linux/tools/testing/selftests/kvm/x86/hyperv_features.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2021, Red Hat, Inc.
 *
 * Tests for Hyper-V features enablement
 */
#include <asm/kvm_para.h>
#include <linux/kvm_para.h>
#include <stdint.h>

#include "test_util.h"
#include "kvm_util.h"
#include "processor.h"
#include "hyperv.h"

/*
 * HYPERV_CPUID_ENLIGHTMENT_INFO.EBX is not a 'feature' CPUID leaf
 * but to activate the feature it is sufficient to set it to a non-zero
 * value. Use BIT(0) for that.
 */
#define HV_PV_SPINLOCKS_TEST            \
	KVM_X86_CPU_FEATURE(HYPERV_CPUID_ENLIGHTMENT_INFO, 0, EBX, 0)

struct msr_data {
	u32 idx;
	bool fault_expected;
	bool write;
	u64 write_val;
};

struct hcall_data {
	u64 control;
	u64 expect;
	bool ud_expected;
};

static bool is_write_only_msr(u32 msr)
{
	return msr == HV_X64_MSR_EOI;
}

static void guest_msr(struct msr_data *msr)
{
	u8 vector = 0;
	u64 msr_val = 0;

	GUEST_ASSERT(msr->idx);

	if (msr->write)
		vector = wrmsr_safe(msr->idx, msr->write_val);

	if (!vector && (!msr->write || !is_write_only_msr(msr->idx)))
		vector = rdmsr_safe(msr->idx, &msr_val);

	if (msr->fault_expected)
		__GUEST_ASSERT(vector == GP_VECTOR,
			       "Expected #GP on %sMSR(0x%x), got %s",
			       msr->write ? "WR" : "RD", msr->idx, ex_str(vector));
	else
		__GUEST_ASSERT(!vector,
			       "Expected success on %sMSR(0x%x), got %s",
			       msr->write ? "WR" : "RD", msr->idx, ex_str(vector));

	if (vector || is_write_only_msr(msr->idx))
		goto done;

	if (msr->write)
		__GUEST_ASSERT(!vector,
			       "WRMSR(0x%x) to '0x%lx', RDMSR read '0x%lx'",
			       msr->idx, msr->write_val, msr_val);

	/* Invariant TSC bit appears when TSC invariant control MSR is written to */
	if (msr->idx == HV_X64_MSR_TSC_INVARIANT_CONTROL) {
		if (!this_cpu_has(HV_ACCESS_TSC_INVARIANT))
			GUEST_ASSERT(this_cpu_has(X86_FEATURE_INVTSC));
		else
			GUEST_ASSERT(this_cpu_has(X86_FEATURE_INVTSC) ==
				     !!(msr_val & HV_INVARIANT_TSC_EXPOSED));
	}

done:
	GUEST_DONE();
}

static void guest_hcall(gpa_t pgs_gpa, struct hcall_data *hcall)
{
	u64 res, input, output;
	u8 vector;

	GUEST_ASSERT_NE(hcall->control, 0);

	wrmsr(HV_X64_MSR_GUEST_OS_ID, HYPERV_LINUX_OS_ID);
	wrmsr(HV_X64_MSR_HYPERCALL, pgs_gpa);

	if (!(hcall->control & HV_HYPERCALL_FAST_BIT)) {
		input = pgs_gpa;
		output = pgs_gpa + PAGE_SIZE;
	} else {
		input = output = 0;
	}

	vector = __hyperv_hypercall(hcall->control, input, output, &res);
	if (hcall->ud_expected) {
		__GUEST_ASSERT(vector == UD_VECTOR,
			       "Expected #UD for control '%lu', got %s",
			       hcall->control, ex_str(vector));
	} else {
		__GUEST_ASSERT(!vector,
			       "Expected no exception for control '%lu', got %s",
			       hcall->control, ex_str(vector));
		GUEST_ASSERT_EQ(res, hcall->expect);
	}

