[PATCH 4/5] KVM: x86: MMU: Remove is_rmap_spte() and use is_shadow_present_pte()

From: Takuya Yoshikawa
Date: Fri Nov 06 2015 - 02:11:10 EST


is_rmap_spte(), originally named is_rmap_pte(), was introduced when the
simple reverse mapping was implemented by commit cd4a4e5374110444
("[PATCH] KVM: MMU: Implement simple reverse mapping"). At that point,
its role was clear and only rmap_add() and rmap_remove() were using it
to select sptes that need to be reverse-mapped.

Independently of that, is_shadow_present_pte() was first introduced by
commit c7addb902054195b ("KVM: Allow not-present guest page faults to
bypass kvm") to do bypass_guest_pf optimization, which does not exist
any more.

These two seem to have changed their roles somewhat, and is_rmap_spte()
just calls is_shadow_present_pte() now.

Since using both of them without no clear distinction just makes the
code confusing, remove is_rmap_spte().

Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@xxxxxxxxxxxxx>
---
arch/x86/kvm/mmu.c | 13 ++++---------
arch/x86/kvm/mmu_audit.c | 2 +-
2 files changed, 5 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 69e7d20..c5e2363 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -311,11 +311,6 @@ static int is_large_pte(u64 pte)
return pte & PT_PAGE_SIZE_MASK;
}

-static int is_rmap_spte(u64 pte)
-{
- return is_shadow_present_pte(pte);
-}
-
static int is_last_spte(u64 pte, int level)
{
if (level == PT_PAGE_TABLE_LEVEL)
@@ -540,7 +535,7 @@ static bool mmu_spte_update(u64 *sptep, u64 new_spte)
u64 old_spte = *sptep;
bool ret = false;

- WARN_ON(!is_rmap_spte(new_spte));
+ WARN_ON(!is_shadow_present_pte(new_spte));

if (!is_shadow_present_pte(old_spte)) {
mmu_spte_set(sptep, new_spte);
@@ -595,7 +590,7 @@ static int mmu_spte_clear_track_bits(u64 *sptep)
else
old_spte = __update_clear_spte_slow(sptep, 0ull);

- if (!is_rmap_spte(old_spte))
+ if (!is_shadow_present_pte(old_spte))
return 0;

pfn = spte_to_pfn(old_spte);
@@ -2575,7 +2570,7 @@ static bool mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep, unsigned pte_access,
pgprintk("%s: spte %llx write_fault %d gfn %llx\n", __func__,
*sptep, write_fault, gfn);

- if (is_rmap_spte(*sptep)) {
+ if (is_shadow_present_pte(*sptep)) {
/*
* If we overwrite a PTE page pointer with a 2MB PMD, unlink
* the parent of the now unreachable PTE.
@@ -2919,7 +2914,7 @@ static bool fast_page_fault(struct kvm_vcpu *vcpu, gva_t gva, int level,
* If the mapping has been changed, let the vcpu fault on the
* same address again.
*/
- if (!is_rmap_spte(spte)) {
+ if (!is_shadow_present_pte(spte)) {
ret = true;
goto exit;
}
diff --git a/arch/x86/kvm/mmu_audit.c b/arch/x86/kvm/mmu_audit.c
index 03d518e..90ee420 100644
--- a/arch/x86/kvm/mmu_audit.c
+++ b/arch/x86/kvm/mmu_audit.c
@@ -183,7 +183,7 @@ static void check_mappings_rmap(struct kvm *kvm, struct kvm_mmu_page *sp)
return;

for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
- if (!is_rmap_spte(sp->spt[i]))
+ if (!is_shadow_present_pte(sp->spt[i]))
continue;

inspect_spte_has_rmap(kvm, sp->spt + i);
--
2.1.0

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/