On Mon, May 04, 2020 at 01:05:45AM +0200, Uros Bizjak wrote: > Improve handle_external_interrupt_irqoff inline assembly in several ways: > - use "re" operand constraint instead of "i" and remove > unneeded %c operand modifiers and "$" prefixes > - use %rsp instead of _ASM_SP, since we are in CONFIG_X86_64 part > - use $-16 immediate to align %rsp > - remove unneeded use of __ASM_SIZE macro > - define "ss" named operand only for X86_64 > > The patch introduces no functional changes. Hmm, for handcoded assembly I would argue that the switch from "i" to "re" is a functional change of sorts. The switch also needs explicit justification to explain why it's correct/desirable. Maybe make it a separate patch? > 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 | 14 ++++++++------ > 1 file changed, 8 insertions(+), 6 deletions(-) > > diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c > index c2c6335a998c..56c742effb30 100644 > --- a/arch/x86/kvm/vmx/vmx.c > +++ b/arch/x86/kvm/vmx/vmx.c > @@ -6283,13 +6283,13 @@ 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" > + "mov %%rsp, %[sp]\n\t" > + "and $-16, %%rsp\n\t" > + "push %[ss]\n\t" > "push %[sp]\n\t" > #endif > "pushf\n\t" > - __ASM_SIZE(push) " $%c[cs]\n\t" > + "push %[cs]\n\t" > CALL_NOSPEC > : > #ifdef CONFIG_X86_64 > @@ -6298,8 +6298,10 @@ static void handle_external_interrupt_irqoff(struct kvm_vcpu *vcpu) > ASM_CALL_CONSTRAINT > : > [thunk_target]"r"(entry), > - [ss]"i"(__KERNEL_DS), > - [cs]"i"(__KERNEL_CS) > +#ifdef CONFIG_X86_64 > + [ss]"re"(__KERNEL_DS), > +#endif > + [cs]"re"(__KERNEL_CS) > ); > > kvm_after_interrupt(vcpu); > -- > 2.25.4 >
