Add a selftest to exercise implicit/explicit conversion functionality
within KVM and verify:
1) Shared memory is visible to host userspace after conversion
2) Private memory is not visible to host userspace before/after conversion
3) Host userspace and guest can communicate over shared memory
Signed-off-by: Vishal Annapurve <vannapurve@xxxxxxxxxx>
---
tools/testing/selftests/kvm/.gitignore | 1 +
tools/testing/selftests/kvm/Makefile | 1 +
.../selftests/kvm/x86_64/private_mem_test.c | 262 ++++++++++++++++++
3 files changed, 264 insertions(+)
create mode 100644 tools/testing/selftests/kvm/x86_64/private_mem_test.c
diff --git a/tools/testing/selftests/kvm/.gitignore b/tools/testing/selftests/kvm/.gitignore
index ec084a61a819..095b67dc632e 100644
--- a/tools/testing/selftests/kvm/.gitignore
+++ b/tools/testing/selftests/kvm/.gitignore
@@ -31,6 +31,7 @@
/x86_64/monitor_mwait_test
/x86_64/nx_huge_pages_test
/x86_64/platform_info_test
+/x86_64/private_mem_test
/x86_64/pmu_event_filter_test
/x86_64/set_boot_cpu_id
/x86_64/set_sregs_test
diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index 8fe72a60aef0..c5fc8ea2c843 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -94,6 +94,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/mmu_role_test
TEST_GEN_PROGS_x86_64 += x86_64/monitor_mwait_test
TEST_GEN_PROGS_x86_64 += x86_64/platform_info_test
TEST_GEN_PROGS_x86_64 += x86_64/pmu_event_filter_test
+TEST_GEN_PROGS_x86_64 += x86_64/private_mem_test
TEST_GEN_PROGS_x86_64 += x86_64/set_boot_cpu_id
TEST_GEN_PROGS_x86_64 += x86_64/set_sregs_test
TEST_GEN_PROGS_x86_64 += x86_64/smm_test
diff --git a/tools/testing/selftests/kvm/x86_64/private_mem_test.c b/tools/testing/selftests/kvm/x86_64/private_mem_test.c
new file mode 100644
index 000000000000..9f491e2a16bb
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86_64/private_mem_test.c
@@ -0,0 +1,262 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * tools/testing/selftests/kvm/lib/kvm_util.c
+ *
+ * Copyright (C) 2022, Google LLC.
+ */
+#define _GNU_SOURCE /* for program_invocation_short_name */
+#include <fcntl.h>
+#include <limits.h>
+#include <sched.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+
+#include <linux/compiler.h>
+#include <linux/kernel.h>
+#include <linux/kvm_para.h>
+#include <linux/memfd.h>
+
+#include <test_util.h>
+#include <kvm_util.h>
+#include <private_mem.h>
+#include <processor.h>
+
+#define VM_MEMSLOT0_PAGES (512 * 10)
+
+#define TEST_AREA_SLOT 10
+#define TEST_AREA_GPA 0xC0000000
+#define TEST_AREA_SIZE (2 * 1024 * 1024)
+#define GUEST_TEST_MEM_OFFSET (1 * 1024 * 1024)
+#define GUEST_TEST_MEM_SIZE (10 * 4096)
+
+#define VM_STAGE_PROCESSED(x) pr_info("Processed stage %s\n", #x)
+
+#define TEST_MEM_DATA_PAT1 0x66
+#define TEST_MEM_DATA_PAT2 0x99
+#define TEST_MEM_DATA_PAT3 0x33
+#define TEST_MEM_DATA_PAT4 0xaa
+#define TEST_MEM_DATA_PAT5 0x12
+
+static bool verify_mem_contents(void *mem, uint32_t size, uint8_t pat)
+{
+ uint8_t *buf = (uint8_t *)mem;
+
+ for (uint32_t i = 0; i < size; i++) {
+ if (buf[i] != pat)
+ return false;
+ }
+
+ return true;
+}
+
+/*
+ * Add custom implementation for memset to avoid using standard/builtin memset
+ * which may use features like SSE/GOT that don't work with guest vm execution
+ * within selftests.
