set_lock(CPU_REG_RSP, &vcpu->reg_updated);
	bitmap_set_lock(CPU_REG_RIP, &vcpu->reg_updated);
	bitmap_set_lock(CPU_REG_CR0, &vcpu->reg_updated);
	bitmap_set_lock(CPU_REG_CR4, &vcpu->reg_updated);

	/* VMCS Execution field */
	exec_vmwrite64(VMX_TSC_OFFSET_FULL, ext_ctx->tsc_offset);

	/* VMCS GUEST field */
	exec_vmwrite(VMX_GUEST_CR3, ext_ctx->cr3);
	exec_vmwrite(VMX_GUEST_DR7, ext_ctx->dr7);
	exec_vmwrite64(VMX_GUEST_IA32_DEBUGCTL_FULL, ext_ctx->ia32_debugctl);
	exec_vmwrite64(VMX_GUEST_IA32_PAT_FULL, ext_ctx->ia32_pat);
	exec_vmwrite32(VMX_GUEST_IA32_SYSENTER_CS, ext_ctx->ia32_sysenter_cs);
	exec_vmwrite(VMX_GUEST_IA32_SYSENTER_ESP, ext_ctx->ia32_sysenter_esp);
	exec_vmwrite(VMX_GUEST_IA32_SYSENTER_EIP, ext_ctx->ia32_sysenter_eip);
	load_segment(ext_ctx->cs, VMX_GUEST_CS);
	load_segment(ext_ctx->ss, VMX_GUEST_SS);
	load_segment(ext_ctx->ds, VMX_GUEST_DS);
	load_segment(ext_ctx->es, VMX_GUEST_ES);
	load_segment(ext_ctx->fs, VMX_GUEST_FS);
	load_segment(ext_ctx->gs, VMX_GUEST_GS);
	load_segment(ext_ctx->tr, VMX_GUEST_TR);
	load_segment(ext_ctx->ldtr, VMX_GUEST_LDTR);
	/* Only base and limit for IDTR and GDTR */
	exec_vmwrite(VMX_GUEST_IDTR_BASE, ext_ctx->idtr.base);
	exec_vmwrite(VMX_GUEST_GDTR_BASE, ext_ctx->gdtr.base);
	exec_vmwrite32(VMX_GUEST_IDTR_LIMIT, ext_ctx->idtr.limit);
	exec_vmwrite32(VMX_GUEST_GDTR_LIMIT, ext_ctx->gdtr.limit);

	/* MSRs which not in the VMCS */
	msr_write(MSR_IA32_STAR, ext_ctx->ia32_star);
	msr_write(MSR_IA32_LSTAR, ext_ctx->ia32_lstar);
	msr_write(MSR_IA32_FMASK, ext_ctx->ia32_fmask);
	msr_write(MSR_IA32_KERNEL_GS_BASE, ext_ctx->ia32_kernel_gs_base);

	/* FX area */
	rstor_fxstore_guest_area(ext_ctx);

	/* For MSRs need isolation between worlds */
	for (i = 0U; i < NUM_WORLD_MSRS; i++) {
		vcpu->arch.guest_msrs[i] = vcpu->arch.contexts[!vcpu->arch.cur_context].world_msrs[i];
	}
}

static void copy_smc_param(const struct run_context *prev_ctx,
				struct run_context *next_ctx)
{
	next_ctx->guest_cpu_regs.regs.rdi = prev_ctx->guest_cpu_regs.regs.rdi;
	next_ctx->guest_cpu_regs.regs.rsi = prev_ctx->guest_cpu_regs.regs.rsi;
	next_ctx->guest_cpu_regs.regs.rdx = prev_ctx->guest_cpu_regs.regs.rdx;
	next_ctx->guest_cpu_regs.regs.rbx = prev_ctx->guest_cpu_regs.regs.rbx;
}

void switch_world(struct acrn_vcpu *vcpu, int32_t next_world)
{
	struct acrn_vcpu_arch *arch = &vcpu->arch;

	/* save previous world context */
	save_world_ctx(vcpu, &arch->contexts[!next_world].ext_ctx);

