[RFC,v2,3/3] KVM: selftests: Add set_memory_region_io to test memslots for MMIO BARs
Commit Message
Added a selftest set_memory_region_io to test memslots for MMIO BARs.
The MMIO BARs' backends are compound/non-compound huge pages serving as
device resources allocated by a mock device driver.
This selftest will assert and report "errno=14 - Bad address" in vcpu_run()
if any failure is met to add such MMIO BAR memslots.
After MMIO memslots removal, page reference counts of the device resources
are also checked.
As this selftest will interacts with a mock device "/dev/kvm_mock_device",
it depends on test driver test_kvm_mock_device.ko in the kernel.
CONFIG_TEST_KVM_MOCK_DEVICE=m must be enabled in the kernel.
Currently, this selftest is only compiled for __x86_64__.
Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
---
tools/testing/selftests/kvm/Makefile | 1 +
.../selftests/kvm/set_memory_region_io.c | 188 ++++++++++++++++++
2 files changed, 189 insertions(+)
create mode 100644 tools/testing/selftests/kvm/set_memory_region_io.c
Comments
On Wed, Jan 03, 2024 at 04:45:35PM +0800, Yan Zhao wrote:
> Added a selftest set_memory_region_io to test memslots for MMIO BARs.
Emm.. "set_memory_region_io" doesn't represent the real testing purpose,
but not sure if things like "memory_region_page_refcount_test" become
better...
> The MMIO BARs' backends are compound/non-compound huge pages serving as
> device resources allocated by a mock device driver.
>
> This selftest will assert and report "errno=14 - Bad address" in vcpu_run()
> if any failure is met to add such MMIO BAR memslots.
> After MMIO memslots removal, page reference counts of the device resources
> are also checked.
>
> As this selftest will interacts with a mock device "/dev/kvm_mock_device",
> it depends on test driver test_kvm_mock_device.ko in the kernel.
> CONFIG_TEST_KVM_MOCK_DEVICE=m must be enabled in the kernel.
>
> Currently, this selftest is only compiled for __x86_64__.
>
> Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
> ---
> tools/testing/selftests/kvm/Makefile | 1 +
> .../selftests/kvm/set_memory_region_io.c | 188 ++++++++++++++++++
> 2 files changed, 189 insertions(+)
> create mode 100644 tools/testing/selftests/kvm/set_memory_region_io.c
>
> diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
> index 4412b42d95de..9d39514b6403 100644
> --- a/tools/testing/selftests/kvm/Makefile
> +++ b/tools/testing/selftests/kvm/Makefile
> @@ -144,6 +144,7 @@ TEST_GEN_PROGS_x86_64 += memslot_modification_stress_test
> TEST_GEN_PROGS_x86_64 += memslot_perf_test
> TEST_GEN_PROGS_x86_64 += rseq_test
> TEST_GEN_PROGS_x86_64 += set_memory_region_test
> +TEST_GEN_PROGS_x86_64 += set_memory_region_io
> TEST_GEN_PROGS_x86_64 += steal_time
> TEST_GEN_PROGS_x86_64 += kvm_binary_stats_test
> TEST_GEN_PROGS_x86_64 += system_counter_offset_test
> diff --git a/tools/testing/selftests/kvm/set_memory_region_io.c b/tools/testing/selftests/kvm/set_memory_region_io.c
> new file mode 100644
> index 000000000000..e221103091f4
> --- /dev/null
> +++ b/tools/testing/selftests/kvm/set_memory_region_io.c
> @@ -0,0 +1,188 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#define _GNU_SOURCE /* for program_invocation_short_name */
> +#include <fcntl.h>
> +#include <pthread.h>
> +#include <sched.h>
> +#include <semaphore.h>
> +#include <signal.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <sys/ioctl.h>
> +#include <sys/mman.h>
> +
> +#include <linux/compiler.h>
> +
> +#include <test_util.h>
> +#include <kvm_util.h>
> +#include <processor.h>
> +
> +#include <../../../../lib/test_kvm_mock_device_uapi.h>
> +
> +/*
> + * Somewhat arbitrary location and slot, intended to not overlap anything.
