Messages in this thread |  | | Subject | Re: [RFC 02/16] KVM: selftests: add hooks for managing encrypted guest memory | From | Krish Sadhukhan <> | Date | Tue, 12 Oct 2021 19:20:41 -0700 |
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On 10/5/21 4:44 PM, Michael Roth wrote: > VM implementations that make use of encrypted memory need a way to > configure things like the encryption/shared bit position for page > table handling, the default encryption policy for internal allocations > made by the core library, and a way to fetch the list/bitmap of > encrypted pages to do the actual memory encryption. Add an interface to > configure these parameters. Also introduce a sparsebit map to track > allocations/mappings that should be treated as encrypted, and provide > a way for VM implementations to retrieve it to handle operations > related memory encryption. > > Signed-off-by: Michael Roth <michael.roth@amd.com> > --- > .../testing/selftests/kvm/include/kvm_util.h | 6 ++ > tools/testing/selftests/kvm/lib/kvm_util.c | 63 +++++++++++++++++-- > .../selftests/kvm/lib/kvm_util_internal.h | 10 +++ > 3 files changed, 75 insertions(+), 4 deletions(-) > > diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h > index 010b59b13917..f417de80596c 100644 > --- a/tools/testing/selftests/kvm/include/kvm_util.h > +++ b/tools/testing/selftests/kvm/include/kvm_util.h > @@ -348,6 +348,12 @@ int vm_create_device(struct kvm_vm *vm, struct kvm_create_device *cd); > > void assert_on_unhandled_exception(struct kvm_vm *vm, uint32_t vcpuid); > > +void vm_set_memory_encryption(struct kvm_vm *vm, bool enc_by_default, bool has_enc_bit, > + uint8_t enc_bit); > +struct sparsebit *vm_get_encrypted_phy_pages(struct kvm_vm *vm, int slot, > + vm_paddr_t *gpa_start, > + uint64_t *size); > + > /* Common ucalls */ > enum { > UCALL_NONE, > diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c > index 92f59adddebe..c58f930dedd2 100644 > --- a/tools/testing/selftests/kvm/lib/kvm_util.c > +++ b/tools/testing/selftests/kvm/lib/kvm_util.c > @@ -631,6 +631,7 @@ static void __vm_mem_region_delete(struct kvm_vm *vm, > "rc: %i errno: %i", ret, errno); > > sparsebit_free(®ion->unused_phy_pages); > + sparsebit_free(®ion->encrypted_phy_pages); > ret = munmap(region->mmap_start, region->mmap_size); > TEST_ASSERT(ret == 0, "munmap failed, rc: %i errno: %i", ret, errno); > > @@ -924,6 +925,7 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm, > } > > region->unused_phy_pages = sparsebit_alloc(); > + region->encrypted_phy_pages = sparsebit_alloc(); > sparsebit_set_num(region->unused_phy_pages, > guest_paddr >> vm->page_shift, npages); > region->region.slot = slot; > @@ -1153,6 +1155,7 @@ void vm_vcpu_add(struct kvm_vm *vm, uint32_t vcpuid) > * num - number of pages > * paddr_min - Physical address minimum > * memslot - Memory region to allocate page from > + * encrypt - Whether to treat the pages as encrypted > * > * Output Args: None > * > @@ -1164,11 +1167,13 @@ void vm_vcpu_add(struct kvm_vm *vm, uint32_t vcpuid) > * and their base address is returned. A TEST_ASSERT failure occurs if > * not enough pages are available at or above paddr_min. > */ > -vm_paddr_t vm_phy_pages_alloc(struct kvm_vm *vm, size_t num, > - vm_paddr_t paddr_min, uint32_t memslot) > +static vm_paddr_t > +_vm_phy_pages_alloc(struct kvm_vm *vm, size_t num, vm_paddr_t paddr_min, > + uint32_t memslot, bool encrypt) > { > struct userspace_mem_region *region; > sparsebit_idx_t pg, base; > + vm_paddr_t gpa; > > TEST_ASSERT(num > 0, "Must allocate at least one page"); > > @@ -1198,10 +1203,25 @@ vm_paddr_t vm_phy_pages_alloc(struct kvm_vm *vm, size_t