+ */
+void *memset(void *mem, int byte, size_t size)
+{
+ uint8_t *buf = (uint8_t *)mem;
+
+ for (uint32_t i = 0; i < size; i++)
+ buf[i] = byte;
+
+ return buf;
+}
+
+static void populate_test_area(void *test_area_base, uint64_t pat)
+{
+ memset(test_area_base, pat, TEST_AREA_SIZE);
+}
+
+static void populate_guest_test_mem(void *guest_test_mem, uint64_t pat)
+{
+ memset(guest_test_mem, pat, GUEST_TEST_MEM_SIZE);
+}
+
+static bool verify_test_area(void *test_area_base, uint64_t area_pat,
+ uint64_t guest_pat)
+{
+ void *test_area1_base = test_area_base;
+ uint64_t test_area1_size = GUEST_TEST_MEM_OFFSET;
+ void *guest_test_mem = test_area_base + test_area1_size;
+ uint64_t guest_test_size = GUEST_TEST_MEM_SIZE;
+ void *test_area2_base = guest_test_mem + guest_test_size;
+ uint64_t test_area2_size = (TEST_AREA_SIZE - (GUEST_TEST_MEM_OFFSET +
+ GUEST_TEST_MEM_SIZE));
+
+ return (verify_mem_contents(test_area1_base, test_area1_size, area_pat) &&
+ verify_mem_contents(guest_test_mem, guest_test_size, guest_pat) &&
+ verify_mem_contents(test_area2_base, test_area2_size, area_pat));
+}
+
+#define GUEST_STARTED 0
+#define GUEST_PRIVATE_MEM_POPULATED 1
+#define GUEST_SHARED_MEM_POPULATED 2
+#define GUEST_PRIVATE_MEM_POPULATED2 3
+#define GUEST_IMPLICIT_MEM_CONV1 4
+#define GUEST_IMPLICIT_MEM_CONV2 5
+
+/*
+ * Run memory conversion tests supporting two types of conversion:
+ * 1) Explicit: Execute KVM hypercall to map/unmap gpa range which will cause
+ * userspace exit to back/unback private memory. Subsequent accesses by guest
+ * to the gpa range will not cause exit to userspace.
+ * 2) Implicit: Execute KVM hypercall to update memory access to a gpa range as
+ * private/shared without exiting to userspace. Subsequent accesses by guest
+ * to the gpa range will result in KVM EPT/NPT faults and then exit to
+ * userspace for each page.
+ *
+ * Test memory conversion scenarios with following steps:
+ * 1) Access private memory using private access and verify that memory contents
+ * are not visible to userspace.
+ * 2) Convert memory to shared using explicit/implicit conversions and ensure
+ * that userspace is able to access the shared regions.
+ * 3) Convert memory back to private using explicit/implicit conversions and
+ * ensure that userspace is again not able to access converted private
+ * regions.
+ */
+static void guest_conv_test_fn(bool test_explicit_conv)
+{
+ void *test_area_base = (void *)TEST_AREA_GPA;
+ void *guest_test_mem = (void *)(TEST_AREA_GPA + GUEST_TEST_MEM_OFFSET);
+ uint64_t guest_test_size = GUEST_TEST_MEM_SIZE;
+
+ guest_map_ucall_page_shared();
+ GUEST_SYNC(GUEST_STARTED);
+
+ populate_test_area(test_area_base, TEST_MEM_DATA_PAT1);
+ GUEST_SYNC(GUEST_PRIVATE_MEM_POPULATED);
+ GUEST_ASSERT(verify_test_area(test_area_base, TEST_MEM_DATA_PAT1,
+ TEST_MEM_DATA_PAT1));
+
+ if (test_explicit_conv)
+ guest_update_mem_map(TO_SHARED, (uint64_t)guest_test_mem,
+ guest_test_size);
+ else {
+ guest_update_mem_access(TO_SHARED, (uint64_t)guest_test_mem,
+ guest_test_size);
+ GUEST_SYNC(GUEST_IMPLICIT_MEM_CONV1);
+ }
+
+ populate_guest_test_mem(guest_test_mem, TEST_MEM_DATA_PAT2);
+
+ GUEST_SYNC(GUEST_SHARED_MEM_POPULATED);
+ GUEST_ASSERT(verify_test_area(test_area_base, TEST_MEM_DATA_PAT1,
+ TEST_MEM_DATA_PAT5));
+
+ if (test_explicit_conv)
+ guest_update_mem_map(TO_PRIVATE, (uint64_t)guest_test_mem,
+ guest_test_size);