> + */
> +#define MEM_REGION_GPA_BASE 0xc0000000
> +#define RANDOM_OFFSET 0x1000
> +#define MEM_REGION_GPA_RANDOM (MEM_REGION_GPA_BASE + RANDOM_OFFSET)
> +#define MEM_REGION_SLOT_ID 10
> +
> +static const bool non_compound_supported;
> +
> +static const uint64_t BASE_VAL = 0x1111;
> +static const uint64_t RANDOM_VAL = 0x2222;
> +
> +static unsigned long bar_size;
> +
> +static sem_t vcpu_ready;
> +
> +static void guest_code_read_bar(void)
> +{
> + uint64_t val;
> +
> + GUEST_SYNC(0);
> +
> + val = READ_ONCE(*((uint64_t *)MEM_REGION_GPA_RANDOM));
> + GUEST_ASSERT_EQ(val, RANDOM_VAL);
> +
> + val = READ_ONCE(*((uint64_t *)MEM_REGION_GPA_BASE));
> + GUEST_ASSERT_EQ(val, BASE_VAL);
> +
> + GUEST_DONE();
> +}
> +
> +static void *vcpu_worker(void *data)
> +{
> + struct kvm_vcpu *vcpu = data;
> + struct kvm_run *run = vcpu->run;
> + struct ucall uc;
> + uint64_t cmd;
> +
> + /*
> + * Loop until the guest is done. Re-enter the guest on all MMIO exits,
> + * which will occur if the guest attempts to access a memslot after it
> + * has been deleted or while it is being moved .
> + */
> + while (1) {
> + vcpu_run(vcpu);
> +
> + if (run->exit_reason == KVM_EXIT_IO) {
> + cmd = get_ucall(vcpu, &uc);
> + if (cmd != UCALL_SYNC)
> + break;
> +
> + sem_post(&vcpu_ready);
> + continue;
> + }
> +
> + if (run->exit_reason != KVM_EXIT_MMIO)
> + break;
Can the KVM_EXIT_MMIO happen on x86 ? IIUC the accessed GVAs
in guest code have 1:1 mapping to MEM_REGION_GPA_BASE, which
is covered by the memslot, and the memory slot is there
until the guest code path done.
> +
> + TEST_ASSERT(!run->mmio.is_write, "Unexpected exit mmio write");
> + TEST_ASSERT(run->mmio.len == 8,
> + "Unexpected exit mmio size = %u", run->mmio.len);
> +
> + TEST_ASSERT(run->mmio.phys_addr < MEM_REGION_GPA_BASE ||
> + run->mmio.phys_addr >= MEM_REGION_GPA_BASE + bar_size,
> + "Unexpected exit mmio address = 0x%llx",
> + run->mmio.phys_addr);
Ditto, I just think you don't need this part in this testing.
> + }
> +
> + if (run->exit_reason == KVM_EXIT_IO && cmd == UCALL_ABORT)
> + REPORT_GUEST_ASSERT(uc);
> +
> + return NULL;
> +}
> +
> +static void wait_for_vcpu(void)
> +{
> + struct timespec ts;
> +
> + TEST_ASSERT(!clock_gettime(CLOCK_REALTIME, &ts),
> + "clock_gettime() failed: %d\n", errno);
> +
> + ts.tv_sec += 2;
> + TEST_ASSERT(!sem_timedwait(&vcpu_ready, &ts),
> + "sem_timedwait() failed: %d\n", errno);
> +
> + /* Wait for the vCPU thread to reenter the guest. */
> + usleep(100000);
In this testing it's not needed.
Because you only check guest state after guest code path done,
so pthread_join() is enough there.