	GUEST_DONE();
}

static void vcpu_reset_hv_cpuid(struct kvm_vcpu *vcpu)
{
	/*
	 * Enable all supported Hyper-V features, then clear the leafs holding
	 * the features that will be tested one by one.
	 */
	vcpu_set_hv_cpuid(vcpu);

	vcpu_clear_cpuid_entry(vcpu, HYPERV_CPUID_FEATURES);
	vcpu_clear_cpuid_entry(vcpu, HYPERV_CPUID_ENLIGHTMENT_INFO);
	vcpu_clear_cpuid_entry(vcpu, HYPERV_CPUID_SYNDBG_PLATFORM_CAPABILITIES);
}

static void guest_test_msrs_access(void)
{
	struct kvm_cpuid2 *prev_cpuid = NULL;
	struct kvm_vcpu *vcpu;
	struct kvm_vm *vm;
	struct ucall uc;
	int stage = 0;
	gva_t msr_gva;
	struct msr_data *msr;
	bool has_invtsc = kvm_cpu_has(X86_FEATURE_INVTSC);

	while (true) {
		vm = vm_create_with_one_vcpu(&vcpu, guest_msr);

		msr_gva = vm_alloc_page(vm);
		memset(addr_gva2hva(vm, msr_gva), 0x0, getpagesize());
		msr = addr_gva2hva(vm, msr_gva);

		vcpu_args_set(vcpu, 1, msr_gva);
		vcpu_enable_cap(vcpu, KVM_CAP_HYPERV_ENFORCE_CPUID, 1);

		if (!prev_cpuid) {
			vcpu_reset_hv_cpuid(vcpu);

			prev_cpuid = allocate_kvm_cpuid2(vcpu->cpuid->nent);
		} else {
			vcpu_init_cpuid(vcpu, prev_cpuid);
		}

		/* TODO: Make this entire test easier to maintain. */
		if (stage >= 21)
			vcpu_enable_cap(vcpu, KVM_CAP_HYPERV_SYNIC2, 0);

		switch (stage) {
		case 0:
			/*
			 * Only available when Hyper-V identification is set
			 */
			msr->idx = HV_X64_MSR_GUEST_OS_ID;
			msr->write = false;
			msr->fault_expected = true;
			break;
		case 1:
			msr->idx = HV_X64_MSR_HYPERCALL;
			msr->write = false;
			msr->fault_expected = true;
			break;
		case 2:
			vcpu_set_cpuid_feature(vcpu, HV_MSR_HYPERCALL_AVAILABLE);
			/*
			 * HV_X64_MSR_GUEST_OS_ID has to be written first to make
			 * HV_X64_MSR_HYPERCALL available.
			 */
			msr->idx = HV_X64_MSR_GUEST_OS_ID;
			msr->write = true;
			msr->write_val = HYPERV_LINUX_OS_ID;
			msr->fault_expected = false;
			break;
		case 3:
			msr->idx = HV_X64_MSR_GUEST_OS_ID;
			msr->write = false;
			msr->fault_expected = false;
			break;
		case 4:
			msr->idx = HV_X64_MSR_HYPERCALL;
			msr->write = false;
			msr->fault_expected = false;
			break;

		case 5:
			msr->idx = HV_X64_MSR_VP_RUNTIME;
			msr->write = false;
			msr->fault_expected = true;
			break;
		case 6:
			vcpu_set_cpuid_feature(vcpu, HV_MSR_VP_RUNTIME_AVAILABLE);
			msr->idx = HV_X64_MSR_VP_RUNTIME;
			msr->write = false;
			msr->fault_expected = false;
			break;
		case 7:
			/* Read only */
			msr->idx = HV_X64_MSR_VP_RUNTIME;
			msr->write = true;
			msr->write_val = 1;
			msr->fault_expected = true;
			break;

		case 8:
			msr->idx = HV_X64_MSR_TIME_REF_COUNT;
			msr->write = false;
			msr->fault_expected = true;
			break;
		case 9:
			vcpu_set_cpuid_feature(vcpu, HV_MSR_TIME_REF_COUNT_AVAILABLE);
			msr->idx = HV_X64_MSR_TIME_REF_COUNT;
			msr->write = false;
			msr->fault_expected = false;
			break;
		case 10:
			/* Read only */
			msr->idx = HV_X64_MSR_TIME_REF_COUNT;
			msr->write = true;
			msr->write_val = 1;
			msr->fault_expected = true;
			break;

