Introduce a set of APIs to execute VM with private memslots.
Host userspace APIs for: 1) Executing a vcpu run loop that handles MAPGPA hypercall 2) Backing/unbacking guest private memory
Guest APIs for: 1) Changing memory mapping type
Signed-off-by: Vishal Annapurve vannapurve@google.com --- tools/testing/selftests/kvm/Makefile | 1 + .../kvm/include/x86_64/private_mem.h | 24 +++ .../selftests/kvm/lib/x86_64/private_mem.c | 139 ++++++++++++++++++ 3 files changed, 164 insertions(+) create mode 100644 tools/testing/selftests/kvm/include/x86_64/private_mem.h create mode 100644 tools/testing/selftests/kvm/lib/x86_64/private_mem.c
diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile index 2275ba861e0e..97f7d52c553b 100644 --- a/tools/testing/selftests/kvm/Makefile +++ b/tools/testing/selftests/kvm/Makefile @@ -55,6 +55,7 @@ LIBKVM_x86_64 += lib/x86_64/apic.c LIBKVM_x86_64 += lib/x86_64/handlers.S LIBKVM_x86_64 += lib/x86_64/hyperv.c LIBKVM_x86_64 += lib/x86_64/memstress.c +LIBKVM_x86_64 += lib/x86_64/private_mem.c LIBKVM_x86_64 += lib/x86_64/processor.c LIBKVM_x86_64 += lib/x86_64/svm.c LIBKVM_x86_64 += lib/x86_64/ucall.c diff --git a/tools/testing/selftests/kvm/include/x86_64/private_mem.h b/tools/testing/selftests/kvm/include/x86_64/private_mem.h new file mode 100644 index 000000000000..3aa6b4d11b28 --- /dev/null +++ b/tools/testing/selftests/kvm/include/x86_64/private_mem.h @@ -0,0 +1,24 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2022, Google LLC. + */ + +#ifndef SELFTEST_KVM_PRIVATE_MEM_H +#define SELFTEST_KVM_PRIVATE_MEM_H + +#include <stdint.h> +#include <kvm_util.h> + +void kvm_hypercall_map_shared(uint64_t gpa, uint64_t size); +void kvm_hypercall_map_private(uint64_t gpa, uint64_t size); + +void vm_unback_private_mem(struct kvm_vm *vm, uint64_t gpa, uint64_t size); + +void vm_allocate_private_mem(struct kvm_vm *vm, uint64_t gpa, uint64_t size); + +void handle_vm_exit_map_gpa_hypercall(struct kvm_vm *vm, uint64_t gpa, + uint64_t npages, uint64_t attrs); + +void vcpu_run_and_handle_mapgpa(struct kvm_vm *vm, struct kvm_vcpu *vcpu); + +#endif /* SELFTEST_KVM_PRIVATE_MEM_H */ diff --git a/tools/testing/selftests/kvm/lib/x86_64/private_mem.c b/tools/testing/selftests/kvm/lib/x86_64/private_mem.c new file mode 100644 index 000000000000..2b97fc34ec4a --- /dev/null +++ b/tools/testing/selftests/kvm/lib/x86_64/private_mem.c @@ -0,0 +1,139 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2022, Google LLC. + */ +#define _GNU_SOURCE /* for program_invocation_name */ +#include <fcntl.h> +#include <limits.h> +#include <sched.h> +#include <signal.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/ioctl.h> + +#include <linux/compiler.h> +#include <linux/kernel.h> +#include <linux/kvm_para.h> + +#include <test_util.h> +#include <kvm_util.h> +#include <private_mem.h> +#include <processor.h> + +static inline uint64_t __kvm_hypercall_map_gpa_range(uint64_t gpa, uint64_t size, + uint64_t flags) +{ + return kvm_hypercall(KVM_HC_MAP_GPA_RANGE, gpa, size >> PAGE_SHIFT, flags, 0); +} + +static inline void kvm_hypercall_map_gpa_range(uint64_t gpa, uint64_t size, + uint64_t flags) +{ + uint64_t ret; + + GUEST_ASSERT_2(IS_PAGE_ALIGNED(gpa) && IS_PAGE_ALIGNED(size), gpa, size); + + ret = __kvm_hypercall_map_gpa_range(gpa, size, flags); + GUEST_ASSERT_1(!ret, ret); +} + +void kvm_hypercall_map_shared(uint64_t gpa, uint64_t size) +{ + kvm_hypercall_map_gpa_range(gpa, size, KVM_MAP_GPA_RANGE_DECRYPTED); +} + +void kvm_hypercall_map_private(uint64_t gpa, uint64_t size) +{ + kvm_hypercall_map_gpa_range(gpa, size, KVM_MAP_GPA_RANGE_ENCRYPTED); +} + +static void vm_update_private_mem(struct kvm_vm *vm, uint64_t gpa, uint64_t size, + bool unback_mem) +{ + int restricted_fd; + uint64_t restricted_fd_offset, guest_phys_base, fd_offset; + struct kvm_memory_attributes attr; + struct kvm_userspace_memory_region_ext *region_ext; + struct kvm_userspace_memory_region *region; + int fallocate_mode = 0; + int ret; + + region_ext = kvm_userspace_memory_region_ext_find(vm, gpa, gpa + size); + TEST_ASSERT(region_ext != NULL, "Region not found"); + region = ®ion_ext->region; + TEST_ASSERT(region->flags & KVM_MEM_PRIVATE, + "Can not update private memfd for non-private memslot\n"); + restricted_fd = region_ext->restricted_fd; + restricted_fd_offset = region_ext->restricted_offset; + guest_phys_base = region->guest_phys_addr; + fd_offset = restricted_fd_offset + (gpa - guest_phys_base); + + if (unback_mem) + fallocate_mode = (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE); + + printf("restricted_fd %d fallocate_mode 0x%x for offset 0x%lx size 0x%lx\n", + restricted_fd, fallocate_mode, fd_offset, size); + ret = fallocate(restricted_fd, fallocate_mode, fd_offset, size); + TEST_ASSERT(ret == 0, "fallocate failed\n"); + attr.attributes = unback_mem ? 0 : KVM_MEMORY_ATTRIBUTE_PRIVATE; + attr.address = gpa; + attr.size = size; + attr.flags = 0; + if (unback_mem) + printf("undoing encryption for gpa 0x%lx size 0x%lx\n", gpa, size); + else + printf("doing encryption for gpa 0x%lx size 0x%lx\n", gpa, size); + + vm_ioctl(vm, KVM_SET_MEMORY_ATTRIBUTES, &attr); +} + +void vm_unback_private_mem(struct kvm_vm *vm, uint64_t gpa, uint64_t size) +{ + vm_update_private_mem(vm, gpa, size, true); +} + +void vm_allocate_private_mem(struct kvm_vm *vm, uint64_t gpa, uint64_t size) +{ + vm_update_private_mem(vm, gpa, size, false); +} + +void handle_vm_exit_map_gpa_hypercall(struct kvm_vm *vm, uint64_t gpa, + uint64_t npages, uint64_t attrs) +{ + uint64_t size; + + size = npages << MIN_PAGE_SHIFT; + pr_info("Explicit conversion off 0x%lx size 0x%lx to %s\n", gpa, size, + (attrs & KVM_MAP_GPA_RANGE_ENCRYPTED) ? "private" : "shared"); + + if (attrs & KVM_MAP_GPA_RANGE_ENCRYPTED) + vm_allocate_private_mem(vm, gpa, size); + else + vm_unback_private_mem(vm, gpa, size); +} + +void vcpu_run_and_handle_mapgpa(struct kvm_vm *vm, struct kvm_vcpu *vcpu) +{ + /* + * Loop until the guest exits with any reason other than + * KVM_HC_MAP_GPA_RANGE hypercall. + */ + + while (true) { + vcpu_run(vcpu); + + if ((vcpu->run->exit_reason == KVM_EXIT_HYPERCALL) && + (vcpu->run->hypercall.nr == KVM_HC_MAP_GPA_RANGE)) { + uint64_t gpa = vcpu->run->hypercall.args[0]; + uint64_t npages = vcpu->run->hypercall.args[1]; + uint64_t attrs = vcpu->run->hypercall.args[2]; + + handle_vm_exit_map_gpa_hypercall(vm, gpa, npages, attrs); + vcpu->run->hypercall.ret = 0; + continue; + } + + return; + } +}