Improve handle_external_interrupt_irqoff inline assembly in several ways:
- use __stringify to use __KERNEL_DS and __KERNEL_CS directly in assembler
- use %rsp instead of _ASM_SP, since we are in CONFIG_X86_64 part
- use $-16 immediate to align %rsp
- avoid earlyclobber by using "l" GCC input operand constraint
- avoid temporary by using current_stack_pointer
The patch introduces no functional change.
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
Signed-off-by: Uros Bizjak <ubizjak@xxxxxxxxx>
---
arch/x86/kvm/vmx/vmx.c | 19 ++++++-------------
1 file changed, 6 insertions(+), 13 deletions(-)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 01330096ff3e..4b0d5f0044ff 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6233,9 +6233,6 @@ static void handle_external_interrupt_irqoff(struct kvm_vcpu *vcpu)
{
unsigned int vector;
unsigned long entry;
-#ifdef CONFIG_X86_64
- unsigned long tmp;
-#endif
gate_desc *desc;
u32 intr_info;
@@ -6252,23 +6249,19 @@ static void handle_external_interrupt_irqoff(struct kvm_vcpu *vcpu)
asm volatile(
#ifdef CONFIG_X86_64
- "mov %%" _ASM_SP ", %[sp]\n\t"
- "and $0xfffffffffffffff0, %%" _ASM_SP "\n\t"
- "push $%c[ss]\n\t"
+ "and $-16, %%rsp\n\t"
+ "push $" __stringify(__KERNEL_DS) "\n\t"
"push %[sp]\n\t"
#endif
"pushf\n\t"
- __ASM_SIZE(push) " $%c[cs]\n\t"
+ __ASM_SIZE(push) " $" __stringify(__KERNEL_CS) "\n\t"
CALL_NOSPEC
+ : ASM_CALL_CONSTRAINT
:
#ifdef CONFIG_X86_64
- [sp]"=&r"(tmp),
+ [sp]"l"(current_stack_pointer),
#endif
- ASM_CALL_CONSTRAINT
- :
- [thunk_target]"r"(entry),
- [ss]"i"(__KERNEL_DS),
- [cs]"i"(__KERNEL_CS)
+ [thunk_target]"r"(entry)
);
kvm_after_interrupt(vcpu);
--
2.25.2