		case 11:
			msr->idx = HV_X64_MSR_VP_INDEX;
			msr->write = false;
			msr->fault_expected = true;
			break;
		case 12:
			vcpu_set_cpuid_feature(vcpu, HV_MSR_VP_INDEX_AVAILABLE);
			msr->idx = HV_X64_MSR_VP_INDEX;
			msr->write = false;
			msr->fault_expected = false;
			break;
		case 13:
			/* Read only */
			msr->idx = HV_X64_MSR_VP_INDEX;
			msr->write = true;
			msr->write_val = 1;
			msr->fault_expected = true;
			break;

		case 14:
			msr->idx = HV_X64_MSR_RESET;
			msr->write = false;
			msr->fault_expected = true;
			break;
		case 15:
			vcpu_set_cpuid_feature(vcpu, HV_MSR_RESET_AVAILABLE);
			msr->idx = HV_X64_MSR_RESET;
			msr->write = false;
			msr->fault_expected = false;
			break;
		case 16:
			msr->idx = HV_X64_MSR_RESET;
			msr->write = true;
			/*
			 * TODO: the test only writes '0' to HV_X64_MSR_RESET
			 * at the moment, writing some other value there will
			 * trigger real vCPU reset and the code is not prepared
			 * to handle it yet.
			 */
			msr->write_val = 0;
			msr->fault_expected = false;
			break;

		case 17:
			msr->idx = HV_X64_MSR_REFERENCE_TSC;
			msr->write = false;
			msr->fault_expected = true;
			break;
		case 18:
			vcpu_set_cpuid_feature(vcpu, HV_MSR_REFERENCE_TSC_AVAILABLE);
			msr->idx = HV_X64_MSR_REFERENCE_TSC;
			msr->write = false;
			msr->fault_expected = false;
			break;
		case 19:
			msr->idx = HV_X64_MSR_REFERENCE_TSC;
			msr->write = true;
			msr->write_val = 0;
			msr->fault_expected = false;
			break;

		case 20:
			msr->idx = HV_X64_MSR_EOM;
			msr->write = false;
			msr->fault_expected = true;
			break;
		case 21:
			/*
			 * Remains unavailable even with KVM_CAP_HYPERV_SYNIC2
			 * capability enabled and guest visible CPUID bit unset.
			 */
			msr->idx = HV_X64_MSR_EOM;
			msr->write = false;
			msr->fault_expected = true;
			break;
		case 22:
			vcpu_set_cpuid_feature(vcpu, HV_MSR_SYNIC_AVAILABLE);
			msr->idx = HV_X64_MSR_EOM;
			msr->write = false;
			msr->fault_expected = false;
			break;
		case 23:
			msr->idx = HV_X64_MSR_EOM;
			msr->write = true;
			msr->write_val = 0;
			msr->fault_expected = false;
			break;

		case 24:
			msr->idx = HV_X64_MSR_STIMER0_CONFIG;
			msr->write = false;
			msr->fault_expected = true;
			break;
		case 25:
			vcpu_set_cpuid_feature(vcpu, HV_MSR_SYNTIMER_AVAILABLE);
			msr->idx = HV_X64_MSR_STIMER0_CONFIG;
			msr->write = false;
			msr->fault_expected = false;
			break;
		case 26:
			msr->idx = HV_X64_MSR_STIMER0_CONFIG;
			msr->write = true;
			msr->write_val = 0;
			msr->fault_expected = false;
			break;
		case 27:
			/* Direct mode test */
			msr->idx = HV_X64_MSR_STIMER0_CONFIG;
			msr->write = true;
			msr->write_val = 1 << 12;
			msr->fault_expected = true;
			break;
		case 28:
			vcpu_set_cpuid_feature(vcpu, HV_STIMER_DIRECT_MODE_AVAILABLE);
			msr->idx = HV_X64_MSR_STIMER0_CONFIG;
			msr->write = true;
			msr->write_val = 1 << 12;
			msr->fault_expected = false;
			break;

