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BACKPORT: KVM: arm64: Don't miss pending interrupts for suspended vCPU

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In order to properly emulate the WFI instruction, KVM reads back
ICH_VMCR_EL2 and enables doorbells for GICv4. These preparations are
necessary in order to recognize pending interrupts in
kvm_arch_vcpu_runnable() and return to the guest. Until recently, this
work was done by kvm_arch_vcpu_{blocking,unblocking}(). Since commit
6109c5a6ab ("KVM: arm64: Move vGIC v4 handling for WFI out arch
callback hook"), these callbacks were gutted and superseded by
kvm_vcpu_wfi().

It is important to note that KVM implements PSCI CPU_SUSPEND calls as
a WFI within the guest. However, the implementation calls directly into
kvm_vcpu_halt(), which skips the needed work done in kvm_vcpu_wfi()
to detect pending interrupts. Fix the issue by calling the WFI helper.

Fixes: 6109c5a6ab ("KVM: arm64: Move vGIC v4 handling for WFI out arch callback hook")
Signed-off-by: Oliver Upton <oupton@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220217101242.3013716-1-oupton@google.com
(cherry picked from commit a867e9d0cc)
[willdeacon@: kvm_vcpu_block() was renamed to kvm_vcpu_halt() upstream]
Signed-off-by: Will Deacon <willdeacon@google.com>
Bug: 233587962
Bug: 233588291
Change-Id: I50aac4b126e2c5a9f0b97fcf6a96ef1714e6dc16
This commit is contained in:
Oliver Upton
2022-02-17 10:12:42 +00:00
committed by Will Deacon
parent 42affdb181
commit 3eefba7840
1 changed files with 1 additions and 2 deletions
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3
arch/arm64/kvm/psci.c
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@@ -46,8 +46,7 @@ static unsigned long kvm_psci_vcpu_suspend(struct kvm_vcpu *vcpu)
* specification (ARM DEN 0022A). This means all suspend states
* for KVM will preserve the register state.
*/
kvm_vcpu_block(vcpu);
kvm_clear_request(KVM_REQ_UNHALT, vcpu);
kvm_vcpu_wfi(vcpu);
return PSCI_RET_SUCCESS;
}