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KVM: selftests: Plumb "struct kvm_mmu" into x86's MMU APIs

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In preparation for generalizing the x86 virt mapping APIs to work with
TDP (stage-2) page tables, plumb "struct kvm_mmu" into all of the helper
functions instead of operating on vm->mmu directly.

Opportunistically swap the order of the check in virt_get_pte() to first
assert that the parent is the PGD, and then check that the PTE is present,
as it makes more sense to check if the parent PTE is the PGD/root (i.e.
not a PTE) before checking that the PTE is PRESENT.

No functional change intended.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Yosry Ahmed <yosry.ahmed@linux.dev>
[sean: rebase on common kvm_mmu structure, rewrite changelog]
Link: https://patch.msgid.link/20251230230150.4150236-8-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Sean Christopherson 2025-12-30 15:01:36 -08:00
parent 9f073ac25b
commit 11825209f5
2 changed files with 39 additions and 28 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
tools/testing/selftests/kvm/include/x86/processor.h
View File

@ -1451,7 +1451,8 @@ 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);
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);

64
tools/testing/selftests/kvm/lib/x86/processor.c
View File

@ -156,26 +156,31 @@ bool kvm_is_tdp_enabled(void)
return get_kvm_amd_param_bool("npt");
}
static void virt_mmu_init(struct kvm_vm *vm, struct kvm_mmu *mmu)
{
/* If needed, create the top-level page table. */
if (!mmu->pgd_created) {
mmu->pgd = vm_alloc_page_table(vm);
mmu->pgd_created = true;
}
}
void virt_arch_pgd_alloc(struct kvm_vm *vm)
{
TEST_ASSERT(vm->mode == VM_MODE_PXXVYY_4K,
"Unknown or unsupported guest mode: 0x%x", vm->mode);
/* If needed, create the top-level page table. */
if (!vm->mmu.pgd_created) {
vm->mmu.pgd = vm_alloc_page_table(vm);
vm->mmu.pgd_created = true;
}
virt_mmu_init(vm, &vm->mmu);
}
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->mmu.pgd,
TEST_ASSERT((*parent_pte == mmu->pgd) || (*parent_pte & PTE_PRESENT_MASK),
"Parent PTE (level %d) not PRESENT for gva: 0x%08lx",
level + 1, vaddr);
@ -183,13 +188,14 @@ 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 +221,11 @@ 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->mmu.pgd;
uint64_t *pte = &mmu->pgd;
int current_level;
TEST_ASSERT(vm->mode == VM_MODE_PXXVYY_4K,
@ -243,17 +250,17 @@ 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->mmu.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 +277,7 @@ 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->mmu, vaddr, paddr, PG_LEVEL_4K);
}
void virt_map_level(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr,
@ -285,7 +292,7 @@ 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->mmu, vaddr, paddr, level);
sparsebit_set_num(vm->vpages_mapped, vaddr >> vm->page_shift,
nr_bytes / PAGE_SIZE);
@ -294,7 +301,8 @@ 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 ||
@ -306,17 +314,19 @@ 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->mmu.pgtable_levels) * 9;
uint64_t *pte = &vm->mmu.pgd;
int va_width = 12 + (mmu->pgtable_levels) * 9;
uint64_t *pte = &mmu->pgd;
int current_level;
TEST_ASSERT(!vm->arch.is_pt_protected,
"Walking page tables of protected guests is impossible");
TEST_ASSERT(*level >= PG_LEVEL_NONE && *level <= vm->mmu.pgtable_levels,
TEST_ASSERT(*level >= PG_LEVEL_NONE && *level <= mmu->pgtable_levels,
"Invalid PG_LEVEL_* '%d'", *level);
TEST_ASSERT(vm->mode == VM_MODE_PXXVYY_4K,
@ -332,22 +342,22 @@ static uint64_t *__vm_get_page_table_entry(struct kvm_vm *vm, uint64_t vaddr,
(((int64_t)vaddr << (64 - va_width) >> (64 - va_width))),
"Canonical check failed. The virtual address is invalid.");
for (current_level = vm->mmu.pgtable_levels;
for (current_level = mmu->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->mmu, vaddr, &level);
}
void virt_arch_dump(FILE *stream, struct kvm_vm *vm, uint8_t indent)
@ -497,7 +507,7 @@ 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);
uint64_t *pte = __vm_get_page_table_entry(vm, &vm->mmu, gva, &level);
TEST_ASSERT(*pte & PTE_PRESENT_MASK,
"Leaf PTE not PRESENT for gva: 0x%08lx", gva);