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| author | Sean Christopherson <seanjc@google.com> | 2022-01-20 04:07:12 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-02-01 19:27:01 +0300 |
| commit | b17cb93dda1dcdc9737c8b334e850c18dc6b0b7d (patch) | |
| tree | 113a31438c74e28989d520f80607f0743a2ada74 | |
| parent | e6023ab8c729b9edb99c6bc5f0169f474deeabe5 (diff) | |
| download | linux-b17cb93dda1dcdc9737c8b334e850c18dc6b0b7d.tar.xz | |
Revert "KVM: SVM: avoid infinite loop on NPF from bad address"
commit 31c25585695abdf03d6160aa6d829e855b256329 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/x86/kvm/svm/svm.c | 7 | ||||
| -rw-r--r-- | virt/kvm/kvm_main.c | 1 |
2 files changed, 0 insertions, 8 deletions
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index e64f16237b60..f7e9cdee0d8d 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -4456,13 +4456,6 @@ 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 c6bfd4e15d28..13aff136e6ee 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -2104,7 +2104,6 @@ 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) { |