KVM: selftests: Add a self test for CMCI and UCNA emulations.

This patch add a self test that verifies user space can inject
UnCorrectable No Action required (UCNA) memory errors to the guest.
It also verifies that incorrectly configured MSRs for Corrected
Machine Check Interrupt (CMCI) emulation will result in #GP.
Signed-off-by: Jue Wang <juew@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20220610171134.772566-9-juew@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

tools/testing/selftests/kvm/.gitignore

@@ -43,6 +43,7 @@
 /x86_64/sync_regs_test
 /x86_64/tsc_msrs_test
 /x86_64/tsc_scaling_sync
+/x86_64/ucna_injection_test
 /x86_64/userspace_io_test
 /x86_64/userspace_msr_exit_test
 /x86_64/vmx_apic_access_test

tools/testing/selftests/kvm/Makefile

@@ -101,6 +101,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/svm_int_ctl_test
 TEST_GEN_PROGS_x86_64 += x86_64/svm_nested_soft_inject_test
 TEST_GEN_PROGS_x86_64 += x86_64/tsc_scaling_sync
 TEST_GEN_PROGS_x86_64 += x86_64/sync_regs_test
+TEST_GEN_PROGS_x86_64 += x86_64/ucna_injection_test
 TEST_GEN_PROGS_x86_64 += x86_64/userspace_io_test
 TEST_GEN_PROGS_x86_64 += x86_64/userspace_msr_exit_test
 TEST_GEN_PROGS_x86_64 += x86_64/vmx_apic_access_test

tools/testing/selftests/kvm/include/x86_64/apic.h

@@ -35,6 +35,7 @@
 #define		APIC_SPIV_APIC_ENABLED		(1 << 8)
 #define APIC_IRR	0x200
 #define	APIC_ICR	0x300
+#define	APIC_LVTCMCI	0x2f0
 #define		APIC_DEST_SELF		0x40000
 #define		APIC_DEST_ALLINC	0x80000
 #define		APIC_DEST_ALLBUT	0xC0000

tools/testing/selftests/kvm/include/x86_64/mce.h

+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * tools/testing/selftests/kvm/include/x86_64/mce.h
+ *
+ * Copyright (C) 2022, Google LLC.
+ */
+
+#ifndef SELFTEST_KVM_MCE_H
+#define SELFTEST_KVM_MCE_H
+
+#define MCG_CTL_P		BIT_ULL(8)   /* MCG_CTL register available */
+#define MCG_SER_P		BIT_ULL(24)  /* MCA recovery/new status bits */
+#define MCG_LMCE_P		BIT_ULL(27)  /* Local machine check supported */
+#define MCG_CMCI_P		BIT_ULL(10)  /* CMCI supported */
+#define KVM_MAX_MCE_BANKS 32
+#define MCG_CAP_BANKS_MASK 0xff       /* Bit 0-7 of the MCG_CAP register are #banks */
+#define MCI_STATUS_VAL (1ULL << 63)   /* valid error */
+#define MCI_STATUS_UC (1ULL << 61)    /* uncorrected error */
+#define MCI_STATUS_EN (1ULL << 60)    /* error enabled */
+#define MCI_STATUS_MISCV (1ULL << 59) /* misc error reg. valid */
+#define MCI_STATUS_ADDRV (1ULL << 58) /* addr reg. valid */
+#define MCM_ADDR_PHYS 2    /* physical address */
+#define MCI_CTL2_CMCI_EN		BIT_ULL(30)
+
+#endif /* SELFTEST_KVM_MCE_H */