	/* load next world context */
	load_world_ctx(vcpu, &arch->contexts[next_world].ext_ctx);

	/* Copy SMC parameters: RDI, RSI, RDX, RBX */
	copy_smc_param(&arch->contexts[!next_world].run_ctx,
			&arch->contexts[next_world].run_ctx);

	if (next_world == NORMAL_WORLD) {
		/* load EPTP for next world */
		exec_vmwrite64(VMX_EPT_POINTER_FULL,
			hva2hpa(vcpu->vm->arch_vm.nworld_eptp) |
			(3UL << 3U) | 0x6UL);

#ifndef CONFIG_L1D_FLUSH_VMENTRY_ENABLED
		cpu_l1d_flush();
#endif
	} else {
		exec_vmwrite64(VMX_EPT_POINTER_FULL,
			hva2hpa(vcpu->vm->arch_vm.sworld_eptp) |
			(3UL << 3U) | 0x6UL);
	}

	/* Update world index */
	arch->cur_context = next_world;
}

/* Put key_info and trusty_startup_param in the first Page of Trusty
 * runtime memory
 */
static bool setup_trusty_info(struct acrn_vcpu *vcpu, uint32_t mem_size, uint64_t mem_base_hpa, uint8_t *rkey)
{
	bool success = false;
	struct trusty_mem *mem;
	struct trusty_key_info key_info;
	struct trusty_startup_param startup_param;

	(void)memset(&key_info, 0U, sizeof(key_info));

	key_info.size_of_this_struct = sizeof(struct trusty_key_info);
	key_info.version = 0U;
	key_info.platform = 3U;

	if (rkey != NULL) {
		(void)memcpy_s(key_info.rpmb_key, 64U, rkey, 64U);
		(void)memset(rkey, 0U, 64U);
	}

	/* Derive dvseed from dseed for Trusty */
	if (derive_virtual_seed(&key_info.dseed_list[0U], &key_info.num_seeds,
				  NULL, 0U,
				  vcpu->vm->uuid, sizeof(vcpu->vm->uuid))) {
		/* Derive encryption key of attestation keybox from dseed */
		if (derive_attkb_enc_key(key_info.attkb_enc_key)) {
			/* Prepare trusty startup param */
			startup_param.size_of_this_struct = sizeof(struct trusty_startup_param);
			startup_param.mem_size = mem_size;
			startup_param.tsc_per_ms = CYCLES_PER_MS;
			startup_param.trusty_mem_base = TRUSTY_EPT_REBASE_GPA;

			/* According to trusty boot protocol, it will use RDI as the
			 * address(GPA) of startup_param on boot. Currently, the startup_param
			 * is put in the first page of trusty memory just followed by key_info.
			 */
			vcpu->arch.contexts[SECURE_WORLD].run_ctx.guest_cpu_regs.regs.rdi
				= (uint64_t)TRUSTY_EPT_REBASE_GPA + sizeof(struct trusty_key_info);

			stac();
			mem = (struct trusty_mem *)(hpa2hva(mem_base_hpa));
			(void)memcpy_s(&mem->first_page.key_info, sizeof(struct trusty_key_info),
				       &key_info, sizeof(key_info));
			(void)memcpy_s(&mem->first_page.startup_param, sizeof(struct trusty_startup_param),
				       &startup_param, sizeof(startup_param));
			clac();
			success = true;
		}
	}

	(void)memset(&key_info, 0U, sizeof(key_info));

	return success;
}

/* Secure World will reuse environment of UOS_Loder since they are
 * both booting from and running in 64bit mode, except GP registers.
 * RIP, RSP and RDI are specified below, other GP registers are leaved
 * as 0.
 */
static bool init_secure_world_env(struct acrn_vcpu *vcpu,
				uint64_t entry_gpa,
				uint64_t base_hpa,
				uint32_t size,
				uint8_t *rpmb_key)
{
	uint32_t i;

	vcpu->arch.inst_len = 0U;
	vcpu->arch.contexts[SECURE_WORLD].run_ctx.rip = entry_gpa;
	vcpu->arch.contexts[SECURE_WORLD].run_ctx.guest_cpu_regs.regs.rsp =
		TRUSTY_EPT_REBASE_GPA + size;

	vcpu->arch.contexts[SECURE_WORLD].ext_ctx.tsc_offset = 0UL;

