[PATCH] KVM: PPC: Book3S HV: Use RADIX_PTE_INDEX_SIZE in Radix MMU code

In kvmppc_unmap_free_pte() in book3s_64_mmu_radix.c, we use the
non-constant value PTE_INDEX_SIZE to clear a PTE page.

We can instead use the constant RADIX_PTE_INDEX_SIZE, because we know
this code will only be running when the Radix MMU is active.

Note that we already use RADIX_PTE_INDEX_SIZE for the allocation of
kvm_pte_cache.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
 arch/powerpc/kvm/book3s_64_mmu_radix.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c b/arch/powerpc/kvm/book3s_64_mmu_radix.c
index 803940d79b73..134fbc1f029f 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_radix.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c

@@ -425,7 +425,7 @@ static void kvmppc_unmap_free_pte(struct kvm *kvm, pte_t *pte, bool full,
 				  unsigned int lpid)
 {
 	if (full) {
-		memset(pte, 0, sizeof(long) << PTE_INDEX_SIZE);
+		memset(pte, 0, sizeof(long) << RADIX_PTE_INDEX_SIZE);
 	} else {
 		pte_t *p = pte;
 		unsigned long it;

-- 
2.21.1

Hello Michael,

On Tue, 2020-02-18 at 15:36 +1100, Michael Ellerman wrote:

Looks fine to mee. 

For book3s_64, pgtable.h says:
extern unsigned long __pte_index_size;
#define PTE_INDEX_SIZE  __pte_index_size

powerpc/mm/pgtable_64.c defines/export the variable:
unsigned long __pte_index_size;
EXPORT_SYMBOL(__pte_index_size);

And book3s64/radix_pgtable.c set the value in radix__early_init_mmu().
__pte_index_size = RADIX_PTE_INDEX_SIZE;

So I think it's ok to use the value directly in book3s_64_mmu_radix.c.
The include dependency looks fine for that to work.

FWIW:
Reviewed-by: Leonardo Bras <redacted>

On Tue, Feb 18, 2020 at 03:36:50PM +1100, Michael Ellerman wrote:

In kvmppc_unmap_free_pte() in book3s_64_mmu_radix.c, we use the
non-constant value PTE_INDEX_SIZE to clear a PTE page.

We can instead use the constant RADIX_PTE_INDEX_SIZE, because we know
this code will only be running when the Radix MMU is active.

Note that we already use RADIX_PTE_INDEX_SIZE for the allocation of
kvm_pte_cache.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Thanks, applied to my kvm-ppc-next branch.

Paul.