1 files changed, 332 insertions, 0 deletions

diff --git a/tools/testing/selftests/kvm/s390x/ucontrol_test.c b/tools/testing/selftests/kvm/s390x/ucontrol_test.c
new file mode 100644
index 000000000000..f257beec1430
--- /dev/null
+++ b/tools/testing/selftests/kvm/s390x/ucontrol_test.c
@@ -0,0 +1,332 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Test code for the s390x kvm ucontrol interface
+ *
+ * Copyright IBM Corp. 2024
+ *
+ * Authors:
+ *  Christoph Schlameuss <schlameuss@linux.ibm.com>
+ */
+#include "debug_print.h"
+#include "kselftest_harness.h"
+#include "kvm_util.h"
+#include "processor.h"
+#include "sie.h"
+
+#include <linux/capability.h>
+#include <linux/sizes.h>
+
+#define VM_MEM_SIZE (4 * SZ_1M)
+
+/* so directly declare capget to check caps without libcap */
+int capget(cap_user_header_t header, cap_user_data_t data);
+
+/**
+ * In order to create user controlled virtual machines on S390,
+ * check KVM_CAP_S390_UCONTROL and use the flag KVM_VM_S390_UCONTROL
+ * as privileged user (SYS_ADMIN).
+ */
+void require_ucontrol_admin(void)
+{
+	struct __user_cap_data_struct data[_LINUX_CAPABILITY_U32S_3];
+	struct __user_cap_header_struct hdr = {
+		.version = _LINUX_CAPABILITY_VERSION_3,
+	};
+	int rc;
+
+	rc = capget(&hdr, data);
+	TEST_ASSERT_EQ(0, rc);
+	TEST_REQUIRE((data->effective & CAP_TO_MASK(CAP_SYS_ADMIN)) > 0);
+
+	TEST_REQUIRE(kvm_has_cap(KVM_CAP_S390_UCONTROL));
+}
+
+/* Test program setting some registers and looping */
+extern char test_gprs_asm[];
+asm("test_gprs_asm:\n"
+	"xgr	%r0, %r0\n"
+	"lgfi	%r1,1\n"
+	"lgfi	%r2,2\n"
+	"lgfi	%r3,3\n"
+	"lgfi	%r4,4\n"
+	"lgfi	%r5,5\n"
+	"lgfi	%r6,6\n"
+	"lgfi	%r7,7\n"
+	"0:\n"
+	"	diag	0,0,0x44\n"
+	"	ahi	%r0,1\n"
+	"	j	0b\n"
+);
+
+FIXTURE(uc_kvm)
+{
+	struct kvm_s390_sie_block *sie_block;
+	struct kvm_run *run;
+	uintptr_t base_gpa;
+	uintptr_t code_gpa;
+	uintptr_t base_hva;
+	uintptr_t code_hva;
+	int kvm_run_size;
+	void *vm_mem;
+	int vcpu_fd;
+	int kvm_fd;
+	int vm_fd;
+};
+
+/**
+ * create VM with single vcpu, map kvm_run and SIE control block for easy access
+ */
+FIXTURE_SETUP(uc_kvm)
+{
+	struct kvm_s390_vm_cpu_processor info;
+	int rc;
+
+	require_ucontrol_admin();
+
+	self->kvm_fd = open_kvm_dev_path_or_exit();
+	self->vm_fd = ioctl(self->kvm_fd, KVM_CREATE_VM, KVM_VM_S390_UCONTROL);
+	ASSERT_GE(self->vm_fd, 0);
+
+	kvm_device_attr_get(self->vm_fd, KVM_S390_VM_CPU_MODEL,
+			    KVM_S390_VM_CPU_PROCESSOR, &info);
+	TH_LOG("create VM 0x%llx", info.cpuid);
+
+	self->vcpu_fd = ioctl(self->vm_fd, KVM_CREATE_VCPU, 0);
+	ASSERT_GE(self->vcpu_fd, 0);
+
+	self->kvm_run_size = ioctl(self->kvm_fd, KVM_GET_VCPU_MMAP_SIZE, NULL);
+	ASSERT_GE(self->kvm_run_size, sizeof(struct kvm_run))
+		  TH_LOG(KVM_IOCTL_ERROR(KVM_GET_VCPU_MMAP_SIZE, self->kvm_run_size));
+	self->run = (struct kvm_run *)mmap(NULL, self->kvm_run_size,
+		    PROT_READ | PROT_WRITE, MAP_SHARED, self->vcpu_fd, 0);
+	ASSERT_NE(self->run, MAP_FAILED);
+	/**
+	 * For virtual cpus that have been created with S390 user controlled
+	 * virtual machines, the resulting vcpu fd can be memory mapped at page
+	 * offset KVM_S390_SIE_PAGE_OFFSET in order to obtain a memory map of
+	 * the virtual cpu's hardware control block.
