[PATCH v2 7/8] KVM: x86/mmu: Hoist ITLB multi-hit workaround check up a level

From: Sean Christopherson
Date: Wed Sep 23 2020 - 14:43:04 EST


Move the "ITLB multi-hit workaround enabled" check into the callers of
disallowed_hugepage_adjust() to make it more obvious that the helper is
specific to the workaround, and to be consistent with the accounting,
i.e. account_huge_nx_page() is called if and only if the workaround is
enabled.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
---
arch/x86/kvm/mmu/mmu.c | 4 ++--
arch/x86/kvm/mmu/paging_tmpl.h | 3 ++-
2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 0957795be384..fbee958927ce 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -3302,7 +3302,6 @@ static void disallowed_hugepage_adjust(struct kvm_shadow_walk_iterator it,
u64 spte = *it.sptep;

if (it.level == level && level > PG_LEVEL_4K &&
- is_nx_huge_page_enabled() &&
is_shadow_present_pte(spte) &&
!is_large_pte(spte)) {
/*
@@ -3344,7 +3343,8 @@ static int __direct_map(struct kvm_vcpu *vcpu, gpa_t gpa, u32 error_code,
* We cannot overwrite existing page tables with an NX
* large page, as the leaf could be executable.
*/
- disallowed_hugepage_adjust(it, gfn, &pfn, &level);
+ if (nx_huge_page_workaround_enabled)
+ disallowed_hugepage_adjust(it, gfn, &pfn, &level);

base_gfn = gfn & ~(KVM_PAGES_PER_HPAGE(it.level) - 1);
if (it.level == level)
diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
index 26dde437abc0..84ea1094fbe2 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -694,7 +694,8 @@ static int FNAME(fetch)(struct kvm_vcpu *vcpu, gpa_t addr,
* We cannot overwrite existing page tables with an NX
* large page, as the leaf could be executable.
*/
- disallowed_hugepage_adjust(it, gw->gfn, &pfn, &level);
+ if (nx_huge_page_workaround_enabled)
+ disallowed_hugepage_adjust(it, gw->gfn, &pfn, &level);

base_gfn = gw->gfn & ~(KVM_PAGES_PER_HPAGE(it.level) - 1);
if (it.level == level)
--
2.28.0