KVM: PPC: Use get/set for to_svcpu to help preemption
When running the 64-bit Book3s PR code without CONFIG_PREEMPT_NONE, we were
doing a few things wrong, most notably access to PACA fields without making
sure that the pointers stay stable accross the access (preempt_disable()).
This patch moves to_svcpu towards a get/put model which allows us to disable
preemption while accessing the shadow vcpu fields in the PACA. That way we
can run preemptible and everyone's happy!
Reported-by: Jörg Sommer <joerg@alea.gnuu.de>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c
index 857ecde..0c31507 100644
--- a/arch/powerpc/kvm/book3s_pr.c
+++ b/arch/powerpc/kvm/book3s_pr.c
@@ -56,10 +56,12 @@
void kvmppc_core_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
{
#ifdef CONFIG_PPC_BOOK3S_64
- memcpy(to_svcpu(vcpu)->slb, to_book3s(vcpu)->slb_shadow, sizeof(to_svcpu(vcpu)->slb));
+ struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
+ memcpy(svcpu->slb, to_book3s(vcpu)->slb_shadow, sizeof(svcpu->slb));
memcpy(&get_paca()->shadow_vcpu, to_book3s(vcpu)->shadow_vcpu,
sizeof(get_paca()->shadow_vcpu));
- to_svcpu(vcpu)->slb_max = to_book3s(vcpu)->slb_shadow_max;
+ svcpu->slb_max = to_book3s(vcpu)->slb_shadow_max;
+ svcpu_put(svcpu);
#endif
#ifdef CONFIG_PPC_BOOK3S_32
@@ -70,10 +72,12 @@
void kvmppc_core_vcpu_put(struct kvm_vcpu *vcpu)
{
#ifdef CONFIG_PPC_BOOK3S_64
- memcpy(to_book3s(vcpu)->slb_shadow, to_svcpu(vcpu)->slb, sizeof(to_svcpu(vcpu)->slb));
+ struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
+ memcpy(to_book3s(vcpu)->slb_shadow, svcpu->slb, sizeof(svcpu->slb));
memcpy(to_book3s(vcpu)->shadow_vcpu, &get_paca()->shadow_vcpu,
sizeof(get_paca()->shadow_vcpu));
- to_book3s(vcpu)->slb_shadow_max = to_svcpu(vcpu)->slb_max;
+ to_book3s(vcpu)->slb_shadow_max = svcpu->slb_max;
+ svcpu_put(svcpu);
#endif
kvmppc_giveup_ext(vcpu, MSR_FP);
@@ -308,19 +312,22 @@
if (page_found == -ENOENT) {
/* Page not found in guest PTE entries */
+ struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
vcpu->arch.shared->dar = kvmppc_get_fault_dar(vcpu);
- vcpu->arch.shared->dsisr = to_svcpu(vcpu)->fault_dsisr;
+ vcpu->arch.shared->dsisr = svcpu->fault_dsisr;
vcpu->arch.shared->msr |=
- (to_svcpu(vcpu)->shadow_srr1 & 0x00000000f8000000ULL);
+ (svcpu->shadow_srr1 & 0x00000000f8000000ULL);
+ svcpu_put(svcpu);
kvmppc_book3s_queue_irqprio(vcpu, vec);
} else if (page_found == -EPERM) {
/* Storage protection */
+ struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
vcpu->arch.shared->dar = kvmppc_get_fault_dar(vcpu);
- vcpu->arch.shared->dsisr =
- to_svcpu(vcpu)->fault_dsisr & ~DSISR_NOHPTE;
+ vcpu->arch.shared->dsisr = svcpu->fault_dsisr & ~DSISR_NOHPTE;
vcpu->arch.shared->dsisr |= DSISR_PROTFAULT;
vcpu->arch.shared->msr |=
- (to_svcpu(vcpu)->shadow_srr1 & 0x00000000f8000000ULL);
+ svcpu->shadow_srr1 & 0x00000000f8000000ULL;