+	 */
+	self->sie_block = (struct kvm_s390_sie_block *)mmap(NULL, PAGE_SIZE,
+			  PROT_READ | PROT_WRITE, MAP_SHARED,
+			  self->vcpu_fd, KVM_S390_SIE_PAGE_OFFSET << PAGE_SHIFT);
+	ASSERT_NE(self->sie_block, MAP_FAILED);
+
+	TH_LOG("VM created %p %p", self->run, self->sie_block);
+
+	self->base_gpa = 0;
+	self->code_gpa = self->base_gpa + (3 * SZ_1M);
+
+	self->vm_mem = aligned_alloc(SZ_1M, VM_MEM_SIZE);
+	ASSERT_NE(NULL, self->vm_mem) TH_LOG("malloc failed %u", errno);
+	self->base_hva = (uintptr_t)self->vm_mem;
+	self->code_hva = self->base_hva - self->base_gpa + self->code_gpa;
+	struct kvm_s390_ucas_mapping map = {
+		.user_addr = self->base_hva,
+		.vcpu_addr = self->base_gpa,
+		.length = VM_MEM_SIZE,
+	};
+	TH_LOG("ucas map %p %p 0x%llx",
+	       (void *)map.user_addr, (void *)map.vcpu_addr, map.length);
+	rc = ioctl(self->vcpu_fd, KVM_S390_UCAS_MAP, &map);
+	ASSERT_EQ(0, rc) TH_LOG("ucas map result %d not expected, %s",
+				rc, strerror(errno));
+
+	TH_LOG("page in %p", (void *)self->base_gpa);
+	rc = ioctl(self->vcpu_fd, KVM_S390_VCPU_FAULT, self->base_gpa);
+	ASSERT_EQ(0, rc) TH_LOG("vcpu fault (%p) result %d not expected, %s",
+				(void *)self->base_hva, rc, strerror(errno));
+
+	self->sie_block->cpuflags &= ~CPUSTAT_STOPPED;
+}
+
+FIXTURE_TEARDOWN(uc_kvm)
+{
+	munmap(self->sie_block, PAGE_SIZE);
+	munmap(self->run, self->kvm_run_size);
+	close(self->vcpu_fd);
+	close(self->vm_fd);
+	close(self->kvm_fd);
+	free(self->vm_mem);
+}
+
+TEST_F(uc_kvm, uc_sie_assertions)
+{
+	/* assert interception of Code 08 (Program Interruption) is set */
+	EXPECT_EQ(0, self->sie_block->ecb & ECB_SPECI);
+}
+
+TEST_F(uc_kvm, uc_attr_mem_limit)
+{
+	u64 limit;
+	struct kvm_device_attr attr = {
+		.group = KVM_S390_VM_MEM_CTRL,
+		.attr = KVM_S390_VM_MEM_LIMIT_SIZE,
+		.addr = (unsigned long)&limit,
+	};
+	int rc;
+
+	rc = ioctl(self->vm_fd, KVM_GET_DEVICE_ATTR, &attr);
+	EXPECT_EQ(0, rc);
+	EXPECT_EQ(~0UL, limit);
+
+	/* assert set not supported */
+	rc = ioctl(self->vm_fd, KVM_SET_DEVICE_ATTR, &attr);
+	EXPECT_EQ(-1, rc);
+	EXPECT_EQ(EINVAL, errno);
+}
+
+TEST_F(uc_kvm, uc_no_dirty_log)
+{
+	struct kvm_dirty_log dlog;
+	int rc;
+
+	rc = ioctl(self->vm_fd, KVM_GET_DIRTY_LOG, &dlog);
+	EXPECT_EQ(-1, rc);
+	EXPECT_EQ(EINVAL, errno);
+}
+
+/**
+ * Assert HPAGE CAP cannot be enabled on UCONTROL VM
+ */
+TEST(uc_cap_hpage)
+{
+	int rc, kvm_fd, vm_fd, vcpu_fd;
+	struct kvm_enable_cap cap = {
+		.cap = KVM_CAP_S390_HPAGE_1M,
+	};
+
+	require_ucontrol_admin();
+
+	kvm_fd = open_kvm_dev_path_or_exit();
+	vm_fd = ioctl(kvm_fd, KVM_CREATE_VM, KVM_VM_S390_UCONTROL);
+	ASSERT_GE(vm_fd, 0);
+
+	/* assert hpages are not supported on ucontrol vm */
+	rc = ioctl(vm_fd, KVM_CHECK_EXTENSION, KVM_CAP_S390_HPAGE_1M);
+	EXPECT_EQ(0, rc);
+
+	/* Test that KVM_CAP_S390_HPAGE_1M can't be enabled for a ucontrol vm */
+	rc = ioctl(vm_fd, KVM_ENABLE_CAP, cap);
+	EXPECT_EQ(-1, rc);
+	EXPECT_EQ(EINVAL, errno);
+
+	/* assert HPAGE CAP is rejected after vCPU creation */
+	vcpu_fd = ioctl(vm_fd, KVM_CREATE_VCPU, 0);
+	ASSERT_GE(vcpu_fd, 0);
+	rc = ioctl(vm_fd, KVM_ENABLE_CAP, cap);
+	EXPECT_EQ(-1, rc);
+	EXPECT_EQ(EBUSY, errno);
+
+	close(vcpu_fd);
+	close(vm_fd);
+	close(kvm_fd);
