From: Paolo Bonzini <pbonzini@redhat.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: dmatlack@google.com, seanjc@google.com,
Lai Jiangshan <jiangshanlai@gmail.com>,
Lai Jiangshan <laijs@linux.alibaba.com>
Subject: [PATCH v3 16/31] KVM: x86/mmu: Verify shadow walk doesn't terminate early in page faults
Date: Fri, 24 Sep 2021 12:31:37 -0400 [thread overview]
Message-ID: <20210924163152.289027-17-pbonzini@redhat.com> (raw)
In-Reply-To: <20210924163152.289027-1-pbonzini@redhat.com>
From: Sean Christopherson <seanjc@google.com>
WARN and bail if the shadow walk for faulting in a SPTE terminates early,
i.e. doesn't reach the expected level because the walk encountered a
terminal SPTE. The shadow walks for page faults are subtle in that they
install non-leaf SPTEs (zapping leaf SPTEs if necessary!) in the loop
body, and consume the newly created non-leaf SPTE in the loop control,
e.g. __shadow_walk_next(). In other words, the walks guarantee that the
walk will stop if and only if the target level is reached by installing
non-leaf SPTEs to guarantee the walk remains valid.
Opportunistically use fault->goal-level instead of it.level in
FNAME(fetch) to further clarify that KVM always installs the leaf SPTE at
the target level.
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Message-Id: <20210906122547.263316-1-jiangshanlai@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/mmu/mmu.c | 3 +++
arch/x86/kvm/mmu/paging_tmpl.h | 7 +++++--
2 files changed, 8 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 5ba0a844f576..2ddbabad5bd2 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -3012,6 +3012,9 @@ static int __direct_map(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
account_huge_nx_page(vcpu->kvm, sp);
}
+ if (WARN_ON_ONCE(it.level != fault->goal_level))
+ return -EFAULT;
+
ret = mmu_set_spte(vcpu, it.sptep, ACC_ALL,
fault->write, fault->goal_level, base_gfn, fault->pfn,
fault->prefault, fault->map_writable);
diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
index 6bc0dbc0baff..7a8a2d14a3c7 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -760,9 +760,12 @@ static int FNAME(fetch)(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault,
}
}
+ if (WARN_ON_ONCE(it.level != fault->goal_level))
+ return -EFAULT;
+
ret = mmu_set_spte(vcpu, it.sptep, gw->pte_access, fault->write,
- it.level, base_gfn, fault->pfn, fault->prefault,
- fault->map_writable);
+ fault->goal_level, base_gfn, fault->pfn,
+ fault->prefault, fault->map_writable);
if (ret == RET_PF_SPURIOUS)
return ret;
--
2.27.0
next prev parent reply other threads:[~2021-09-24 16:32 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-24 16:31 [PATCH v3 00/31] KVM: x86: pass arguments on the page fault path via struct kvm_page_fault Paolo Bonzini
2021-09-24 16:31 ` [PATCH v3 01/31] KVM: MMU: pass unadulterated gpa to direct_page_fault Paolo Bonzini
2021-09-24 16:31 ` [PATCH v3 02/31] KVM: MMU: Introduce struct kvm_page_fault Paolo Bonzini
2021-09-28 23:25 ` David Matlack
2021-09-29 11:13 ` Paolo Bonzini
