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authorSean Christopherson <seanjc@google.com>2022-01-20 01:07:12 +0000
committerPaolo Bonzini <pbonzini@redhat.com>2022-01-26 12:14:59 -0500
commit31c25585695abdf03d6160aa6d829e855b256329 (patch)
tree90f8530f05f5a80529e6d43d7a7f26f6fe4915b9
parent55467fcd55b89c622e62b4afe60ac0eb2fae91f2 (diff)
Revert "KVM: SVM: avoid infinite loop on NPF from bad address"
Revert a completely broken check on an "invalid" RIP in SVM's workaround for the DecodeAssists SMAP errata. kvm_vcpu_gfn_to_memslot() obviously expects a gfn, i.e. operates in the guest physical address space, whereas RIP is a virtual (not even linear) address. The "fix" worked for the problematic KVM selftest because the test identity mapped RIP. Fully revert the hack instead of trying to translate RIP to a GPA, as the non-SEV case is now handled earlier, and KVM cannot access guest page tables to translate RIP. This reverts commit e72436bc3a5206f95bb384e741154166ddb3202e. Fixes: e72436bc3a52 ("KVM: SVM: avoid infinite loop on NPF from bad address") Reported-by: Liam Merwick <liam.merwick@oracle.com> Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Liam Merwick <liam.merwick@oracle.com> Message-Id: <20220120010719.711476-3-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-rw-r--r--arch/x86/kvm/svm/svm.c7
-rw-r--r--virt/kvm/kvm_main.c1
2 files changed, 0 insertions, 8 deletions
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index a46e1c6abf0e..37eb3168e0ea 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -4312,13 +4312,6 @@ static bool svm_can_emulate_instruction(struct kvm_vcpu *vcpu, void *insn, int i
if (likely(!insn || insn_len))
return true;
- /*
- * If RIP is invalid, go ahead with emulation which will cause an
- * internal error exit.
- */
- if (!kvm_vcpu_gfn_to_memslot(vcpu, kvm_rip_read(vcpu) >> PAGE_SHIFT))
- return true;
-
cr4 = kvm_read_cr4(vcpu);
smep = cr4 & X86_CR4_SMEP;
smap = cr4 & X86_CR4_SMAP;
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 0bbb3cbf6014..2755ba4177d6 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2248,7 +2248,6 @@ struct kvm_memory_slot *kvm_vcpu_gfn_to_memslot(struct kvm_vcpu *vcpu, gfn_t gfn
return NULL;
}
-EXPORT_SYMBOL_GPL(kvm_vcpu_gfn_to_memslot);
bool kvm_is_visible_gfn(struct kvm *kvm, gfn_t gfn)
{