+}
+
+/* verify SIEIC exit
+ * * fail on codes not expected in the test cases
+ */
+static bool uc_handle_sieic(FIXTURE_DATA(uc_kvm) * self)
+{
+	struct kvm_s390_sie_block *sie_block = self->sie_block;
+	struct kvm_run *run = self->run;
+
+	/* check SIE interception code */
+	pr_info("sieic: 0x%.2x 0x%.4x 0x%.4x\n",
+		run->s390_sieic.icptcode,
+		run->s390_sieic.ipa,
+		run->s390_sieic.ipb);
+	switch (run->s390_sieic.icptcode) {
+	case ICPT_INST:
+		/* end execution in caller on intercepted instruction */
+		pr_info("sie instruction interception\n");
+		return false;
+	case ICPT_OPEREXC:
+		/* operation exception */
+		TEST_FAIL("sie exception on %.4x%.8x", sie_block->ipa, sie_block->ipb);
+	default:
+		TEST_FAIL("UNEXPECTED SIEIC CODE %d", run->s390_sieic.icptcode);
+	}
+	return true;
+}
+
+/* verify VM state on exit */
+static bool uc_handle_exit(FIXTURE_DATA(uc_kvm) * self)
+{
+	struct kvm_run *run = self->run;
+
+	switch (run->exit_reason) {
+	case KVM_EXIT_S390_SIEIC:
+		return uc_handle_sieic(self);
+	default:
+		pr_info("exit_reason %2d not handled\n", run->exit_reason);
+	}
+	return true;
+}
+
+/* run the VM until interrupted */
+static int uc_run_once(FIXTURE_DATA(uc_kvm) * self)
+{
+	int rc;
+
+	rc = ioctl(self->vcpu_fd, KVM_RUN, NULL);
+	print_run(self->run, self->sie_block);
+	print_regs(self->run);
+	pr_debug("run %d / %d %s\n", rc, errno, strerror(errno));
+	return rc;
+}
+
+static void uc_assert_diag44(FIXTURE_DATA(uc_kvm) * self)
+{
+	struct kvm_s390_sie_block *sie_block = self->sie_block;
+
+	/* assert vm was interrupted by diag 0x0044 */
+	TEST_ASSERT_EQ(KVM_EXIT_S390_SIEIC, self->run->exit_reason);
+	TEST_ASSERT_EQ(ICPT_INST, sie_block->icptcode);
+	TEST_ASSERT_EQ(0x8300, sie_block->ipa);
+	TEST_ASSERT_EQ(0x440000, sie_block->ipb);
+}
+
+TEST_F(uc_kvm, uc_gprs)
+{
+	struct kvm_sync_regs *sync_regs = &self->run->s.regs;
+	struct kvm_run *run = self->run;
+	struct kvm_regs regs = {};
+
+	/* Set registers to values that are different from the ones that we expect below */
+	for (int i = 0; i < 8; i++)
+		sync_regs->gprs[i] = 8;
+	run->kvm_dirty_regs |= KVM_SYNC_GPRS;
+
+	/* copy test_gprs_asm to code_hva / code_gpa */
+	TH_LOG("copy code %p to vm mapped memory %p / %p",
+	       &test_gprs_asm, (void *)self->code_hva, (void *)self->code_gpa);
+	memcpy((void *)self->code_hva, &test_gprs_asm, PAGE_SIZE);
+
+	/* DAT disabled + 64 bit mode */
+	run->psw_mask = 0x0000000180000000ULL;
+	run->psw_addr = self->code_gpa;
+
+	/* run and expect interception of diag 44 */
+	ASSERT_EQ(0, uc_run_once(self));
+	ASSERT_EQ(false, uc_handle_exit(self));
+	uc_assert_diag44(self);
+
+	/* Retrieve and check guest register values */
+	ASSERT_EQ(0, ioctl(self->vcpu_fd, KVM_GET_REGS, &regs));
+	for (int i = 0; i < 8; i++) {
+		ASSERT_EQ(i, regs.gprs[i]);
+		ASSERT_EQ(i, sync_regs->gprs[i]);
+	}
+
+	/* run and expect interception of diag 44 again */
+	ASSERT_EQ(0, uc_run_once(self));
+	ASSERT_EQ(false, uc_handle_exit(self));
+	uc_assert_diag44(self);
+
+	/* check continued increment of register 0 value */
+	ASSERT_EQ(0, ioctl(self->vcpu_fd, KVM_GET_REGS, &regs));
+	ASSERT_EQ(1, regs.gprs[0]);
+	ASSERT_EQ(1, sync_regs->gprs[0]);
+}
+
+TEST_HARNESS_MAIN