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authorSean Christopherson <seanjc@google.com>2021-10-09 05:11:57 +0300
committerPaolo Bonzini <pbonzini@redhat.com>2021-12-08 12:24:46 +0300
commit510958e997217e39a16b47afb5a44dfa39013964 (patch)
tree16592511358ed082554d278cc95e27e437922dd1 /virt
parent6f390916c4fb359507d9ac4bf1b28a4f8abee5c0 (diff)
downloadlinux-510958e997217e39a16b47afb5a44dfa39013964.tar.xz
KVM: Force PPC to define its own rcuwait object
Do not define/reference kvm_vcpu.wait if __KVM_HAVE_ARCH_WQP is true, and instead force the architecture (PPC) to define its own rcuwait object. Allowing common KVM to directly access vcpu->wait without a guard makes it all too easy to introduce potential bugs, e.g. kvm_vcpu_block(), kvm_vcpu_on_spin(), and async_pf_execute() all operate on vcpu->wait, not the result of kvm_arch_vcpu_get_wait(), and so may do the wrong thing for PPC. Due to PPC's shenanigans with respect to callbacks and waits (it switches to the virtual core's wait object at KVM_RUN!?!?), it's not clear whether or not this fixes any bugs. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20211009021236.4122790-5-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'virt')
-rw-r--r--virt/kvm/async_pf.c2
-rw-r--r--virt/kvm/kvm_main.c9
2 files changed, 7 insertions, 4 deletions
diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c
index dd777688d14a..ccb35c22785e 100644
--- a/virt/kvm/async_pf.c
+++ b/virt/kvm/async_pf.c
@@ -85,7 +85,7 @@ static void async_pf_execute(struct work_struct *work)
trace_kvm_async_pf_completed(addr, cr2_or_gpa);
- rcuwait_wake_up(&vcpu->wait);
+ rcuwait_wake_up(kvm_arch_vcpu_get_wait(vcpu));
mmput(mm);
kvm_put_kvm(vcpu->kvm);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index a26b069a6929..11db44f4110e 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -422,7 +422,9 @@ static void kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id)
vcpu->kvm = kvm;
vcpu->vcpu_id = id;
vcpu->pid = NULL;
+#ifndef __KVM_HAVE_ARCH_WQP
rcuwait_init(&vcpu->wait);
+#endif
kvm_async_pf_vcpu_init(vcpu);
vcpu->pre_pcpu = -1;
@@ -3284,6 +3286,7 @@ update_halt_poll_stats(struct kvm_vcpu *vcpu, u64 poll_ns, bool waited)
*/
void kvm_vcpu_block(struct kvm_vcpu *vcpu)
{
+ struct rcuwait *wait = kvm_arch_vcpu_get_wait(vcpu);
bool halt_poll_allowed = !kvm_arch_no_poll(vcpu);
ktime_t start, cur, poll_end;
bool waited = false;
@@ -3322,7 +3325,7 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu)
}
- prepare_to_rcuwait(&vcpu->wait);
+ prepare_to_rcuwait(wait);
for (;;) {
set_current_state(TASK_INTERRUPTIBLE);
@@ -3332,7 +3335,7 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu)
waited = true;
schedule();
}
- finish_rcuwait(&vcpu->wait);
+ finish_rcuwait(wait);
cur = ktime_get();
if (waited) {
vcpu->stat.generic.halt_wait_ns +=
@@ -3544,7 +3547,7 @@ void kvm_vcpu_on_spin(struct kvm_vcpu *me, bool yield_to_kernel_mode)
continue;
if (vcpu == me)
continue;
- if (rcuwait_active(&vcpu->wait) &&
+ if (rcuwait_active(kvm_arch_vcpu_get_wait(vcpu)) &&
!vcpu_dy_runnable(vcpu))
continue;
if (READ_ONCE(vcpu->preempted) && yield_to_kernel_mode &&