+ else {
+ guest_update_mem_access(TO_PRIVATE, (uint64_t)guest_test_mem,
+ guest_test_size);
+ GUEST_SYNC(GUEST_IMPLICIT_MEM_CONV2);
+ }
+
+ populate_guest_test_mem(guest_test_mem, TEST_MEM_DATA_PAT3);
+ GUEST_SYNC(GUEST_PRIVATE_MEM_POPULATED2);
+
+ GUEST_ASSERT(verify_test_area(test_area_base, TEST_MEM_DATA_PAT1,
+ TEST_MEM_DATA_PAT3));
+ GUEST_DONE();
+}
+
+static void conv_test_ioexit_fn(struct kvm_vm *vm, uint32_t uc_arg1)
+{
+ void *test_area_hva = addr_gpa2hva(vm, TEST_AREA_GPA);
+ void *guest_test_mem_hva = (test_area_hva + GUEST_TEST_MEM_OFFSET);
+ uint64_t guest_mem_gpa = (TEST_AREA_GPA + GUEST_TEST_MEM_OFFSET);
+ uint64_t guest_test_size = GUEST_TEST_MEM_SIZE;
+
+ switch (uc_arg1) {
+ case GUEST_STARTED:
+ populate_test_area(test_area_hva, TEST_MEM_DATA_PAT4);
+ VM_STAGE_PROCESSED(GUEST_STARTED);
+ break;
+ case GUEST_PRIVATE_MEM_POPULATED:
+ TEST_ASSERT(verify_test_area(test_area_hva, TEST_MEM_DATA_PAT4,
+ TEST_MEM_DATA_PAT4), "failed");
+ VM_STAGE_PROCESSED(GUEST_PRIVATE_MEM_POPULATED);
+ break;
+ case GUEST_SHARED_MEM_POPULATED:
+ TEST_ASSERT(verify_test_area(test_area_hva, TEST_MEM_DATA_PAT4,
+ TEST_MEM_DATA_PAT2), "failed");
+ populate_guest_test_mem(guest_test_mem_hva, TEST_MEM_DATA_PAT5);
+ VM_STAGE_PROCESSED(GUEST_SHARED_MEM_POPULATED);
+ break;
+ case GUEST_PRIVATE_MEM_POPULATED2:
+ TEST_ASSERT(verify_test_area(test_area_hva, TEST_MEM_DATA_PAT4,
+ TEST_MEM_DATA_PAT5), "failed");
+ VM_STAGE_PROCESSED(GUEST_PRIVATE_MEM_POPULATED2);
+ break;
+ case GUEST_IMPLICIT_MEM_CONV1:
+ /*
+ * For first implicit conversion, memory is already private so
+ * mark it private again just to zap the pte entries for the gpa
+ * range, so that subsequent accesses from the guest will
+ * generate ept/npt fault and memory conversion path will be
+ * exercised by KVM.
+ */
+ vm_update_private_mem(vm, guest_mem_gpa, guest_test_size,
+ ALLOCATE_MEM);
+ VM_STAGE_PROCESSED(GUEST_IMPLICIT_MEM_CONV1);
+ break;
+ case GUEST_IMPLICIT_MEM_CONV2:
+ /*
+ * For second implicit conversion, memory is already shared so
+ * mark it shared again just to zap the pte entries for the gpa
+ * range, so that subsequent accesses from the guest will
+ * generate ept/npt fault and memory conversion path will be
+ * exercised by KVM.
+ */
+ vm_update_private_mem(vm, guest_mem_gpa, guest_test_size,
+ UNBACK_MEM);
+ VM_STAGE_PROCESSED(GUEST_IMPLICIT_MEM_CONV2);
+ break;
+ default:
+ TEST_FAIL("Unknown stage %d\n", uc_arg1);
+ break;
+ }
+}
+
+static void guest_explicit_conv_test_fn(void)
+{
+ guest_conv_test_fn(true);
+}
+
+static void guest_implicit_conv_test_fn(void)
+{
+ guest_conv_test_fn(false);
+}
+
+static void execute_memory_conversion_test(void)
+{
+ struct vm_setup_info info;
+ struct test_setup_info *test_info = &info.test_info;
+
+ info.vm_mem_src = VM_MEM_SRC_ANONYMOUS;
+ info.memslot0_pages = VM_MEMSLOT0_PAGES;
+ test_info->test_area_gpa = TEST_AREA_GPA;
+ test_info->test_area_size = TEST_AREA_SIZE;
+ test_info->test_area_slot = TEST_AREA_SLOT;
+ info.ioexit_cb = conv_test_ioexit_fn;
+
+ info.guest_fn = guest_explicit_conv_test_fn;
+ execute_vm_with_private_mem(&info);
+
+ info.guest_fn = guest_implicit_conv_test_fn;
+ execute_vm_with_private_mem(&info);
+}
+
+int main(int argc, char *argv[])
+{
+ /* Tell stdout not to buffer its content */
+ setbuf(stdout, NULL);
+
+ execute_memory_conversion_test();
+ return 0;
+}
--
2.37.1.595.g718a3a8f04-goog
