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authorJim Mattson <jmattson@google.com>2018-09-21 10:36:17 -0700
committerPaolo Bonzini <pbonzini@redhat.com>2018-10-17 00:29:39 +0200
commitcfb634fe3052aefc4e1360fa322018c9a0b49755 (patch)
tree87d79c308789f14e160376b6a883804fab9990a8 /arch/x86/kvm/vmx.c
parent5b8ee8792f6bda46978e6e86fda4650bcbae07ab (diff)
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KVM: nVMX: Clear reserved bits of #DB exit qualification
According to volume 3 of the SDM, bits 63:15 and 12:4 of the exit qualification field for debug exceptions are reserved (cleared to 0). However, the SDM is incorrect about bit 16 (corresponding to DR6.RTM). This bit should be set if a debug exception (#DB) or a breakpoint exception (#BP) occurred inside an RTM region while advanced debugging of RTM transactional regions was enabled. Note that this is the opposite of DR6.RTM, which "indicates (when clear) that a debug exception (#DB) or breakpoint exception (#BP) occurred inside an RTM region while advanced debugging of RTM transactional regions was enabled." There is still an issue with stale DR6 bits potentially being misreported for the current debug exception. DR6 should not have been modified before vectoring the #DB exception, and the "new DR6 bits" should be available somewhere, but it was and they aren't. Fixes: b96fb439774e1 ("KVM: nVMX: fixes to nested virt interrupt injection") Signed-off-by: Jim Mattson <jmattson@google.com> Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/vmx.c')
-rw-r--r--arch/x86/kvm/vmx.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index b3c5517a89b3..14d446366ca5 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3290,10 +3290,13 @@ static int nested_vmx_check_exception(struct kvm_vcpu *vcpu, unsigned long *exit
}
} else {
if (vmcs12->exception_bitmap & (1u << nr)) {
- if (nr == DB_VECTOR)
+ if (nr == DB_VECTOR) {
*exit_qual = vcpu->arch.dr6;
- else
+ *exit_qual &= ~(DR6_FIXED_1 | DR6_BT);
+ *exit_qual ^= DR6_RTM;
+ } else {
*exit_qual = 0;
+ }
return 1;
}
}