diff --git a/tools/testing/selftests/kvm/Makefile.kvm b/tools/testing/selftests/kvm/Makefile.kvm
index 9118a5a51b89..82fa943b9503 100644
--- a/tools/testing/selftests/kvm/Makefile.kvm
+++ b/tools/testing/selftests/kvm/Makefile.kvm
@@ -140,6 +140,7 @@ TEST_GEN_PROGS_x86 += x86/tsc_msrs_test
 TEST_GEN_PROGS_x86 += x86/vmx_pmu_caps_test
 TEST_GEN_PROGS_x86 += x86/xen_shinfo_test
 TEST_GEN_PROGS_x86 += x86/xen_vmcall_test
+TEST_GEN_PROGS_x86 += x86/sev_dbg_test
 TEST_GEN_PROGS_x86 += x86/sev_init2_tests
 TEST_GEN_PROGS_x86 += x86/sev_migrate_tests
 TEST_GEN_PROGS_x86 += x86/sev_smoke_test
diff --git a/tools/testing/selftests/kvm/include/x86/sev.h b/tools/testing/selftests/kvm/include/x86/sev.h
index 1af44c151d60..dec383e59a47 100644
--- a/tools/testing/selftests/kvm/include/x86/sev.h
+++ b/tools/testing/selftests/kvm/include/x86/sev.h
@@ -144,4 +144,28 @@ static inline void snp_launch_update_data(struct kvm_vm *vm, gpa_t gpa,
 	vm_sev_ioctl(vm, KVM_SEV_SNP_LAUNCH_UPDATE, &update_data);
 }
 
+static inline void sev_dbg_crypt_memory(struct kvm_vm *vm, unsigned int cmd,
+					void *dst, void *src, unsigned int len)
+{
+	struct kvm_sev_dbg dbg = {
+		.src_uaddr = (unsigned long)src,
+		.dst_uaddr = (unsigned long)dst,
+		.len = len,
+	};
+
+	vm_sev_ioctl(vm, cmd, &dbg);
+}
+
+static inline void sev_decrypt_memory(struct kvm_vm *vm, void *dst, void *src,
+				      unsigned int len)
+{
+	sev_dbg_crypt_memory(vm, KVM_SEV_DBG_DECRYPT, dst, src, len);
+}
+
+static inline void sev_encrypt_memory(struct kvm_vm *vm, void *dst, void *src,
+				      unsigned int len)
+{
+	sev_dbg_crypt_memory(vm, KVM_SEV_DBG_ENCRYPT, dst, src, len);
+}
+
 #endif /* SELFTEST_KVM_SEV_H */
diff --git a/tools/testing/selftests/kvm/x86/sev_dbg_test.c b/tools/testing/selftests/kvm/x86/sev_dbg_test.c
new file mode 100644
index 000000000000..a9d8e4c059f9
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86/sev_dbg_test.c
@@ -0,0 +1,118 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <fcntl.h>
+#include <string.h>
+#include <sys/ioctl.h>
+
+#include "test_util.h"
+#include "kvm_util.h"
+#include "processor.h"
+#include "sev.h"
+
+#define BUFFER_SIZE	(PAGE_SIZE * 2)
+
+static u8 *data;
+static u8 src[BUFFER_SIZE] __aligned(PAGE_SIZE);
+static u8 dst[BUFFER_SIZE] __aligned(PAGE_SIZE);
+
+static void validate_dst(int i, int nr_bytes, u8 pattern)
+{
+	for ( ; i < nr_bytes; i++)
+		TEST_ASSERT(dst[i] == pattern,
+			    "Expected 0x%x at byte %u, got 0x%x",
+			    pattern, i, dst[i]);
+}
+
+static void validate_buffers(void)
+{
+	int i;
+
+	for (i = 0; i < BUFFER_SIZE; i++)
+		TEST_ASSERT(src[i] == dst[i],
+			    "Expected src[%u] (0x%x) == dst[%u] (0x%x)",
+			    i, src[i], i, dst[i]);
+}
+
+static void ____test_sev_dbg(struct kvm_vm *vm, int i, int j, int nr_bytes)
+{
+	u8 pattern = guest_random_u32(&guest_rng);
+
+	if (i + nr_bytes > BUFFER_SIZE || j + nr_bytes > BUFFER_SIZE)
+		return;
+
+	memset(&src[i], pattern, nr_bytes);
+	sev_encrypt_memory(vm, &data[j], &src[i], nr_bytes);
+	sev_decrypt_memory(vm, &dst[i], &data[j], nr_bytes);
+	validate_buffers();
+	validate_dst(i, nr_bytes, pattern);
+}
+
+static void __test_sev_dbg(struct kvm_vm *vm, int nr_bytes)
+{
+	/*
+	 * In a perfect world, all sizes at all combinations within the buffers
+	 * would be tested.  In reality, even this much testing is quite slow.
