Re: [PATCH 0 of 7] x86/paravirt: optimise pvop calls and register use

[Jeremy Fitzhardinge <jeremy@goop.org>]

Ingo Molnar wrote:
> there's some build trouble on VMI:
>
> arch/x86/kernel/vmi_32.c: In function ‘activate_vmi’:
> arch/x86/kernel/vmi_32.c:673: error: incompatible types in assignment
> arch/x86/kernel/vmi_32.c:673: error: incompatible types in assignment
> arch/x86/kernel/vmi_32.c:674: error: incompatible types in assignment
> arch/x86/kernel/vmi_32.c:674: error: incompatible types in assignment
> arch/x86/kernel/vmi_32.c:675: error: incompatible types in assignment
> arch/x86/kernel/vmi_32.c:675: error: incompatible types in assignment
> arch/x86/kernel/vmi_32.c:676: error: incompatible types in assignment
> arch/x86/kernel/vmi_32.c:676: error: incompatible types in assignment
>   

Yes.  I sent a couple of fix patches last night, which included a fix 
for this.

    J

Subject: x86/vmi: fix interrupt enable/disable/save/restore calling convention.

Zach says:
> Enable/Disable have no clobbers at all.
> Save clobbers only return value, %eax
> Restore also clobbers nothing.

This is precisely compatible with the calling convention, so we can
just call them directly without wrapping.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
---
 arch/x86/kernel/vmi_32.c |    9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

===================================================================
--- a/arch/x86/kernel/vmi_32.c
+++ b/arch/x86/kernel/vmi_32.c
@@ -670,10 +670,11 @@
 	para_fill(pv_mmu_ops.write_cr2, SetCR2);
 	para_fill(pv_mmu_ops.write_cr3, SetCR3);
 	para_fill(pv_cpu_ops.write_cr4, SetCR4);
-	para_fill(pv_irq_ops.save_fl, GetInterruptMask);
-	para_fill(pv_irq_ops.restore_fl, SetInterruptMask);
-	para_fill(pv_irq_ops.irq_disable, DisableInterrupts);
-	para_fill(pv_irq_ops.irq_enable, EnableInterrupts);
+
+	para_fill(pv_irq_ops.save_fl.func, GetInterruptMask);
+	para_fill(pv_irq_ops.restore_fl.func, SetInterruptMask);
+	para_fill(pv_irq_ops.irq_disable.func, DisableInterrupts);
+	para_fill(pv_irq_ops.irq_enable.func, EnableInterrupts);
 
 	para_fill(pv_cpu_ops.wbinvd, WBINVD);
 	para_fill(pv_cpu_ops.read_tsc, RDTSC);