		case 29:
			msr->idx = HV_X64_MSR_EOI;
			msr->write = false;
			msr->fault_expected = true;
			break;
		case 30:
			vcpu_set_cpuid_feature(vcpu, HV_MSR_APIC_ACCESS_AVAILABLE);
			msr->idx = HV_X64_MSR_EOI;
			msr->write = true;
			msr->write_val = 1;
			msr->fault_expected = false;
			break;

		case 31:
			msr->idx = HV_X64_MSR_TSC_FREQUENCY;
			msr->write = false;
			msr->fault_expected = true;
			break;
		case 32:
			vcpu_set_cpuid_feature(vcpu, HV_ACCESS_FREQUENCY_MSRS);
			msr->idx = HV_X64_MSR_TSC_FREQUENCY;
			msr->write = false;
			msr->fault_expected = false;
			break;
		case 33:
			/* Read only */
			msr->idx = HV_X64_MSR_TSC_FREQUENCY;
			msr->write = true;
			msr->write_val = 1;
			msr->fault_expected = true;
			break;

		case 34:
			msr->idx = HV_X64_MSR_REENLIGHTENMENT_CONTROL;
			msr->write = false;
			msr->fault_expected = true;
			break;
		case 35:
			vcpu_set_cpuid_feature(vcpu, HV_ACCESS_REENLIGHTENMENT);
			msr->idx = HV_X64_MSR_REENLIGHTENMENT_CONTROL;
			msr->write = false;
			msr->fault_expected = false;
			break;
		case 36:
			msr->idx = HV_X64_MSR_REENLIGHTENMENT_CONTROL;
			msr->write = true;
			msr->write_val = 1;
			msr->fault_expected = false;
			break;
		case 37:
			/* Can only write '0' */
			msr->idx = HV_X64_MSR_TSC_EMULATION_STATUS;
			msr->write = true;
			msr->write_val = 1;
			msr->fault_expected = true;
			break;

		case 38:
			msr->idx = HV_X64_MSR_CRASH_P0;
			msr->write = false;
			msr->fault_expected = true;
			break;
		case 39:
			vcpu_set_cpuid_feature(vcpu, HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE);
			msr->idx = HV_X64_MSR_CRASH_P0;
			msr->write = false;
			msr->fault_expected = false;
			break;
		case 40:
			msr->idx = HV_X64_MSR_CRASH_P0;
			msr->write = true;
			msr->write_val = 1;
			msr->fault_expected = false;
			break;

		case 41:
			msr->idx = HV_X64_MSR_SYNDBG_STATUS;
			msr->write = false;
			msr->fault_expected = true;
			break;
		case 42:
			vcpu_set_cpuid_feature(vcpu, HV_FEATURE_DEBUG_MSRS_AVAILABLE);
			vcpu_set_cpuid_feature(vcpu, HV_X64_SYNDBG_CAP_ALLOW_KERNEL_DEBUGGING);
			msr->idx = HV_X64_MSR_SYNDBG_STATUS;
			msr->write = false;
			msr->fault_expected = false;
			break;
		case 43:
			msr->idx = HV_X64_MSR_SYNDBG_STATUS;
			msr->write = true;
			msr->write_val = 0;
			msr->fault_expected = false;
			break;

		case 44:
			/* MSR is not available when CPUID feature bit is unset */
			if (!has_invtsc)
				goto next_stage;
			msr->idx = HV_X64_MSR_TSC_INVARIANT_CONTROL;
			msr->write = false;
			msr->fault_expected = true;
			break;
		case 45:
			/* MSR is vailable when CPUID feature bit is set */
			if (!has_invtsc)
				goto next_stage;
			vcpu_set_cpuid_feature(vcpu, HV_ACCESS_TSC_INVARIANT);
			msr->idx = HV_X64_MSR_TSC_INVARIANT_CONTROL;
			msr->write = false;
			msr->fault_expected = false;
			break;
		case 46:
			/* Writing bits other than 0 is forbidden */
			if (!has_invtsc)
				goto next_stage;
			msr->idx = HV_X64_MSR_TSC_INVARIANT_CONTROL;
			msr->write = true;
			msr->write_val = 0xdeadbeef;
			msr->fault_expected = true;
			break;
		case 47:
			/* Setting bit 0 enables the feature */
			if (!has_invtsc)
				goto next_stage;
			msr->idx = HV_X64_MSR_TSC_INVARIANT_CONTROL;
			msr->write = true;
			msr->write_val = 1;
			msr->fault_expected = false;
			break;

