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

2018-02-14 Thread Andrew Cooper
On 14/02/18 11:47, Roger Pau Monné wrote: > >> diff --git a/xen/include/asm-x86/spec_ctrl_asm.h >> b/xen/include/asm-x86/spec_ctrl_asm.h >> index 814f53d..1f78599 100644 >> --- a/xen/include/asm-x86/spec_ctrl_asm.h >> +++ b/xen/include/asm-x86/spec_ctrl_asm.h >> @@ -79,10 +79,10 @@ >> * -

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

2018-02-14 Thread Wei Liu
On Wed, Feb 14, 2018 at 11:10:55AM +, Andrew Cooper wrote: > 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 the >

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

2018-02-14 Thread Roger Pau Monné
On Wed, Feb 14, 2018 at 11:10:55AM +, Andrew Cooper wrote: > DO_OVERWRITE_RSB clobbers %rax, meaning in practice that that the bti_ist_info ^dup > field gets zeroed. Older versions of this code had the DO_OVERWRITE_RSB > register

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

2018-02-14 Thread Jan Beulich
>>> On 14.02.18 at 12:10, wrote: > 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 the >