Messages in this thread Patch in this message | | | Date | Mon, 2 May 2022 19:56:16 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH V6 6/8] x86/entry: Convert SWAPGS to swapgs and remove the definition of SWAPGS |
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On Mon, May 02, 2022 at 02:18:35PM +0200, Juergen Gross wrote: > The syscall will land in the hypervisor, which then will activate > the related registered callback (xen_sysenter_target).
Aha, that would do a bit of a fixup and then go to the common label entry_SYSENTER_compat_after_hwframe.
We probably should document this so that it is clear what uses those...
--- diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 9da5eef9affe..93065c4914ad 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -103,6 +103,11 @@ SYM_INNER_LABEL(entry_SYSCALL_64_safe_stack, SYM_L_GLOBAL) pushq %r11 /* pt_regs->flags */ pushq $__USER_CS /* pt_regs->cs */ pushq %rcx /* pt_regs->ip */ + + /* + * XENPV jumps here after frame fixup in the respective entry points in + * ...xen-asm.S. + */ SYM_INNER_LABEL(entry_SYSCALL_64_after_hwframe, SYM_L_GLOBAL) pushq %rax /* pt_regs->orig_ax */ diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S index c5aeb0819707..b473f8e17afc 100644 --- a/arch/x86/entry/entry_64_compat.S +++ b/arch/x86/entry/entry_64_compat.S @@ -71,6 +71,11 @@ SYM_CODE_START(entry_SYSENTER_compat) pushfq /* pt_regs->flags (except IF = 0) */ pushq $__USER32_CS /* pt_regs->cs */ pushq $0 /* pt_regs->ip = 0 (placeholder) */ + + /* + * XENPV jumps here after frame fixup in the respective entry points in + * ...xen-asm.S. + */ SYM_INNER_LABEL(entry_SYSENTER_compat_after_hwframe, SYM_L_GLOBAL) /* > I wouldn't insist on the CONFIG_DEBUG_ENTRY chunk.
Ok, simpler asm, cool, let's do it then.
Thx.
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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