KVM: selftests: Fix nx_huge_pages_test on TDP-disabled hosts

Map the test's huge page region with 2MiB virtual mappings when TDP is
disabled so that KVM can shadow the region with huge pages. This fixes
nx_huge_pages_test on hosts where TDP hardware support is disabled.

Purposely do not skip this test on TDP-disabled hosts. While we don't
care about NX Huge Pages on TDP-disabled hosts from a security
perspective, KVM does support it, and so we should test it.

For TDP-enabled hosts, continue mapping the region with 4KiB pages to
ensure that KVM can map it with huge pages irrespective of the guest
mappings.

Fixes: 8448ec5993be ("KVM: selftests: Add NX huge pages test")
Signed-off-by: David Matlack <dmatlack@google.com>
Message-Id: <20220929181207.2281449-4-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 27 insertions, 0 deletions

diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c
index fab0f526fb81..39c4409ef56a 100644
--- a/tools/testing/selftests/kvm/lib/x86_64/processor.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c
@@ -111,6 +111,14 @@ static void sregs_dump(FILE *stream, struct kvm_sregs *sregs, uint8_t indent)
 	}
 }
 
+bool kvm_is_tdp_enabled(void)
+{
+	if (is_intel_cpu())
+		return get_kvm_intel_param_bool("ept");
+	else
+		return get_kvm_amd_param_bool("npt");
+}
+
 void virt_arch_pgd_alloc(struct kvm_vm *vm)
 {
 	TEST_ASSERT(vm->mode == VM_MODE_PXXV48_4K, "Attempt to use "
@@ -214,6 +222,25 @@ void virt_arch_pg_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr)
 	__virt_pg_map(vm, vaddr, paddr, PG_LEVEL_4K);
 }
 
+void virt_map_level(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr,
+		    uint64_t nr_bytes, int level)
+{
+	uint64_t pg_size = PG_LEVEL_SIZE(level);
+	uint64_t nr_pages = nr_bytes / pg_size;
+	int i;
+
+	TEST_ASSERT(nr_bytes % pg_size == 0,
+		    "Region size not aligned: nr_bytes: 0x%lx, page size: 0x%lx",
+		    nr_bytes, pg_size);
+
+	for (i = 0; i < nr_pages; i++) {
+		__virt_pg_map(vm, vaddr, paddr, level);
+
+		vaddr += pg_size;
+		paddr += pg_size;
+	}
+}
+
 static uint64_t *_vm_get_page_table_entry(struct kvm_vm *vm,
 					  struct kvm_vcpu *vcpu,
 					  uint64_t vaddr)