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Message-ID: <20251127013440.3324671-7-yosry.ahmed@linux.dev>
Date: Thu, 27 Nov 2025 01:34:30 +0000
From: Yosry Ahmed <yosry.ahmed@...ux.dev>
To: Sean Christopherson <seanjc@...gle.com>
Cc: Paolo Bonzini <pbonzini@...hat.com>,
kvm@...r.kernel.org,
linux-kernel@...r.kernel.org,
Yosry Ahmed <yosry.ahmed@...ux.dev>
Subject: [PATCH v3 06/16] KVM: selftests: Introduce struct kvm_mmu
In preparation for generalizing the virt mapping functions to work with
TDP page tables, introduce struct kvm_mmu. This struct currently only
holds the root GPA and number of page table levels. Parameterize virt
mapping functions by the kvm_mmu, and use the root GPA and page table
levels instead of hardcoding vm->pgd and vm->pgtable_levels.
There's a subtle change here, instead of checking that the parent
pointer is the address of the vm->pgd, check if the value pointed at by
the parent pointer is the root GPA (i.e. the value of vm->pgd in this
case). No change in behavior expected.
Opportunistically, switch the ordering of the checks in the assertion in
virt_get_pte(), as it makes more sense to check if the parent PTE is the
root (in which case, not a PTE) before checking the present flag.
vm->arch.mmu is dynamically allocated to avoid a circular dependency
chain if kvm_util_arch.h includes processor.h for the struct definition:
kvm_util_arch.h -> processor.h -> kvm_util.h -> kvm_util_arch.h
No functional change intended.
Suggested-by: Sean Christopherson <seanjc@...gle.com>
Signed-off-by: Yosry Ahmed <yosry.ahmed@...ux.dev>
---
.../selftests/kvm/include/x86/kvm_util_arch.h | 4 ++
.../selftests/kvm/include/x86/processor.h | 8 ++-
.../testing/selftests/kvm/lib/x86/processor.c | 61 +++++++++++++------
3 files changed, 53 insertions(+), 20 deletions(-)
diff --git a/tools/testing/selftests/kvm/include/x86/kvm_util_arch.h b/tools/testing/selftests/kvm/include/x86/kvm_util_arch.h
index 972bb1c4ab4c..d8808fa33faa 100644
--- a/tools/testing/selftests/kvm/include/x86/kvm_util_arch.h
+++ b/tools/testing/selftests/kvm/include/x86/kvm_util_arch.h
@@ -10,6 +10,8 @@
extern bool is_forced_emulation_enabled;
+struct kvm_mmu;
+
struct kvm_vm_arch {
vm_vaddr_t gdt;
vm_vaddr_t tss;
@@ -19,6 +21,8 @@ struct kvm_vm_arch {
uint64_t s_bit;
int sev_fd;
bool is_pt_protected;
+
+ struct kvm_mmu *mmu;
};
static inline bool __vm_arch_has_protected_memory(struct kvm_vm_arch *arch)
diff --git a/tools/testing/selftests/kvm/include/x86/processor.h b/tools/testing/selftests/kvm/include/x86/processor.h
index c00c0fbe62cd..0c295097c714 100644
--- a/tools/testing/selftests/kvm/include/x86/processor.h
+++ b/tools/testing/selftests/kvm/include/x86/processor.h
@@ -1449,7 +1449,13 @@ enum pg_level {
#define PG_SIZE_2M PG_LEVEL_SIZE(PG_LEVEL_2M)
#define PG_SIZE_1G PG_LEVEL_SIZE(PG_LEVEL_1G)
-void __virt_pg_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr, int level);
+struct kvm_mmu {
+ uint64_t root_gpa;
+ int pgtable_levels;
+};
+