tools/testing/selftests/kvm/x86_64/ucna_injection_test.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ucna_injection_test
+ *
+ * Copyright (C) 2022, Google LLC.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.
+ *
+ * Test that user space can inject UnCorrectable No Action required (UCNA)
+ * memory errors to the guest.
+ *
+ * The test starts one vCPU with the MCG_CMCI_P enabled. It verifies that
+ * proper UCNA errors can be injected to a vCPU with MCG_CMCI_P and
+ * corresponding per-bank control register (MCI_CTL2) bit enabled.
+ * The test also checks that the UCNA errors get recorded in the
+ * Machine Check bank registers no matter the error signal interrupts get
+ * delivered into the guest or not.
+ *
+ */
+
+#define _GNU_SOURCE /* for program_invocation_short_name */
+#include <pthread.h>
+#include <inttypes.h>
+#include <string.h>
+#include <time.h>
+
+#include "kvm_util_base.h"
+#include "kvm_util.h"
+#include "mce.h"
+#include "processor.h"
+#include "test_util.h"
+#include "apic.h"
+
+#define SYNC_FIRST_UCNA 9
+#define SYNC_SECOND_UCNA 10
+#define SYNC_GP 11
+#define FIRST_UCNA_ADDR 0xdeadbeef
+#define SECOND_UCNA_ADDR 0xcafeb0ba
+
+/*
+ * Vector for the CMCI interrupt.
+ * Value is arbitrary. Any value in 0x20-0xFF should work:
+ * https://wiki.osdev.org/Interrupt_Vector_Table
+ */
+#define CMCI_VECTOR  0xa9
+
+#define UCNA_BANK  0x7	// IMC0 bank
+
+#define MCI_CTL2_RESERVED_BIT BIT_ULL(29)
+
+static uint64_t supported_mcg_caps;
+
+/*
+ * Record states about the injected UCNA.
+ * The variables started with the 'i_' prefixes are recorded in interrupt
+ * handler. Variables without the 'i_' prefixes are recorded in guest main
+ * execution thread.
+ */
+static volatile uint64_t i_ucna_rcvd;
+static volatile uint64_t i_ucna_addr;
+static volatile uint64_t ucna_addr;
+static volatile uint64_t ucna_addr2;
+
+struct thread_params {
+	struct kvm_vcpu *vcpu;
+	uint64_t *p_i_ucna_rcvd;
+	uint64_t *p_i_ucna_addr;
+	uint64_t *p_ucna_addr;
+	uint64_t *p_ucna_addr2;
+};
+
+static void verify_apic_base_addr(void)
+{
+	uint64_t msr = rdmsr(MSR_IA32_APICBASE);
+	uint64_t base = GET_APIC_BASE(msr);
+
+	GUEST_ASSERT(base == APIC_DEFAULT_GPA);
+}
+
+static void ucna_injection_guest_code(void)
+{
+	uint64_t ctl2;
+	verify_apic_base_addr();
+	xapic_enable();
+
+	/* Sets up the interrupt vector and enables per-bank CMCI sigaling. */
+	xapic_write_reg(APIC_LVTCMCI, CMCI_VECTOR | APIC_DM_FIXED);
+	ctl2 = rdmsr(MSR_IA32_MCx_CTL2(UCNA_BANK));
+	wrmsr(MSR_IA32_MCx_CTL2(UCNA_BANK), ctl2 | MCI_CTL2_CMCI_EN);
+
+	/* Enables interrupt in guest. */
+	asm volatile("sti");
+
+	/* Let user space inject the first UCNA */
+	GUEST_SYNC(SYNC_FIRST_UCNA);
+
+	ucna_addr = rdmsr(MSR_IA32_MCx_ADDR(UCNA_BANK));
+
+	/* Disables the per-bank CMCI signaling. */
+	ctl2 = rdmsr(MSR_IA32_MCx_CTL2(UCNA_BANK));
+	wrmsr(MSR_IA32_MCx_CTL2(UCNA_BANK), ctl2 & ~MCI_CTL2_CMCI_EN);
+
+	/* Let the user space inject the second UCNA */
+	GUEST_SYNC(SYNC_SECOND_UCNA);
+
+	ucna_addr2 = rdmsr(MSR_IA32_MCx_ADDR(UCNA_BANK));
+	GUEST_DONE();
+}
+
+static void cmci_disabled_guest_code(void)
+{
+	uint64_t ctl2 = rdmsr(MSR_IA32_MCx_CTL2(UCNA_BANK));
+	wrmsr(MSR_IA32_MCx_CTL2(UCNA_BANK), ctl2 | MCI_CTL2_CMCI_EN);
+
+	GUEST_DONE();
+}
+
