Add support for guest side functionality to modify encryption/shared masks for entries in page table to allow accessing GPA ranges as private or shared.
Signed-off-by: Vishal Annapurve vannapurve@google.com --- .../selftests/kvm/include/x86_64/processor.h | 4 ++ .../selftests/kvm/lib/x86_64/processor.c | 39 +++++++++++++++++++ 2 files changed, 43 insertions(+)
diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h index 3617f83bb2e5..c8c55f54c14f 100644 --- a/tools/testing/selftests/kvm/include/x86_64/processor.h +++ b/tools/testing/selftests/kvm/include/x86_64/processor.h @@ -945,6 +945,10 @@ void vcpu_init_descriptor_tables(struct kvm_vcpu *vcpu); void vm_install_exception_handler(struct kvm_vm *vm, int vector, void (*handler)(struct ex_regs *));
+void guest_set_region_shared(void *vaddr, uint64_t size); + +void guest_set_region_private(void *vaddr, uint64_t size); + /* If a toddler were to say "abracadabra". */ #define KVM_EXCEPTION_MAGIC 0xabacadabaULL
diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c index ab7d4cc4b848..42d1e4074f32 100644 --- a/tools/testing/selftests/kvm/lib/x86_64/processor.c +++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c @@ -276,6 +276,45 @@ static uint64_t *guest_code_get_pte(uint64_t vaddr) return (uint64_t *)&pte[index[0]]; }
+static void guest_code_change_region_prot(void *vaddr_start, uint64_t mem_size, + bool private) +{ + uint64_t vaddr = (uint64_t)vaddr_start; + uint32_t num_pages; + + GUEST_ASSERT(gpgt_info != NULL); + uint32_t guest_page_size = gpgt_info->page_size; + + GUEST_ASSERT(!(mem_size % guest_page_size) && !(vaddr % guest_page_size)); + GUEST_ASSERT(gpgt_info->enc_mask | gpgt_info->shared_mask); + + num_pages = mem_size / guest_page_size; + for (uint32_t i = 0; i < num_pages; i++) { + uint64_t *pte = guest_code_get_pte(vaddr); + + GUEST_ASSERT(pte); + if (private) { + *pte &= ~(gpgt_info->shared_mask); + *pte |= gpgt_info->enc_mask; + } else { + *pte &= ~(gpgt_info->enc_mask); + *pte |= gpgt_info->shared_mask; + } + asm volatile("invlpg (%0)" :: "r"(vaddr) : "memory"); + vaddr += guest_page_size; + } +} + +void guest_set_region_shared(void *vaddr, uint64_t size) +{ + guest_code_change_region_prot(vaddr, size, /* shared */ false); +} + +void guest_set_region_private(void *vaddr, uint64_t size) +{ + guest_code_change_region_prot(vaddr, size, /* private */ true); +} + void sync_vm_gpgt_info(struct kvm_vm *vm, vm_vaddr_t pgt_info) { gpgt_info = (struct guest_pgt_info *)pgt_info;