num, > abort(); > } > > - for (pg = base; pg < base + num; ++pg) > + for (pg = base; pg < base + num; ++pg) { > sparsebit_clear(region->unused_phy_pages, pg); > + if (encrypt) > + sparsebit_set(region->encrypted_phy_pages, pg); > + } > + > + gpa = base * vm->page_size; > > - return base * vm->page_size; > + if (encrypt && vm->memcrypt.has_enc_bit) > + gpa |= (1ULL << vm->memcrypt.enc_bit); > + > + return gpa; > +} > + > +vm_paddr_t vm_phy_pages_alloc(struct kvm_vm *vm, size_t num, > + vm_paddr_t paddr_min, uint32_t memslot) > +{ > + return _vm_phy_pages_alloc(vm, 1, paddr_min, memslot, > + vm->memcrypt.enc_by_default); > } > > vm_paddr_t vm_phy_page_alloc(struct kvm_vm *vm, vm_paddr_t paddr_min, > @@ -2146,6 +2166,10 @@ void vm_dump(FILE *stream, struct kvm_vm *vm, uint8_t indent) > region->host_mem); > fprintf(stream, "%*sunused_phy_pages: ", indent + 2, ""); > sparsebit_dump(stream, region->unused_phy_pages, 0); > + if (vm->memcrypt.enabled) { > + fprintf(stream, "%*sencrypted_phy_pages: ", indent + 2, ""); > + sparsebit_dump(stream, region->encrypted_phy_pages, 0); > + } > } > fprintf(stream, "%*sMapped Virtual Pages:\n", indent, ""); > sparsebit_dump(stream, vm->vpages_mapped, indent + 2); > @@ -2343,3 +2367,34 @@ int vcpu_get_stats_fd(struct kvm_vm *vm, uint32_t vcpuid) > > return ioctl(vcpu->fd, KVM_GET_STATS_FD, NULL); > } > + > +void vm_set_memory_encryption(struct kvm_vm *vm, bool enc_by_default, bool has_enc_bit, > + uint8_t enc_bit) > +{ > + vm->memcrypt.enabled = true; > + vm->memcrypt.enc_by_default = enc_by_default; > + vm->memcrypt.has_enc_bit = has_enc_bit; > + vm->memcrypt.enc_bit = enc_bit; > +} > + > +struct sparsebit * > +vm_get_encrypted_phy_pages(struct kvm_vm *vm, int slot, vm_paddr_t *gpa_start, > + uint64_t *size) > +{ > + struct userspace_mem_region *region; > + struct sparsebit *encrypted_phy_pages; > + > + if (!vm->memcrypt.enabled) > + return NULL; > + > + region = memslot2region(vm, slot); > + if (!region) > + return NULL; > + > + encrypted_phy_pages = sparsebit_alloc(); > + sparsebit_copy(encrypted_phy_pages, region->encrypted_phy_pages); > + *size = region->region.memory_size; > + *gpa_start = region->region.guest_phys_addr; > + > + return encrypted_phy_pages; > +} > diff --git a/tools/testing/selftests/kvm/lib/kvm_util_internal.h b/tools/testing/selftests/kvm/lib/kvm_util_internal.h > index a03febc24ba6..99ccab86115c 100644 > --- a/tools/testing/selftests/kvm/lib/kvm_util_internal.h > +++ b/tools/testing/selftests/kvm/lib/kvm_util_internal.h > @@ -16,6 +16,7 @@ > struct userspace_mem_region { > struct kvm_userspace_memory_region region; > struct sparsebit *unused_phy_pages; > + struct sparsebit *encrypted_phy_pages; > int fd; > off_t offset; > void *host_mem; > @@ -44,6 +45,14 @@ struct userspace_mem_regions { > DECLARE_HASHTABLE(slot_hash, 9); > }; > > +/* Memory encryption policy/configuration. */ > +struct vm_memcrypt { > + bool enabled; > + int8_t enc_by_default; > + bool has_enc_bit; > + int8_t enc_bit; > +}; > + > struct kvm_vm { > int mode; > unsigned long type; > @@ -67,6 +76,7 @@ struct kvm_vm { > vm_vaddr_t idt; > vm_vaddr_t handlers; > uint32_t dirty_ring_size; > + struct vm_memcrypt memcrypt;
For readability, it's probably better to adopt a standard naming convention for structures, members and functions ? For example,
encrypted_phy_pages -> enc_phy_pages
struct vm_memcrypt { -> struct vm_mem_enc {
struct vm_memcrypt memcrypt -> struct vm_mem_enc mem_enc
vm_get_encrypted_phy_pages() -> vm_get_enc_phy_pages
> }; > > struct vcpu *vcpu_find(struct kvm_vm *vm, uint32_t vcpuid);
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