> +}
> +
> +static void test_kvm_mock_device_bar(bool compound)
> +{
> + struct kvm_vm *vm;
> + void *mem;
> + struct kvm_vcpu *vcpu;
> + pthread_t vcpu_thread;
> + int fd, ret;
> + u32 param_compound = compound;
> + u32 inequal = 0;
> +
> + fd = open("/dev/kvm_mock_device", O_RDWR);
> + if (fd < 0) {
> + pr_info("Please ensure \"CONFIG_TEST_KVM_MOCK_DEVICE=m\" is enabled in the kernel");
> + pr_info(", and execute\n\"modprobe test_kvm_mock_device\n");
> + }
> + TEST_ASSERT(fd >= 0, "Failed to open kvm mock device.");
Minor:
May better to move this part into main(), highlight it's a
must have dependency at beginning.
> +
> + ret = ioctl(fd, KVM_MOCK_DEVICE_GET_BAR_SIZE, &bar_size);
> + TEST_ASSERT(ret == 0, "Failed to get bar size of kvm mock device");
> +
> + ret = ioctl(fd, KVM_MOCK_DEVICE_PREPARE_RESOURCE, ¶m_compound);
> + TEST_ASSERT(ret == 0, "Failed to prepare resource of kvm mock device");
> +
> + mem = mmap(NULL, (size_t)bar_size, PROT_READ | PROT_WRITE, MAP_SHARED,
> + fd, 0);
> + TEST_ASSERT(mem != MAP_FAILED, "Failed to mmap() kvm mock device bar");
> +
> + *(u64 *)mem = BASE_VAL;
> + *(u64 *)(mem + RANDOM_OFFSET) = RANDOM_VAL;
> +
> + vm = vm_create_with_one_vcpu(&vcpu, guest_code_read_bar);
> +
> + vm_set_user_memory_region(vm, MEM_REGION_SLOT_ID, 0, MEM_REGION_GPA_BASE,
> + bar_size, mem);
> +
> + virt_map(vm, MEM_REGION_GPA_BASE, MEM_REGION_GPA_BASE,
> + (RANDOM_OFFSET / getpagesize()) + 1);
> +
> + pthread_create(&vcpu_thread, NULL, vcpu_worker, vcpu);
> +
> + /* Ensure the guest thread is spun up. */
> + wait_for_vcpu();
> +
> + pthread_join(vcpu_thread, NULL);
> +
> + vm_set_user_memory_region(vm, MEM_REGION_SLOT_ID, 0, 0, 0, 0);
> + kvm_vm_free(vm);
> +
> + ret = ioctl(fd, KVM_MOCK_DEVICE_CHECK_BACKEND_REF, &inequal);
> + TEST_ASSERT(ret == 0 && inequal == 0, "Incorrect resource ref of KVM device");
> +
> + munmap(mem, bar_size);
> + close(fd);
> +}
> +
> +static void test_non_compound_backend(void)
> +{
> + pr_info("Testing non-compound huge page backend for mem slot\n");
> + test_kvm_mock_device_bar(false);
> +}
> +
> +static void test_compound_backend(void)
> +{
> + pr_info("Testing compound huge page backend for mem slot\n");
> + test_kvm_mock_device_bar(true);
> +}
> +
> +int main(int argc, char *argv[])
> +{
> +#ifdef __x86_64__
> + test_compound_backend();
> + if (non_compound_supported)
Nobody set this, but the mock device looks already supported
it, so how about just run the 2 testings directly here ?
> + test_non_compound_backend();
> +#endif
> +
> + return 0;
> +}
> --
> 2.17.1
>
>
On Fri, Jan 05, 2024 at 02:25:26PM +0800, Yuan Yao wrote:
> On Wed, Jan 03, 2024 at 04:45:35PM +0800, Yan Zhao wrote:
> > Added a selftest set_memory_region_io to test memslots for MMIO BARs.
>
> Emm.. "set_memory_region_io" doesn't represent the real testing purpose,
> but not sure if things like "memory_region_page_refcount_test" become
> better...
