From: Sean Christopherson <seanjc@google•com>
To: Paolo Bonzini <pbonzini@redhat•com>,
Marc Zyngier <maz@kernel•org>,
Oliver Upton <oliver.upton@linux•dev>,
Sean Christopherson <seanjc@google•com>
Cc: kvm@vger•kernel.org, linux-arm-kernel@lists•infradead.org,
kvmarm@lists•linux.dev, linux-kernel@vger•kernel.org,
Ira Weiny <ira.weiny@intel•com>, Gavin Shan <gshan@redhat•com>,
Shivank Garg <shivankg@amd•com>,
Vlastimil Babka <vbabka@suse•cz>,
Xiaoyao Li <xiaoyao.li@intel•com>,
David Hildenbrand <david@redhat•com>,
Fuad Tabba <tabba@google•com>,
Ackerley Tng <ackerleytng@google•com>,
Tao Chan <chentao@kylinos•cn>,
James Houghton <jthoughton@google•com>
Subject: [PATCH v17 24/24] KVM: selftests: Add guest_memfd testcase to fault-in on !mmap()'d memory
Date: Tue, 29 Jul 2025 15:54:55 -0700 [thread overview]
Message-ID: <20250729225455.670324-25-seanjc@google.com> (raw)
In-Reply-To: <20250729225455.670324-1-seanjc@google.com>
Add a guest_memfd testcase to verify that a vCPU can fault-in guest_memfd
memory that supports mmap(), but that is not currently mapped into host
userspace and/or has a userspace address (in the memslot) that points at
something other than the target guest_memfd range. Mapping guest_memfd
memory into the guest is supposed to operate completely independently from
any userspace mappings.
Signed-off-by: Sean Christopherson <seanjc@google•com>
---
.../testing/selftests/kvm/guest_memfd_test.c | 64 +++++++++++++++++++
1 file changed, 64 insertions(+)
diff --git a/tools/testing/selftests/kvm/guest_memfd_test.c b/tools/testing/selftests/kvm/guest_memfd_test.c
index 088053d5f0f5..b86bf89a71e0 100644
--- a/tools/testing/selftests/kvm/guest_memfd_test.c
+++ b/tools/testing/selftests/kvm/guest_memfd_test.c
@@ -13,6 +13,7 @@
#include <linux/bitmap.h>
#include <linux/falloc.h>
+#include <linux/sizes.h>
#include <setjmp.h>
#include <signal.h>
#include <sys/mman.h>
@@ -21,6 +22,7 @@
#include "kvm_util.h"
#include "test_util.h"
+#include "ucall_common.h"
static void test_file_read_write(int fd)
{
@@ -298,6 +300,66 @@ static void test_guest_memfd(unsigned long vm_type)
kvm_vm_free(vm);
}
+static void guest_code(uint8_t *mem, uint64_t size)
+{
+ size_t i;
+
+ for (i = 0; i < size; i++)
+ __GUEST_ASSERT(mem[i] == 0xaa,
+ "Guest expected 0xaa at offset %lu, got 0x%x", i, mem[i]);
+
+ memset(mem, 0xff, size);
+ GUEST_DONE();
+}
+
+static void test_guest_memfd_guest(void)
+{
+ /*
+ * Skip the first 4gb and slot0. slot0 maps <1gb and is used to back
+ * the guest's code, stack, and page tables, and low memory contains
+ * the PCI hole and other MMIO regions that need to be avoided.
