Hi Narayana.
On 10/1/26 4:56 PM, Narayana Murty N wrote:
Hi Shrikanth,
Thanks for the fixes. I had one question on patch 1.
See response below.
diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index 13ad4cf5fa71..5b9118eefe1d 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -1404,10 +1404,17 @@ int kvmppc_handle_exit(struct kvm_vcpu *vcpu, unsigned
int exit_nr)
if (s <= 0)
r = (s << 2) | RESUME_HOST | (r & RESUME_FLAG_NV);
else {
- /* interrupts now hard-disabled */
+ /*
+ * kvmppc_fix_ee_before_entry() marks the software
+ * IRQ state enabled while interrupts are still
+ * hard-disabled. So disable preemption while loading
+ * guest FP and Altivec.
+ */
kvmppc_fix_ee_before_entry();
+ preempt_disable();
kvmppc_load_guest_fp(vcpu);
kvmppc_load_guest_altivec(vcpu);
+ preempt_enable_no_resched();
Would it be simpler to move kvmppc_fix_ee_before_entry() after the
FP/Altivec loads instead?
The normal kvmppc_vcpu_run() entry path already loads the guest
FP/Altivec state while interrupts are still disabled and calls
kvmppc_fix_ee_before_entry() immediately before entering the guest.
So could this path follow the same ordering:
kvmppc_load_guest_fp(vcpu);
kvmppc_load_guest_altivec(vcpu);
kvmppc_fix_ee_before_entry();
That would avoid making the software IRQ state enabled before loading
the guest FP/Altivec state, and also avoid the additional
preempt_disable()/preempt_enable_no_resched() pair.
Thanks,
Narayana Murty.
}
}
I thought I had put that for discussion after ---, but looks like I forgot.
I don't mind the above too. but I didn't have a way to test it.
So kept it as is based on what Christian said works for him.
If you have a way to test the patches, please let me know.
We can try that too.
