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yamahatabonzini
yamahata
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KVM: selftests: x86: Add test for KVM_PRE_FAULT_MEMORY
Add a test case to exercise KVM_PRE_FAULT_MEMORY and run the guest to access the pre-populated area. It tests KVM_PRE_FAULT_MEMORY ioctl for KVM_X86_DEFAULT_VM and KVM_X86_SW_PROTECTED_VM. Signed-off-by: Isaku Yamahata <[email protected]> Message-ID: <32427791ef42e5efaafb05d2ac37fa4372715f47.1712785629.git.isaku.yamahata@intel.com> Signed-off-by: Paolo Bonzini <[email protected]>
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3 files changed

+159
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‎tools/include/uapi/linux/kvm.h

Lines changed: 12 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -917,6 +917,7 @@ struct kvm_enable_cap {
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#define KVM_CAP_MEMORY_ATTRIBUTES 233
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#define KVM_CAP_GUEST_MEMFD 234
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#define KVM_CAP_VM_TYPES 235
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#define KVM_CAP_PRE_FAULT_MEMORY 236
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921922
struct kvm_irq_routing_irqchip {
922923
__u32 irqchip;
@@ -1221,9 +1222,9 @@ struct kvm_vfio_spapr_tce {
12211222
/* Available with KVM_CAP_SPAPR_RESIZE_HPT */
12221223
#define KVM_PPC_RESIZE_HPT_PREPARE _IOR(KVMIO, 0xad, struct kvm_ppc_resize_hpt)
12231224
#define KVM_PPC_RESIZE_HPT_COMMIT _IOR(KVMIO, 0xae, struct kvm_ppc_resize_hpt)
1224-
/* Available with KVM_CAP_PPC_RADIX_MMU or KVM_CAP_PPC_MMU_HASH_V3 */
1225+
/* Available with KVM_CAP_PPC_MMU_RADIX or KVM_CAP_PPC_MMU_HASH_V3 */
12251226
#define KVM_PPC_CONFIGURE_V3_MMU _IOW(KVMIO, 0xaf, struct kvm_ppc_mmuv3_cfg)
1226-
/* Available with KVM_CAP_PPC_RADIX_MMU */
1227+
/* Available with KVM_CAP_PPC_MMU_RADIX */
12271228
#define KVM_PPC_GET_RMMU_INFO _IOW(KVMIO, 0xb0, struct kvm_ppc_rmmu_info)
12281229
/* Available with KVM_CAP_PPC_GET_CPU_CHAR */
12291230
#define KVM_PPC_GET_CPU_CHAR _IOR(KVMIO, 0xb1, struct kvm_ppc_cpu_char)
@@ -1548,4 +1549,13 @@ struct kvm_create_guest_memfd {
15481549
__u64 reserved[6];
15491550
};
15501551

1552+
#define KVM_PRE_FAULT_MEMORY _IOWR(KVMIO, 0xd5, struct kvm_pre_fault_memory)
1553+
1554+
struct kvm_pre_fault_memory {
1555+
__u64 gpa;
1556+
__u64 size;
1557+
__u64 flags;
1558+
__u64 padding[5];
1559+
};
1560+
15511561
#endif /* __LINUX_KVM_H */

‎tools/testing/selftests/kvm/Makefile

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -145,6 +145,7 @@ TEST_GEN_PROGS_x86_64 += set_memory_region_test
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TEST_GEN_PROGS_x86_64 += steal_time
146146
TEST_GEN_PROGS_x86_64 += kvm_binary_stats_test
147147
TEST_GEN_PROGS_x86_64 += system_counter_offset_test
148+
TEST_GEN_PROGS_x86_64 += pre_fault_memory_test
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149150
# Compiled outputs used by test targets
150151
TEST_GEN_PROGS_EXTENDED_x86_64 += x86_64/nx_huge_pages_test

