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Message-ID: <20231105163040.14904-34-pbonzini@redhat.com>
Date:   Sun,  5 Nov 2023 17:30:36 +0100
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Paolo Bonzini <pbonzini@...hat.com>, Marc Zyngier <maz@...nel.org>,
        Oliver Upton <oliver.upton@...ux.dev>,
        Huacai Chen <chenhuacai@...nel.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        Anup Patel <anup@...infault.org>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        Sean Christopherson <seanjc@...gle.com>,
        Alexander Viro <viro@...iv.linux.org.uk>,
        Christian Brauner <brauner@...nel.org>,
        "Matthew Wilcox (Oracle)" <willy@...radead.org>,
        Andrew Morton <akpm@...ux-foundation.org>
Cc:     kvm@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        kvmarm@...ts.linux.dev, linux-mips@...r.kernel.org,
        linuxppc-dev@...ts.ozlabs.org, kvm-riscv@...ts.infradead.org,
        linux-riscv@...ts.infradead.org, linux-fsdevel@...r.kernel.org,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        Xiaoyao Li <xiaoyao.li@...el.com>,
        Xu Yilun <yilun.xu@...el.com>,
        Chao Peng <chao.p.peng@...ux.intel.com>,
        Fuad Tabba <tabba@...gle.com>,
        Jarkko Sakkinen <jarkko@...nel.org>,
        Anish Moorthy <amoorthy@...gle.com>,
        David Matlack <dmatlack@...gle.com>,
        Yu Zhang <yu.c.zhang@...ux.intel.com>,
        Isaku Yamahata <isaku.yamahata@...el.com>,
        Mickaël Salaün <mic@...ikod.net>,
        Vlastimil Babka <vbabka@...e.cz>,
        Vishal Annapurve <vannapurve@...gle.com>,
        Ackerley Tng <ackerleytng@...gle.com>,
        Maciej Szmigiero <mail@...iej.szmigiero.name>,
        David Hildenbrand <david@...hat.com>,
        Quentin Perret <qperret@...gle.com>,
        Michael Roth <michael.roth@....com>,
        Wang <wei.w.wang@...el.com>,
        Liam Merwick <liam.merwick@...cle.com>,
        Isaku Yamahata <isaku.yamahata@...il.com>,
        "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Subject: [PATCH 33/34] KVM: selftests: Test KVM exit behavior for private memory/access

From: Ackerley Tng <ackerleytng@...gle.com>

"Testing private access when memslot gets deleted" tests the behavior
of KVM when a private memslot gets deleted while the VM is using the
private memslot. When KVM looks up the deleted (slot = NULL) memslot,
KVM should exit to userspace with KVM_EXIT_MEMORY_FAULT.

In the second test, upon a private access to non-private memslot, KVM
should also exit to userspace with KVM_EXIT_MEMORY_FAULT.

Intentionally don't take a requirement on KVM_CAP_GUEST_MEMFD,
KVM_CAP_MEMORY_FAULT_INFO, KVM_MEMORY_ATTRIBUTE_PRIVATE, etc., as it's a
KVM bug to advertise KVM_X86_SW_PROTECTED_VM without its prerequisites.

Signed-off-by: Ackerley Tng <ackerleytng@...gle.com>
[sean: call out the similarities with set_memory_region_test]
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
Message-Id: <20231027182217.3615211-36-seanjc@...gle.com>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
 tools/testing/selftests/kvm/Makefile          |   1 +
 .../kvm/x86_64/private_mem_kvm_exits_test.c   | 120 ++++++++++++++++++
 2 files changed, 121 insertions(+)
 create mode 100644 tools/testing/selftests/kvm/x86_64/private_mem_kvm_exits_test.c

diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index fd3b30a4ca7b..69ce8e06b3a3 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -92,6 +92,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/nested_exceptions_test
 TEST_GEN_PROGS_x86_64 += x86_64/platform_info_test
 TEST_GEN_PROGS_x86_64 += x86_64/pmu_event_filter_test
 TEST_GEN_PROGS_x86_64 += x86_64/private_mem_conversions_test
+TEST_GEN_PROGS_x86_64 += x86_64/private_mem_kvm_exits_test
 TEST_GEN_PROGS_x86_64 += x86_64/set_boot_cpu_id
 TEST_GEN_PROGS_x86_64 += x86_64/set_sregs_test
 TEST_GEN_PROGS_x86_64 += x86_64/smaller_maxphyaddr_emulation_test
diff --git a/tools/testing/selftests/kvm/x86_64/private_mem_kvm_exits_test.c b/tools/testing/selftests/kvm/x86_64/private_mem_kvm_exits_test.c
new file mode 100644
index 000000000000..2f02f6128482
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86_64/private_mem_kvm_exits_test.c
@@ -0,0 +1,120 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2022, Google LLC.
+ */
+#include <linux/kvm.h>
+#include <pthread.h>
+#include <stdint.h>
+
+#include "kvm_util.h"
+#include "processor.h"
+#include "test_util.h"
+
+/* Arbitrarily selected to avoid overlaps with anything else */
+#define EXITS_TEST_GVA 0xc0000000
+#define EXITS_TEST_GPA EXITS_TEST_GVA
+#define EXITS_TEST_NPAGES 1
+#define EXITS_TEST_SIZE (EXITS_TEST_NPAGES * PAGE_SIZE)
+#define EXITS_TEST_SLOT 10
+
+static uint64_t guest_repeatedly_read(void)
+{
+	volatile uint64_t value;
+
+	while (true)
+		value = *((uint64_t *) EXITS_TEST_GVA);
+
+	return value;
+}
+
+static uint32_t run_vcpu_get_exit_reason(struct kvm_vcpu *vcpu)
+{
+	int r;
+
+	r = _vcpu_run(vcpu);
+	if (r) {
+		TEST_ASSERT(errno == EFAULT, KVM_IOCTL_ERROR(KVM_RUN, r));
+		TEST_ASSERT_EQ(vcpu->run->exit_reason, KVM_EXIT_MEMORY_FAULT);
+	}
+	return vcpu->run->exit_reason;
+}
+
+const struct vm_shape protected_vm_shape = {
+	.mode = VM_MODE_DEFAULT,
+	.type = KVM_X86_SW_PROTECTED_VM,
+};
+
+static void test_private_access_memslot_deleted(void)
+{
+	struct kvm_vm *vm;
+	struct kvm_vcpu *vcpu;
+	pthread_t vm_thread;
+	void *thread_return;
+	uint32_t exit_reason;
+
+	vm = vm_create_shape_with_one_vcpu(protected_vm_shape, &vcpu,
+					   guest_repeatedly_read);
+
+	vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,
+				    EXITS_TEST_GPA, EXITS_TEST_SLOT,
+				    EXITS_TEST_NPAGES,
+				    KVM_MEM_GUEST_MEMFD);
+
+	virt_map(vm, EXITS_TEST_GVA, EXITS_TEST_GPA, EXITS_TEST_NPAGES);
+
+	/* Request to access page privately */
+	vm_mem_set_private(vm, EXITS_TEST_GPA, EXITS_TEST_SIZE);
+
+	pthread_create(&vm_thread, NULL,
+		       (void *(*)(void *))run_vcpu_get_exit_reason,
+		       (void *)vcpu);
+
+	vm_mem_region_delete(vm, EXITS_TEST_SLOT);
+
+	pthread_join(vm_thread, &thread_return);
+	exit_reason = (uint32_t)(uint64_t)thread_return;
+
+	TEST_ASSERT_EQ(exit_reason, KVM_EXIT_MEMORY_FAULT);
+	TEST_ASSERT_EQ(vcpu->run->memory_fault.flags, KVM_MEMORY_EXIT_FLAG_PRIVATE);
+	TEST_ASSERT_EQ(vcpu->run->memory_fault.gpa, EXITS_TEST_GPA);
+	TEST_ASSERT_EQ(vcpu->run->memory_fault.size, EXITS_TEST_SIZE);
+
+	kvm_vm_free(vm);
+}
+
+static void test_private_access_memslot_not_private(void)
+{
+	struct kvm_vm *vm;
+	struct kvm_vcpu *vcpu;
+	uint32_t exit_reason;
+
+	vm = vm_create_shape_with_one_vcpu(protected_vm_shape, &vcpu,
+					   guest_repeatedly_read);
+
+	/* Add a non-private memslot (flags = 0) */
+	vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,
+				    EXITS_TEST_GPA, EXITS_TEST_SLOT,
+				    EXITS_TEST_NPAGES, 0);
+
+	virt_map(vm, EXITS_TEST_GVA, EXITS_TEST_GPA, EXITS_TEST_NPAGES);
+
+	/* Request to access page privately */
+	vm_mem_set_private(vm, EXITS_TEST_GPA, EXITS_TEST_SIZE);
+
+	exit_reason = run_vcpu_get_exit_reason(vcpu);
+
+	TEST_ASSERT_EQ(exit_reason, KVM_EXIT_MEMORY_FAULT);
+	TEST_ASSERT_EQ(vcpu->run->memory_fault.flags, KVM_MEMORY_EXIT_FLAG_PRIVATE);
+	TEST_ASSERT_EQ(vcpu->run->memory_fault.gpa, EXITS_TEST_GPA);
+	TEST_ASSERT_EQ(vcpu->run->memory_fault.size, EXITS_TEST_SIZE);
+
+	kvm_vm_free(vm);
+}
+
+int main(int argc, char *argv[])
+{
+	TEST_REQUIRE(kvm_check_cap(KVM_CAP_VM_TYPES) & BIT(KVM_X86_SW_PROTECTED_VM));
+
+	test_private_access_memslot_deleted();
+	test_private_access_memslot_not_private();
+}
-- 
2.39.1


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