[RFC v3 02/10] KVM: selftests: Add aligned guest physical page allocator
From: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Date: 2026-05-27 12:50:23
Also in:
kvm, lkml
Subsystem:
kernel selftest framework, kernel virtual machine (kvm), the rest · Maintainers:
Shuah Khan, Paolo Bonzini, Linus Torvalds
From: Nicholas Piggin <npiggin@gmail.com> powerpc will require this to allocate MMU tables in guest memory that are larger than guest base page size. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> [Rebased to latest mainline tree] Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> --- .../testing/selftests/kvm/include/kvm_util.h | 20 +++++++++-- tools/testing/selftests/kvm/lib/kvm_util.c | 33 +++++++++---------- 2 files changed, 33 insertions(+), 20 deletions(-)
diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index 3666a8530f31..c515c918c2c9 100644
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h@@ -991,8 +991,8 @@ void kvm_gsi_routing_write(struct kvm_vm *vm, struct kvm_irq_routing *routing); const char *exit_reason_str(unsigned int exit_reason); gpa_t vm_phy_page_alloc(struct kvm_vm *vm, gpa_t min_gpa, u32 memslot); -gpa_t __vm_phy_pages_alloc(struct kvm_vm *vm, size_t num, gpa_t min_gpa, - u32 memslot, bool protected); +gpa_t __vm_phy_pages_alloc(struct kvm_vm *vm, size_t num, size_t align, + gpa_t min_gpa, u32 memslot, bool protected); gpa_t vm_alloc_page_table(struct kvm_vm *vm); static inline gpa_t vm_phy_pages_alloc(struct kvm_vm *vm, size_t num,
@@ -1003,10 +1003,24 @@ static inline gpa_t vm_phy_pages_alloc(struct kvm_vm *vm, size_t num, * protected memory, as the majority of memory for such VMs is * protected, i.e. using shared memory is effectively opt-in. */ - return __vm_phy_pages_alloc(vm, num, min_gpa, memslot, + return __vm_phy_pages_alloc(vm, num, 1, min_gpa, memslot, vm_arch_has_protected_memory(vm)); } +static inline gpa_t vm_phy_pages_alloc_align(struct kvm_vm *vm, size_t num, + size_t align, gpa_t min_gpa, + u32 memslot) +{ + /* + * By default, allocate memory as protected for VMs that support + * protected memory, as the majority of memory for such VMs is + * protected, i.e. using shared memory is effectively opt-in. + */ + return __vm_phy_pages_alloc(vm, num, align, min_gpa, memslot, + vm_arch_has_protected_memory(vm)); +} + + /* * ____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 e08967ef7b7b..ac7215824203 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c@@ -1442,7 +1442,7 @@ static gva_t ____vm_alloc(struct kvm_vm *vm, size_t sz, gva_t min_gva, u64 pages = (sz >> vm->page_shift) + ((sz % vm->page_size) != 0); virt_pgd_alloc(vm); - gpa_t gpa = __vm_phy_pages_alloc(vm, pages, + gpa_t gpa = __vm_phy_pages_alloc(vm, pages, 1, KVM_UTIL_MIN_PFN * vm->page_size, vm->memslots[type], protected);
@@ -2021,7 +2021,7 @@ 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 min_gpa. */ -gpa_t __vm_phy_pages_alloc(struct kvm_vm *vm, size_t num, +gpa_t __vm_phy_pages_alloc(struct kvm_vm *vm, size_t num, size_t align, gpa_t min_gpa, u32 memslot, bool protected) {
@@ -2039,23 +2039,22 @@ gpa_t __vm_phy_pages_alloc(struct kvm_vm *vm, size_t num, TEST_ASSERT(!protected || region->protected_phy_pages, "Region doesn't support protected memory"); - base = pg = min_gpa >> vm->page_shift; - do { - for (; pg < base + num; ++pg) { - if (!sparsebit_is_set(region->unused_phy_pages, pg)) { - base = pg = sparsebit_next_set(region->unused_phy_pages, pg); - break; + base = min_gpa >> vm->page_shift; +again: + base = (base + align - 1) & ~(align - 1); + for (pg = base; pg < base + num; ++pg) { + if (!sparsebit_is_set(region->unused_phy_pages, pg)) { + base = sparsebit_next_set(region->unused_phy_pages, pg); + if (!base) { + fprintf(stderr, "No guest physical page available, " + "min_gpa: 0x%lx page_size: 0x%x memslot: %u\n", + min_gpa, vm->page_size, memslot); + fputs("---- vm dump ----\n", stderr); + vm_dump(stderr, vm, 2); + abort(); } + goto again; } - } while (pg && pg != base + num); - - if (pg == 0) { - fprintf(stderr, "No guest physical page available, " - "min_gpa: 0x%lx page_size: 0x%x memslot: %u\n", - min_gpa, vm->page_size, memslot); - fputs("---- vm dump ----\n", stderr); - vm_dump(stderr, vm, 2); - abort(); } for (pg = base; pg < base + num; ++pg) {
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2.39.5