+ */
+ const uint64_t gpa = SZ_4G;
+ const int slot = 1;
+
+ struct kvm_vcpu *vcpu;
+ struct kvm_vm *vm;
+ uint8_t *mem;
+ size_t size;
+ int fd, i;
+
+ if (!kvm_has_cap(KVM_CAP_GUEST_MEMFD_MMAP))
+ return;
+
+ vm = __vm_create_shape_with_one_vcpu(VM_SHAPE_DEFAULT, &vcpu, 1, guest_code);
+
+ TEST_ASSERT(vm_check_cap(vm, KVM_CAP_GUEST_MEMFD_MMAP),
+ "Default VM type should always support guest_memfd mmap()");
+
+ size = vm->page_size;
+ fd = vm_create_guest_memfd(vm, size, GUEST_MEMFD_FLAG_MMAP);
+ vm_set_user_memory_region2(vm, slot, KVM_MEM_GUEST_MEMFD, gpa, size, NULL, fd, 0);
+
+ mem = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+ TEST_ASSERT(mem != MAP_FAILED, "mmap() on guest_memfd failed");
+ memset(mem, 0xaa, size);
+ munmap(mem, size);
+
+ virt_pg_map(vm, gpa, gpa);
+ vcpu_args_set(vcpu, 2, gpa, size);
+ vcpu_run(vcpu);
+
+ TEST_ASSERT_EQ(get_ucall(vcpu, NULL), UCALL_DONE);
+
+ mem = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+ TEST_ASSERT(mem != MAP_FAILED, "mmap() on guest_memfd failed");
+ for (i = 0; i < size; i++)
+ TEST_ASSERT_EQ(mem[i], 0xff);
+
+ close(fd);
+ kvm_vm_free(vm);
+}
+
int main(int argc, char *argv[])
{
unsigned long vm_types, vm_type;
@@ -314,4 +376,6 @@ int main(int argc, char *argv[])
for_each_set_bit(vm_type, &vm_types, BITS_PER_TYPE(vm_types))
test_guest_memfd(vm_type);
+
+ test_guest_memfd_guest();
}
--
2.50.1.552.g942d659e1b-goog
next prev parent reply other threads:[~2025-07-30 0:00 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-07-29 22:54 [PATCH v17 00/24] KVM: Enable mmap() for guest_memfd Sean Christopherson
2025-07-29 22:54 ` [PATCH v17 01/24] KVM: Rename CONFIG_KVM_PRIVATE_MEM to CONFIG_KVM_GUEST_MEMFD Sean Christopherson
2025-07-29 22:54 ` [PATCH v17 02/24] KVM: x86: Have all vendor neutral sub-configs depend on KVM_X86, not just KVM Sean Christopherson
2025-07-31 8:08 ` Fuad Tabba
2025-07-29 22:54 ` [PATCH v17 03/24] KVM: x86: Select KVM_GENERIC_PRIVATE_MEM directly from KVM_SW_PROTECTED_VM Sean Christopherson
2025-07-31 8:08 ` Fuad Tabba
2025-07-29 22:54 ` [PATCH v17 04/24] KVM: x86: Select TDX's KVM_GENERIC_xxx dependencies iff CONFIG_KVM_INTEL_TDX=y Sean Christopherson
2025-07-31 8:07 ` Fuad Tabba
2025-07-29 22:54 ` [PATCH v17 05/24] KVM: Rename CONFIG_KVM_GENERIC_PRIVATE_MEM to CONFIG_HAVE_KVM_ARCH_GMEM_POPULATE Sean Christopherson
2025-07-29 22:54 ` [PATCH v17 06/24] KVM: Rename kvm_slot_can_be_private() to kvm_slot_has_gmem() Sean Christopherson
2025-07-29 22:54 ` [PATCH v17 07/24] KVM: Fix comments that refer to slots_lock Sean Christopherson
2025-07-29 22:54 ` [PATCH v17 08/24] KVM: Fix comment that refers to kvm uapi header path Sean Christopherson
2025-07-29 22:54 ` [PATCH v17 09/24] KVM: x86: Enable KVM_GUEST_MEMFD for all 64-bit builds Sean Christopherson
2025-07-29 22:54 ` [PATCH v17 10/24] KVM: guest_memfd: Add plumbing to host to map guest_memfd pages Sean Christopherson
