[PATCH 3/7] KVM: selftests: Remove useless shifts when creating guest page tables

From: Sean Christopherson
Date: Wed Oct 05 2022 - 20:45:43 EST


Remove the pointless shift from GPA=>GFN and immediately back to
GFN=>GPA when creating guest page tables. Ignore the other walkers
that have a similar pattern for the moment, they will be converted
to use virt_get_pte() in the near future.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
.../selftests/kvm/include/x86_64/processor.h | 3 ++-
.../selftests/kvm/lib/x86_64/processor.c | 17 ++++++++---------
2 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h
index 53d52a5ace48..9676a3464758 100644
--- a/tools/testing/selftests/kvm/include/x86_64/processor.h
+++ b/tools/testing/selftests/kvm/include/x86_64/processor.h
@@ -177,7 +177,8 @@ struct kvm_x86_cpu_feature {
#define PAGE_MASK (~(PAGE_SIZE-1))

#define PHYSICAL_PAGE_MASK GENMASK_ULL(51, 12)
-#define PTE_GET_PFN(pte) (((pte) & PHYSICAL_PAGE_MASK) >> PAGE_SHIFT)
+#define PTE_GET_PA(pte) ((pte) & PHYSICAL_PAGE_MASK)
+#define PTE_GET_PFN(pte) (PTE_GET_PA(pte) >> PAGE_SHIFT)

/* General Registers in 64-Bit Mode */
struct gpr64_regs {
diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c
index 9e196837a794..324bf24564a1 100644
--- a/tools/testing/selftests/kvm/lib/x86_64/processor.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c
@@ -131,23 +131,23 @@ void virt_arch_pgd_alloc(struct kvm_vm *vm)
}
}

-static void *virt_get_pte(struct kvm_vm *vm, uint64_t pt_pfn, uint64_t vaddr,
+static void *virt_get_pte(struct kvm_vm *vm, uint64_t pt_gpa, uint64_t vaddr,
int level)
{
- uint64_t *page_table = addr_gpa2hva(vm, pt_pfn << vm->page_shift);
+ uint64_t *page_table = addr_gpa2hva(vm, pt_gpa);
int index = (vaddr >> PG_LEVEL_SHIFT(level)) & 0x1ffu;

return &page_table[index];
}

static uint64_t *virt_create_upper_pte(struct kvm_vm *vm,
- uint64_t pt_pfn,
+ uint64_t pt_gpa,
uint64_t vaddr,
uint64_t paddr,
int current_level,
int target_level)
{
- uint64_t *pte = virt_get_pte(vm, pt_pfn, vaddr, current_level);
+ uint64_t *pte = virt_get_pte(vm, pt_gpa, vaddr, current_level);

if (!(*pte & PTE_PRESENT_MASK)) {
*pte = PTE_PRESENT_MASK | PTE_WRITABLE_MASK;
@@ -197,21 +197,20 @@ 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.
*/
- pml4e = virt_create_upper_pte(vm, vm->pgd >> vm->page_shift,
- vaddr, paddr, PG_LEVEL_512G, level);
+ pml4e = virt_create_upper_pte(vm, vm->pgd, vaddr, paddr, PG_LEVEL_512G, level);
if (*pml4e & PTE_LARGE_MASK)
return;

- pdpe = virt_create_upper_pte(vm, PTE_GET_PFN(*pml4e), vaddr, paddr, PG_LEVEL_1G, level);
+ pdpe = virt_create_upper_pte(vm, PTE_GET_PA(*pml4e), vaddr, paddr, PG_LEVEL_1G, level);
if (*pdpe & PTE_LARGE_MASK)
return;

- pde = virt_create_upper_pte(vm, PTE_GET_PFN(*pdpe), vaddr, paddr, PG_LEVEL_2M, level);
+ pde = virt_create_upper_pte(vm, PTE_GET_PA(*pdpe), vaddr, paddr, PG_LEVEL_2M, level);
if (*pde & PTE_LARGE_MASK)
return;

/* Fill in page table entry. */
- pte = virt_get_pte(vm, PTE_GET_PFN(*pde), vaddr, PG_LEVEL_4K);
+ pte = virt_get_pte(vm, PTE_GET_PA(*pde), vaddr, PG_LEVEL_4K);
TEST_ASSERT(!(*pte & PTE_PRESENT_MASK),
"PTE already present for 4k page at vaddr: 0x%lx\n", vaddr);
*pte = PTE_PRESENT_MASK | PTE_WRITABLE_MASK | (paddr & PHYSICAL_PAGE_MASK);
--
2.38.0.rc1.362.ged0d419d3c-goog