From: Zenghui Yu yuzenghui@huawei.com
commit e3e880bb1518eb10a4b4bb4344ed614d6856f190 upstream.
Commit 26778aaa134a ("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: 26778aaa134a ("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 [yuz: stable-5.12.y backport] Signed-off-by: Zenghui Yu yuzenghui@huawei.com Reviewed-by: Marc Zyngier maz@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/arm64/kvm/arm.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
--- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -715,11 +715,13 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_v 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; @@ -892,6 +894,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_v
kvm_sigset_deactivate(vcpu);
+out: /* * In the unlikely event that we are returning to userspace * with pending exceptions or PC adjustment, commit these