linux-kernel - [PATCH v6 01/30] KVM: selftests: Add function to allow one-to-one GVA to GPA mappings

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Message-ID: <20250414214801.2693294-2-sagis@google.com>
Date: Mon, 14 Apr 2025 14:47:30 -0700
From: Sagi Shahar <sagis@...gle.com>
To: linux-kselftest@...r.kernel.org, Paolo Bonzini <pbonzini@...hat.com>, 
	Shuah Khan <shuah@...nel.org>, Sean Christopherson <seanjc@...gle.com>, 
	Ackerley Tng <ackerleytng@...gle.com>, Ryan Afranji <afranji@...gle.com>, 
	Andrew Jones <ajones@...tanamicro.com>, Isaku Yamahata <isaku.yamahata@...el.com>, 
	Erdem Aktas <erdemaktas@...gle.com>, Rick Edgecombe <rick.p.edgecombe@...el.com>, 
	Sagi Shahar <sagis@...gle.com>, Roger Wang <runanwang@...gle.com>, 
	Binbin Wu <binbin.wu@...ux.intel.com>, Oliver Upton <oliver.upton@...ux.dev>, 
	"Pratik R. Sampat" <pratikrajesh.sampat@....com>, Reinette Chatre <reinette.chatre@...el.com>
Cc: linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Subject: [PATCH v6 01/30] KVM: selftests: Add function to allow one-to-one GVA
 to GPA mappings

From: Ackerley Tng <ackerleytng@...gle.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@...gle.com>
Signed-off-by: Sagi Shahar <sagis@...gle.com>
---
 .../testing/selftests/kvm/include/kvm_util.h  |  3 +++
 tools/testing/selftests/kvm/lib/kvm_util.c    | 27 +++++++++++++++----
 2 files changed, 25 insertions(+), 5 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index 373912464fb4..1bc0b44e78de 100644
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h
@@ -609,6 +609,9 @@ 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,
 				 enum kvm_mem_region_type type);
+vm_vaddr_t vm_vaddr_identity_alloc(struct kvm_vm *vm, size_t sz,
+				   vm_vaddr_t vaddr_min,
+				   enum kvm_mem_region_type type);
 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,
 				 enum kvm_mem_region_type type);
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index 0be1c61263eb..40dd63f2bd05 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -1443,15 +1443,14 @@ vm_vaddr_t vm_vaddr_unused_gap(struct kvm_vm *vm, size_t sz,
 }
 
 static vm_vaddr_t ____vm_vaddr_alloc(struct kvm_vm *vm, size_t sz,
-				     vm_vaddr_t vaddr_min,
+				     vm_vaddr_t vaddr_min, vm_paddr_t paddr_min,
 				     enum kvm_mem_region_type type,
 				     bool protected)
 {
 	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,
+	vm_paddr_t paddr = __vm_phy_pages_alloc(vm, pages, paddr_min,
 						vm->memslots[type], protected);
 
 	/*
@@ -1475,7 +1474,7 @@ static vm_vaddr_t ____vm_vaddr_alloc(struct kvm_vm *vm, size_t sz,
 vm_vaddr_t __vm_vaddr_alloc(struct kvm_vm *vm, size_t sz, vm_vaddr_t vaddr_min,
 			    enum kvm_mem_region_type type)
 {
-	return ____vm_vaddr_alloc(vm, sz, vaddr_min, type,
+	return ____vm_vaddr_alloc(vm, sz, vaddr_min, KVM_UTIL_MIN_PFN * vm->page_size, type,
 				  vm_arch_has_protected_memory(vm));
 }
 
@@ -1483,7 +1482,25 @@ vm_vaddr_t vm_vaddr_alloc_shared(struct kvm_vm *vm, size_t sz,
 				 vm_vaddr_t vaddr_min,
 				 enum kvm_mem_region_type type)
 {
-	return ____vm_vaddr_alloc(vm, sz, vaddr_min, type, false);
+	return ____vm_vaddr_alloc(vm, sz, vaddr_min, KVM_UTIL_MIN_PFN * vm->page_size, type, false);
+}
+
+/*
+ * Allocate memory in @vm of size @sz beginning with the desired virtual address
+ * of @vaddr_min and backed by physical address equal to returned virtual
+ * address.
+ *
+ * Return the address where the memory is allocated.
+ */
+vm_vaddr_t vm_vaddr_identity_alloc(struct kvm_vm *vm, size_t sz, vm_vaddr_t vaddr_min,
+				   enum kvm_mem_region_type type)
+{
+	vm_vaddr_t gva = ____vm_vaddr_alloc(vm, sz, vaddr_min,
+					    (vm_paddr_t)vaddr_min, type,
+					    vm_arch_has_protected_memory(vm));
+	TEST_ASSERT_EQ(gva, addr_gva2gpa(vm, gva));
+
+	return gva;
 }
 
 /*
-- 
2.49.0.504.g3bcea36a83-goog