+void __virt_pg_map(struct kvm_vm *vm, struct kvm_mmu *mmu, uint64_t vaddr,
+ uint64_t paddr, int level);
void virt_map_level(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr,
uint64_t nr_bytes, int level);
diff --git a/tools/testing/selftests/kvm/lib/x86/processor.c b/tools/testing/selftests/kvm/lib/x86/processor.c
index c14bf2b5f28f..871de49c35ee 100644
--- a/tools/testing/selftests/kvm/lib/x86/processor.c
+++ b/tools/testing/selftests/kvm/lib/x86/processor.c
@@ -156,6 +156,23 @@ bool kvm_is_tdp_enabled(void)
return get_kvm_amd_param_bool("npt");
}
+static struct kvm_mmu *mmu_create(struct kvm_vm *vm,
+ int pgtable_levels)
+{
+ struct kvm_mmu *mmu = calloc(1, sizeof(*mmu));
+
+ TEST_ASSERT(mmu, "-ENOMEM when allocating MMU");
+ mmu->root_gpa = vm_alloc_page_table(vm);
+ mmu->pgtable_levels = pgtable_levels;
+ return mmu;
+}
+
+static void mmu_init(struct kvm_vm *vm)
+{
+ vm->arch.mmu = mmu_create(vm, vm->pgtable_levels);
+ vm->pgd = vm->arch.mmu->root_gpa;
+}
+
void virt_arch_pgd_alloc(struct kvm_vm *vm)
{
TEST_ASSERT(vm->mode == VM_MODE_PXXVYY_4K,
@@ -163,19 +180,19 @@ void virt_arch_pgd_alloc(struct kvm_vm *vm)
/* If needed, create the top-level page table. */
if (!vm->pgd_created) {
- vm->pgd = vm_alloc_page_table(vm);
+ mmu_init(vm);
vm->pgd_created = true;
}
}
-static void *virt_get_pte(struct kvm_vm *vm, uint64_t *parent_pte,
- uint64_t vaddr, int level)
+static void *virt_get_pte(struct kvm_vm *vm, struct kvm_mmu *mmu,
+ uint64_t *parent_pte, uint64_t vaddr, int level)
{
uint64_t pt_gpa = PTE_GET_PA(*parent_pte);
uint64_t *page_table = addr_gpa2hva(vm, pt_gpa);
int index = (vaddr >> PG_LEVEL_SHIFT(level)) & 0x1ffu;
- TEST_ASSERT((*parent_pte & PTE_PRESENT_MASK) || parent_pte == &vm->pgd,
+ TEST_ASSERT((*parent_pte == mmu->root_gpa) || (*parent_pte & PTE_PRESENT_MASK),
"Parent PTE (level %d) not PRESENT for gva: 0x%08lx",
level + 1, vaddr);
@@ -183,13 +200,14 @@ static void *virt_get_pte(struct kvm_vm *vm, uint64_t *parent_pte,
}
static uint64_t *virt_create_upper_pte(struct kvm_vm *vm,
+ struct kvm_mmu *mmu,
uint64_t *parent_pte,
uint64_t vaddr,
uint64_t paddr,
int current_level,
int target_level)
{
- uint64_t *pte = virt_get_pte(vm, parent_pte, vaddr, current_level);
+ uint64_t *pte = virt_get_pte(vm, mmu, parent_pte, vaddr, current_level);
paddr = vm_untag_gpa(vm, paddr);
@@ -215,10 +233,11 @@ static uint64_t *virt_create_upper_pte(struct kvm_vm *vm,
return pte;
}
-void __virt_pg_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr, int level)
+void __virt_pg_map(struct kvm_vm *vm, struct kvm_mmu *mmu, uint64_t vaddr,
+ uint64_t paddr, int level)
{
const uint64_t pg_size = PG_LEVEL_SIZE(level);
- uint64_t *pte = &vm->pgd;
+ uint64_t *pte = &mmu->root_gpa;
int current_level;
TEST_ASSERT(vm->mode == VM_MODE_PXXVYY_4K,
@@ -243,17 +262,17 @@ void __virt_pg_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr, int level)
* Allocate upper level page tables, if not already present. Return
* early if a hugepage was created.
