linux_kernel/tools/testing/selftests/kvm/lib/vmx.c

/*
 * tools/testing/selftests/kvm/lib/x86.c
 *
 * Copyright (C) 2018, Google LLC.
 *
 * This work is licensed under the terms of the GNU GPL, version 2.
 */

#define _GNU_SOURCE /* for program_invocation_name */

#include "test_util.h"
#include "kvm_util.h"
#include "x86.h"
#include "vmx.h"

/* Create a default VM for VMX tests.
 *
 * Input Args:
 *   vcpuid - The id of the single VCPU to add to the VM.
 *   guest_code - The vCPU's entry point
 *
 * Output Args: None
 *
 * Return:
 *   Pointer to opaque structure that describes the created VM.
 */
struct kvm_vm *
vm_create_default_vmx(uint32_t vcpuid, vmx_guest_code_t guest_code)
{
	struct kvm_cpuid2 *cpuid;
	struct kvm_vm *vm;
	vm_vaddr_t vmxon_vaddr;
	vm_paddr_t vmxon_paddr;
	vm_vaddr_t vmcs_vaddr;
	vm_paddr_t vmcs_paddr;

	vm = vm_create_default(vcpuid, (void *) guest_code);

	/* Enable nesting in CPUID */
	vcpu_set_cpuid(vm, vcpuid, kvm_get_supported_cpuid());

	/* Setup of a region of guest memory for the vmxon region. */
	vmxon_vaddr = vm_vaddr_alloc(vm, getpagesize(), 0, 0, 0);
	vmxon_paddr = addr_gva2gpa(vm, vmxon_vaddr);

	/* Setup of a region of guest memory for a vmcs. */
	vmcs_vaddr = vm_vaddr_alloc(vm, getpagesize(), 0, 0, 0);
	vmcs_paddr = addr_gva2gpa(vm, vmcs_vaddr);

	vcpu_args_set(vm, vcpuid, 4, vmxon_vaddr, vmxon_paddr, vmcs_vaddr,
		      vmcs_paddr);

	return vm;
}

void prepare_for_vmx_operation(void)
{
	uint64_t feature_control;
	uint64_t required;
	unsigned long cr0;
	unsigned long cr4;

	/*
	 * Ensure bits in CR0 and CR4 are valid in VMX operation:
	 * - Bit X is 1 in _FIXED0: bit X is fixed to 1 in CRx.
	 * - Bit X is 0 in _FIXED1: bit X is fixed to 0 in CRx.
	 */
	__asm__ __volatile__("mov %%cr0, %0" : "=r"(cr0) : : "memory");
	cr0 &= rdmsr(MSR_IA32_VMX_CR0_FIXED1);
	cr0 |= rdmsr(MSR_IA32_VMX_CR0_FIXED0);
	__asm__ __volatile__("mov %0, %%cr0" : : "r"(cr0) : "memory");

	__asm__ __volatile__("mov %%cr4, %0" : "=r"(cr4) : : "memory");
	cr4 &= rdmsr(MSR_IA32_VMX_CR4_FIXED1);
	cr4 |= rdmsr(MSR_IA32_VMX_CR4_FIXED0);
	/* Enable VMX operation */
	cr4 |= X86_CR4_VMXE;
	__asm__ __volatile__("mov %0, %%cr4" : : "r"(cr4) : "memory");

	/*
	 * Configure IA32_FEATURE_CONTROL MSR to allow VMXON:
	 *  Bit 0: Lock bit. If clear, VMXON causes a #GP.
	 *  Bit 2: Enables VMXON outside of SMX operation. If clear, VMXON
	 *    outside of SMX causes a #GP.
	 */
	required = FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX;
	required |= FEATURE_CONTROL_LOCKED;
	feature_control = rdmsr(MSR_IA32_FEATURE_CONTROL);
	if ((feature_control & required) != required)
		wrmsr(MSR_IA32_FEATURE_CONTROL, feature_control | required);
}

/*
 * Initialize the control fields to the most basic settings possible.
 */
static inline void init_vmcs_control_fields(void)
{
	vmwrite(VIRTUAL_PROCESSOR_ID, 0);
	vmwrite(POSTED_INTR_NV, 0);