2021-09-24 16:31 ` [PATCH v3 03/31] KVM: MMU: change mmu->page_fault() arguments to kvm_page_fault Paolo Bonzini
2021-09-24 16:31 ` [PATCH v3 04/31] KVM: MMU: change direct_page_fault() " Paolo Bonzini
2021-09-24 16:31 ` [PATCH v3 05/31] KVM: MMU: change page_fault_handle_page_track() " Paolo Bonzini
2021-09-24 16:31 ` [PATCH v3 06/31] KVM: MMU: change kvm_faultin_pfn() " Paolo Bonzini
2021-09-24 16:31 ` [PATCH v3 07/31] KVM: MMU: change handle_abnormal_pfn() " Paolo Bonzini
2021-09-24 16:31 ` [PATCH v3 08/31] KVM: MMU: change __direct_map() " Paolo Bonzini
2021-09-24 16:31 ` [PATCH v3 09/31] KVM: MMU: change FNAME(fetch)() " Paolo Bonzini
2021-09-24 16:31 ` [PATCH v3 10/31] KVM: MMU: change kvm_tdp_mmu_map() " Paolo Bonzini
2021-09-24 16:31 ` [PATCH v3 11/31] KVM: MMU: change tdp_mmu_map_handle_target_level() " Paolo Bonzini
2021-09-24 16:31 ` [PATCH v3 12/31] KVM: MMU: change fast_page_fault() " Paolo Bonzini
2021-09-24 16:31 ` [PATCH v3 13/31] KVM: MMU: change kvm_mmu_hugepage_adjust() " Paolo Bonzini
2021-09-24 16:31 ` [PATCH v3 14/31] KVM: MMU: change disallowed_hugepage_adjust() " Paolo Bonzini
2021-09-24 16:31 ` [PATCH v3 15/31] KVM: MMU: change tracepoints " Paolo Bonzini
2021-09-24 16:31 ` Paolo Bonzini [this message]
2021-09-24 16:31 ` [PATCH v3 17/31] KVM: x86/mmu: Fold rmap_recycle into rmap_add Paolo Bonzini
2021-09-24 16:31 ` [PATCH v3 18/31] KVM: MMU: mark page dirty in make_spte Paolo Bonzini
2021-09-24 16:31 ` [PATCH v3 19/31] KVM: MMU: unify tdp_mmu_map_set_spte_atomic and tdp_mmu_set_spte_atomic_no_dirty_log Paolo Bonzini
2021-09-24 16:31 ` [PATCH v3 20/31] KVM: x86/mmu: Pass the memslot around via struct kvm_page_fault Paolo Bonzini
2021-09-24 16:31 ` [PATCH v3 21/31] KVM: x86/mmu: Avoid memslot lookup in page_fault_handle_page_track Paolo Bonzini
2021-09-24 16:31 ` [PATCH v3 22/31] KVM: MMU: inline set_spte in mmu_set_spte Paolo Bonzini
2021-09-24 16:31 ` [PATCH v3 23/31] KVM: MMU: inline set_spte in FNAME(sync_page) Paolo Bonzini
2021-09-24 16:31 ` [PATCH v3 24/31] KVM: MMU: clean up make_spte return value Paolo Bonzini
2021-09-24 16:31 ` [PATCH v3 25/31] KVM: MMU: remove unnecessary argument to mmu_set_spte Paolo Bonzini
2021-09-24 16:31 ` [PATCH v3 26/31] KVM: MMU: set ad_disabled in TDP MMU role Paolo Bonzini
2021-09-24 16:31 ` [PATCH v3 27/31] KVM: MMU: pass kvm_mmu_page struct to make_spte Paolo Bonzini
2021-09-24 16:31 ` [PATCH v3 28/31] KVM: MMU: pass struct kvm_page_fault to mmu_set_spte Paolo Bonzini
2021-09-24 16:31 ` [PATCH v3 29/31] KVM: x86/mmu: Avoid memslot lookup in rmap_add Paolo Bonzini
2021-09-24 16:31 ` [PATCH v3 30/31] KVM: x86/mmu: Avoid memslot lookup in make_spte and mmu_try_to_unsync_pages Paolo Bonzini
2021-09-24 16:31 ` [PATCH v3 31/31] KVM: MMU: make spte an in-out argument in make_spte Paolo Bonzini
2021-09-28 23:20 ` David Matlack
2021-09-29 11:14 ` Paolo Bonzini
2021-09-28 23:27 ` [PATCH v3 00/31] KVM: x86: pass arguments on the page fault path via struct kvm_page_fault David Matlack
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