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SubjectRe: [PATCH] x86/sev: Add ENCODE_FRAME_POINTER after stack changed for #VC
On Wed, Mar 16, 2022 at 12:16:12PM +0800, Lai Jiangshan wrote:
> From: Lai Jiangshan <jiangshan.ljs@antgroup.com>
>
> In idtentry_vc(), the real frame is changed after it switches to new
> stack, ENCODE_FRAME_POINTER should be called in case for unwinder.
>
> Cc: Joerg Roedel <jroedel@suse.de>
> Cc: Josh Poimboeuf <jpoimboe@redhat.com>
> Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
> ---
> arch/x86/entry/entry_64.S | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
> index e20eabaa56b8..f99f2881ed83 100644
> --- a/arch/x86/entry/entry_64.S
> +++ b/arch/x86/entry/entry_64.S
> @@ -540,6 +540,7 @@ SYM_CODE_START(\asmsym)
> call vc_switch_off_ist
> movq %rax, %rsp /* Switch to new stack */
>
> + ENCODE_FRAME_POINTER
> UNWIND_HINT_REGS
>
> /* Update pt_regs */

Looks right to me. Any chance you have the ability to test this
scenario by unwinding from #VC with CONFIG_FRAME_POINTER?

--
Josh

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