selftests: kvm: Mmap the entire vcpu mmap area

The vcpu mmap area may consist of more than just the kvm_run struct.
Allocate enough space for the entire vcpu mmap area. Without this, on
x86, the PIO page, for example, will be missing.  This is problematic
when dealing with an unhandled exception from the guest as the exception
vector will be incorrectly reported as 0x0.

Message-Id: <20210210165035.3712489-1-aaronlewis@google.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Co-developed-by: Steve Rutherford <srutherford@google.com>
Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

tools/testing/selftests/kvm/lib/kvm_util.c

@@ -21,6 +21,8 @@
 #define KVM_UTIL_PGS_PER_HUGEPG 512
 #define KVM_UTIL_MIN_PFN	2
 
+static int vcpu_mmap_sz(void);
+
 /* Aligns x up to the next multiple of size. Size must be a power of 2. */
 static void *align(void *x, size_t size)
 {
@@ -509,7 +511,7 @@ static void vm_vcpu_rm(struct kvm_vm *vm, struct vcpu *vcpu)
 		vcpu->dirty_gfns = NULL;
 	}
 
-	ret = munmap(vcpu->state, sizeof(*vcpu->state));
+	ret = munmap(vcpu->state, vcpu_mmap_sz());
 	TEST_ASSERT(ret == 0, "munmap of VCPU fd failed, rc: %i "
 		"errno: %i", ret, errno);
 	close(vcpu->fd);
@@ -978,7 +980,7 @@ void vm_vcpu_add(struct kvm_vm *vm, uint32_t vcpuid)
 	TEST_ASSERT(vcpu_mmap_sz() >= sizeof(*vcpu->state), "vcpu mmap size "
 		"smaller than expected, vcpu_mmap_sz: %i expected_min: %zi",
 		vcpu_mmap_sz(), sizeof(*vcpu->state));
-	vcpu->state = (struct kvm_run *) mmap(NULL, sizeof(*vcpu->state),
+	vcpu->state = (struct kvm_run *) mmap(NULL, vcpu_mmap_sz(),
 		PROT_READ | PROT_WRITE, MAP_SHARED, vcpu->fd, 0);
 	TEST_ASSERT(vcpu->state != MAP_FAILED, "mmap vcpu_state failed, "
 		"vcpu id: %u errno: %i", vcpuid, errno);