forked from Minki/linux
72e3244512
In kvm_arch_vcpu_ioctl_run() we use guest_enter_irqoff() and guest_exit_irqoff() directly, with interrupts masked between these. As we don't handle any timer ticks during this window, we will not account time spent within the guest as guest time, which is unfortunate. Additionally, we do not inform lockdep or tracing that interrupts will be enabled during guest execution, which caan lead to misleading traces and warnings that interrupts have been enabled for overly-long periods. This patch fixes these issues by using the new timing and context entry/exit helpers to ensure that interrupts are handled during guest vtime but with RCU watching, with a sequence: guest_timing_enter_irqoff(); guest_state_enter_irqoff(); < run the vcpu > guest_state_exit_irqoff(); < take any pending IRQs > guest_timing_exit_irqoff(); In addition, as guest exits during the "run the vcpu" step are handled by kvm_mips_handle_exit(), a wrapper function is added which ensures that such exists are handled with a sequence: guest_state_exit_irqoff(); < handle the exit > guest_state_enter_irqoff(); This means that exits which stop the vCPU running will have a redundant guest_state_enter_irqoff() .. guest_state_exit_irqoff() sequence, which can be addressed with future rework. Since instrumentation may make use of RCU, we must also ensure that no instrumented code is run during the EQS. I've split out the critical section into a new kvm_mips_enter_exit_vcpu() helper which is marked noinstr. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Aleksandar Markovic <aleksandar.qemu.devel@gmail.com> Cc: Frederic Weisbecker <frederic@kernel.org> Cc: Huacai Chen <chenhuacai@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Message-Id: <20220201132926.3301912-6-mark.rutland@arm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> |
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