3.2.74-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Paolo Bonzini <pbonz...@redhat.com>
commit cbdb967af3d54993f5814f1cee0ed311a055377d upstream.
This is needed to avoid the possibility that the guest triggers
an infinite stream of #DB exceptions (CVE-2015-8104).
VMX is not affected: because it does not save DR6 in the VMCS,
it already intercepts #DB unconditionally.
Reported-by: Jan Beulich <jbeul...@suse.com>
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
[bwh: Backported to 3.2: #DB and #BP did not share a function, and there is
no operation pointer referring to it, so remove update_db_intercept()
entirely]
Signed-off-by: Ben Hutchings <b...@decadent.org.uk>
---
arch/x86/kvm/svm.c | 14 +++-----------
1 file changed, 3 insertions(+), 11 deletions(-)
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1015,6 +1015,7 @@ static void init_vmcb(struct vcpu_svm *s
set_exception_intercept(svm, UD_VECTOR);
set_exception_intercept(svm, MC_VECTOR);
set_exception_intercept(svm, AC_VECTOR);
+ set_exception_intercept(svm, DB_VECTOR);
set_intercept(svm, INTERCEPT_INTR);
set_intercept(svm, INTERCEPT_NMI);
@@ -1550,26 +1551,6 @@ static void svm_set_segment(struct kvm_v
mark_dirty(svm->vmcb, VMCB_SEG);
}
-static void update_db_intercept(struct kvm_vcpu *vcpu)
-{
- struct vcpu_svm *svm = to_svm(vcpu);
-
- clr_exception_intercept(svm, DB_VECTOR);
- clr_exception_intercept(svm, BP_VECTOR);
-
- if (svm->nmi_singlestep)
- set_exception_intercept(svm, DB_VECTOR);
-
- if (vcpu->guest_debug & KVM_GUESTDBG_ENABLE) {
- if (vcpu->guest_debug &
- (KVM_GUESTDBG_SINGLESTEP | KVM_GUESTDBG_USE_HW_BP))
- set_exception_intercept(svm, DB_VECTOR);
- if (vcpu->guest_debug & KVM_GUESTDBG_USE_SW_BP)
- set_exception_intercept(svm, BP_VECTOR);
- } else
- vcpu->guest_debug = 0;
-}
-
static void svm_guest_debug(struct kvm_vcpu *vcpu, struct kvm_guest_debug *dbg)
{
struct vcpu_svm *svm = to_svm(vcpu);
@@ -1580,8 +1561,6 @@ static void svm_guest_debug(struct kvm_v
svm->vmcb->save.dr7 = vcpu->arch.dr7;
mark_dirty(svm->vmcb, VMCB_DR);
-
- update_db_intercept(vcpu);
}
static void new_asid(struct vcpu_svm *svm, struct svm_cpu_data *sd)
@@ -1655,7 +1634,6 @@ static int db_interception(struct vcpu_s
if (!(svm->vcpu.guest_debug & KVM_GUESTDBG_SINGLESTEP))
svm->vmcb->save.rflags &=
~(X86_EFLAGS_TF | X86_EFLAGS_RF);
- update_db_intercept(&svm->vcpu);
}
if (svm->vcpu.guest_debug &
@@ -3557,7 +3535,6 @@ static void enable_nmi_window(struct kvm
*/
svm->nmi_singlestep = true;
svm->vmcb->save.rflags |= (X86_EFLAGS_TF | X86_EFLAGS_RF);
- update_db_intercept(vcpu);
}
static int svm_set_tss_addr(struct kvm *kvm, unsigned int addr)
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
