KVM: selftests: test behavior of unmapped L2 APIC-access address (97a71a54) · Commits · 戴 / test

tools/testing/selftests/kvm/.gitignore

+1 −0

Original line number	Diff line number	Diff line
		@@ -15,6 +15,7 @@
		/x86_64/vmx_preemption_timer_test
		/x86_64/svm_vmcall_test
		/x86_64/sync_regs_test
		/x86_64/vmx_apic_access_test
		/x86_64/vmx_close_while_nested_test
		/x86_64/vmx_dirty_log_test
		/x86_64/vmx_set_nested_state_test

tools/testing/selftests/kvm/Makefile

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		@@ -49,6 +49,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/state_test
		TEST_GEN_PROGS_x86_64 += x86_64/vmx_preemption_timer_test
		TEST_GEN_PROGS_x86_64 += x86_64/svm_vmcall_test
		TEST_GEN_PROGS_x86_64 += x86_64/sync_regs_test
		TEST_GEN_PROGS_x86_64 += x86_64/vmx_apic_access_test
		TEST_GEN_PROGS_x86_64 += x86_64/vmx_close_while_nested_test
		TEST_GEN_PROGS_x86_64 += x86_64/vmx_dirty_log_test
		TEST_GEN_PROGS_x86_64 += x86_64/vmx_set_nested_state_test

tools/testing/selftests/kvm/include/x86_64/vmx.h

+6 −0

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		@@ -573,6 +573,10 @@ struct vmx_pages {
		void *eptp_hva;
		uint64_t eptp_gpa;
		void *eptp;

		void *apic_access_hva;
		uint64_t apic_access_gpa;
		void *apic_access;
		};

		union vmx_basic {
		@@ -615,5 +619,7 @@ void nested_map_memslot(struct vmx_pages vmx, struct kvm_vm vm,
		uint32_t memslot, uint32_t eptp_memslot);
		void prepare_eptp(struct vmx_pages vmx, struct kvm_vm vm,
		uint32_t eptp_memslot);
		void prepare_virtualize_apic_accesses(struct vmx_pages vmx, struct kvm_vm vm,
		uint32_t eptp_memslot);

		#endif /* SELFTEST_KVM_VMX_H */

tools/testing/selftests/kvm/lib/x86_64/vmx.c

+9 −0

Original line number	Diff line number	Diff line
		@@ -542,3 +542,12 @@ void prepare_eptp(struct vmx_pages vmx, struct kvm_vm vm,
		vmx->eptp_hva = addr_gva2hva(vm, (uintptr_t)vmx->eptp);
		vmx->eptp_gpa = addr_gva2gpa(vm, (uintptr_t)vmx->eptp);
		}

		void prepare_virtualize_apic_accesses(struct vmx_pages vmx, struct kvm_vm vm,
		uint32_t eptp_memslot)
		{
		vmx->apic_access = (void *)vm_vaddr_alloc(vm, getpagesize(),
		0x10000, 0, 0);
		vmx->apic_access_hva = addr_gva2hva(vm, (uintptr_t)vmx->apic_access);
		vmx->apic_access_gpa = addr_gva2gpa(vm, (uintptr_t)vmx->apic_access);
		}

tools/testing/selftests/kvm/x86_64/vmx_apic_access_test.c

0 → 100644

+142 −0

Original line number	Diff line number	Diff line
		// SPDX-License-Identifier: GPL-2.0-only
		/*
		* vmx_apic_access_test
		*
		* Copyright (C) 2020, Google LLC.
		*
		* This work is licensed under the terms of the GNU GPL, version 2.
		*
		* The first subtest simply checks to see that an L2 guest can be
		* launched with a valid APIC-access address that is backed by a
		* page of L1 physical memory.
		*
		* The second subtest sets the APIC-access address to a (valid) L1
		* physical address that is not backed by memory. KVM can't handle
		* this situation, so resuming L2 should result in a KVM exit for
		* internal error (emulation). This is not an architectural
		* requirement. It is just a shortcoming of KVM. The internal error
		* is unfortunate, but it's better than what used to happen!
		*/

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

		#include <string.h>
		#include <sys/ioctl.h>

		#include "kselftest.h"

