Re: [Xen-devel] 回复: [PATCH] x86/spec_ctrl: Fix several bugs in SPEC_CTRL_ENTRY_FROM_INTR_IST

On 14/02/18 12:08, zhenzhong.duan wrote: > > > @@ -286,13 +286,13 @@ > > setz %dl > > and %dl, STACK_CPUINFO_FIELD(use_shadow_spec_ctrl)(%r14) > Is it safe to remove the 'xor %edx, %edx' above? setz set whole byte 1 > or 0. > It is safe, but it is not a good idea. Using setz is an 8bit

[Xen-devel] 回复: [PATCH] x86/spec_ctrl: Fix several bugs in SPEC_CTRL_ENTRY_FROM_INTR_IST

2018年2月14日 19:10于 Andrew Cooper 写道： > > DO_OVERWRITE_RSB clobbers %rax, meaning in practice that that the > bti_ist_info > field gets zeroed.  Older versions of this code had the DO_OVERWRITE_RSB > register selectable, so reintroduce this ability and use it to cause