		default:
			kvm_vm_free(vm);
			return;
		}

		vcpu_set_cpuid(vcpu);

		memcpy(prev_cpuid, vcpu->cpuid, kvm_cpuid2_size(vcpu->cpuid->nent));

		pr_debug("Stage %d: testing msr: 0x%x for %s\n", stage,
			 msr->idx, msr->write ? "write" : "read");

		vcpu_run(vcpu);
		TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);

		switch (get_ucall(vcpu, &uc)) {
		case UCALL_ABORT:
			REPORT_GUEST_ASSERT(uc);
			return;
		case UCALL_DONE:
			break;
		default:
			TEST_FAIL("Unhandled ucall: %ld", uc.cmd);
			return;
		}

next_stage:
		stage++;
		kvm_vm_free(vm);
	}
}

static void guest_test_hcalls_access(void)
{
	struct kvm_cpuid2 *prev_cpuid = NULL;
	struct kvm_vcpu *vcpu;
	struct kvm_vm *vm;
	struct ucall uc;
	int stage = 0;
	gva_t hcall_page, hcall_params;
	struct hcall_data *hcall;

	while (true) {
		vm = vm_create_with_one_vcpu(&vcpu, guest_hcall);

		/* Hypercall input/output */
		hcall_page = vm_alloc_pages(vm, 2);
		memset(addr_gva2hva(vm, hcall_page), 0x0, 2 * getpagesize());

		hcall_params = vm_alloc_page(vm);
		memset(addr_gva2hva(vm, hcall_params), 0x0, getpagesize());
		hcall = addr_gva2hva(vm, hcall_params);

		vcpu_args_set(vcpu, 2, addr_gva2gpa(vm, hcall_page), hcall_params);
		vcpu_enable_cap(vcpu, KVM_CAP_HYPERV_ENFORCE_CPUID, 1);

		if (!prev_cpuid) {
			vcpu_reset_hv_cpuid(vcpu);

			prev_cpuid = allocate_kvm_cpuid2(vcpu->cpuid->nent);
		} else {
			vcpu_init_cpuid(vcpu, prev_cpuid);
		}

		switch (stage) {
		case 0:
			vcpu_set_cpuid_feature(vcpu, HV_MSR_HYPERCALL_AVAILABLE);
			hcall->control = 0xbeef;
			hcall->expect = HV_STATUS_INVALID_HYPERCALL_CODE;
			break;

		case 1:
			hcall->control = HVCALL_POST_MESSAGE;
			hcall->expect = HV_STATUS_ACCESS_DENIED;
			break;
		case 2:
			vcpu_set_cpuid_feature(vcpu, HV_POST_MESSAGES);
			hcall->control = HVCALL_POST_MESSAGE;
			hcall->expect = HV_STATUS_INVALID_HYPERCALL_INPUT;
			break;

		case 3:
			hcall->control = HVCALL_SIGNAL_EVENT;
			hcall->expect = HV_STATUS_ACCESS_DENIED;
			break;
		case 4:
			vcpu_set_cpuid_feature(vcpu, HV_SIGNAL_EVENTS);
			hcall->control = HVCALL_SIGNAL_EVENT;
			hcall->expect = HV_STATUS_INVALID_HYPERCALL_INPUT;
			break;

		case 5:
			hcall->control = HVCALL_RESET_DEBUG_SESSION;
			hcall->expect = HV_STATUS_INVALID_HYPERCALL_CODE;
			break;
		case 6:
			vcpu_set_cpuid_feature(vcpu, HV_X64_SYNDBG_CAP_ALLOW_KERNEL_DEBUGGING);
			hcall->control = HVCALL_RESET_DEBUG_SESSION;
			hcall->expect = HV_STATUS_ACCESS_DENIED;
			break;
		case 7:
			vcpu_set_cpuid_feature(vcpu, HV_DEBUGGING);
			hcall->control = HVCALL_RESET_DEBUG_SESSION;
			hcall->expect = HV_STATUS_OPERATION_DENIED;
			break;

