[PATCH V5 2/7] KVM: selftests: add hooks for managing protected guest memory

Peter Gonda
2022-10-18T20:59:09Z

Add kvm_vm.protected metadata. Protected VMs memory, potentially
register and other state may not be accessible to KVM. This combined
with a new protected_phy_pages bitmap will allow the selftests to check
if a given pages is accessible.

Originally-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Peter Gonda <pgonda@google.com>
---
.../selftests/kvm/include/kvm_util_base.h | 14 ++++++++++++--
tools/testing/selftests/kvm/lib/kvm_util.c | 16 +++++++++++++---
2 files changed, 25 insertions(+), 5 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/kvm_util_base.h b/tools/testing/selftests/kvm/include/kvm_util_base.h
index c14d531a942a..625f13cf3b58 100644
--- a/tools/testing/selftests/kvm/include/kvm_util_base.h
+++ b/tools/testing/selftests/kvm/include/kvm_util_base.h
@@ -33,6 +33,7 @@ typedef uint64_t vm_vaddr_t; /* Virtual Machine (Guest) virtual address */
struct userspace_mem_region {
struct kvm_userspace_memory_region region;
struct sparsebit *unused_phy_pages;
+ struct sparsebit *protected_phy_pages;
int fd;
off_t offset;
void *host_mem;
@@ -90,6 +91,9 @@ struct kvm_vm {
vm_vaddr_t handlers;
uint32_t dirty_ring_size;

+ /* VM protection enabled: SEV, etc*/
+ bool protected;
+
/* Cache of information for binary stats interface */
int stats_fd;
struct kvm_stats_header stats_header;
@@ -638,10 +642,16 @@ const char *exit_reason_str(unsigned int exit_reason);

vm_paddr_t vm_phy_page_alloc(struct kvm_vm *vm, vm_paddr_t paddr_min,
uint32_t memslot);
-vm_paddr_t vm_phy_pages_alloc(struct kvm_vm *vm, size_t num,
- vm_paddr_t paddr_min, uint32_t memslot);
+vm_paddr_t _vm_phy_pages_alloc(struct kvm_vm *vm, size_t num,
+ vm_paddr_t paddr_min, uint32_t memslot, bool protected);
vm_paddr_t vm_alloc_page_table(struct kvm_vm *vm);

+static inline 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, num, paddr_min, memslot, vm->protected);
+}
+
/*
* ____vm_create() does KVM_CREATE_VM and little else. __vm_create() also
* loads the test binary into guest memory and creates an IRQ chip (x86 only).
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index f12ebd27f6e5..0ce5cdb52f0c 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -595,6 +595,7 @@ static void __vm_mem_region_delete(struct kvm_vm *vm,
vm_ioctl(vm, KVM_SET_USER_MEMORY_REGION, &region->region);

sparsebit_free(&region->unused_phy_pages);
+ sparsebit_free(&region->protected_phy_pages);
ret = munmap(region->mmap_start, region->mmap_size);
TEST_ASSERT(!ret, __KVM_SYSCALL_ERROR("munmap()", ret));

@@ -935,6 +936,7 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm,
}

region->unused_phy_pages = sparsebit_alloc();
+ region->protected_phy_pages = sparsebit_alloc();
sparsebit_set_num(region->unused_phy_pages,
guest_paddr >> vm->page_shift, npages);
region->region.slot = slot;
@@ -1711,6 +1713,10 @@ 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->protected) {
+ fprintf(stream, "%*sprotected_phy_pages: ", indent + 2, "");
+ sparsebit_dump(stream, region->protected_phy_pages, 0);
+ }
}
fprintf(stream, "%*sMapped Virtual Pages:\n", indent, "");
sparsebit_dump(stream, vm->vpages_mapped, indent + 2);
@@ -1807,8 +1813,9 @@ const char *exit_reason_str(unsigned int exit_reason)
* 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)
+vm_paddr_t _vm_phy_pages_alloc(struct kvm_vm *vm, size_t num,
+ vm_paddr_t paddr_min, uint32_t memslot,
+ bool protected)
{
struct userspace_mem_region *region;
sparsebit_idx_t pg, base;
@@ -1841,8 +1848,11 @@ 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 (protected)
+ sparsebit_set(region->protected_phy_pages, pg);
+ }

return base * vm->page_size;
}
--
2.38.0.413.g74048e4d9e-goog