Hmm, memory_region_io_page_test?
Not just ref count is tested.
Without patch 1, mapping of pages will even fail.
>
> > The MMIO BARs' backends are compound/non-compound huge pages serving as
> > device resources allocated by a mock device driver.
> >
> > This selftest will assert and report "errno=14 - Bad address" in vcpu_run()
> > if any failure is met to add such MMIO BAR memslots.
> > After MMIO memslots removal, page reference counts of the device resources
> > are also checked.
> >
> > As this selftest will interacts with a mock device "/dev/kvm_mock_device",
> > it depends on test driver test_kvm_mock_device.ko in the kernel.
> > CONFIG_TEST_KVM_MOCK_DEVICE=m must be enabled in the kernel.
> >
> > Currently, this selftest is only compiled for __x86_64__.
> >
> > Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
...
> > +static void *vcpu_worker(void *data)
> > +{
> > + struct kvm_vcpu *vcpu = data;
> > + struct kvm_run *run = vcpu->run;
> > + struct ucall uc;
> > + uint64_t cmd;
> > +
> > + /*
> > + * Loop until the guest is done. Re-enter the guest on all MMIO exits,
> > + * which will occur if the guest attempts to access a memslot after it
> > + * has been deleted or while it is being moved .
> > + */
> > + while (1) {
> > + vcpu_run(vcpu);
> > +
> > + if (run->exit_reason == KVM_EXIT_IO) {
> > + cmd = get_ucall(vcpu, &uc);
> > + if (cmd != UCALL_SYNC)
> > + break;
> > +
> > + sem_post(&vcpu_ready);
> > + continue;
> > + }
> > +
> > + if (run->exit_reason != KVM_EXIT_MMIO)
> > + break;
>
> Can the KVM_EXIT_MMIO happen on x86 ? IIUC the accessed GVAs
> in guest code have 1:1 mapping to MEM_REGION_GPA_BASE, which
> is covered by the memslot, and the memory slot is there
> until the guest code path done.
>
It can, if the GPAs accessed by guest code are not even mapped as a
memslot.
This check is to ensure GPAs are read from the testing memslot for mock IO.
> > +
> > + TEST_ASSERT(!run->mmio.is_write, "Unexpected exit mmio write");
> > + TEST_ASSERT(run->mmio.len == 8,
> > + "Unexpected exit mmio size = %u", run->mmio.len);
> > +
> > + TEST_ASSERT(run->mmio.phys_addr < MEM_REGION_GPA_BASE ||
> > + run->mmio.phys_addr >= MEM_REGION_GPA_BASE + bar_size,
> > + "Unexpected exit mmio address = 0x%llx",
> > + run->mmio.phys_addr);
>
> Ditto, I just think you don't need this part in this testing.
>
> > + }
> > +
> > + if (run->exit_reason == KVM_EXIT_IO && cmd == UCALL_ABORT)
> > + REPORT_GUEST_ASSERT(uc);
> > +
> > + return NULL;
> > +}
> > +
> > +static void wait_for_vcpu(void)
> > +{
> > + struct timespec ts;
> > +
> > + TEST_ASSERT(!clock_gettime(CLOCK_REALTIME, &ts),
> > + "clock_gettime() failed: %d\n", errno);
> > +
> > + ts.tv_sec += 2;
> > + TEST_ASSERT(!sem_timedwait(&vcpu_ready, &ts),
> > + "sem_timedwait() failed: %d\n", errno);
> > +
> > + /* Wait for the vCPU thread to reenter the guest. */
> > + usleep(100000);
>
> In this testing it's not needed.
> Because you only check guest state after guest code path done,
> so pthread_join() is enough there.
