[PATCH RFC 5/5] KVM: selftests: add KVM_MEM_ALLONES test

From: Vitaly Kuznetsov
Date: Thu May 14 2020 - 14:06:18 EST

Test the newly introduced KVM_MEM_ALLONES memslots:
- Reads from all pages return '0xff'
- Writes to all pages cause KVM_EXIT_MMIO

Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
---
tools/testing/selftests/kvm/Makefile | 1 +
.../testing/selftests/kvm/include/kvm_util.h | 1 +
tools/testing/selftests/kvm/lib/kvm_util.c | 81 +++++++------
.../kvm/x86_64/memory_region_allones.c | 112 ++++++++++++++++++
4 files changed, 162 insertions(+), 33 deletions(-)
create mode 100644 tools/testing/selftests/kvm/x86_64/memory_region_allones.c

diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index 7af62030c12f..0c9aff445755 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -15,6 +15,7 @@ LIBKVM_s390x = lib/s390x/processor.c lib/s390x/ucall.c
TEST_GEN_PROGS_x86_64 = x86_64/cr4_cpuid_sync_test
TEST_GEN_PROGS_x86_64 += x86_64/evmcs_test
TEST_GEN_PROGS_x86_64 += x86_64/hyperv_cpuid
+TEST_GEN_PROGS_x86_64 += x86_64/memory_region_allones
TEST_GEN_PROGS_x86_64 += x86_64/mmio_warning_test
TEST_GEN_PROGS_x86_64 += x86_64/platform_info_test
TEST_GEN_PROGS_x86_64 += x86_64/set_sregs_test
diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index 53b11d725d81..8f5ebc8520b8 100644
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h
@@ -59,6 +59,7 @@ enum vm_mem_backing_src_type {
VM_MEM_SRC_ANONYMOUS,
VM_MEM_SRC_ANONYMOUS_THP,
VM_MEM_SRC_ANONYMOUS_HUGETLB,
+ VM_MEM_SRC_NONE,
};

int kvm_check_cap(long cap);
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index 33ab0a36d230..232b63ba0b4b 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -446,8 +446,11 @@ static void __vm_mem_region_delete(struct kvm_vm *vm,
"rc: %i errno: %i", ret, errno);

sparsebit_free(&region->unused_phy_pages);
- ret = munmap(region->mmap_start, region->mmap_size);
- TEST_ASSERT(ret == 0, "munmap failed, rc: %i errno: %i", ret, errno);
+ if (region->mmap_start) {
+ ret = munmap(region->mmap_start, region->mmap_size);
+ TEST_ASSERT(ret == 0, "munmap failed, rc: %i errno: %i", ret,
+ errno);
+ }

free(region);
}
@@ -636,34 +639,42 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm,
alignment = 1;
#endif

- if (src_type == VM_MEM_SRC_ANONYMOUS_THP)
- alignment = max(huge_page_size, alignment);
-
- /* Add enough memory to align up if necessary */
- if (alignment > 1)
- region->mmap_size += alignment;
-
- region->mmap_start = mmap(NULL, region->mmap_size,
- PROT_READ | PROT_WRITE,
- MAP_PRIVATE | MAP_ANONYMOUS
- | (src_type == VM_MEM_SRC_ANONYMOUS_HUGETLB ? MAP_HUGETLB : 0),
- -1, 0);
- TEST_ASSERT(region->mmap_start != MAP_FAILED,
- "test_malloc failed, mmap_start: %p errno: %i",
- region->mmap_start, errno);
-
- /* Align host address */
- region->host_mem = align(region->mmap_start, alignment);
-
- /* As needed perform madvise */
- if (src_type == VM_MEM_SRC_ANONYMOUS || src_type == VM_MEM_SRC_ANONYMOUS_THP) {
- ret = madvise(region->host_mem, npages * vm->page_size,
- src_type == VM_MEM_SRC_ANONYMOUS ? MADV_NOHUGEPAGE : MADV_HUGEPAGE);
- TEST_ASSERT(ret == 0, "madvise failed,\n"
- " addr: %p\n"
- " length: 0x%lx\n"
- " src_type: %x",
- region->host_mem, npages * vm->page_size, src_type);
+ if (src_type != VM_MEM_SRC_NONE) {
+ if (src_type == VM_MEM_SRC_ANONYMOUS_THP)
+ alignment = max(huge_page_size, alignment);
+
+ /* Add enough memory to align up if necessary */
+ if (alignment > 1)
+ region->mmap_size += alignment;
+
+ region->mmap_start = mmap(NULL, region->mmap_size,
+ PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS
+ | (src_type == VM_MEM_SRC_ANONYMOUS_HUGETLB ?
+ MAP_HUGETLB : 0), -1, 0);
+ TEST_ASSERT(region->mmap_start != MAP_FAILED,
+ "test_malloc failed, mmap_start: %p errno: %i",
+ region->mmap_start, errno);
+
+ /* Align host address */
+ region->host_mem = align(region->mmap_start, alignment);
+
+ /* As needed perform madvise */
+ if (src_type == VM_MEM_SRC_ANONYMOUS ||
+ src_type == VM_MEM_SRC_ANONYMOUS_THP) {
+ ret = madvise(region->host_mem, npages * vm->page_size,
+ src_type == VM_MEM_SRC_ANONYMOUS ?
+ MADV_NOHUGEPAGE : MADV_HUGEPAGE);
+ TEST_ASSERT(ret == 0, "madvise failed,\n"
+ " addr: %p\n"
+ " length: 0x%lx\n"
+ " src_type: %x",
+ region->host_mem, npages * vm->page_size,
+ src_type);
+ }
+ } else {
+ region->mmap_start = NULL;
+ region->host_mem = NULL;
}