	vmwrite(PIN_BASED_VM_EXEC_CONTROL, rdmsr(MSR_IA32_VMX_PINBASED_CTLS));
	vmwrite(CPU_BASED_VM_EXEC_CONTROL, rdmsr(MSR_IA32_VMX_PROCBASED_CTLS));
	vmwrite(EXCEPTION_BITMAP, 0);
	vmwrite(PAGE_FAULT_ERROR_CODE_MASK, 0);
	vmwrite(PAGE_FAULT_ERROR_CODE_MATCH, -1); /* Never match */
	vmwrite(CR3_TARGET_COUNT, 0);
	vmwrite(VM_EXIT_CONTROLS, rdmsr(MSR_IA32_VMX_EXIT_CTLS) |
		VM_EXIT_HOST_ADDR_SPACE_SIZE);	  /* 64-bit host */
	vmwrite(VM_EXIT_MSR_STORE_COUNT, 0);
	vmwrite(VM_EXIT_MSR_LOAD_COUNT, 0);
	vmwrite(VM_ENTRY_CONTROLS, rdmsr(MSR_IA32_VMX_ENTRY_CTLS) |
		VM_ENTRY_IA32E_MODE);		  /* 64-bit guest */
	vmwrite(VM_ENTRY_MSR_LOAD_COUNT, 0);
	vmwrite(VM_ENTRY_INTR_INFO_FIELD, 0);
	vmwrite(TPR_THRESHOLD, 0);
	vmwrite(SECONDARY_VM_EXEC_CONTROL, 0);

	vmwrite(CR0_GUEST_HOST_MASK, 0);
	vmwrite(CR4_GUEST_HOST_MASK, 0);
	vmwrite(CR0_READ_SHADOW, get_cr0());
	vmwrite(CR4_READ_SHADOW, get_cr4());
}

/*
 * Initialize the host state fields based on the current host state, with
 * the exception of HOST_RSP and HOST_RIP, which should be set by vmlaunch
 * or vmresume.
 */
static inline void init_vmcs_host_state(void)
{
	uint32_t exit_controls = vmreadz(VM_EXIT_CONTROLS);

	vmwrite(HOST_ES_SELECTOR, get_es());
	vmwrite(HOST_CS_SELECTOR, get_cs());
	vmwrite(HOST_SS_SELECTOR, get_ss());
	vmwrite(HOST_DS_SELECTOR, get_ds());
	vmwrite(HOST_FS_SELECTOR, get_fs());
	vmwrite(HOST_GS_SELECTOR, get_gs());
	vmwrite(HOST_TR_SELECTOR, get_tr());

	if (exit_controls & VM_EXIT_LOAD_IA32_PAT)
		vmwrite(HOST_IA32_PAT, rdmsr(MSR_IA32_CR_PAT));
	if (exit_controls & VM_EXIT_LOAD_IA32_EFER)
		vmwrite(HOST_IA32_EFER, rdmsr(MSR_EFER));
	if (exit_controls & VM_EXIT_LOAD_IA32_PERF_GLOBAL_CTRL)
		vmwrite(HOST_IA32_PERF_GLOBAL_CTRL,
			rdmsr(MSR_CORE_PERF_GLOBAL_CTRL));

	vmwrite(HOST_IA32_SYSENTER_CS, rdmsr(MSR_IA32_SYSENTER_CS));

	vmwrite(HOST_CR0, get_cr0());
	vmwrite(HOST_CR3, get_cr3());
	vmwrite(HOST_CR4, get_cr4());
	vmwrite(HOST_FS_BASE, rdmsr(MSR_FS_BASE));
	vmwrite(HOST_GS_BASE, rdmsr(MSR_GS_BASE));
	vmwrite(HOST_TR_BASE,
		get_desc64_base((struct desc64 *)(get_gdt_base() + get_tr())));
	vmwrite(HOST_GDTR_BASE, get_gdt_base());
	vmwrite(HOST_IDTR_BASE, get_idt_base());
	vmwrite(HOST_IA32_SYSENTER_ESP, rdmsr(MSR_IA32_SYSENTER_ESP));
	vmwrite(HOST_IA32_SYSENTER_EIP, rdmsr(MSR_IA32_SYSENTER_EIP));
}

/*
 * Initialize the guest state fields essentially as a clone of
 * the host state fields. Some host state fields have fixed
 * values, and we set the corresponding guest state fields accordingly.
 */
static inline void init_vmcs_guest_state(void *rip, void *rsp)
{
	vmwrite(GUEST_ES_SELECTOR, vmreadz(HOST_ES_SELECTOR));
	vmwrite(GUEST_CS_SELECTOR, vmreadz(HOST_CS_SELECTOR));
	vmwrite(GUEST_SS_SELECTOR, vmreadz(HOST_SS_SELECTOR));
	vmwrite(GUEST_DS_SELECTOR, vmreadz(HOST_DS_SELECTOR));
	vmwrite(GUEST_FS_SELECTOR, vmreadz(HOST_FS_SELECTOR));
	vmwrite(GUEST_GS_SELECTOR, vmreadz(HOST_GS_SELECTOR));
	vmwrite(GUEST_LDTR_SELECTOR, 0);
	vmwrite(GUEST_TR_SELECTOR, vmreadz(HOST_TR_SELECTOR));
	vmwrite(GUEST_INTR_STATUS, 0);
	vmwrite(GUEST_PML_INDEX, 0);