Right. Just keep to the convention :)
>
> > +}
> > +
> > +static void test_kvm_mock_device_bar(bool compound)
> > +{
> > + struct kvm_vm *vm;
> > + void *mem;
> > + struct kvm_vcpu *vcpu;
> > + pthread_t vcpu_thread;
> > + int fd, ret;
> > + u32 param_compound = compound;
> > + u32 inequal = 0;
> > +
> > + fd = open("/dev/kvm_mock_device", O_RDWR);
> > + if (fd < 0) {
> > + pr_info("Please ensure \"CONFIG_TEST_KVM_MOCK_DEVICE=m\" is enabled in the kernel");
> > + pr_info(", and execute\n\"modprobe test_kvm_mock_device\n");
> > + }
> > + TEST_ASSERT(fd >= 0, "Failed to open kvm mock device.");
>
> Minor:
> May better to move this part into main(), highlight it's a
> must have dependency at beginning.
I don't think so.
main() can do other tests that are not relying on the mock device.
Actually I'm not even sure if this test needs to be put in
set_memory_region_test.c.
>
> > +
> > + ret = ioctl(fd, KVM_MOCK_DEVICE_GET_BAR_SIZE, &bar_size);
> > + TEST_ASSERT(ret == 0, "Failed to get bar size of kvm mock device");
> > +
> > + ret = ioctl(fd, KVM_MOCK_DEVICE_PREPARE_RESOURCE, ¶m_compound);
> > + TEST_ASSERT(ret == 0, "Failed to prepare resource of kvm mock device");
> > +
> > + mem = mmap(NULL, (size_t)bar_size, PROT_READ | PROT_WRITE, MAP_SHARED,
> > + fd, 0);
> > + TEST_ASSERT(mem != MAP_FAILED, "Failed to mmap() kvm mock device bar");
> > +
> > + *(u64 *)mem = BASE_VAL;
> > + *(u64 *)(mem + RANDOM_OFFSET) = RANDOM_VAL;
> > +
> > + vm = vm_create_with_one_vcpu(&vcpu, guest_code_read_bar);
> > +
> > + vm_set_user_memory_region(vm, MEM_REGION_SLOT_ID, 0, MEM_REGION_GPA_BASE,
> > + bar_size, mem);
> > +
> > + virt_map(vm, MEM_REGION_GPA_BASE, MEM_REGION_GPA_BASE,
> > + (RANDOM_OFFSET / getpagesize()) + 1);
> > +
> > + pthread_create(&vcpu_thread, NULL, vcpu_worker, vcpu);
> > +
> > + /* Ensure the guest thread is spun up. */
> > + wait_for_vcpu();
> > +
> > + pthread_join(vcpu_thread, NULL);
> > +
> > + vm_set_user_memory_region(vm, MEM_REGION_SLOT_ID, 0, 0, 0, 0);
> > + kvm_vm_free(vm);
> > +
> > + ret = ioctl(fd, KVM_MOCK_DEVICE_CHECK_BACKEND_REF, &inequal);
> > + TEST_ASSERT(ret == 0 && inequal == 0, "Incorrect resource ref of KVM device");
> > +
> > + munmap(mem, bar_size);
> > + close(fd);
> > +}
> > +
> > +static void test_non_compound_backend(void)
> > +{
> > + pr_info("Testing non-compound huge page backend for mem slot\n");
> > + test_kvm_mock_device_bar(false);
> > +}
> > +
> > +static void test_compound_backend(void)
> > +{
> > + pr_info("Testing compound huge page backend for mem slot\n");
> > + test_kvm_mock_device_bar(true);
> > +}
> > +
> > +int main(int argc, char *argv[])
> > +{
> > +#ifdef __x86_64__
> > + test_compound_backend();
> > + if (non_compound_supported)
>
> Nobody set this, but the mock device looks already supported
> it, so how about just run the 2 testings directly here ?
Without the series "allow mapping non-refcounted pages" [1], the test
test_non_compound_backend() will simply fail.
I added this test case is to show it non-compound pages as backend can
also be tested with this selftest. And actually, I did tested that
series with this selftets.
So, can remove the "if non_compound_supported" after [1] is merged.
