linux-kernel - [PATCH v13 21/21] KVM: selftest: Add tests for KVM_{GET,SET}_ONE

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Message-ID: <20250821133132.72322-22-chao.gao@intel.com>
Date: Thu, 21 Aug 2025 06:30:55 -0700
From: Chao Gao <chao.gao@...el.com>
To: kvm@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-kselftest@...r.kernel.org
Cc: chao.gao@...el.com,
	bp@...en8.de,
	dave.hansen@...ux.intel.com,
	hpa@...or.com,
	john.allen@....com,
	mingo@...hat.com,
	minipli@...ecurity.net,
	mlevitsk@...hat.com,
	pbonzini@...hat.com,
	rick.p.edgecombe@...el.com,
	seanjc@...gle.com,
	tglx@...utronix.de,
	weijiang.yang@...el.com,
	x86@...nel.org,
	xin@...or.com,
	Shuah Khan <shuah@...nel.org>,
	Arnaldo Carvalho de Melo <acme@...hat.com>,
	Namhyung Kim <namhyung@...nel.org>,
	"Pratik R. Sampat" <prsampat@....com>
Subject: [PATCH v13 21/21] KVM: selftest: Add tests for KVM_{GET,SET}_ONE_REG

Add tests for newly added KVM_{GET,SET}_ONE_REG support for x86. Verify the
new ioctls can read and write real MSRs and synthetic MSRs.

Signed-off-by: Chao Gao <chao.gao@...el.com>
---
 tools/arch/x86/include/uapi/asm/kvm.h         | 24 +++++++++++++
 tools/testing/selftests/kvm/Makefile.kvm      |  1 +
 .../selftests/kvm/x86/get_set_one_reg.c       | 35 +++++++++++++++++++
 3 files changed, 60 insertions(+)
 create mode 100644 tools/testing/selftests/kvm/x86/get_set_one_reg.c

diff --git a/tools/arch/x86/include/uapi/asm/kvm.h b/tools/arch/x86/include/uapi/asm/kvm.h
index 6f3499507c5e..590762820a61 100644
--- a/tools/arch/x86/include/uapi/asm/kvm.h
+++ b/tools/arch/x86/include/uapi/asm/kvm.h
@@ -411,6 +411,30 @@ struct kvm_xcrs {
 	__u64 padding[16];
 };
 
+#define KVM_X86_REG_TYPE_MSR		2
+#define KVM_X86_REG_TYPE_SYNTHETIC_MSR	3
+
+#define KVM_X86_REG_TYPE_SIZE(type)						\
+({										\
+	__u64 type_size = (__u64)type << 32;					\
+										\
+	type_size |= type == KVM_X86_REG_TYPE_MSR ? KVM_REG_SIZE_U64 :		\
+		     type == KVM_X86_REG_TYPE_SYNTHETIC_MSR ? KVM_REG_SIZE_U64 :\
+		     0;								\
+	type_size;								\
+})
+
+#define KVM_X86_REG_ENCODE(type, index)				\
+	(KVM_REG_X86 | KVM_X86_REG_TYPE_SIZE(type) | index)
+
+#define KVM_X86_REG_MSR(index)					\
+	KVM_X86_REG_ENCODE(KVM_X86_REG_TYPE_MSR, index)
+#define KVM_X86_REG_SYNTHETIC_MSR(index)			\
+	KVM_X86_REG_ENCODE(KVM_X86_REG_TYPE_SYNTHETIC_MSR, index)
+
+/* KVM synthetic MSR index staring from 0 */
+#define KVM_SYNTHETIC_GUEST_SSP 0
+
 #define KVM_SYNC_X86_REGS      (1UL << 0)
 #define KVM_SYNC_X86_SREGS     (1UL << 1)
 #define KVM_SYNC_X86_EVENTS    (1UL << 2)
diff --git a/tools/testing/selftests/kvm/Makefile.kvm b/tools/testing/selftests/kvm/Makefile.kvm
index f6fe7a07a0a2..9a375d5faf1c 100644
--- a/tools/testing/selftests/kvm/Makefile.kvm
+++ b/tools/testing/selftests/kvm/Makefile.kvm
@@ -136,6 +136,7 @@ TEST_GEN_PROGS_x86 += x86/max_vcpuid_cap_test
 TEST_GEN_PROGS_x86 += x86/triple_fault_event_test
 TEST_GEN_PROGS_x86 += x86/recalc_apic_map_test
 TEST_GEN_PROGS_x86 += x86/aperfmperf_test
+TEST_GEN_PROGS_x86 += x86/get_set_one_reg
 TEST_GEN_PROGS_x86 += access_tracking_perf_test
 TEST_GEN_PROGS_x86 += coalesced_io_test
 TEST_GEN_PROGS_x86 += dirty_log_perf_test
diff --git a/tools/testing/selftests/kvm/x86/get_set_one_reg.c b/tools/testing/selftests/kvm/x86/get_set_one_reg.c
new file mode 100644
index 000000000000..8b069155ddc7
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86/get_set_one_reg.c
@@ -0,0 +1,35 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <fcntl.h>
+#include <stdint.h>
+#include <sys/ioctl.h>
+
+#include "test_util.h"
+#include "kvm_util.h"
+#include "processor.h"
+
+int main(int argc, char *argv[])
+{
+	struct kvm_vcpu *vcpu;
+	struct kvm_vm *vm;
+	u64 data;
+	int r;
+
+	TEST_REQUIRE(kvm_has_cap(KVM_CAP_ONE_REG));
+
+	vm = vm_create_with_one_vcpu(&vcpu, NULL);
+
+	TEST_ASSERT_EQ(__vcpu_get_reg(vcpu, KVM_X86_REG_MSR(MSR_EFER), &data), 0);
+	TEST_ASSERT_EQ(__vcpu_set_reg(vcpu, KVM_X86_REG_MSR(MSR_EFER), data), 0);
+
+	if (kvm_cpu_has(X86_FEATURE_SHSTK)) {
+		r = __vcpu_get_reg(vcpu, KVM_X86_REG_SYNTHETIC_MSR(KVM_SYNTHETIC_GUEST_SSP),
+				   &data);
+		TEST_ASSERT_EQ(r, 0);
+		r = __vcpu_set_reg(vcpu, KVM_X86_REG_SYNTHETIC_MSR(KVM_SYNTHETIC_GUEST_SSP),
+				   data);
+		TEST_ASSERT_EQ(r, 0);
+	}
+
+	kvm_vm_free(vm);
+	return 0;
+}
-- 
2.47.3