Re: [PATCH 36/37] KVM: PPC: booke: expose guest registers on irq reinject
flat view
From: Scott Wood <hidden>
Date: 2012-02-24 23:40:27
Also in:
kvm
On 02/24/2012 08:26 AM, Alexander Graf wrote:
quoted hunk ↗ jump to hunk
+static void kvmppc_fill_pt_regs(struct kvm_vcpu *vcpu, struct pt_regs *regs) { - int r = RESUME_HOST; + int i; - /* update before a new last_exit_type is rewritten */ - kvmppc_update_timing_stats(vcpu); + for (i = 0; i < 32; i++) + regs->gpr[i] = kvmppc_get_gpr(vcpu, i); + regs->nip = vcpu->arch.pc; + regs->msr = vcpu->arch.shared->msr; + regs->ctr = vcpu->arch.ctr; + regs->link = vcpu->arch.lr; + regs->xer = kvmppc_get_xer(vcpu); + regs->ccr = kvmppc_get_cr(vcpu); + regs->dar = get_guest_dear(vcpu); + regs->dsisr = get_guest_esr(vcpu); +}
How much overhead does this add to every interrupt? Can't we keep this to the minimum that perf cares about?
quoted hunk ↗ jump to hunk
+ +static void kvmppc_restart_interrupt(struct kvm_vcpu *vcpu, + unsigned int exit_nr) +{ + struct pt_regs regs = *current->thread.regs; + kvmppc_fill_pt_regs(vcpu, ®s);
Why are you copying out of current->thread.regs? That's old junk data, set by some previous exception and possibly overwritten since. -Scott