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Message-Id: <20211103161833.3769487-1-seanjc@google.com>
Date: Wed, 3 Nov 2021 09:18:33 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Paolo Bonzini <pbonzini@...hat.com>
Cc: Sean Christopherson <seanjc@...gle.com>,
Vitaly Kuznetsov <vkuznets@...hat.com>,
Wanpeng Li <wanpengli@...cent.com>,
Jim Mattson <jmattson@...gle.com>,
Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
linux-kernel@...r.kernel.org, Ben Gardon <bgardon@...gle.com>
Subject: [PATCH] KVM: x86/mmu: Properly dereference rcu-protected TDP MMU
sptep iterator
Wrap the read of iter->sptep in tdp_mmu_map_handle_target_level() with
rcu_dereference(). Shadow pages in the TDP MMU, and thus their SPTEs,
are protected by rcu.
This fixes a Sparse warning at tdp_mmu.c:900:51:
warning: incorrect type in argument 1 (different address spaces)
expected unsigned long long [usertype] *sptep
got unsigned long long [noderef] [usertype] __rcu *[usertype] sptep
Fixes: 7158bee4b475 ("KVM: MMU: pass kvm_mmu_page struct to make_spte")
Cc: Ben Gardon <bgardon@...gle.com>
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
arch/x86/kvm/mmu/tdp_mmu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index 7c5dd83e52de..a54c3491af42 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -897,7 +897,7 @@ static int tdp_mmu_map_handle_target_level(struct kvm_vcpu *vcpu,
struct kvm_page_fault *fault,
struct tdp_iter *iter)
{
- struct kvm_mmu_page *sp = sptep_to_sp(iter->sptep);
+ struct kvm_mmu_page *sp = sptep_to_sp(rcu_dereference(iter->sptep));
u64 new_spte;
int ret = RET_PF_FIXED;
bool wrprot = false;
--
2.33.1.1089.g2158813163f-goog
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