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Message-ID: <20250424030634.369-1-yan.y.zhao@intel.com>
Date: Thu, 24 Apr 2025 11:06:34 +0800
From: Yan Zhao <yan.y.zhao@...el.com>
To: pbonzini@...hat.com,
seanjc@...gle.com
Cc: linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
x86@...nel.org, rick.p.edgecombe@...el.com, dave.hansen@...el.com,
kirill.shutemov@...el.com, tabba@...gle.com, ackerleytng@...gle.com,
quic_eberman@...cinc.com, michael.roth@....com, david@...hat.com,
vannapurve@...gle.com, vbabka@...e.cz, jroedel@...e.de,
thomas.lendacky@....com, pgonda@...gle.com, zhiquan1.li@...el.com,
fan.du@...el.com, jun.miao@...el.com, ira.weiny@...el.com,
isaku.yamahata@...el.com, xiaoyao.li@...el.com,
binbin.wu@...ux.intel.com, chao.p.peng@...el.com,
Edgecombe@....codeaurora.org, Yan Zhao <yan.y.zhao@...el.com>
Subject: [RFC PATCH 10/21] KVM: x86/mmu: Disallow page merging (huge page adjustment) for mirror root
From: "Edgecombe, Rick P" <rick.p.edgecombe@...el.com>
Disallow page merging (huge page adjustment) for mirror root by leveraging
the disallowed_hugepage_adjust().
[Yan: Passing is_mirror to disallowed_hugepage_adjust()]
Signed-off-by: Edgecombe, Rick P <rick.p.edgecombe@...el.com>
Signed-off-by: Yan Zhao <yan.y.zhao@...el.com>
---
arch/x86/kvm/mmu/mmu.c | 6 +++---
arch/x86/kvm/mmu/mmu_internal.h | 2 +-
arch/x86/kvm/mmu/paging_tmpl.h | 2 +-
arch/x86/kvm/mmu/tdp_mmu.c | 7 ++++---
4 files changed, 9 insertions(+), 8 deletions(-)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index a284dce227a0..b923deeeb62e 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -3326,13 +3326,13 @@ void kvm_mmu_hugepage_adjust(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault
fault->pfn &= ~mask;
}
-void disallowed_hugepage_adjust(struct kvm_page_fault *fault, u64 spte, int cur_level)
+void disallowed_hugepage_adjust(struct kvm_page_fault *fault, u64 spte, int cur_level, bool is_mirror)
{
if (cur_level > PG_LEVEL_4K &&
cur_level == fault->goal_level &&
is_shadow_present_pte(spte) &&
!is_large_pte(spte) &&
- spte_to_child_sp(spte)->nx_huge_page_disallowed) {
+ (spte_to_child_sp(spte)->nx_huge_page_disallowed || is_mirror)) {
/*
* A small SPTE exists for this pfn, but FNAME(fetch),
* direct_map(), or kvm_tdp_mmu_map() would like to create a
@@ -3363,7 +3363,7 @@ static int direct_map(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
* large page, as the leaf could be executable.
*/
if (fault->nx_huge_page_workaround_enabled)
- disallowed_hugepage_adjust(fault, *it.sptep, it.level);
+ disallowed_hugepage_adjust(fault, *it.sptep, it.level, false);
base_gfn = gfn_round_for_level(fault->gfn, it.level);
if (it.level == fault->goal_level)
diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h
index db8f33e4de62..1c1764f46e66 100644
--- a/arch/x86/kvm/mmu/mmu_internal.h
+++ b/arch/x86/kvm/mmu/mmu_internal.h
@@ -411,7 +411,7 @@ static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
int kvm_mmu_max_mapping_level(struct kvm *kvm,
const struct kvm_memory_slot *slot, gfn_t gfn);
void kvm_mmu_hugepage_adjust(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault);
-void disallowed_hugepage_adjust(struct kvm_page_fault *fault, u64 spte, int cur_level);
+void disallowed_hugepage_adjust(struct kvm_page_fault *fault, u64 spte, int cur_level, bool is_mirror);
void track_possible_nx_huge_page(struct kvm *kvm, struct kvm_mmu_page *sp);
void untrack_possible_nx_huge_page(struct kvm *kvm, struct kvm_mmu_page *sp);
diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
index 68e323568e95..1559182038e3 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -717,7 +717,7 @@ static int FNAME(fetch)(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault,
* large page, as the leaf could be executable.
*/
if (fault->nx_huge_page_workaround_enabled)
- disallowed_hugepage_adjust(fault, *it.sptep, it.level);
+ disallowed_hugepage_adjust(fault, *it.sptep, it.level, false);
base_gfn = gfn_round_for_level(fault->gfn, it.level);
if (it.level == fault->goal_level)
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index 405874f4d088..8ee01277cc07 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -1244,6 +1244,7 @@ int kvm_tdp_mmu_map(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
struct tdp_iter iter;
struct kvm_mmu_page *sp;
int ret = RET_PF_RETRY;
+ bool is_mirror = is_mirror_sp(root);
kvm_mmu_hugepage_adjust(vcpu, fault);
@@ -1254,8 +1255,8 @@ int kvm_tdp_mmu_map(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
for_each_tdp_pte(iter, kvm, root, fault->gfn, fault->gfn + 1) {
int r;
- if (fault->nx_huge_page_workaround_enabled)
- disallowed_hugepage_adjust(fault, iter.old_spte, iter.level);
+ if (fault->nx_huge_page_workaround_enabled || is_mirror)
+ disallowed_hugepage_adjust(fault, iter.old_spte, iter.level, is_mirror);
/*
* If SPTE has been frozen by another thread, just give up and
@@ -1278,7 +1279,7 @@ int kvm_tdp_mmu_map(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
*/
sp = tdp_mmu_alloc_sp(vcpu);
tdp_mmu_init_child_sp(sp, &iter);
- if (is_mirror_sp(sp))
+ if (is_mirror)
kvm_mmu_alloc_external_spt(vcpu, sp);
sp->nx_huge_page_disallowed = fault->huge_page_disallowed;
--
2.43.2
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