diff --git a/tools/testing/selftests/kvm/lib/x86/ucall.c b/tools/testing/selftests/kvm/lib/x86/ucall.c index e7dd5791959b..38050c60a067 100644 --- a/tools/testing/selftests/kvm/lib/x86/ucall.c +++ b/tools/testing/selftests/kvm/lib/x86/ucall.c @@ -10,36 +10,8 @@ void ucall_arch_do_ucall(gva_t uc) { - /* - * FIXME: Revert this hack (the entire commit that added it) once nVMX - * preserves L2 GPRs across a nested VM-Exit. If a ucall from L2, e.g. - * to do a GUEST_SYNC(), lands the vCPU in L1, any and all GPRs can be - * clobbered by L1. Save and restore non-volatile GPRs (clobbering RBP - * in particular is problematic) along with RDX and RDI (which are - * inputs), and clobber volatile GPRs. *sigh* - */ -#define HORRIFIC_L2_UCALL_CLOBBER_HACK \ - "rcx", "rsi", "r8", "r9", "r10", "r11" - - asm volatile("push %%rbp\n\t" - "push %%r15\n\t" - "push %%r14\n\t" - "push %%r13\n\t" - "push %%r12\n\t" - "push %%rbx\n\t" - "push %%rdx\n\t" - "push %%rdi\n\t" - "in %[port], %%al\n\t" - "pop %%rdi\n\t" - "pop %%rdx\n\t" - "pop %%rbx\n\t" - "pop %%r12\n\t" - "pop %%r13\n\t" - "pop %%r14\n\t" - "pop %%r15\n\t" - "pop %%rbp\n\t" - : : [port] "d" (UCALL_PIO_PORT), "D" (uc) : "rax", "memory", - HORRIFIC_L2_UCALL_CLOBBER_HACK); + asm volatile("in %[port], %%al" + : : [port] "d" (UCALL_PIO_PORT), "D" (uc) : "rax", "memory"); } void *ucall_arch_get_ucall(struct kvm_vcpu *vcpu)