+ svcpu_put(svcpu);
kvmppc_book3s_queue_irqprio(vcpu, vec);
} else if (page_found == -EINVAL) {
/* Page not found in guest SLB */
@@ -521,21 +528,25 @@
kvm_resched(vcpu);
switch (exit_nr) {
case BOOK3S_INTERRUPT_INST_STORAGE:
+ {
+ struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
+ ulong shadow_srr1 = svcpu->shadow_srr1;
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) {
+ if (svcpu->sr[kvmppc_get_pc(vcpu) >> SID_SHIFT] == SR_INVALID) {
kvmppc_mmu_map_segment(vcpu, kvmppc_get_pc(vcpu));
r = RESUME_GUEST;
+ svcpu_put(svcpu);
break;
}
#endif
+ svcpu_put(svcpu);
/* only care about PTEG not found errors, but leave NX alone */
- if (to_svcpu(vcpu)->shadow_srr1 & 0x40000000) {
+ if (shadow_srr1 & 0x40000000) {
r = kvmppc_handle_pagefault(run, vcpu, kvmppc_get_pc(vcpu), exit_nr);
vcpu->stat.sp_instruc++;
} else if (vcpu->arch.mmu.is_dcbz32(vcpu) &&
@@ -548,33 +559,37 @@
kvmppc_mmu_pte_flush(vcpu, kvmppc_get_pc(vcpu), ~0xFFFUL);
r = RESUME_GUEST;
} else {
- vcpu->arch.shared->msr |=
- to_svcpu(vcpu)->shadow_srr1 & 0x58000000;
+ vcpu->arch.shared->msr |= shadow_srr1 & 0x58000000;
kvmppc_book3s_queue_irqprio(vcpu, exit_nr);
r = RESUME_GUEST;
}
break;
+ }
case BOOK3S_INTERRUPT_DATA_STORAGE:
{
ulong dar = kvmppc_get_fault_dar(vcpu);
+ struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
+ u32 fault_dsisr = svcpu->fault_dsisr;
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) {
+ if ((svcpu->sr[dar >> SID_SHIFT]) == SR_INVALID) {
kvmppc_mmu_map_segment(vcpu, dar);
r = RESUME_GUEST;
+ svcpu_put(svcpu);
break;
}
#endif
+ svcpu_put(svcpu);
/* The only case we need to handle is missing shadow PTEs */
- if (to_svcpu(vcpu)->fault_dsisr & DSISR_NOHPTE) {
+ if (fault_dsisr & DSISR_NOHPTE) {
r = kvmppc_handle_pagefault(run, vcpu, dar, exit_nr);
} else {
vcpu->arch.shared->dar = dar;
- vcpu->arch.shared->dsisr = to_svcpu(vcpu)->fault_dsisr;
+ vcpu->arch.shared->dsisr = fault_dsisr;
kvmppc_book3s_queue_irqprio(vcpu, exit_nr);
r = RESUME_GUEST;
}
@@ -610,10 +625,13 @@
case BOOK3S_INTERRUPT_PROGRAM:
{
enum emulation_result er;
+ struct kvmppc_book3s_shadow_vcpu *svcpu;
ulong flags;
program_interrupt:
- flags = to_svcpu(vcpu)->shadow_srr1 & 0x1f0000ull;
+ svcpu = svcpu_get(vcpu);
+ flags = svcpu->shadow_srr1 & 0x1f0000ull;
+ svcpu_put(svcpu);
if (vcpu->arch.shared->msr & MSR_PR) {
#ifdef EXIT_DEBUG
@@ -741,14 +759,18 @@
r = RESUME_GUEST;
break;
default:
+ {
+ struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
+ ulong shadow_srr1 = svcpu->shadow_srr1;
+ svcpu_put(svcpu);
/* Ugh - bork here! What did we get? */
printk(KERN_EMERG "exit_nr=0x%x | pc=0x%lx | msr=0x%lx\n",
- exit_nr, kvmppc_get_pc(vcpu), to_svcpu(vcpu)->shadow_srr1);
+ exit_nr, kvmppc_get_pc(vcpu), shadow_srr1);
r = RESUME_HOST;
BUG();
break;
}
-
+ }
if (!(r & RESUME_HOST)) {
/* To avoid clobbering exit_reason, only check for signals if