		case 8:
			hcall->control = HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE;
			hcall->expect = HV_STATUS_ACCESS_DENIED;
			break;
		case 9:
			vcpu_set_cpuid_feature(vcpu, HV_X64_REMOTE_TLB_FLUSH_RECOMMENDED);
			hcall->control = HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE;
			hcall->expect = HV_STATUS_SUCCESS;
			break;
		case 10:
			hcall->control = HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX;
			hcall->expect = HV_STATUS_ACCESS_DENIED;
			break;
		case 11:
			vcpu_set_cpuid_feature(vcpu, HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED);
			hcall->control = HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX;
			hcall->expect = HV_STATUS_SUCCESS;
			break;

		case 12:
			hcall->control = HVCALL_SEND_IPI;
			hcall->expect = HV_STATUS_ACCESS_DENIED;
			break;
		case 13:
			vcpu_set_cpuid_feature(vcpu, HV_X64_CLUSTER_IPI_RECOMMENDED);
			hcall->control = HVCALL_SEND_IPI;
			hcall->expect = HV_STATUS_INVALID_HYPERCALL_INPUT;
			break;
		case 14:
			/* Nothing in 'sparse banks' -> success */
			hcall->control = HVCALL_SEND_IPI_EX;
			hcall->expect = HV_STATUS_SUCCESS;
			break;

		case 15:
			hcall->control = HVCALL_NOTIFY_LONG_SPIN_WAIT;
			hcall->expect = HV_STATUS_ACCESS_DENIED;
			break;
		case 16:
			vcpu_set_cpuid_feature(vcpu, HV_PV_SPINLOCKS_TEST);
			hcall->control = HVCALL_NOTIFY_LONG_SPIN_WAIT;
			hcall->expect = HV_STATUS_SUCCESS;
			break;
		case 17:
			/* XMM fast hypercall */
			hcall->control = HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE | HV_HYPERCALL_FAST_BIT;
			hcall->ud_expected = true;
			break;
		case 18:
			vcpu_set_cpuid_feature(vcpu, HV_X64_HYPERCALL_XMM_INPUT_AVAILABLE);
			hcall->control = HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE | HV_HYPERCALL_FAST_BIT;
			hcall->ud_expected = false;
			hcall->expect = HV_STATUS_SUCCESS;
			break;
		case 19:
			hcall->control = HV_EXT_CALL_QUERY_CAPABILITIES;
			hcall->expect = HV_STATUS_ACCESS_DENIED;
			break;
		case 20:
			vcpu_set_cpuid_feature(vcpu, HV_ENABLE_EXTENDED_HYPERCALLS);
			hcall->control = HV_EXT_CALL_QUERY_CAPABILITIES | HV_HYPERCALL_FAST_BIT;
			hcall->expect = HV_STATUS_INVALID_PARAMETER;
			break;
		case 21:
			kvm_vm_free(vm);
			return;
		}

		vcpu_set_cpuid(vcpu);

		memcpy(prev_cpuid, vcpu->cpuid, kvm_cpuid2_size(vcpu->cpuid->nent));

		pr_debug("Stage %d: testing hcall: 0x%lx\n", stage, hcall->control);

		vcpu_run(vcpu);
		TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);

		switch (get_ucall(vcpu, &uc)) {
		case UCALL_ABORT:
			REPORT_GUEST_ASSERT(uc);
			return;
		case UCALL_DONE:
			break;
		default:
			TEST_FAIL("Unhandled ucall: %ld", uc.cmd);
			return;
		}

		stage++;
		kvm_vm_free(vm);
	}
}

int main(void)
{
	TEST_REQUIRE(kvm_has_cap(KVM_CAP_HYPERV_ENFORCE_CPUID));

	pr_info("Testing access to Hyper-V specific MSRs\n");
	guest_test_msrs_access();

	pr_info("Testing access to Hyper-V hypercalls\n");
	guest_test_hcalls_access();
}