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KVM: arm64: Resolve all pending PC updates before immediate exit

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Commit 26778aaa13 ("KVM: arm64: Commit pending PC adjustemnts before
returning to userspace") fixed the PC updating issue by forcing an explicit
synchronisation of the exception state on vcpu exit to userspace.

However, we forgot to take into account the case where immediate_exit is
set by userspace and KVM_RUN will exit immediately. Fix it by resolving all
pending PC updates before returning to userspace.

Since __kvm_adjust_pc() relies on a loaded vcpu context, I moved the
immediate_exit checking right after vcpu_load(). We will get some overhead
if immediate_exit is true (which should hopefully be rare).

Fixes: 26778aaa13 ("KVM: arm64: Commit pending PC adjustemnts before returning to userspace")
Signed-off-by: Zenghui Yu <yuzenghui@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210526141831.1662-1-yuzenghui@huawei.com
Cc: stable@vger.kernel.org # 5.11
This commit is contained in:
Zenghui Yu 2021-05-26 22:18:31 +08:00 committed by Marc Zyngier
parent cb853ded1d
commit e3e880bb15
1 changed files with 6 additions and 3 deletions
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9
arch/arm64/kvm/arm.c
View file

@ -720,11 +720,13 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
return ret;
}
if (run->immediate_exit)
return -EINTR;
vcpu_load(vcpu);
if (run->immediate_exit) {
ret = -EINTR;
goto out;
}
kvm_sigset_activate(vcpu);
ret = 1;
@ -897,6 +899,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
kvm_sigset_deactivate(vcpu);
out:
/*
* In the unlikely event that we are returning to userspace
* with pending exceptions or PC adjustment, commit these