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KVM: PPC: Emulate segment fault

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Book3S_32 doesn't know about segment faults. It only knows about page faults.
So in order to know that we didn't map a segment, we need to fake segment
faults.

We do this by setting invalid segment registers to an invalid VSID and then
check for that VSID on normal page faults.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
This commit is contained in:
Alexander Graf 2010-04-16 00:11:52 +02:00 committed by Avi Kivity
parent 97e492558f
commit 61db97cc1e
1 changed files with 23 additions and 0 deletions
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23
arch/powerpc/kvm/book3s.c
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@ -775,6 +775,18 @@ int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
switch (exit_nr) {
case BOOK3S_INTERRUPT_INST_STORAGE:
vcpu->stat.pf_instruc++;
#ifdef CONFIG_PPC_BOOK3S_32
/* We set segments as unused segments when invalidating them. So
* treat the respective fault as segment fault. */
if (to_svcpu(vcpu)->sr[kvmppc_get_pc(vcpu) >> SID_SHIFT]
== SR_INVALID) {
kvmppc_mmu_map_segment(vcpu, kvmppc_get_pc(vcpu));
r = RESUME_GUEST;
break;
}
#endif
/* only care about PTEG not found errors, but leave NX alone */
if (to_svcpu(vcpu)->shadow_srr1 & 0x40000000) {
r = kvmppc_handle_pagefault(run, vcpu, kvmppc_get_pc(vcpu), exit_nr);
@ -799,6 +811,17 @@ int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
{
ulong dar = kvmppc_get_fault_dar(vcpu);
vcpu->stat.pf_storage++;
#ifdef CONFIG_PPC_BOOK3S_32
/* We set segments as unused segments when invalidating them. So
* treat the respective fault as segment fault. */
if ((to_svcpu(vcpu)->sr[dar >> SID_SHIFT]) == SR_INVALID) {
kvmppc_mmu_map_segment(vcpu, dar);
r = RESUME_GUEST;
break;
}
#endif
/* The only case we need to handle is missing shadow PTEs */
if (to_svcpu(vcpu)->fault_dsisr & DSISR_NOHPTE) {
r = kvmppc_handle_pagefault(run, vcpu, dar, exit_nr);