Commit 62e41f6b authored by Ivan Orlov's avatar Ivan Orlov Committed by Sean Christopherson
Browse files

KVM: selftests: Add test case for MMIO during vectoring on x86 



Extend the 'set_memory_region_test' with an x86-only test case which
covers emulated MMIO during event vectoring error handling. The test case

1) Sets an IDT descriptor base to point to an MMIO address
2) Generates a #GP in the guest
3) Verifies userspace gets the correct exit reason, suberror code, and
   GPA in internal.data[3]

Opportunistically add a definition for a non-canonical address to
processor.h so that the source of the #GP is somewhat self-documenting,
and so that future tests don't have to reinvent the wheel.

Signed-off-by: default avatarIvan Orlov <iorlov@amazon.com>
Link: https://lore.kernel.org/r/20241217181458.68690-8-iorlov@amazon.com


[sean: massage changelog]
Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent 4e9427ae

tools/testing/selftests/kvm/include/x86/processor.h

+2 −0
Original line number Diff line number Diff line
@@ -27,6 +27,8 @@ extern uint64_t guest_tsc_khz; 
#define MAX_NR_CPUID_ENTRIES 100

#endif



#define NONCANONICAL 0xaaaaaaaaaaaaaaaaull



/* Forced emulation prefix, used to invoke the emulator unconditionally. */

#define KVM_FEP "ud2; .byte 'k', 'v', 'm';"

tools/testing/selftests/kvm/set_memory_region_test.c

+51 −0
Original line number Diff line number Diff line
@@ -553,6 +553,56 @@ static void test_add_overlapping_private_memory_regions(void) 
	close(memfd);

	kvm_vm_free(vm);

}



static void guest_code_mmio_during_vectoring(void)

{

	const struct desc_ptr idt_desc = {

		.address = MEM_REGION_GPA,

		.size = 0xFFF,

	};



	set_idt(&idt_desc);



	/* Generate a #GP by dereferencing a non-canonical address */

	*((uint8_t *)NONCANONICAL) = 0x1;



	GUEST_ASSERT(0);

}



/*

 * This test points the IDT descriptor base to an MMIO address. It should cause

 * a KVM internal error when an event occurs in the guest.

 */

static void test_mmio_during_vectoring(void)

{

	struct kvm_vcpu *vcpu;

	struct kvm_run *run;

	struct kvm_vm *vm;

	u64 expected_gpa;



	pr_info("Testing MMIO during vectoring error handling\n");



	vm = vm_create_with_one_vcpu(&vcpu, guest_code_mmio_during_vectoring);

	virt_map(vm, MEM_REGION_GPA, MEM_REGION_GPA, 1);



	run = vcpu->run;



	vcpu_run(vcpu);

	TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_INTERNAL_ERROR);

	TEST_ASSERT(run->internal.suberror == KVM_INTERNAL_ERROR_DELIVERY_EV,

		    "Unexpected suberror = %d", vcpu->run->internal.suberror);

	TEST_ASSERT(run->internal.ndata != 4, "Unexpected internal error data array size = %d",

		    run->internal.ndata);



	/* The reported GPA should be IDT base + offset of the GP vector */

	expected_gpa = MEM_REGION_GPA + GP_VECTOR * sizeof(struct idt_entry);



	TEST_ASSERT(run->internal.data[3] == expected_gpa,

		    "Unexpected GPA = %llx (expected %lx)",

		    vcpu->run->internal.data[3], expected_gpa);



	kvm_vm_free(vm);

}

#endif



int main(int argc, char *argv[])
@@ -568,6 +618,7 @@ int main(int argc, char *argv[]) 
	 * KVM_RUN fails with ENOEXEC or EFAULT.

	 */

	test_zero_memory_regions();

	test_mmio_during_vectoring();

#endif



	test_invalid_memory_region_flags();