• Jim Mattson's avatar
    KVM: nVMX: Clear reserved bits of #DB exit qualification · 7d6c6f83
    Jim Mattson authored
    [ Upstream commit cfb634fe3052aefc4e1360fa322018c9a0b49755 ]
    
    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: b96fb439 ("KVM: nVMX: fixes to nested virt interrupt injection")
    Signed-off-by: 's avatarJim Mattson <jmattson@google.com>
    Reviewed-by: 's avatarSean Christopherson <sean.j.christopherson@intel.com>
    Signed-off-by: 's avatarPaolo Bonzini <pbonzini@redhat.com>
    Signed-off-by: 's avatarSasha Levin <sashal@kernel.org>
    Signed-off-by: 's avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    7d6c6f83
kvm_host.h 41.1 KB