Merge tag 'kvmarm-fixes-5.17-2' of git://git.kernel.org/pub/scm/linux/kernel/git...

[mirror_ubuntu-kernels.git] / arch / arm64 / kvm / arm.c

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index a4a0063df456ca0f963f62ece504e9991edcf5da..ecc5958e27fe2b3fc69b9b1121a626495cb13c46 100644 (file)
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -797,6 +797,24 @@ static bool kvm_vcpu_exit_request(struct kvm_vcpu *vcpu, int *ret)
                        xfer_to_guest_mode_work_pending();
 }
 
+/*
+ * Actually run the vCPU, entering an RCU extended quiescent state (EQS) while
+ * the vCPU is running.
+ *
+ * This must be noinstr as instrumentation may make use of RCU, and this is not
+ * safe during the EQS.
+ */
+static int noinstr kvm_arm_vcpu_enter_exit(struct kvm_vcpu *vcpu)
+{
+       int ret;
+
+       guest_state_enter_irqoff();
+       ret = kvm_call_hyp_ret(__kvm_vcpu_run, vcpu);
+       guest_state_exit_irqoff();
+
+       return ret;
+}
+
 /**
  * kvm_arch_vcpu_ioctl_run - the main VCPU run function to execute guest code
  * @vcpu:      The VCPU pointer
@@ -881,9 +899,9 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
                 * Enter the guest
                 */
                trace_kvm_entry(*vcpu_pc(vcpu));
-               guest_enter_irqoff();
+               guest_timing_enter_irqoff();
 
-               ret = kvm_call_hyp_ret(__kvm_vcpu_run, vcpu);
+               ret = kvm_arm_vcpu_enter_exit(vcpu);
 
                vcpu->mode = OUTSIDE_GUEST_MODE;
                vcpu->stat.exits++;
@@ -918,26 +936,23 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
                kvm_arch_vcpu_ctxsync_fp(vcpu);
 
                /*
-                * We may have taken a host interrupt in HYP mode (ie
-                * while executing the guest). This interrupt is still
-                * pending, as we haven't serviced it yet!
+                * We must ensure that any pending interrupts are taken before
+                * we exit guest timing so that timer ticks are accounted as
+                * guest time. Transiently unmask interrupts so that any
+                * pending interrupts are taken.
                 *
-                * We're now back in SVC mode, with interrupts
-                * disabled.  Enabling the interrupts now will have
-                * the effect of taking the interrupt again, in SVC
-                * mode this time.
+                * Per ARM DDI 0487G.b section D1.13.4, an ISB (or other
+                * context synchronization event) is necessary to ensure that
+                * pending interrupts are taken.
                 */
                local_irq_enable();
+               isb();
+               local_irq_disable();
+
+               guest_timing_exit_irqoff();
+
+               local_irq_enable();
 
-               /*
-                * We do local_irq_enable() before calling guest_exit() so
-                * that if a timer interrupt hits while running the guest we
-                * account that tick as being spent in the guest.  We enable
-                * preemption after calling guest_exit() so that if we get
-                * preempted we make sure ticks after that is not counted as
-                * guest time.
-                */
-               guest_exit();
                trace_kvm_exit(ret, kvm_vcpu_trap_get_class(vcpu), *vcpu_pc(vcpu));
 
                /* Exit types that need handling before we can be preempted */