With the following commit, shadow pages can be zapped at random during
a shadow page talbe walk:
KVM: MMU: Move kvm_mmu_free_some_pages() into kvm_mmu_alloc_page()
7ddca7e43c8f28f9419da81a0e7730b66aa60fe9
This patch reverts it and fixes __direct_map() and FNAME(fetch)().
Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@xxxxxxxxxxxxx>
---
arch/x86/kvm/mmu.c | 11 +++++++----
arch/x86/kvm/paging_tmpl.h | 1 +
2 files changed, 8 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 633e30c..004cc87 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1501,15 +1501,11 @@ static void drop_parent_pte(struct kvm_mmu_page *sp,
mmu_spte_clear_no_track(parent_pte);
}
-static void make_mmu_pages_available(struct kvm_vcpu *vcpu);
-
static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu,
u64 *parent_pte, int direct)
{
struct kvm_mmu_page *sp;
- make_mmu_pages_available(vcpu);
-
sp = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache);
sp->spt = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache);
if (!direct)
@@ -2806,6 +2802,7 @@ exit:
static bool try_async_pf(struct kvm_vcpu *vcpu, bool prefault, gfn_t gfn,
gva_t gva, pfn_t *pfn, bool write, bool *writable);
+static void make_mmu_pages_available(struct kvm_vcpu *vcpu);
static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, u32 error_code,
gfn_t gfn, bool prefault)
@@ -2847,6 +2844,7 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, u32 error_code,
spin_lock(&vcpu->kvm->mmu_lock);
if (mmu_notifier_retry(vcpu->kvm, mmu_seq))
goto out_unlock;
+ make_mmu_pages_available(vcpu);
if (likely(!force_pt_level))
transparent_hugepage_adjust(vcpu, &gfn, &pfn, &level);
r = __direct_map(vcpu, v, write, map_writable, level, gfn, pfn,
@@ -2924,6 +2922,7 @@ static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu)
if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
spin_lock(&vcpu->kvm->mmu_lock);
+ make_mmu_pages_available(vcpu);
sp = kvm_mmu_get_page(vcpu, 0, 0, PT64_ROOT_LEVEL,
1, ACC_ALL, NULL);
++sp->root_count;
@@ -2935,6 +2934,7 @@ static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu)
ASSERT(!VALID_PAGE(root));
spin_lock(&vcpu->kvm->mmu_lock);
+ make_mmu_pages_available(vcpu);
sp = kvm_mmu_get_page(vcpu, i << (30 - PAGE_SHIFT),
i << 30,
PT32_ROOT_LEVEL, 1, ACC_ALL,
@@ -2973,6 +2973,7 @@ static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu)
ASSERT(!VALID_PAGE(root));
spin_lock(&vcpu->kvm->mmu_lock);
+ make_mmu_pages_available(vcpu);
sp = kvm_mmu_get_page(vcpu, root_gfn, 0, PT64_ROOT_LEVEL,
0, ACC_ALL, NULL);
root = __pa(sp->spt);
@@ -3006,6 +3007,7 @@ static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu)
return 1;
}
spin_lock(&vcpu->kvm->mmu_lock);
+ make_mmu_pages_available(vcpu);
sp = kvm_mmu_get_page(vcpu, root_gfn, i << 30,
PT32_ROOT_LEVEL, 0,
ACC_ALL, NULL);
@@ -3311,6 +3313,7 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa, u32 error_code,
spin_lock(&vcpu->kvm->mmu_lock);
if (mmu_notifier_retry(vcpu->kvm, mmu_seq))
goto out_unlock;
+ make_mmu_pages_available(vcpu);
if (likely(!force_pt_level))
transparent_hugepage_adjust(vcpu, &gfn, &pfn, &level);
r = __direct_map(vcpu, gpa, write, map_writable,
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index af143f0..da20860 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -627,6 +627,7 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, u32 error_code,
goto out_unlock;
kvm_mmu_audit(vcpu, AUDIT_PRE_PAGE_FAULT);
+ make_mmu_pages_available(vcpu);
if (!force_pt_level)
transparent_hugepage_adjust(vcpu, &walker.gfn, &pfn, &level);
r = FNAME(fetch)(vcpu, addr, &walker, write_fault,
--
1.7.5.4
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