	vmwrite(VMCS_LINK_POINTER, -1ll);
	vmwrite(GUEST_IA32_DEBUGCTL, 0);
	vmwrite(GUEST_IA32_PAT, vmreadz(HOST_IA32_PAT));
	vmwrite(GUEST_IA32_EFER, vmreadz(HOST_IA32_EFER));
	vmwrite(GUEST_IA32_PERF_GLOBAL_CTRL,
		vmreadz(HOST_IA32_PERF_GLOBAL_CTRL));

	vmwrite(GUEST_ES_LIMIT, -1);
	vmwrite(GUEST_CS_LIMIT, -1);
	vmwrite(GUEST_SS_LIMIT, -1);
	vmwrite(GUEST_DS_LIMIT, -1);
	vmwrite(GUEST_FS_LIMIT, -1);
	vmwrite(GUEST_GS_LIMIT, -1);
	vmwrite(GUEST_LDTR_LIMIT, -1);
	vmwrite(GUEST_TR_LIMIT, 0x67);
	vmwrite(GUEST_GDTR_LIMIT, 0xffff);
	vmwrite(GUEST_IDTR_LIMIT, 0xffff);
	vmwrite(GUEST_ES_AR_BYTES,
		vmreadz(GUEST_ES_SELECTOR) == 0 ? 0x10000 : 0xc093);
	vmwrite(GUEST_CS_AR_BYTES, 0xa09b);
	vmwrite(GUEST_SS_AR_BYTES, 0xc093);
	vmwrite(GUEST_DS_AR_BYTES,
		vmreadz(GUEST_DS_SELECTOR) == 0 ? 0x10000 : 0xc093);
	vmwrite(GUEST_FS_AR_BYTES,
		vmreadz(GUEST_FS_SELECTOR) == 0 ? 0x10000 : 0xc093);
	vmwrite(GUEST_GS_AR_BYTES,
		vmreadz(GUEST_GS_SELECTOR) == 0 ? 0x10000 : 0xc093);
	vmwrite(GUEST_LDTR_AR_BYTES, 0x10000);
	vmwrite(GUEST_TR_AR_BYTES, 0x8b);
	vmwrite(GUEST_INTERRUPTIBILITY_INFO, 0);
	vmwrite(GUEST_ACTIVITY_STATE, 0);
	vmwrite(GUEST_SYSENTER_CS, vmreadz(HOST_IA32_SYSENTER_CS));
	vmwrite(VMX_PREEMPTION_TIMER_VALUE, 0);

	vmwrite(GUEST_CR0, vmreadz(HOST_CR0));
	vmwrite(GUEST_CR3, vmreadz(HOST_CR3));
	vmwrite(GUEST_CR4, vmreadz(HOST_CR4));
	vmwrite(GUEST_ES_BASE, 0);
	vmwrite(GUEST_CS_BASE, 0);
	vmwrite(GUEST_SS_BASE, 0);
	vmwrite(GUEST_DS_BASE, 0);
	vmwrite(GUEST_FS_BASE, vmreadz(HOST_FS_BASE));
	vmwrite(GUEST_GS_BASE, vmreadz(HOST_GS_BASE));
	vmwrite(GUEST_LDTR_BASE, 0);
	vmwrite(GUEST_TR_BASE, vmreadz(HOST_TR_BASE));
	vmwrite(GUEST_GDTR_BASE, vmreadz(HOST_GDTR_BASE));
	vmwrite(GUEST_IDTR_BASE, vmreadz(HOST_IDTR_BASE));
	vmwrite(GUEST_DR7, 0x400);
	vmwrite(GUEST_RSP, (uint64_t)rsp);
	vmwrite(GUEST_RIP, (uint64_t)rip);
	vmwrite(GUEST_RFLAGS, 2);
	vmwrite(GUEST_PENDING_DBG_EXCEPTIONS, 0);
	vmwrite(GUEST_SYSENTER_ESP, vmreadz(HOST_IA32_SYSENTER_ESP));
	vmwrite(GUEST_SYSENTER_EIP, vmreadz(HOST_IA32_SYSENTER_EIP));
}

void prepare_vmcs(void *guest_rip, void *guest_rsp)
{
	init_vmcs_control_fields();
	init_vmcs_host_state();
	init_vmcs_guest_state(guest_rip, guest_rsp);
}