[1] https://lore.kernel.org/all/20230911021637.1941096-1-stevensd@google.com/,
Thanks
>
> > + test_non_compound_backend();
> > +#endif
> > +
> > + return 0;
> > +}
> > --
> > 2.17.1
> >
>
@@ -144,6 +144,7 @@ TEST_GEN_PROGS_x86_64 += memslot_modification_stress_test
TEST_GEN_PROGS_x86_64 += memslot_perf_test
TEST_GEN_PROGS_x86_64 += rseq_test
TEST_GEN_PROGS_x86_64 += set_memory_region_test
+TEST_GEN_PROGS_x86_64 += set_memory_region_io
TEST_GEN_PROGS_x86_64 += steal_time
TEST_GEN_PROGS_x86_64 += kvm_binary_stats_test
TEST_GEN_PROGS_x86_64 += system_counter_offset_test
new file mode 100644
@@ -0,0 +1,188 @@
+// SPDX-License-Identifier: GPL-2.0
+#define _GNU_SOURCE /* for program_invocation_short_name */
+#include <fcntl.h>
+#include <pthread.h>
+#include <sched.h>
+#include <semaphore.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+
+#include <linux/compiler.h>
+
+#include <test_util.h>
+#include <kvm_util.h>
+#include <processor.h>
+
+#include <../../../../lib/test_kvm_mock_device_uapi.h>
+
+/*
+ * Somewhat arbitrary location and slot, intended to not overlap anything.
+ */
+#define MEM_REGION_GPA_BASE 0xc0000000
+#define RANDOM_OFFSET 0x1000
+#define MEM_REGION_GPA_RANDOM (MEM_REGION_GPA_BASE + RANDOM_OFFSET)
+#define MEM_REGION_SLOT_ID 10
+
+static const bool non_compound_supported;
+
+static const uint64_t BASE_VAL = 0x1111;
+static const uint64_t RANDOM_VAL = 0x2222;
+
+static unsigned long bar_size;
+
+static sem_t vcpu_ready;
+
+static void guest_code_read_bar(void)
+{
+ uint64_t val;
+
+ GUEST_SYNC(0);
+
+ val = READ_ONCE(*((uint64_t *)MEM_REGION_GPA_RANDOM));
+ GUEST_ASSERT_EQ(val, RANDOM_VAL);
+
+ val = READ_ONCE(*((uint64_t *)MEM_REGION_GPA_BASE));
+ GUEST_ASSERT_EQ(val, BASE_VAL);
+
+ GUEST_DONE();
+}
+
+static void *vcpu_worker(void *data)
+{
+ struct kvm_vcpu *vcpu = data;
+ struct kvm_run *run = vcpu->run;
+ struct ucall uc;
+ uint64_t cmd;
+
+ /*
+ * Loop until the guest is done. Re-enter the guest on all MMIO exits,
+ * which will occur if the guest attempts to access a memslot after it
+ * has been deleted or while it is being moved .
