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| author | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2025-08-03 23:28:48 -0700 | 
|---|---|---|
| committer | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2025-08-03 23:28:48 -0700 | 
| commit | a7bee4e7f78089c101be2ad51f4b5ec64782053e (patch) | |
| tree | 01c730cd0a71026fb1e74d601e1cbb4d0143126a /tools/testing/selftests/kvm/x86/kvm_buslock_test.c | |
| parent | 61c6fef7c4b06b4bdbf3142f4e5cace70597e0de (diff) | |
| parent | 45ee66c37f9bd8cff7718c70d84e0291d385a093 (diff) | |
Merge tag 'ib-mfd-gpio-input-pwm-v6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd into next
Merge an immutable branch between MFD, GPIO, Input and PWM to resolve
conflicts for the merge window pull request.
Diffstat (limited to 'tools/testing/selftests/kvm/x86/kvm_buslock_test.c')
| -rw-r--r-- | tools/testing/selftests/kvm/x86/kvm_buslock_test.c | 135 | 
1 files changed, 135 insertions, 0 deletions
| diff --git a/tools/testing/selftests/kvm/x86/kvm_buslock_test.c b/tools/testing/selftests/kvm/x86/kvm_buslock_test.c new file mode 100644 index 000000000000..d88500c118eb --- /dev/null +++ b/tools/testing/selftests/kvm/x86/kvm_buslock_test.c @@ -0,0 +1,135 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2024 Advanced Micro Devices, Inc. + */ +#include <linux/atomic.h> + +#include "kvm_util.h" +#include "processor.h" +#include "svm_util.h" +#include "vmx.h" +#include "test_util.h" + +#define NR_BUS_LOCKS_PER_LEVEL 100 +#define CACHE_LINE_SIZE		64 + +/* + * To generate a bus lock, carve out a buffer that precisely occupies two cache + * lines and perform an atomic access that splits the two lines. + */ +static u8 buffer[CACHE_LINE_SIZE * 2] __aligned(CACHE_LINE_SIZE); +static atomic_t *val = (void *)&buffer[CACHE_LINE_SIZE - (sizeof(*val) / 2)]; + +static void guest_generate_buslocks(void) +{ +	for (int i = 0; i < NR_BUS_LOCKS_PER_LEVEL; i++) +		atomic_inc(val); +} + +#define L2_GUEST_STACK_SIZE	64 + +static void l2_guest_code(void) +{ +	guest_generate_buslocks(); +	GUEST_DONE(); +} + +static void l1_svm_code(struct svm_test_data *svm) +{ +	unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE]; +	struct vmcb *vmcb = svm->vmcb; + +	generic_svm_setup(svm, l2_guest_code, &l2_guest_stack[L2_GUEST_STACK_SIZE]); +	run_guest(vmcb, svm->vmcb_gpa); +} + +static void l1_vmx_code(struct vmx_pages *vmx) +{ +	unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE]; + +	GUEST_ASSERT_EQ(prepare_for_vmx_operation(vmx), true); +	GUEST_ASSERT_EQ(load_vmcs(vmx), true); + +	prepare_vmcs(vmx, NULL, &l2_guest_stack[L2_GUEST_STACK_SIZE]); + +	GUEST_ASSERT(!vmwrite(GUEST_RIP, (u64)l2_guest_code)); +	GUEST_ASSERT(!vmlaunch()); +} + +static void guest_code(void *test_data) +{ +	guest_generate_buslocks(); + +	if (this_cpu_has(X86_FEATURE_SVM)) +		l1_svm_code(test_data); +	else if (this_cpu_has(X86_FEATURE_VMX)) +		l1_vmx_code(test_data); +	else +		GUEST_DONE(); + +	TEST_FAIL("L2 should have signaled 'done'"); +} + +int main(int argc, char *argv[]) +{ +	const bool has_nested = kvm_cpu_has(X86_FEATURE_SVM) || kvm_cpu_has(X86_FEATURE_VMX); +	vm_vaddr_t nested_test_data_gva; +	struct kvm_vcpu *vcpu; +	struct kvm_run *run; +	struct kvm_vm *vm; +	int i, bus_locks = 0; + +	TEST_REQUIRE(kvm_has_cap(KVM_CAP_X86_BUS_LOCK_EXIT)); + +	vm = vm_create(1); +	vm_enable_cap(vm, KVM_CAP_X86_BUS_LOCK_EXIT, KVM_BUS_LOCK_DETECTION_EXIT); +	vcpu = vm_vcpu_add(vm, 0, guest_code); + +	if (kvm_cpu_has(X86_FEATURE_SVM)) +		vcpu_alloc_svm(vm, &nested_test_data_gva); +	else +		vcpu_alloc_vmx(vm, &nested_test_data_gva); + +	vcpu_args_set(vcpu, 1, nested_test_data_gva); + +	run = vcpu->run; + +	for (i = 0; i <= NR_BUS_LOCKS_PER_LEVEL * (1 + has_nested); i++) { +		struct ucall uc; + +		vcpu_run(vcpu); + +		if (run->exit_reason == KVM_EXIT_IO) { +			switch (get_ucall(vcpu, &uc)) { +			case UCALL_ABORT: +				REPORT_GUEST_ASSERT(uc); +				goto done; +			case UCALL_SYNC: +				continue; +			case UCALL_DONE: +				goto done; +			default: +				TEST_FAIL("Unknown ucall 0x%lx.", uc.cmd); +			} +		} + +		TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_X86_BUS_LOCK); + +		/* +		 * Verify the counter is actually getting incremented, e.g. that +		 * KVM isn't skipping the instruction.  On Intel, the exit is +		 * trap-like, i.e. the counter should already have been +		 * incremented.  On AMD, it's fault-like, i.e. the counter will +		 * be incremented when the guest re-executes the instruction. +		 */ +		sync_global_from_guest(vm, *val); +		TEST_ASSERT_EQ(atomic_read(val), bus_locks + host_cpu_is_intel); + +		bus_locks++; +	} +	TEST_FAIL("Didn't receive UCALL_DONE, took %u bus lock exits\n", bus_locks); +done: +	TEST_ASSERT_EQ(i, bus_locks); +	kvm_vm_free(vm); +	return 0; +} | 