+static void cmci_enabled_guest_code(void)
+{
+	uint64_t ctl2 = rdmsr(MSR_IA32_MCx_CTL2(UCNA_BANK));
+	wrmsr(MSR_IA32_MCx_CTL2(UCNA_BANK), ctl2 | MCI_CTL2_RESERVED_BIT);
+
+	GUEST_DONE();
+}
+
+static void guest_cmci_handler(struct ex_regs *regs)
+{
+	i_ucna_rcvd++;
+	i_ucna_addr = rdmsr(MSR_IA32_MCx_ADDR(UCNA_BANK));
+	xapic_write_reg(APIC_EOI, 0);
+}
+
+static void guest_gp_handler(struct ex_regs *regs)
+{
+	GUEST_SYNC(SYNC_GP);
+}
+
+static void run_vcpu_expect_gp(struct kvm_vcpu *vcpu)
+{
+	unsigned int exit_reason;
+	struct ucall uc;
+
+	vcpu_run(vcpu);
+
+	exit_reason = vcpu->run->exit_reason;
+	TEST_ASSERT(exit_reason == KVM_EXIT_IO,
+		    "exited with unexpected exit reason %u-%s, expected KVM_EXIT_IO",
+		    exit_reason, exit_reason_str(exit_reason));
+	TEST_ASSERT(get_ucall(vcpu, &uc) == UCALL_SYNC,
+		    "Expect UCALL_SYNC\n");
+	TEST_ASSERT(uc.args[1] == SYNC_GP, "#GP is expected.");
+	printf("vCPU received GP in guest.\n");
+}
+
+static void inject_ucna(struct kvm_vcpu *vcpu, uint64_t addr) {
+	/*
+	 * A UCNA error is indicated with VAL=1, UC=1, PCC=0, S=0 and AR=0 in
+	 * the IA32_MCi_STATUS register.
+	 * MSCOD=1 (BIT[16] - MscodDataRdErr).
+	 * MCACOD=0x0090 (Memory controller error format, channel 0)
+	 */
+	uint64_t status = MCI_STATUS_VAL | MCI_STATUS_UC | MCI_STATUS_EN |
+			  MCI_STATUS_MISCV | MCI_STATUS_ADDRV | 0x10090;
+	struct kvm_x86_mce mce = {};
+	mce.status = status;
+	mce.mcg_status = 0;
+	/*
+	 * MCM_ADDR_PHYS indicates the reported address is a physical address.
+	 * Lowest 6 bits is the recoverable address LSB, i.e., the injected MCE
+	 * is at 4KB granularity.
+	 */
+	mce.misc = (MCM_ADDR_PHYS << 6) | 0xc;
+	mce.addr = addr;
+	mce.bank = UCNA_BANK;
+
+	vcpu_ioctl(vcpu, KVM_X86_SET_MCE, &mce);
+}
+
+static void *run_ucna_injection(void *arg)
+{
+	struct thread_params *params = (struct thread_params *)arg;
+	struct ucall uc;
+	int old;
+	int r;
+	unsigned int exit_reason;
+
+	r = pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, &old);
+	TEST_ASSERT(r == 0,
+		    "pthread_setcanceltype failed with errno=%d",
+		    r);
+
+	vcpu_run(params->vcpu);
+
+	exit_reason = params->vcpu->run->exit_reason;
+	TEST_ASSERT(exit_reason == KVM_EXIT_IO,
+		    "unexpected exit reason %u-%s, expected KVM_EXIT_IO",
+		    exit_reason, exit_reason_str(exit_reason));
+	TEST_ASSERT(get_ucall(params->vcpu, &uc) == UCALL_SYNC,
+		    "Expect UCALL_SYNC\n");
+	TEST_ASSERT(uc.args[1] == SYNC_FIRST_UCNA, "Injecting first UCNA.");
+
+	printf("Injecting first UCNA at %#x.\n", FIRST_UCNA_ADDR);
+
+	inject_ucna(params->vcpu, FIRST_UCNA_ADDR);
+	vcpu_run(params->vcpu);
+
+	exit_reason = params->vcpu->run->exit_reason;
+	TEST_ASSERT(exit_reason == KVM_EXIT_IO,
+		    "unexpected exit reason %u-%s, expected KVM_EXIT_IO",
+		    exit_reason, exit_reason_str(exit_reason));
+	TEST_ASSERT(get_ucall(params->vcpu, &uc) == UCALL_SYNC,
+		    "Expect UCALL_SYNC\n");
+	TEST_ASSERT(uc.args[1] == SYNC_SECOND_UCNA, "Injecting second UCNA.");
+
+	printf("Injecting second UCNA at %#x.\n", SECOND_UCNA_ADDR);
+
+	inject_ucna(params->vcpu, SECOND_UCNA_ADDR);
+	vcpu_run(params->vcpu);
+
+	exit_reason = params->vcpu->run->exit_reason;
+	TEST_ASSERT(exit_reason == KVM_EXIT_IO,
+		    "unexpected exit reason %u-%s, expected KVM_EXIT_IO",