+ */
+ while (1) {
+ vcpu_run(vcpu);
+
+ if (run->exit_reason == KVM_EXIT_IO) {
+ cmd = get_ucall(vcpu, &uc);
+ if (cmd != UCALL_SYNC)
+ break;
+
+ sem_post(&vcpu_ready);
+ continue;
+ }
+
+ if (run->exit_reason != KVM_EXIT_MMIO)
+ break;
+
+ TEST_ASSERT(!run->mmio.is_write, "Unexpected exit mmio write");
+ TEST_ASSERT(run->mmio.len == 8,
+ "Unexpected exit mmio size = %u", run->mmio.len);
+
+ TEST_ASSERT(run->mmio.phys_addr < MEM_REGION_GPA_BASE ||
+ run->mmio.phys_addr >= MEM_REGION_GPA_BASE + bar_size,
+ "Unexpected exit mmio address = 0x%llx",
+ run->mmio.phys_addr);
+ }
+
+ if (run->exit_reason == KVM_EXIT_IO && cmd == UCALL_ABORT)
+ REPORT_GUEST_ASSERT(uc);
+
+ return NULL;
+}
+
+static void wait_for_vcpu(void)
+{
+ struct timespec ts;
+
+ TEST_ASSERT(!clock_gettime(CLOCK_REALTIME, &ts),
+ "clock_gettime() failed: %d\n", errno);
+
+ ts.tv_sec += 2;
+ TEST_ASSERT(!sem_timedwait(&vcpu_ready, &ts),
+ "sem_timedwait() failed: %d\n", errno);
+
+ /* Wait for the vCPU thread to reenter the guest. */
+ usleep(100000);
+}
+
+static void test_kvm_mock_device_bar(bool compound)
+{
+ struct kvm_vm *vm;
+ void *mem;
+ struct kvm_vcpu *vcpu;
+ pthread_t vcpu_thread;
+ int fd, ret;
+ u32 param_compound = compound;
+ u32 inequal = 0;
+
+ fd = open("/dev/kvm_mock_device", O_RDWR);
+ if (fd < 0) {
+ pr_info("Please ensure \"CONFIG_TEST_KVM_MOCK_DEVICE=m\" is enabled in the kernel");
+ pr_info(", and execute\n\"modprobe test_kvm_mock_device\n");
+ }
+ TEST_ASSERT(fd >= 0, "Failed to open kvm mock device.");
+
+ ret = ioctl(fd, KVM_MOCK_DEVICE_GET_BAR_SIZE, &bar_size);
+ TEST_ASSERT(ret == 0, "Failed to get bar size of kvm mock device");
+
+ ret = ioctl(fd, KVM_MOCK_DEVICE_PREPARE_RESOURCE, ¶m_compound);
+ TEST_ASSERT(ret == 0, "Failed to prepare resource of kvm mock device");
+
+ mem = mmap(NULL, (size_t)bar_size, PROT_READ | PROT_WRITE, MAP_SHARED,
+ fd, 0);
+ TEST_ASSERT(mem != MAP_FAILED, "Failed to mmap() kvm mock device bar");
+
+ *(u64 *)mem = BASE_VAL;
+ *(u64 *)(mem + RANDOM_OFFSET) = RANDOM_VAL;
+
+ vm = vm_create_with_one_vcpu(&vcpu, guest_code_read_bar);
+
+ vm_set_user_memory_region(vm, MEM_REGION_SLOT_ID, 0, MEM_REGION_GPA_BASE,
+ bar_size, mem);
+
+ virt_map(vm, MEM_REGION_GPA_BASE, MEM_REGION_GPA_BASE,
+ (RANDOM_OFFSET / getpagesize()) + 1);
+
+ pthread_create(&vcpu_thread, NULL, vcpu_worker, vcpu);
+
+ /* Ensure the guest thread is spun up. */
+ wait_for_vcpu();
+
+ pthread_join(vcpu_thread, NULL);
+
+ vm_set_user_memory_region(vm, MEM_REGION_SLOT_ID, 0, 0, 0, 0);
+ kvm_vm_free(vm);
+
+ ret = ioctl(fd, KVM_MOCK_DEVICE_CHECK_BACKEND_REF, &inequal);
+ TEST_ASSERT(ret == 0 && inequal == 0, "Incorrect resource ref of KVM device");
+
+ munmap(mem, bar_size);
+ close(fd);
+}
+
+static void test_non_compound_backend(void)
+{
+ pr_info("Testing non-compound huge page backend for mem slot\n");
+ test_kvm_mock_device_bar(false);
+}
+
+static void test_compound_backend(void)
+{
+ pr_info("Testing compound huge page backend for mem slot\n");
+ test_kvm_mock_device_bar(true);
+}
+
+int main(int argc, char *argv[])
+{
+#ifdef __x86_64__
+ test_compound_backend();
+ if (non_compound_supported)
+ test_non_compound_backend();
+#endif
+
+ return 0;
+}