x86/traps: replace plain numbers ... making the code better document itself. No functional change intended. Note that for now (as we don't support RTM yet) DR_STATUS_RESERVED_ONE and its users don't take DR_NOT_RTM into consideration yet. Signed-off-by: Jan Beulich --- a/xen/arch/x86/traps.c +++ b/xen/arch/x86/traps.c @@ -531,9 +531,9 @@ static void instruction_done( regs->eflags &= ~X86_EFLAGS_RF; if ( bpmatch || (regs->eflags & X86_EFLAGS_TF) ) { - current->arch.debugreg[6] |= bpmatch | 0xffff0ff0; + current->arch.debugreg[6] |= bpmatch | DR_STATUS_RESERVED_ONE; if ( regs->eflags & X86_EFLAGS_TF ) - current->arch.debugreg[6] |= 0x4000; + current->arch.debugreg[6] |= DR_STEP; do_guest_trap(TRAP_debug, regs, 0); } } @@ -3872,8 +3872,8 @@ long set_debugreg(struct vcpu *v, unsign * DR6: Bits 4-11,16-31 reserved (set to 1). * Bit 12 reserved (set to 0). */ - value &= 0xffffefff; /* reserved bits => 0 */ - value |= 0xffff0ff0; /* reserved bits => 1 */ + value &= ~DR_STATUS_RESERVED_ZERO; /* reserved bits => 0 */ + value |= DR_STATUS_RESERVED_ONE; /* reserved bits => 1 */ if ( v == curr ) write_debugreg(6, value); break; --- a/xen/include/asm-x86/debugreg.h +++ b/xen/include/asm-x86/debugreg.h @@ -21,6 +21,8 @@ #define DR_STEP (0x4000) /* single-step */ #define DR_SWITCH (0x8000) /* task switch */ #define DR_NOT_RTM (0x10000) /* clear: #BP inside RTM region */ +#define DR_STATUS_RESERVED_ZERO (~0xffffeffful) /* Reserved, read as zero */ +#define DR_STATUS_RESERVED_ONE 0xffff0ff0ul /* Reserved, read as one */ /* Now define a bunch of things for manipulating the control register. The top two bytes of the control register consist of 4 fields of 4