+		    exit_reason, exit_reason_str(exit_reason));
+	if (get_ucall(params->vcpu, &uc) == UCALL_ABORT) {
+		TEST_ASSERT(false, "vCPU assertion failure: %s.\n",
+			    (const char *)uc.args[0]);
+	}
+
+	return NULL;
+}
+
+static void test_ucna_injection(struct kvm_vcpu *vcpu, struct thread_params *params)
+{
+	struct kvm_vm *vm = vcpu->vm;
+	params->vcpu = vcpu;
+	params->p_i_ucna_rcvd = (uint64_t *)addr_gva2hva(vm, (uint64_t)&i_ucna_rcvd);
+	params->p_i_ucna_addr = (uint64_t *)addr_gva2hva(vm, (uint64_t)&i_ucna_addr);
+	params->p_ucna_addr = (uint64_t *)addr_gva2hva(vm, (uint64_t)&ucna_addr);
+	params->p_ucna_addr2 = (uint64_t *)addr_gva2hva(vm, (uint64_t)&ucna_addr2);
+
+	run_ucna_injection(params);
+
+	TEST_ASSERT(*params->p_i_ucna_rcvd == 1, "Only first UCNA get signaled.");
+	TEST_ASSERT(*params->p_i_ucna_addr == FIRST_UCNA_ADDR,
+		    "Only first UCNA reported addr get recorded via interrupt.");
+	TEST_ASSERT(*params->p_ucna_addr == FIRST_UCNA_ADDR,
+		    "First injected UCNAs should get exposed via registers.");
+	TEST_ASSERT(*params->p_ucna_addr2 == SECOND_UCNA_ADDR,
+		    "Second injected UCNAs should get exposed via registers.");
+
+	printf("Test successful.\n"
+	       "UCNA CMCI interrupts received: %ld\n"
+	       "Last UCNA address received via CMCI: %lx\n"
+	       "First UCNA address in vCPU thread: %lx\n"
+	       "Second UCNA address in vCPU thread: %lx\n",
+	       *params->p_i_ucna_rcvd, *params->p_i_ucna_addr,
+	       *params->p_ucna_addr, *params->p_ucna_addr2);
+}
+
+static void setup_mce_cap(struct kvm_vcpu *vcpu, bool enable_cmci_p)
+{
+	uint64_t mcg_caps = MCG_CTL_P | MCG_SER_P | MCG_LMCE_P | KVM_MAX_MCE_BANKS;
+	if (enable_cmci_p)
+		mcg_caps |= MCG_CMCI_P;
+
+	mcg_caps &= supported_mcg_caps | MCG_CAP_BANKS_MASK;
+	vcpu_ioctl(vcpu, KVM_X86_SETUP_MCE, &mcg_caps);
+}
+
+static struct kvm_vcpu *create_vcpu_with_mce_cap(struct kvm_vm *vm, uint32_t vcpuid,
+						 bool enable_cmci_p, void *guest_code)
+{
+	struct kvm_vcpu *vcpu = vm_vcpu_add(vm, vcpuid, guest_code);
+	setup_mce_cap(vcpu, enable_cmci_p);
+	return vcpu;
+}
+
+int main(int argc, char *argv[])
+{
+	struct thread_params params;
+	struct kvm_vm *vm;
+	struct kvm_vcpu *ucna_vcpu;
+	struct kvm_vcpu *cmcidis_vcpu;
+	struct kvm_vcpu *cmci_vcpu;
+
+	kvm_check_cap(KVM_CAP_MCE);
+
+	vm = __vm_create(VM_MODE_DEFAULT, 3, 0);
+
+	kvm_ioctl(vm->kvm_fd, KVM_X86_GET_MCE_CAP_SUPPORTED,
+		  &supported_mcg_caps);
+
+	if (!(supported_mcg_caps & MCG_CMCI_P)) {
+		print_skip("MCG_CMCI_P is not supported");
+		exit(KSFT_SKIP);
+	}
+
+	ucna_vcpu = create_vcpu_with_mce_cap(vm, 0, true, ucna_injection_guest_code);
+	cmcidis_vcpu = create_vcpu_with_mce_cap(vm, 1, false, cmci_disabled_guest_code);
+	cmci_vcpu = create_vcpu_with_mce_cap(vm, 2, true, cmci_enabled_guest_code);
+
+	vm_init_descriptor_tables(vm);
+	vcpu_init_descriptor_tables(ucna_vcpu);
+	vcpu_init_descriptor_tables(cmcidis_vcpu);
+	vcpu_init_descriptor_tables(cmci_vcpu);
+	vm_install_exception_handler(vm, CMCI_VECTOR, guest_cmci_handler);
+	vm_install_exception_handler(vm, GP_VECTOR, guest_gp_handler);
+
+	virt_pg_map(vm, APIC_DEFAULT_GPA, APIC_DEFAULT_GPA);
+
+	test_ucna_injection(ucna_vcpu, &params);
+	run_vcpu_expect_gp(cmcidis_vcpu);
+	run_vcpu_expect_gp(cmci_vcpu);
+
+	kvm_vm_free(vm);
+}