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RISC-V: KVM: move preempt_disable() call in kvm_arch_vcpu_ioctl_run

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local_irq_disable provides stronger guarantees than preempt_disable so
calling the latter is redundant when interrupts are disabled. Instead,
explicitly disable preemption right before interrupts are enabled/disabled
to ensure that the time accounted in guest_timing_exit_irqoff
includes time taken by the guest or interrupts.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Anup Patel <anup@brainfault.org>
This commit is contained in:
Nikolay Borisov 2022-07-29 17:14:34 +05:30 committed by Anup Patel
parent cca986fab9
commit fe283e5fa1
1 changed files with 2 additions and 3 deletions
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5
arch/riscv/kvm/vcpu.c
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@ -936,8 +936,6 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
kvm_riscv_check_vcpu_requests(vcpu); kvm_riscv_check_vcpu_requests(vcpu);
preempt_disable();
local_irq_disable(); local_irq_disable();
/* /*
@ -974,7 +972,6 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
kvm_request_pending(vcpu)) { kvm_request_pending(vcpu)) {
vcpu->mode = OUTSIDE_GUEST_MODE; vcpu->mode = OUTSIDE_GUEST_MODE;
local_irq_enable(); local_irq_enable();
preempt_enable();
kvm_vcpu_srcu_read_lock(vcpu); kvm_vcpu_srcu_read_lock(vcpu);
continue; continue;
} }
@ -1008,6 +1005,8 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
/* Syncup interrupts state with HW */ /* Syncup interrupts state with HW */
kvm_riscv_vcpu_sync_interrupts(vcpu); kvm_riscv_vcpu_sync_interrupts(vcpu);
preempt_disable();
/* /*
* We must ensure that any pending interrupts are taken before * We must ensure that any pending interrupts are taken before
* we exit guest timing so that timer ticks are accounted as * we exit guest timing so that timer ticks are accounted as