KVM: selftests: aarch64: Test read-only PT memory regions

Extend the read-only memslot tests in page_fault_test to test
read-only PT (Page table) memslots. Note that this was not allowed
before commit 406504c ("KVM: arm64: Fix S1PTW handling on RO
memslots") as all S1PTW faults were treated as writes which resulted
in an (unrecoverable) exception inside the guest.

Signed-off-by: Ricardo Koller <ricarkol@google.com>
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230127214353.245671-5-ricarkol@google.com

tools/testing/selftests/kvm/aarch64/page_fault_test.c

@@ -829,8 +829,9 @@ static void help(char *name)
 
 #define TEST_RO_MEMSLOT(_access, _mmio_handler, _mmio_exits)			\
 {										\
-	.name			= SCAT3(ro_memslot, _access, _with_af),		\
+	.name			= SCAT2(ro_memslot, _access),			\
 	.data_memslot_flags	= KVM_MEM_READONLY,				\
+	.pt_memslot_flags	= KVM_MEM_READONLY,				\
 	.guest_prepare		= { _PREPARE(_access) },			\
 	.guest_test		= _access,					\
 	.mmio_handler		= _mmio_handler,				\
@@ -841,6 +842,7 @@ static void help(char *name)
 {										\
 	.name			= SCAT2(ro_memslot_no_syndrome, _access),	\
 	.data_memslot_flags	= KVM_MEM_READONLY,				\
+	.pt_memslot_flags	= KVM_MEM_READONLY,				\
 	.guest_test		= _access,					\
 	.fail_vcpu_run_handler	= fail_vcpu_run_mmio_no_syndrome_handler,	\
 	.expected_events	= { .fail_vcpu_runs = 1 },			\
@@ -849,9 +851,9 @@ static void help(char *name)
 #define TEST_RO_MEMSLOT_AND_DIRTY_LOG(_access, _mmio_handler, _mmio_exits,	\
 				      _test_check)				\
 {										\
-	.name			= SCAT3(ro_memslot, _access, _with_af),		\
+	.name			= SCAT2(ro_memslot, _access),			\
 	.data_memslot_flags	= KVM_MEM_READONLY | KVM_MEM_LOG_DIRTY_PAGES,	\
-	.pt_memslot_flags	= KVM_MEM_LOG_DIRTY_PAGES,			\
+	.pt_memslot_flags	= KVM_MEM_READONLY | KVM_MEM_LOG_DIRTY_PAGES,	\
 	.guest_prepare		= { _PREPARE(_access) },			\
 	.guest_test		= _access,					\
 	.guest_test_check	= { _test_check },				\
@@ -863,7 +865,7 @@ static void help(char *name)
 {										\
 	.name			= SCAT2(ro_memslot_no_syn_and_dlog, _access),	\
 	.data_memslot_flags	= KVM_MEM_READONLY | KVM_MEM_LOG_DIRTY_PAGES,	\
-	.pt_memslot_flags	= KVM_MEM_LOG_DIRTY_PAGES,			\
+	.pt_memslot_flags	= KVM_MEM_READONLY | KVM_MEM_LOG_DIRTY_PAGES,	\
 	.guest_test		= _access,					\
 	.guest_test_check	= { _test_check },				\
 	.fail_vcpu_run_handler	= fail_vcpu_run_mmio_no_syndrome_handler,	\
@@ -875,6 +877,7 @@ static void help(char *name)
 {										\
 	.name			= SCAT2(ro_memslot_uffd, _access),		\
 	.data_memslot_flags	= KVM_MEM_READONLY,				\
+	.pt_memslot_flags	= KVM_MEM_READONLY,				\
 	.mem_mark_cmd		= CMD_HOLE_DATA | CMD_HOLE_PT,			\
 	.guest_prepare		= { _PREPARE(_access) },			\
 	.guest_test		= _access,					\
@@ -890,6 +893,7 @@ static void help(char *name)
 {										\
 	.name			= SCAT2(ro_memslot_no_syndrome, _access),	\
 	.data_memslot_flags	= KVM_MEM_READONLY,				\
+	.pt_memslot_flags	= KVM_MEM_READONLY,				\
 	.mem_mark_cmd		= CMD_HOLE_DATA | CMD_HOLE_PT,			\
 	.guest_test		= _access,					\
 	.uffd_data_handler	= _uffd_data_handler,				\
@@ -1024,7 +1028,7 @@ static struct test_desc tests[] = {
 				guest_check_write_in_dirty_log,
 				guest_check_s1ptw_wr_in_dirty_log),
 	/*
-	 * Try accesses when the data memory region is marked read-only
+	 * Access when both the PT and data regions are marked read-only
 	 * (with KVM_MEM_READONLY). Writes with a syndrome result in an
 	 * MMIO exit, writes with no syndrome (e.g., CAS) result in a
 	 * failed vcpu run, and reads/execs with and without syndroms do
@@ -1040,7 +1044,7 @@ static struct test_desc tests[] = {
 	TEST_RO_MEMSLOT_NO_SYNDROME(guest_st_preidx),
 
 	/*
-	 * Access when both the data region is both read-only and marked
+	 * The PT and data regions are both read-only and marked
 	 * for dirty logging at the same time. The expected result is that
 	 * for writes there should be no write in the dirty log. The
 	 * readonly handling is the same as if the memslot was not marked
@@ -1065,7 +1069,7 @@ static struct test_desc tests[] = {
 						  guest_check_no_write_in_dirty_log),
 
 	/*
-	 * Access when the data region is both read-only and punched with
+	 * The PT and data regions are both read-only and punched with
 	 * holes tracked with userfaultfd.  The expected result is the
 	 * union of both userfaultfd and read-only behaviors. For example,
 	 * write accesses result in a userfaultfd write fault and an MMIO