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authorLinus Torvalds <torvalds@linux-foundation.org>2017-11-10 12:24:42 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-11-10 12:24:42 -0800
commit5cf2360ba6eceee13ac2e72f4c21fdd31613f59b (patch)
tree751abdc68ebb4fa9a26201df26a20fb040fa60d1
parenta579e949378eab7b992d2bf942b655ca407f2948 (diff)
parentd850a255d5b961fbe085f06ddd116910378b78f1 (diff)
Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM fix from Radim Krčmář: "Fix PPC HV host crash that can occur as a result of resizing the guest hashed page table" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: KVM: PPC: Book3S HV: Fix exclusion between HPT resizing and other HPT updates
-rw-r--r--arch/powerpc/kvm/book3s_64_mmu_hv.c10
-rw-r--r--arch/powerpc/kvm/book3s_hv.c29
2 files changed, 29 insertions, 10 deletions
diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
index 7c62967d672c..59247af5fd45 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -646,6 +646,16 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
hnow_v = hpte_new_to_old_v(hnow_v, hnow_r);
hnow_r = hpte_new_to_old_r(hnow_r);
}
+
+ /*
+ * If the HPT is being resized, don't update the HPTE,
+ * instead let the guest retry after the resize operation is complete.
+ * The synchronization for hpte_setup_done test vs. set is provided
+ * by the HPTE lock.
+ */
+ if (!kvm->arch.hpte_setup_done)
+ goto out_unlock;
+
if ((hnow_v & ~HPTE_V_HVLOCK) != hpte[0] || hnow_r != hpte[1] ||
rev->guest_rpte != hpte[2])
/* HPTE has been changed under us; let the guest retry */
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 73bf1ebfa78f..8d43cf205d34 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -2705,11 +2705,14 @@ static noinline void kvmppc_run_core(struct kvmppc_vcore *vc)
* Hard-disable interrupts, and check resched flag and signals.
* If we need to reschedule or deliver a signal, clean up
* and return without going into the guest(s).
+ * If the hpte_setup_done flag has been cleared, don't go into the
+ * guest because that means a HPT resize operation is in progress.
*/
local_irq_disable();
hard_irq_disable();
if (lazy_irq_pending() || need_resched() ||
- recheck_signals(&core_info)) {
+ recheck_signals(&core_info) ||
+ (!kvm_is_radix(vc->kvm) && !vc->kvm->arch.hpte_setup_done)) {
local_irq_enable();
vc->vcore_state = VCORE_INACTIVE;
/* Unlock all except the primary vcore */
@@ -3078,7 +3081,7 @@ out:
static int kvmppc_run_vcpu(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
{
- int n_ceded, i;
+ int n_ceded, i, r;
struct kvmppc_vcore *vc;
struct kvm_vcpu *v;
@@ -3132,6 +3135,20 @@ static int kvmppc_run_vcpu(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
while (vcpu->arch.state == KVMPPC_VCPU_RUNNABLE &&
!signal_pending(current)) {
+ /* See if the HPT and VRMA are ready to go */
+ if (!kvm_is_radix(vcpu->kvm) &&
+ !vcpu->kvm->arch.hpte_setup_done) {
+ spin_unlock(&vc->lock);
+ r = kvmppc_hv_setup_htab_rma(vcpu);
+ spin_lock(&vc->lock);
+ if (r) {
+ kvm_run->exit_reason = KVM_EXIT_FAIL_ENTRY;
+ kvm_run->fail_entry.hardware_entry_failure_reason = 0;
+ vcpu->arch.ret = r;
+ break;
+ }
+ }
+
if (vc->vcore_state == VCORE_PREEMPT && vc->runner == NULL)
kvmppc_vcore_end_preempt(vc);
@@ -3249,13 +3266,6 @@ static int kvmppc_vcpu_run_hv(struct kvm_run *run, struct kvm_vcpu *vcpu)
/* Order vcpus_running vs. hpte_setup_done, see kvmppc_alloc_reset_hpt */
smp_mb();
- /* On the first time here, set up HTAB and VRMA */
- if (!kvm_is_radix(vcpu->kvm) && !vcpu->kvm->arch.hpte_setup_done) {
- r = kvmppc_hv_setup_htab_rma(vcpu);
- if (r)
- goto out;
- }
-
flush_all_to_thread(current);
/* Save userspace EBB and other register values */
@@ -3303,7 +3313,6 @@ static int kvmppc_vcpu_run_hv(struct kvm_run *run, struct kvm_vcpu *vcpu)
}
mtspr(SPRN_VRSAVE, user_vrsave);
- out:
vcpu->arch.state = KVMPPC_VCPU_NOTREADY;
atomic_dec(&vcpu->kvm->arch.vcpus_running);
return r;

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