[RFC PATCH v3 01/31] KVM: selftests: Add function to allow one-to-one GVA to GPA mappings

[Ackerley Tng <ackerleytng@google.com>]

One-to-one GVA to GPA mappings can be used in the guest to set up boot
sequences during which paging is enabled, hence requiring a transition
from using physical to virtual addresses in consecutive instructions.

Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 .../selftests/kvm/include/kvm_util_base.h     |  2 ++
 tools/testing/selftests/kvm/lib/kvm_util.c    | 35 ++++++++++++++++---
 2 files changed, 32 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 8dac0f49d20b9..0db5cd4b8383a 100644
--- a/tools/testing/selftests/kvm/include/kvm_util_base.h
+++ b/tools/testing/selftests/kvm/include/kvm_util_base.h
@@ -402,6 +402,8 @@ void vm_mem_region_delete(struct kvm_vm *vm, uint32_t slot);
 struct kvm_vcpu *__vm_vcpu_add(struct kvm_vm *vm, uint32_t vcpu_id);
 vm_vaddr_t vm_vaddr_alloc(struct kvm_vm *vm, size_t sz, vm_vaddr_t vaddr_min);
 vm_vaddr_t vm_vaddr_alloc_shared(struct kvm_vm *vm, size_t sz, vm_vaddr_t vaddr_min);
+vm_vaddr_t vm_vaddr_alloc_1to1(struct kvm_vm *vm, size_t sz, vm_vaddr_t vaddr_min,
+			       uint32_t data_memslot);
 vm_vaddr_t vm_vaddr_alloc_pages(struct kvm_vm *vm, int nr_pages);
 vm_vaddr_t vm_vaddr_alloc_page(struct kvm_vm *vm);
 
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index fa8aea97cdb62..5257bce6f546d 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -1237,6 +1237,8 @@ static vm_vaddr_t vm_vaddr_unused_gap(struct kvm_vm *vm, size_t sz,
  *   vm - Virtual Machine
  *   sz - Size in bytes
  *   vaddr_min - Minimum starting virtual address
+ *   paddr_min - Minimum starting physical address
+ *   data_memslot - memslot number to allocate in
  *   encrypt - Whether the region should be handled as encrypted
  *
  * Output Args: None
@@ -1251,14 +1253,15 @@ static vm_vaddr_t vm_vaddr_unused_gap(struct kvm_vm *vm, size_t sz,
  * a page.
  */
 static vm_vaddr_t
-_vm_vaddr_alloc(struct kvm_vm *vm, size_t sz, vm_vaddr_t vaddr_min, bool encrypt)
+_vm_vaddr_alloc(struct kvm_vm *vm, size_t sz, vm_vaddr_t vaddr_min,
+		vm_paddr_t paddr_min, uint32_t data_memslot, bool encrypt)
 {
 	uint64_t pages = (sz >> vm->page_shift) + ((sz % vm->page_size) != 0);
 
 	virt_pgd_alloc(vm);
 	vm_paddr_t paddr = _vm_phy_pages_alloc(vm, pages,
-					       KVM_UTIL_MIN_PFN * vm->page_size,
-					       0, encrypt);
+					       paddr_min,
+					       data_memslot, encrypt);
 
 	/*
 	 * Find an unused range of virtual page addresses of at least
@@ -1281,12 +1284,34 @@ _vm_vaddr_alloc(struct kvm_vm *vm, size_t sz, vm_vaddr_t vaddr_min, bool encrypt
 
 vm_vaddr_t vm_vaddr_alloc(struct kvm_vm *vm, size_t sz, vm_vaddr_t vaddr_min)
 {
-	return _vm_vaddr_alloc(vm, sz, vaddr_min, vm->protected);
+	return _vm_vaddr_alloc(vm, sz, vaddr_min,
+			       KVM_UTIL_MIN_PFN * vm->page_size, 0,
+			       vm->protected);
 }
 
 vm_vaddr_t vm_vaddr_alloc_shared(struct kvm_vm *vm, size_t sz, vm_vaddr_t vaddr_min)
 {
-	return _vm_vaddr_alloc(vm, sz, vaddr_min, false);
+	return _vm_vaddr_alloc(vm, sz, vaddr_min,
+			       KVM_UTIL_MIN_PFN * vm->page_size, 0, false);
+}
+
+/**
+ * Allocate memory in @vm of size @sz in memslot with id @data_memslot,
+ * beginning with the desired address of @vaddr_min.
+ *
+ * If there isn't enough memory at @vaddr_min, find the next possible address
+ * that can meet the requested size in the given memslot.
+ *
+ * Return the address where the memory is allocated.
+ */
+vm_vaddr_t vm_vaddr_alloc_1to1(struct kvm_vm *vm, size_t sz, vm_vaddr_t vaddr_min,
+			       uint32_t data_memslot)
+{
+	vm_vaddr_t gva = _vm_vaddr_alloc(vm, sz, vaddr_min, (vm_paddr_t) vaddr_min,
+					 data_memslot, vm->protected);
+	ASSERT_EQ(gva, addr_gva2gpa(vm, gva));
+
+	return gva;
 }
 
 /*
-- 
2.39.0.246.g2a6d74b583-goog