	/* Init per world MSRs */
	for (i = 0U; i < NUM_WORLD_MSRS; i++) {
		vcpu->arch.contexts[NORMAL_WORLD].world_msrs[i] = vcpu->arch.guest_msrs[i];
		vcpu->arch.contexts[SECURE_WORLD].world_msrs[i] = vcpu->arch.guest_msrs[i];
	}

	return setup_trusty_info(vcpu, size, base_hpa, rpmb_key);
}

bool initialize_trusty(struct acrn_vcpu *vcpu, struct trusty_boot_param *boot_param)
{
	bool success = true;
	uint64_t trusty_entry_gpa, trusty_base_gpa, trusty_base_hpa;
	uint32_t trusty_mem_size;
	struct acrn_vm *vm = vcpu->vm;
	uint8_t *rpmb_key = NULL;

	switch (boot_param->version) {
	case TRUSTY_VERSION_2:
		trusty_entry_gpa = ((uint64_t)boot_param->entry_point) |
			(((uint64_t)boot_param->entry_point_high) << 32U);
		trusty_base_gpa = ((uint64_t)boot_param->base_addr) |
			(((uint64_t)boot_param->base_addr_high) << 32U);
		rpmb_key = boot_param->rpmb_key;
		break;
	case TRUSTY_VERSION:
		trusty_entry_gpa = (uint64_t)boot_param->entry_point;
		trusty_base_gpa = (uint64_t)boot_param->base_addr;
		break;
	default:
		pr_err("%s: Version(%u) not supported!\n", __func__, boot_param->version);
		success = false;
		break;
	}

	if (success) {
		if ((vm->sworld_control.flag.supported == 0UL)
				|| (vm->arch_vm.sworld_eptp != NULL)) {
			pr_err("Sworld is not supported or Sworld eptp is not NULL");
			success = false;
		} else {
			trusty_mem_size = boot_param->mem_size;
			create_secure_world_ept(vm, trusty_base_gpa, trusty_mem_size,
								TRUSTY_EPT_REBASE_GPA);
			trusty_base_hpa = vm->sworld_control.sworld_memory.base_hpa;

			exec_vmwrite64(VMX_EPT_POINTER_FULL,
					hva2hpa(vm->arch_vm.sworld_eptp) | (3UL << 3U) | 0x6UL);

			/* save Normal World context */
			save_world_ctx(vcpu, &vcpu->arch.contexts[NORMAL_WORLD].ext_ctx);

			/* init secure world environment */
			if (init_secure_world_env(vcpu,
				(trusty_entry_gpa - trusty_base_gpa) + TRUSTY_EPT_REBASE_GPA,
				trusty_base_hpa, trusty_mem_size, rpmb_key)) {

				/* switch to Secure World */
				vcpu->arch.cur_context = SECURE_WORLD;
			} else {
				success = false;
			}
		}
	}

	return success;
}

void save_sworld_context(struct acrn_vcpu *vcpu)
{
	(void)memcpy_s(&vcpu->vm->sworld_snapshot,
			sizeof(struct cpu_context),
			&vcpu->arch.contexts[SECURE_WORLD],
			sizeof(struct cpu_context));
}

void restore_sworld_context(struct acrn_vcpu *vcpu)
{
	struct secure_world_control *sworld_ctl =
		&vcpu->vm->sworld_control;

	create_secure_world_ept(vcpu->vm,
		sworld_ctl->sworld_memory.base_gpa_in_uos,
		sworld_ctl->sworld_memory.length,
		TRUSTY_EPT_REBASE_GPA);

	(void)memcpy_s(&vcpu->arch.contexts[SECURE_WORLD],
			sizeof(struct cpu_context),
			&vcpu->vm->sworld_snapshot,
			sizeof(struct cpu_context));
}

/**
 * @}
 */
/* End of trusty_apis */