[PATCH v3 23/31] KVM: MMU: inline set_spte in FNAME(sync_page)

From: Paolo Bonzini
Date: Fri Sep 24 2021 - 12:33:11 EST


Since the two callers of set_spte do different things with the results,
inlining it actually makes the code simpler to reason about. For example,
FNAME(sync_page) already has a struct kvm_mmu_page *, but set_spte had to
fish it back out of sptep's private page data.

Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
arch/x86/kvm/mmu/mmu.c | 21 ---------------------
arch/x86/kvm/mmu/paging_tmpl.h | 21 ++++++++++++---------
2 files changed, 12 insertions(+), 30 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 6ba7c60bd4f8..19c2fd2189a3 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -2674,27 +2674,6 @@ int mmu_try_to_unsync_pages(struct kvm_vcpu *vcpu, gfn_t gfn, bool can_unsync,
return 0;
}

-static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
- unsigned int pte_access, int level,
- gfn_t gfn, kvm_pfn_t pfn, bool speculative,
- bool can_unsync, bool host_writable)
-{
- u64 spte;
- struct kvm_mmu_page *sp;
- int ret;
-
- sp = sptep_to_sp(sptep);
-
- ret = make_spte(vcpu, pte_access, level, gfn, pfn, *sptep, speculative,
- can_unsync, host_writable, sp_ad_disabled(sp), &spte);
-
- if (*sptep == spte)
- ret |= SET_SPTE_SPURIOUS;
- else if (mmu_spte_update(sptep, spte))
- ret |= SET_SPTE_NEED_REMOTE_TLB_FLUSH;
- return ret;
-}
-
static int mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
unsigned int pte_access, bool write_fault, int level,
gfn_t gfn, kvm_pfn_t pfn, bool speculative,
diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
index e4c7bf3deac8..500962dceda0 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -1061,7 +1061,7 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
int i;
bool host_writable;
gpa_t first_pte_gpa;
- int set_spte_ret = 0;
+ bool flush = false;

/*
* Ignore various flags when verifying that it's safe to sync a shadow
@@ -1091,6 +1091,7 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
first_pte_gpa = FNAME(get_level1_sp_gpa)(sp);

for (i = 0; i < PT64_ENT_PER_PAGE; i++) {
+ u64 *sptep, spte;
unsigned pte_access;
pt_element_t gpte;
gpa_t pte_gpa;
@@ -1106,7 +1107,7 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
return -1;

if (FNAME(prefetch_invalid_gpte)(vcpu, sp, &sp->spt[i], gpte)) {
- set_spte_ret |= SET_SPTE_NEED_REMOTE_TLB_FLUSH;
+ flush = true;
continue;
}

@@ -1120,19 +1121,21 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)

if (gfn != sp->gfns[i]) {
drop_spte(vcpu->kvm, &sp->spt[i]);
- set_spte_ret |= SET_SPTE_NEED_REMOTE_TLB_FLUSH;
+ flush = true;
continue;
}

- host_writable = sp->spt[i] & shadow_host_writable_mask;
+ sptep = &sp->spt[i];
+ spte = *sptep;
+ host_writable = spte & shadow_host_writable_mask;
+ make_spte(vcpu, pte_access, PG_LEVEL_4K, gfn,
+ spte_to_pfn(spte), spte, true, false,
+ host_writable, sp_ad_disabled(sp), &spte);

- set_spte_ret |= set_spte(vcpu, &sp->spt[i],
- pte_access, PG_LEVEL_4K,
- gfn, spte_to_pfn(sp->spt[i]),
- true, false, host_writable);
+ flush |= mmu_spte_update(sptep, spte);
}

- return set_spte_ret & SET_SPTE_NEED_REMOTE_TLB_FLUSH;
+ return flush;
}

#undef pt_element_t
--
2.27.0