linux-kernel - [RFC PATCH v2 5/6] KVM: selftests: Add test cases for KVM_GUEST_MEMORY

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Date:   Thu, 21 Sep 2023 13:14:38 -0700
From:   isaku.yamahata@...el.com
To:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     isaku.yamahata@...el.com, isaku.yamahata@...il.com,
        Michael Roth <michael.roth@....com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>, erdemaktas@...gle.com,
        Sagi Shahar <sagis@...gle.com>,
        David Matlack <dmatlack@...gle.com>,
        Kai Huang <kai.huang@...el.com>,
        Zhi Wang <zhi.wang.linux@...il.com>, chen.bo@...el.com,
        linux-coco@...ts.linux.dev,
        Chao Peng <chao.p.peng@...ux.intel.com>,
        Ackerley Tng <ackerleytng@...gle.com>,
        Vishal Annapurve <vannapurve@...gle.com>,
        Yuan Yao <yuan.yao@...ux.intel.com>,
        Jarkko Sakkinen <jarkko@...nel.org>,
        Xu Yilun <yilun.xu@...el.com>,
        Quentin Perret <qperret@...gle.com>, wei.w.wang@...el.com,
        Fuad Tabba <tabba@...gle.com>
Subject: [RFC PATCH v2 5/6] KVM: selftests: Add test cases for KVM_GUEST_MEMORY_FAILURE

From: Isaku Yamahata <isaku.yamahata@...el.com>

Add text cases for guest_memfd KVM_GUEST_MEMORY_FAILURE ioctl.
+ ioctl(KVM_GUEST_MEMORY_FAILURE) success with backing pages
+ ioctl(KVM_GUEST_MEMORY_FAILURE) fails with ENOENT without backing page
+ interaction with fallocate(PUNCH_HOLE)

Signed-off-by: Isaku Yamahata <isaku.yamahata@...el.com>
---
 .../testing/selftests/kvm/guest_memfd_test.c  | 48 +++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git a/tools/testing/selftests/kvm/guest_memfd_test.c b/tools/testing/selftests/kvm/guest_memfd_test.c
index d5b4bfcdc3fe..f8b242c9319d 100644
--- a/tools/testing/selftests/kvm/guest_memfd_test.c
+++ b/tools/testing/selftests/kvm/guest_memfd_test.c
@@ -122,6 +122,53 @@ static void test_fallocate_fail(int fd, size_t page_size, size_t total_size)
 	}
 }
 
+static void test_memory_failure(int fd, size_t page_size, size_t total_size)
+{
+	struct kvm_guest_memory_failure mf;
+	int ret;
+	int i;
+
+	/* Make whole file unallocated as known initial state */
+	ret = fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE,
+			0, total_size);
+	TEST_ASSERT(!ret, "fallocate(PUNCH_HOLE) at while file should succeed");
+
+	/* Because there is no backing page, fail to inject memory failure. */
+	for (i = 0; i < total_size / page_size; i++) {
+		mf = (struct kvm_guest_memory_failure) {
+			.offset = i * page_size,
+		};
+
+		ret = ioctl(fd, KVM_GUEST_MEMORY_FAILURE, &mf);
+		if (ret == -1 && errno == EPERM) {
+			pr_info("KVM_GUEST_MEMORY_FAILURE requires CAP_SYS_ADMIN. Skipping.\n")
+			return;
+		}
+		TEST_ASSERT(ret == -1 && errno == ENOENT,
+			    "ioctl(KVM_GUEST_MEMORY_FAILURE) should fail i %d", i);
+	}
+
+	/* Allocate pages with index one and two. */
+	ret = fallocate(fd, FALLOC_FL_KEEP_SIZE, page_size, page_size * 2);
+	TEST_ASSERT(!ret, "fallocate beginning at page_size should succeed");
+
+	for (i = 0; i < total_size / page_size; i++) {
+		mf = (struct kvm_guest_memory_failure) {
+			.offset = i * page_size,
+		};
+
+		ret = ioctl(fd, KVM_GUEST_MEMORY_FAILURE, &mf);
+
+		if (i == 1 || i == 2) {
+			TEST_ASSERT(!ret || (ret == -1 && errno == EBUSY),
+				    "ioctl(KVM_GUEST_MEMORY_FAILURE) should succeed i %d", i);
+		} else {
+			TEST_ASSERT(ret == -1 && errno == ENOENT,
+				    "ioctl(KVM_GUEST_MEMORY_FAILURE) should fail i %d", i);
+		}
+	}
+}
+
 static void test_create_guest_memfd_invalid(struct kvm_vm *vm)
 {
 	uint64_t valid_flags = 0;
@@ -192,6 +239,7 @@ int main(int argc, char *argv[])
 	test_file_size(fd, page_size, total_size);
 	test_fallocate(fd, page_size, total_size);
 	test_fallocate_fail(fd, page_size, total_size);
+	test_memory_failure(fd, page_size, total_size);
 
 	close(fd);
 }
-- 
2.25.1