On Fri, Apr 29, 2022 at 06:39:27PM +0000, David Matlack wrote:
> x86_page_size is an enum used to communicate the desired page size with
> which to map a range of memory. Under the hood they just encode the
> desired level at which to map the page. This ends up being clunky in a
> few ways:
>
> - The name suggests it encodes the size of the page rather than the
> level.
> - In other places in x86_64/processor.c we just use a raw int to encode
> the level.
>
> Simplify this by just admitting that x86_page_size is just the level and
> using an int and some more obviously named macros (e.g. PG_LEVEL_1G).
>
> Signed-off-by: David Matlack <dmatlack@xxxxxxxxxx>
> ---
> .../selftests/kvm/include/x86_64/processor.h | 14 +++++-----
> .../selftests/kvm/lib/x86_64/processor.c | 27 +++++++++----------
> .../selftests/kvm/max_guest_memory_test.c | 2 +-
> .../selftests/kvm/x86_64/mmu_role_test.c | 2 +-
> 4 files changed, 22 insertions(+), 23 deletions(-)
>
> diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h
> index 37db341d4cc5..b512f9f508ae 100644
> --- a/tools/testing/selftests/kvm/include/x86_64/processor.h
> +++ b/tools/testing/selftests/kvm/include/x86_64/processor.h
> @@ -465,13 +465,13 @@ void vcpu_set_hv_cpuid(struct kvm_vm *vm, uint32_t vcpuid);
> struct kvm_cpuid2 *vcpu_get_supported_hv_cpuid(struct kvm_vm *vm, uint32_t vcpuid);
> void vm_xsave_req_perm(int bit);
>
> -enum x86_page_size {
> - X86_PAGE_SIZE_4K = 0,
> - X86_PAGE_SIZE_2M,
> - X86_PAGE_SIZE_1G,
> -};
> -void __virt_pg_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr,
> - enum x86_page_size page_size);
> +#define PG_LEVEL_4K 0
> +#define PG_LEVEL_2M 1
> +#define PG_LEVEL_1G 2
A nitpick is: we could have named those as PG_LEVEL_[PTE|PMD|PUD|PGD..]
rather than 4K|2M|..., then...
> +
> +#define PG_LEVEL_SIZE(_level) (1ull << (((_level) * 9) + 12))
> +
> +void __virt_pg_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr, int level);
>
> /*
> * Basic CPU control in CR0
> diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c
> index 9f000dfb5594..1a7de69e2495 100644
> --- a/tools/testing/selftests/kvm/lib/x86_64/processor.c
> +++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c
> @@ -199,15 +199,15 @@ static struct pageUpperEntry *virt_create_upper_pte(struct kvm_vm *vm,
> uint64_t pt_pfn,
> uint64_t vaddr,
> uint64_t paddr,
> - int level,
> - enum x86_page_size page_size)
> + int current_level,
> + int target_level)
> {
> - struct pageUpperEntry *pte = virt_get_pte(vm, pt_pfn, vaddr, level);
> + struct pageUpperEntry *pte = virt_get_pte(vm, pt_pfn, vaddr, current_level);
>
> if (!pte->present) {
> pte->writable = true;
> pte->present = true;
> - pte->page_size = (level == page_size);
> + pte->page_size = (current_level == target_level);
> if (pte->page_size)
> pte->pfn = paddr >> vm->page_shift;
> else
> @@ -218,20 +218,19 @@ static struct pageUpperEntry *virt_create_upper_pte(struct kvm_vm *vm,
> * a hugepage at this level, and that there isn't a hugepage at
> * this level.
> */
> - TEST_ASSERT(level != page_size,
> + TEST_ASSERT(current_level != target_level,
> "Cannot create hugepage at level: %u, vaddr: 0x%lx\n",
> - page_size, vaddr);
> + current_level, vaddr);
> TEST_ASSERT(!pte->page_size,
> "Cannot create page table at level: %u, vaddr: 0x%lx\n",
> - level, vaddr);
> + current_level, vaddr);
> }
> return pte;
> }
>
> -void __virt_pg_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr,
> - enum x86_page_size page_size)
> +void __virt_pg_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr, int level)
> {
> - const uint64_t pg_size = 1ull << ((page_size * 9) + 12);
> + const uint64_t pg_size = PG_LEVEL_SIZE(level);
> struct pageUpperEntry *pml4e, *pdpe, *pde;
> struct pageTableEntry *pte;
>
> @@ -256,15 +255,15 @@ void __virt_pg_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr,
> * early if a hugepage was created.
> */
> pml4e = virt_create_upper_pte(vm, vm->pgd >> vm->page_shift,
> - vaddr, paddr, 3, page_size);
> + vaddr, paddr, 3, level);
> if (pml4e->page_size)
> return;
>
> - pdpe = virt_create_upper_pte(vm, pml4e->pfn, vaddr, paddr, 2, page_size);
> + pdpe = virt_create_upper_pte(vm, pml4e->pfn, vaddr, paddr, 2, level);
> if (pdpe->page_size)
> return;
>
> - pde = virt_create_upper_pte(vm, pdpe->pfn, vaddr, paddr, 1, page_size);
> + pde = virt_create_upper_pte(vm, pdpe->pfn, vaddr, paddr, 1, level);
... here we could also potentially replace the 3/2/1s with the new macro
(or with existing naming number 3 will be missing a macro)?
> if (pde->page_size)
> return;
--
Peter Xu