		#define VCPU_ID 0

		/* The virtual machine object. */
		static struct kvm_vm *vm;

		static void l2_guest_code(void)
		{
		/* Exit to L1 */
		__asm__ __volatile__("vmcall");
		}

		static void l1_guest_code(struct vmx_pages *vmx_pages, unsigned long high_gpa)
		{
		#define L2_GUEST_STACK_SIZE 64
		unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];
		uint32_t control;

		GUEST_ASSERT(prepare_for_vmx_operation(vmx_pages));
		GUEST_ASSERT(load_vmcs(vmx_pages));

		/* Prepare the VMCS for L2 execution. */
		prepare_vmcs(vmx_pages, l2_guest_code,
		&l2_guest_stack[L2_GUEST_STACK_SIZE]);
		control = vmreadz(CPU_BASED_VM_EXEC_CONTROL);
		control \|= CPU_BASED_ACTIVATE_SECONDARY_CONTROLS;
		vmwrite(CPU_BASED_VM_EXEC_CONTROL, control);
		control = vmreadz(SECONDARY_VM_EXEC_CONTROL);
		control \|= SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES;
		vmwrite(SECONDARY_VM_EXEC_CONTROL, control);
		vmwrite(APIC_ACCESS_ADDR, vmx_pages->apic_access_gpa);

		/* Try to launch L2 with the memory-backed APIC-access address. */
		GUEST_SYNC(vmreadz(APIC_ACCESS_ADDR));
		GUEST_ASSERT(!vmlaunch());
		GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);

		vmwrite(APIC_ACCESS_ADDR, high_gpa);

		/* Try to resume L2 with the unbacked APIC-access address. */
		GUEST_SYNC(vmreadz(APIC_ACCESS_ADDR));
		GUEST_ASSERT(!vmresume());
		GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);

		GUEST_DONE();
		}

		int main(int argc, char *argv[])
		{
		unsigned long apic_access_addr = ~0ul;
		unsigned int paddr_width;
		unsigned int vaddr_width;
		vm_vaddr_t vmx_pages_gva;
		unsigned long high_gpa;
		struct vmx_pages *vmx;
		bool done = false;

		nested_vmx_check_supported();

		vm = vm_create_default(VCPU_ID, 0, (void *) l1_guest_code);
		vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());

		kvm_get_cpu_address_width(&paddr_width, &vaddr_width);
		high_gpa = (1ul << paddr_width) - getpagesize();
		if ((unsigned long)DEFAULT_GUEST_PHY_PAGES * getpagesize() > high_gpa) {
		print_skip("No unbacked physical page available");
		exit(KSFT_SKIP);
		}

		vmx = vcpu_alloc_vmx(vm, &vmx_pages_gva);
		prepare_virtualize_apic_accesses(vmx, vm, 0);
		vcpu_args_set(vm, VCPU_ID, 2, vmx_pages_gva, high_gpa);

		while (!done) {
		volatile struct kvm_run *run = vcpu_state(vm, VCPU_ID);
		struct ucall uc;

		vcpu_run(vm, VCPU_ID);
		if (apic_access_addr == high_gpa) {
		TEST_ASSERT(run->exit_reason ==
		KVM_EXIT_INTERNAL_ERROR,
		"Got exit reason other than KVM_EXIT_INTERNAL_ERROR: %u (%s)\n",
		run->exit_reason,
		exit_reason_str(run->exit_reason));
		TEST_ASSERT(run->internal.suberror ==
		KVM_INTERNAL_ERROR_EMULATION,
		"Got internal suberror other than KVM_INTERNAL_ERROR_EMULATION: %u\n",
		run->internal.suberror);
		break;
		}
		TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
		"Got exit_reason other than KVM_EXIT_IO: %u (%s)\n",
		run->exit_reason,
		exit_reason_str(run->exit_reason));

		switch (get_ucall(vm, VCPU_ID, &uc)) {
		case UCALL_ABORT:
		TEST_FAIL("%s at %s:%ld", (const char *)uc.args[0],
		__FILE__, uc.args[1]);
		/* NOT REACHED */
		case UCALL_SYNC:
		apic_access_addr = uc.args[1];
		break;
		case UCALL_DONE:
		done = true;
		break;
		default:
		TEST_ASSERT(false, "Unknown ucall %lu", uc.cmd);
		}
		}
		kvm_vm_free(vm);
		return 0;
		}

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