region->unused_phy_pages = sparsebit_alloc();
@@ -1069,9 +1080,13 @@ void *addr_gpa2hva(struct kvm_vm *vm, vm_paddr_t gpa)
list_for_each_entry(region, &vm->userspace_mem_regions, list) {
if ((gpa >= region->region.guest_phys_addr)
&& (gpa <= (region->region.guest_phys_addr
- + region->region.memory_size - 1)))
- return (void *) ((uintptr_t) region->host_mem
- + (gpa - region->region.guest_phys_addr));
+ + region->region.memory_size - 1))) {
+ if (region->host_mem)
+ return (void *) ((uintptr_t) region->host_mem
+ + (gpa - region->region.guest_phys_addr));
+ else
+ return NULL;
+ }
}

TEST_FAIL("No vm physical memory at 0x%lx", gpa);
diff --git a/tools/testing/selftests/kvm/x86_64/memory_region_allones.c b/tools/testing/selftests/kvm/x86_64/memory_region_allones.c
new file mode 100644
index 000000000000..23fec4873422
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86_64/memory_region_allones.c
@@ -0,0 +1,112 @@
+// SPDX-License-Identifier: GPL-2.0
+#define _GNU_SOURCE /* for program_invocation_short_name */
+#include <fcntl.h>
+#include <pthread.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 <test_util.h>
+#include <kvm_util.h>
+#include <processor.h>
+
+#define VCPU_ID 0
+
+#define MEM_REGION_GPA 0xc0000000
+#define MEM_REGION_SIZE 0x4000
+#define MEM_REGION_SLOT 10
+
+static void guest_code(void)
+{
+ uint8_t val;
+
+ /* First byte in the first page */
+ val = READ_ONCE(*((uint8_t *)MEM_REGION_GPA));
+ GUEST_ASSERT(val == 0xff);
+
+ GUEST_SYNC(1);
+
+ /* Random byte in the second page */
+ val = READ_ONCE(*((uint8_t *)MEM_REGION_GPA + 5000));
+ GUEST_ASSERT(val == 0xff);
+
+ GUEST_SYNC(2);
+
+ /* Write to the first page */
+ WRITE_ONCE(*((uint64_t *)MEM_REGION_GPA + 1024/8), 0xdeafbeef);
+
+ GUEST_SYNC(3);
+
+ /* Write to the second page */
+ WRITE_ONCE(*((uint64_t *)MEM_REGION_GPA + 8000/8), 0xdeafbeef);
+
+ GUEST_SYNC(4);
+
+ GUEST_DONE();
+}
+
+int main(int argc, char *argv[])
+{
+ struct kvm_vm *vm;
+ struct kvm_run *run;
+ struct ucall uc;
+ int stage, rv;
+
+ rv = kvm_check_cap(KVM_CAP_ALLONES_MEM);
+ if (!rv) {
+ print_skip("KVM_CAP_ALLONES_MEM not supported");
+ exit(KSFT_SKIP);
+ }
+
+ vm = vm_create_default(VCPU_ID, 0, guest_code);
+
+ run = vcpu_state(vm, VCPU_ID);
+
+ vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());
+
+ vm_userspace_mem_region_add(vm, VM_MEM_SRC_NONE,
+ MEM_REGION_GPA, MEM_REGION_SLOT,
+ MEM_REGION_SIZE / getpagesize(),
+ KVM_MEM_ALLONES);
+
+ virt_map(vm, MEM_REGION_GPA, MEM_REGION_GPA,
+ MEM_REGION_SIZE / getpagesize(), 0);
+
+ for (stage = 1;; stage++) {
+ _vcpu_run(vm, VCPU_ID);
+
+ if (stage == 3 || stage == 5) {
+ TEST_ASSERT(run->exit_reason == KVM_EXIT_MMIO,
+ "Write to ALLONES page should cause KVM_EXIT_MMIO");
+ continue;
+ }
+
+ TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
+ "Stage %d: unexpected exit reason: %u (%s),\n",
+ stage, run->exit_reason,
+ exit_reason_str(run->exit_reason));
+
+ switch (get_ucall(vm, VCPU_ID, &uc)) {
+ case UCALL_ABORT:
+ TEST_FAIL("%s at %s:%ld", (const char *)uc.args[0],
+ __FILE__, uc.args[1]);
+ /* NOT REACHED */
+ case UCALL_SYNC:
+ break;
+ case UCALL_DONE:
+ goto done;
+ default:
+ TEST_FAIL("Unknown ucall %lu", uc.cmd);
+ }
+ }
+
+done:
+ kvm_vm_free(vm);
+
+ return 0;
+}
--
2.25.4