KVM: PPC: elide struct thread_struct instances from stack
Instead of instantiating a whole thread_struct on the stack use only the
required parts of it.
Signed-off-by: Andreas Schwab <schwab@linux-m68k.org>
Tested-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/arch/powerpc/kvm/book3s.c b/arch/powerpc/kvm/book3s.c
index f6eac2f..801d9f3 100644
--- a/arch/powerpc/kvm/book3s.c
+++ b/arch/powerpc/kvm/book3s.c
@@ -1293,12 +1293,17 @@
int __kvmppc_vcpu_run(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
{
int ret;
- struct thread_struct ext_bkp;
+ double fpr[32][TS_FPRWIDTH];
+ unsigned int fpscr;
+ int fpexc_mode;
#ifdef CONFIG_ALTIVEC
- bool save_vec = current->thread.used_vr;
+ vector128 vr[32];
+ vector128 vscr;
+ unsigned long uninitialized_var(vrsave);
+ int used_vr;
#endif
#ifdef CONFIG_VSX
- bool save_vsx = current->thread.used_vsr;
+ int used_vsr;
#endif
ulong ext_msr;
@@ -1311,27 +1316,27 @@
/* Save FPU state in stack */
if (current->thread.regs->msr & MSR_FP)
giveup_fpu(current);
- memcpy(ext_bkp.fpr, current->thread.fpr, sizeof(current->thread.fpr));
- ext_bkp.fpscr = current->thread.fpscr;
- ext_bkp.fpexc_mode = current->thread.fpexc_mode;
+ memcpy(fpr, current->thread.fpr, sizeof(current->thread.fpr));
+ fpscr = current->thread.fpscr.val;
+ fpexc_mode = current->thread.fpexc_mode;
#ifdef CONFIG_ALTIVEC
/* Save Altivec state in stack */
- if (save_vec) {
+ used_vr = current->thread.used_vr;
+ if (used_vr) {
if (current->thread.regs->msr & MSR_VEC)
giveup_altivec(current);
- memcpy(ext_bkp.vr, current->thread.vr, sizeof(ext_bkp.vr));
- ext_bkp.vscr = current->thread.vscr;
- ext_bkp.vrsave = current->thread.vrsave;
+ memcpy(vr, current->thread.vr, sizeof(current->thread.vr));
+ vscr = current->thread.vscr;
+ vrsave = current->thread.vrsave;
}
- ext_bkp.used_vr = current->thread.used_vr;
#endif
#ifdef CONFIG_VSX
/* Save VSX state in stack */
- if (save_vsx && (current->thread.regs->msr & MSR_VSX))
+ used_vsr = current->thread.used_vsr;
+ if (used_vsr && (current->thread.regs->msr & MSR_VSX))
__giveup_vsx(current);
- ext_bkp.used_vsr = current->thread.used_vsr;
#endif
/* Remember the MSR with disabled extensions */
@@ -1356,22 +1361,22 @@
kvmppc_giveup_ext(vcpu, MSR_VSX);
/* Restore FPU state from stack */
- memcpy(current->thread.fpr, ext_bkp.fpr, sizeof(ext_bkp.fpr));
- current->thread.fpscr = ext_bkp.fpscr;
- current->thread.fpexc_mode = ext_bkp.fpexc_mode;
+ memcpy(current->thread.fpr, fpr, sizeof(current->thread.fpr));
+ current->thread.fpscr.val = fpscr;
+ current->thread.fpexc_mode = fpexc_mode;
#ifdef CONFIG_ALTIVEC
/* Restore Altivec state from stack */
- if (save_vec && current->thread.used_vr) {
- memcpy(current->thread.vr, ext_bkp.vr, sizeof(ext_bkp.vr));
- current->thread.vscr = ext_bkp.vscr;
- current->thread.vrsave= ext_bkp.vrsave;
+ if (used_vr && current->thread.used_vr) {
+ memcpy(current->thread.vr, vr, sizeof(current->thread.vr));
+ current->thread.vscr = vscr;
+ current->thread.vrsave = vrsave;
}
- current->thread.used_vr = ext_bkp.used_vr;
+ current->thread.used_vr = used_vr;
#endif
#ifdef CONFIG_VSX
- current->thread.used_vsr = ext_bkp.used_vsr;
+ current->thread.used_vsr = used_vsr;
#endif
return ret;