2025-07-29 22:54 ` [PATCH v17 11/24] KVM: guest_memfd: Track guest_memfd mmap support in memslot Sean Christopherson
2025-07-29 22:54 ` [PATCH v17 12/24] KVM: x86/mmu: Rename .private_max_mapping_level() to .gmem_max_mapping_level() Sean Christopherson
2025-07-31 8:15 ` Fuad Tabba
2025-07-31 8:29 ` David Hildenbrand
2025-07-31 8:33 ` Fuad Tabba
2025-07-29 22:54 ` [PATCH v17 13/24] KVM: x86/mmu: Hoist guest_memfd max level/order helpers "up" in mmu.c Sean Christopherson
2025-07-31 7:59 ` David Hildenbrand
2025-07-31 8:06 ` Fuad Tabba
2025-07-29 22:54 ` [PATCH v17 14/24] KVM: x86/mmu: Enforce guest_memfd's max order when recovering hugepages Sean Christopherson
2025-07-30 7:33 ` Xiaoyao Li
2025-07-31 8:06 ` David Hildenbrand
2025-07-31 8:10 ` Fuad Tabba
2025-07-29 22:54 ` [PATCH v17 15/24] KVM: x86/mmu: Extend guest_memfd's max mapping level to shared mappings Sean Christopherson
2025-07-30 7:36 ` Xiaoyao Li
2025-07-31 8:01 ` David Hildenbrand
2025-07-31 8:05 ` Fuad Tabba
2025-07-29 22:54 ` [PATCH v17 16/24] KVM: x86/mmu: Handle guest page faults for guest_memfd with shared memory Sean Christopherson
2025-07-30 7:37 ` Xiaoyao Li
2025-07-29 22:54 ` [PATCH v17 17/24] KVM: arm64: Refactor user_mem_abort() Sean Christopherson
2025-07-29 22:54 ` [PATCH v17 18/24] KVM: arm64: Handle guest_memfd-backed guest page faults Sean Christopherson
2025-07-29 22:54 ` [PATCH v17 19/24] KVM: arm64: nv: Handle VNCR_EL2-triggered faults backed by guest_memfd Sean Christopherson
2025-07-29 22:54 ` [PATCH v17 20/24] KVM: arm64: Enable support for guest_memfd backed memory Sean Christopherson
2025-07-29 22:54 ` [PATCH v17 21/24] KVM: Allow and advertise support for host mmap() on guest_memfd files Sean Christopherson
2025-07-29 22:54 ` [PATCH v17 22/24] KVM: selftests: Do not use hardcoded page sizes in guest_memfd test Sean Christopherson
2025-07-30 11:04 ` Xiaoyao Li
2025-07-29 22:54 ` [PATCH v17 23/24] KVM: selftests: guest_memfd mmap() test when mmap is supported Sean Christopherson
2025-07-30 11:39 ` Xiaoyao Li
2025-07-30 12:57 ` Sean Christopherson
2025-07-31 7:49 ` Xiaoyao Li
2025-08-07 8:12 ` Shivank Garg
2025-07-29 22:54 ` Sean Christopherson [this message]
2025-07-30 8:20 ` [PATCH v17 24/24] KVM: selftests: Add guest_memfd testcase to fault-in on !mmap()'d memory Xiaoyao Li
2025-07-30 15:51 ` Fuad Tabba
2026-03-30 6:21 ` Zenghui Yu
2026-04-17 16:47 ` Sean Christopherson
2026-05-12 7:28 ` Zenghui Yu
2026-05-12 15:53 ` Sean Christopherson
2025-07-30 21:34 ` [PATCH v17 00/24] KVM: Enable mmap() for guest_memfd Ackerley Tng
2025-07-30 22:44 ` Ackerley Tng
2025-08-27 8:43 ` Paolo Bonzini
2025-08-27 12:57 ` Sean Christopherson
2025-08-27 13:08 ` Marc Zyngier
2025-08-27 13:11 ` Paolo Bonzini
2025-08-27 13:14 ` Marc Zyngier
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