[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH RFC v12 03/21] Remove an unnecessary assert from vmx_update_debug_state
>>> On 18.09.13 at 12:39, George Dunlap <George.Dunlap@xxxxxxxxxxxxx> wrote: > On Mon, Sep 16, 2013 at 10:09 PM, Mukesh Rathor > <mukesh.rathor@xxxxxxxxxx> wrote: >> On Fri, 13 Sep 2013 17:25:03 +0100 >> George Dunlap <george.dunlap@xxxxxxxxxxxxx> wrote: >> >>> As far as I can tell, there's nothing here that requires v to be >>> current. vmx_update_exception_bitmap() is updated in other situations >>> where v!=current. >>> >>> Removing this allows the PVH code to call this during vmcs >>> construction in a later patch, making the code more robust by removing >>> duplicate code. >>> >>> Signed-off-by: George Dunlap <george.dunlap@xxxxxxxxxxxxx> >>> CC: Mukesh Rathor <mukesh.rathor@xxxxxxxxxx> >>> CC: Jan Beulich <jan.beulich@xxxxxxxx> >>> CC: Tim Deegan <tim@xxxxxxx> >>> CC: Keir Fraser <keir@xxxxxxx> >>> --- >>> xen/arch/x86/hvm/vmx/vmx.c | 2 -- >>> 1 file changed, 2 deletions(-) >>> >>> diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c >>> index 8ed7026..f02e47a 100644 >>> --- a/xen/arch/x86/hvm/vmx/vmx.c >>> +++ b/xen/arch/x86/hvm/vmx/vmx.c >>> @@ -1041,8 +1041,6 @@ void vmx_update_debug_state(struct vcpu *v) >>> { >>> unsigned long mask; >>> >>> - ASSERT(v == current); >>> - >>> mask = 1u << TRAP_int3; >>> if ( !cpu_has_monitor_trap_flag ) >>> mask |= 1u << TRAP_debug; >> >> >> vmx_update_exception_bitmap() writes EXCEPTION_BITMAP of current vmcs, >> ie of current vcpu. If v != current, you'd be writing the bitmap of >> wrong vcpu. If the assertion is removed, then the function would need >> to vmx enter... > > You mean, callers would need to call vmcs_enter before calling it. > Hmm... is there an assert for that? This is basically what the assertion you're removing does, albeit restricting it more than it needs to be. But - do you have a use case for the function when v != current? Jan _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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