‎tools/testing/selftests/kvm/pre_fault_memory_test.c

Lines changed: 146 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,146 @@
1+
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2024, Intel, Inc
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*
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* Author:
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* Isaku Yamahata <isaku.yamahata at gmail.com>
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*/
8+
#include <linux/sizes.h>
9+
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#include <test_util.h>
11+
#include <kvm_util.h>
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#include <processor.h>
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/* Arbitrarily chosen values */
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#define TEST_SIZE (SZ_2M + PAGE_SIZE)
16+
#define TEST_NPAGES (TEST_SIZE / PAGE_SIZE)
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#define TEST_SLOT 10
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static void guest_code(uint64_t base_gpa)
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{
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volatile uint64_t val __used;
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int i;
23+
24+
for (i = 0; i < TEST_NPAGES; i++) {
25+
uint64_t *src = (uint64_t *)(base_gpa + i * PAGE_SIZE);
26+
27+
val = *src;
28+
}
29+
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GUEST_DONE();
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}
32+
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static void pre_fault_memory(struct kvm_vcpu *vcpu, u64 gpa, u64 size,
34+
u64 left)
35+
{
36+
struct kvm_pre_fault_memory range = {
37+
.gpa = gpa,
38+
.size = size,
39+
.flags = 0,
40+
};
41+
u64 prev;
42+
int ret, save_errno;
43+
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do {
45+
prev = range.size;
46+
ret = __vcpu_ioctl(vcpu, KVM_PRE_FAULT_MEMORY, &range);
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save_errno = errno;
48+
TEST_ASSERT((range.size < prev) ^ (ret < 0),
49+
"%sexpecting range.size to change on %s",
50+
ret < 0 ? "not " : "",
51+
ret < 0 ? "failure" : "success");
52+
} while (ret >= 0 ? range.size : save_errno == EINTR);
53+
54+
TEST_ASSERT(range.size == left,
55+
"Completed with %lld bytes left, expected %" PRId64,
56+
range.size, left);
57+
58+
if (left == 0)
59+
__TEST_ASSERT_VM_VCPU_IOCTL(!ret, "KVM_PRE_FAULT_MEMORY", ret, vcpu->vm);
60+
else
61+
/* No memory slot causes RET_PF_EMULATE. it results in -ENOENT. */
62+
__TEST_ASSERT_VM_VCPU_IOCTL(ret && save_errno == ENOENT,
63+
"KVM_PRE_FAULT_MEMORY", ret, vcpu->vm);
64+
}
65+
66+
static void __test_pre_fault_memory(unsigned long vm_type, bool private)
67+
{
68+
const struct vm_shape shape = {
69+
.mode = VM_MODE_DEFAULT,
70+
.type = vm_type,
71+
};
72+
struct kvm_vcpu *vcpu;
73+
struct kvm_run *run;
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struct kvm_vm *vm;
75+
struct ucall uc;
76+
77+
uint64_t guest_test_phys_mem;
78+
uint64_t guest_test_virt_mem;
79+
uint64_t alignment, guest_page_size;
80+
81+
vm = vm_create_shape_with_one_vcpu(shape, &vcpu, guest_code);
82+
83+
alignment = guest_page_size = vm_guest_mode_params[VM_MODE_DEFAULT].page_size;
84+
guest_test_phys_mem = (vm->max_gfn - TEST_NPAGES) * guest_page_size;
85+
#ifdef __s390x__
86+
alignment = max(0x100000UL, guest_page_size);
87+
#else
88+
alignment = SZ_2M;
89+
#endif
90+
guest_test_phys_mem = align_down(guest_test_phys_mem, alignment);
91+
guest_test_virt_mem = guest_test_phys_mem & ((1ULL << (vm->va_bits - 1)) - 1);
92+
93+
vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,
94+
guest_test_phys_mem, TEST_SLOT, TEST_NPAGES,
95+
private ? KVM_MEM_GUEST_MEMFD : 0);
96+
virt_map(vm, guest_test_virt_mem, guest_test_phys_mem, TEST_NPAGES);
97+
98+
if (private)
99+
vm_mem_set_private(vm, guest_test_phys_mem, TEST_SIZE);
100+
pre_fault_memory(vcpu, guest_test_phys_mem, SZ_2M, 0);
101+
pre_fault_memory(vcpu, guest_test_phys_mem + SZ_2M, PAGE_SIZE * 2, PAGE_SIZE);
102+
pre_fault_memory(vcpu, guest_test_phys_mem + TEST_SIZE, PAGE_SIZE, PAGE_SIZE);
103+
104+
vcpu_args_set(vcpu, 1, guest_test_virt_mem);
105+
vcpu_run(vcpu);
106+
107+
run = vcpu->run;
108+
TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
109+
"Wanted KVM_EXIT_IO, got exit reason: %u (%s)",
110+
run->exit_reason, exit_reason_str(run->exit_reason));
111+
112+
switch (get_ucall(vcpu, &uc)) {
113+
case UCALL_ABORT:
114+
REPORT_GUEST_ASSERT(uc);
115+
break;
116+
case UCALL_DONE:
117+
break;
118+
default:
119+
TEST_FAIL("Unknown ucall 0x%lx.", uc.cmd);
120+
break;
121+
}
122+
123+
kvm_vm_free(vm);
124+
}
125+
126+
static void test_pre_fault_memory(unsigned long vm_type, bool private)
127+
{
128+
if (vm_type && !(kvm_check_cap(KVM_CAP_VM_TYPES) & BIT(vm_type))) {
129+
pr_info("Skipping tests for vm_type 0x%lx\n", vm_type);
130+
return;
131+
}
132+
133+
__test_pre_fault_memory(vm_type, private);
134+
}
135+
136+
int main(int argc, char *argv[])
137+
{
138+
TEST_REQUIRE(kvm_check_cap(KVM_CAP_PRE_FAULT_MEMORY));
139+
140+
test_pre_fault_memory(0, false);
141+
#ifdef __x86_64__
142+
test_pre_fault_memory(KVM_X86_SW_PROTECTED_VM, false);
143+
test_pre_fault_memory(KVM_X86_SW_PROTECTED_VM, true);
144+
#endif
145+
return 0;
146+
}

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