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KVM: selftests: Test KVM exit behavior for private memory/access

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"Testing private access when memslot gets deleted" tests the behavior
of KVM when a private memslot gets deleted while the VM is using the
private memslot. When KVM looks up the deleted (slot = NULL) memslot,
KVM should exit to userspace with KVM_EXIT_MEMORY_FAULT.

In the second test, upon a private access to non-private memslot, KVM
should also exit to userspace with KVM_EXIT_MEMORY_FAULT.

Intentionally don't take a requirement on KVM_CAP_GUEST_MEMFD,
KVM_CAP_MEMORY_FAULT_INFO, KVM_MEMORY_ATTRIBUTE_PRIVATE, etc., as it's a
KVM bug to advertise KVM_X86_SW_PROTECTED_VM without its prerequisites.

Signed-off-by: Ackerley Tng <ackerleytng@google.com>
[sean: call out the similarities with set_memory_region_test]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20231027182217.3615211-36-seanjc@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Ackerley Tng 2023-10-27 11:22:17 -07:00 committed by Paolo Bonzini
parent 8a89efd434
commit e3577788de
2 changed files with 121 additions and 0 deletions
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1
tools/testing/selftests/kvm/Makefile
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@ -92,6 +92,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/nested_exceptions_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_conversions_test
TEST_GEN_PROGS_x86_64 += x86_64/private_mem_kvm_exits_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/smaller_maxphyaddr_emulation_test

120
tools/testing/selftests/kvm/x86_64/private_mem_kvm_exits_test.c Normal file
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@ -0,0 +1,120 @@
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2023, Google LLC.
*/
#include <linux/kvm.h>
#include <pthread.h>
#include <stdint.h>
#include "kvm_util.h"
#include "processor.h"
#include "test_util.h"
/* Arbitrarily selected to avoid overlaps with anything else */
#define EXITS_TEST_GVA 0xc0000000
#define EXITS_TEST_GPA EXITS_TEST_GVA
#define EXITS_TEST_NPAGES 1
#define EXITS_TEST_SIZE (EXITS_TEST_NPAGES * PAGE_SIZE)
#define EXITS_TEST_SLOT 10
static uint64_t guest_repeatedly_read(void)
{
volatile uint64_t value;
while (true)
value = *((uint64_t *) EXITS_TEST_GVA);
return value;
}
static uint32_t run_vcpu_get_exit_reason(struct kvm_vcpu *vcpu)
{
int r;
r = _vcpu_run(vcpu);
if (r) {
TEST_ASSERT(errno == EFAULT, KVM_IOCTL_ERROR(KVM_RUN, r));
TEST_ASSERT_EQ(vcpu->run->exit_reason, KVM_EXIT_MEMORY_FAULT);
}
return vcpu->run->exit_reason;
}
const struct vm_shape protected_vm_shape = {
.mode = VM_MODE_DEFAULT,
.type = KVM_X86_SW_PROTECTED_VM,
};
static void test_private_access_memslot_deleted(void)
{
struct kvm_vm *vm;
struct kvm_vcpu *vcpu;
pthread_t vm_thread;
void *thread_return;
uint32_t exit_reason;
vm = vm_create_shape_with_one_vcpu(protected_vm_shape, &vcpu,
guest_repeatedly_read);
vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,
EXITS_TEST_GPA, EXITS_TEST_SLOT,
EXITS_TEST_NPAGES,
KVM_MEM_GUEST_MEMFD);
virt_map(vm, EXITS_TEST_GVA, EXITS_TEST_GPA, EXITS_TEST_NPAGES);
/* Request to access page privately */
vm_mem_set_private(vm, EXITS_TEST_GPA, EXITS_TEST_SIZE);
pthread_create(&vm_thread, NULL,
(void *(*)(void *))run_vcpu_get_exit_reason,
(void *)vcpu);
vm_mem_region_delete(vm, EXITS_TEST_SLOT);
pthread_join(vm_thread, &thread_return);
exit_reason = (uint32_t)(uint64_t)thread_return;
TEST_ASSERT_EQ(exit_reason, KVM_EXIT_MEMORY_FAULT);
TEST_ASSERT_EQ(vcpu->run->memory_fault.flags, KVM_MEMORY_EXIT_FLAG_PRIVATE);
TEST_ASSERT_EQ(vcpu->run->memory_fault.gpa, EXITS_TEST_GPA);
TEST_ASSERT_EQ(vcpu->run->memory_fault.size, EXITS_TEST_SIZE);
kvm_vm_free(vm);
}
static void test_private_access_memslot_not_private(void)
{
struct kvm_vm *vm;
struct kvm_vcpu *vcpu;
uint32_t exit_reason;
vm = vm_create_shape_with_one_vcpu(protected_vm_shape, &vcpu,
guest_repeatedly_read);
/* Add a non-private memslot (flags = 0) */
vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,
EXITS_TEST_GPA, EXITS_TEST_SLOT,
EXITS_TEST_NPAGES, 0);
virt_map(vm, EXITS_TEST_GVA, EXITS_TEST_GPA, EXITS_TEST_NPAGES);
/* Request to access page privately */
vm_mem_set_private(vm, EXITS_TEST_GPA, EXITS_TEST_SIZE);
exit_reason = run_vcpu_get_exit_reason(vcpu);
TEST_ASSERT_EQ(exit_reason, KVM_EXIT_MEMORY_FAULT);
TEST_ASSERT_EQ(vcpu->run->memory_fault.flags, KVM_MEMORY_EXIT_FLAG_PRIVATE);
TEST_ASSERT_EQ(vcpu->run->memory_fault.gpa, EXITS_TEST_GPA);
TEST_ASSERT_EQ(vcpu->run->memory_fault.size, EXITS_TEST_SIZE);
kvm_vm_free(vm);
}
int main(int argc, char *argv[])
{
TEST_REQUIRE(kvm_check_cap(KVM_CAP_VM_TYPES) & BIT(KVM_X86_SW_PROTECTED_VM));
test_private_access_memslot_deleted();
test_private_access_memslot_not_private();
}