+	 * Target sizes and offsets around the chunk (16 bytes) and page (4096
+	 * bytes) sizes.
+	 */
+	int x[] = { 1, 8, 15, 16, 23 };
+	int p = PAGE_SIZE - 24;
+	int i, j;
+
+	____test_sev_dbg(vm, 0, 0, nr_bytes);
+
+	for (i = 0; i < ARRAY_SIZE(x); i++) {
+		for (j = 0; j < ARRAY_SIZE(x); j++) {
+			____test_sev_dbg(vm, x[i], x[j], nr_bytes);
+			____test_sev_dbg(vm, x[i], p + x[j], nr_bytes);
+			____test_sev_dbg(vm, p + x[i], x[j], nr_bytes);
+			____test_sev_dbg(vm, p + x[i], p + x[j], nr_bytes);
+		}
+	}
+}
+
+static void test_sev_dbg(u32 type, u64 policy)
+{
+	int sizes[] = { 1, 8, 15, 16, 17, 32, 33 };
+	struct kvm_vcpu *vcpu;
+	struct kvm_vm *vm;
+	int i;
+
+	if (!(kvm_check_cap(KVM_CAP_VM_TYPES) & BIT(type)))
+		return;
+
+	vm = vm_sev_create_with_one_vcpu(type, NULL, &vcpu);
+
+	data = addr_gva2hva(vm, vm_alloc(vm, BUFFER_SIZE, KVM_UTIL_MIN_VADDR));
+	memset(data, 0xaa, BUFFER_SIZE);
+
+	vm_sev_launch(vm, policy, NULL);
+
+	sev_decrypt_memory(vm, dst, data, BUFFER_SIZE);
+	validate_dst(0, BUFFER_SIZE, 0xaa);
+
+	memset(src, 0x55, BUFFER_SIZE);
+	sev_encrypt_memory(vm, data, src, BUFFER_SIZE);
+	sev_decrypt_memory(vm, dst, data, BUFFER_SIZE);
+	validate_dst(0, BUFFER_SIZE, 0x55);
+
+	__test_sev_dbg(vm, PAGE_SIZE);
+
+	for (i = 0; i < ARRAY_SIZE(sizes); i++) {
+		__test_sev_dbg(vm, sizes[i]);
+		__test_sev_dbg(vm, PAGE_SIZE - sizes[i]);
+		__test_sev_dbg(vm, PAGE_SIZE + sizes[i]);
+		__test_sev_dbg(vm, BUFFER_SIZE - sizes[i]);
+	}
+
+	kvm_vm_free(vm);
+}
+
+int main(int argc, char *argv[])
+{
+	TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_SEV));
+
+	/* Note, KVM doesn't support {de,en}crypt commands for SNP. */
+	test_sev_dbg(KVM_X86_SEV_VM, 0);
+	test_sev_dbg(KVM_X86_SEV_ES_VM, SEV_POLICY_ES);
+	return 0;
+}