*/
- for (current_level = vm->pgtable_levels;
+ for (current_level = mmu->pgtable_levels;
current_level > PG_LEVEL_4K;
current_level--) {
- pte = virt_create_upper_pte(vm, pte, vaddr, paddr,
+ pte = virt_create_upper_pte(vm, mmu, pte, vaddr, paddr,
current_level, level);
if (*pte & PTE_LARGE_MASK)
return;
}
/* Fill in page table entry. */
- pte = virt_get_pte(vm, pte, vaddr, PG_LEVEL_4K);
+ pte = virt_get_pte(vm, mmu, pte, vaddr, PG_LEVEL_4K);
TEST_ASSERT(!(*pte & PTE_PRESENT_MASK),
"PTE already present for 4k page at vaddr: 0x%lx", vaddr);
*pte = PTE_PRESENT_MASK | PTE_WRITABLE_MASK | (paddr & PHYSICAL_PAGE_MASK);
@@ -270,7 +289,7 @@ void __virt_pg_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr, int level)
void virt_arch_pg_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr)
{
- __virt_pg_map(vm, vaddr, paddr, PG_LEVEL_4K);
+ __virt_pg_map(vm, vm->arch.mmu, vaddr, paddr, PG_LEVEL_4K);
}
void virt_map_level(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr,
@@ -285,7 +304,7 @@ void virt_map_level(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr,
nr_bytes, pg_size);
for (i = 0; i < nr_pages; i++) {
- __virt_pg_map(vm, vaddr, paddr, level);
+ __virt_pg_map(vm, vm->arch.mmu, vaddr, paddr, level);
sparsebit_set_num(vm->vpages_mapped, vaddr >> vm->page_shift,
nr_bytes / PAGE_SIZE);
@@ -294,7 +313,8 @@ void virt_map_level(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr,
}
}
-static bool vm_is_target_pte(uint64_t *pte, int *level, int current_level)
+static bool vm_is_target_pte(struct kvm_mmu *mmu, uint64_t *pte,
+ int *level, int current_level)
{
if (*pte & PTE_LARGE_MASK) {
TEST_ASSERT(*level == PG_LEVEL_NONE ||
@@ -306,7 +326,9 @@ static bool vm_is_target_pte(uint64_t *pte, int *level, int current_level)
return *level == current_level;
}
-static uint64_t *__vm_get_page_table_entry(struct kvm_vm *vm, uint64_t vaddr,
+static uint64_t *__vm_get_page_table_entry(struct kvm_vm *vm,
+ struct kvm_mmu *mmu,
+ uint64_t vaddr,
int *level)
{
int va_width = 12 + (vm->pgtable_levels) * 9;
@@ -335,19 +357,19 @@ static uint64_t *__vm_get_page_table_entry(struct kvm_vm *vm, uint64_t vaddr,
for (current_level = vm->pgtable_levels;
current_level > PG_LEVEL_4K;
current_level--) {
- pte = virt_get_pte(vm, pte, vaddr, current_level);
- if (vm_is_target_pte(pte, level, current_level))
+ pte = virt_get_pte(vm, mmu, pte, vaddr, current_level);
+ if (vm_is_target_pte(mmu, pte, level, current_level))
return pte;
}
- return virt_get_pte(vm, pte, vaddr, PG_LEVEL_4K);
+ return virt_get_pte(vm, mmu, pte, vaddr, PG_LEVEL_4K);
}
uint64_t *vm_get_page_table_entry(struct kvm_vm *vm, uint64_t vaddr)
{
int level = PG_LEVEL_4K;
- return __vm_get_page_table_entry(vm, vaddr, &level);
+ return __vm_get_page_table_entry(vm, vm->arch.mmu, vaddr, &level);
}
void virt_arch_dump(FILE *stream, struct kvm_vm *vm, uint8_t indent)
@@ -497,7 +519,8 @@ static void kvm_seg_set_kernel_data_64bit(struct kvm_segment *segp)
vm_paddr_t addr_arch_gva2gpa(struct kvm_vm *vm, vm_vaddr_t gva)
{
int level = PG_LEVEL_NONE;
- uint64_t *pte = __vm_get_page_table_entry(vm, gva, &level);
+ struct kvm_mmu *mmu = vm->arch.mmu;
+ uint64_t *pte = __vm_get_page_table_entry(vm, mmu, gva, &level);
TEST_ASSERT(*pte & PTE_PRESENT_MASK,
"Leaf PTE not PRESENT for gva: 0x%08lx", gva);
--
2.52.0.158.g65b55ccf14-goog
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