From mboxrd@z Thu Jan 1 00:00:00 1970 From: christoffer.dall@linaro.org (Christoffer Dall) Date: Fri, 29 Aug 2014 11:59:16 +0200 Subject: [GIT PULL 2/2] arm/arm64: KVM: Complete WFI/WFE instructions In-Reply-To: <1409306356-11170-1-git-send-email-christoffer.dall@linaro.org> References: <1409306356-11170-1-git-send-email-christoffer.dall@linaro.org> Message-ID: <1409306356-11170-3-git-send-email-christoffer.dall@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org The architecture specifies that when the processor wakes up from a WFE or WFI instruction, the instruction is considered complete, however we currrently return to EL1 (or EL0) at the WFI/WFE instruction itself. While most guests may not be affected by this because their local exception handler performs an exception returning setting the event bit or with an interrupt pending, some guests like UEFI will get wedged due this little mishap. Simply skip the instruction when we have completed the emulation. Cc: Acked-by: Marc Zyngier Cc: Ard Biesheuvel Signed-off-by: Christoffer Dall --- arch/arm/kvm/handle_exit.c | 2 ++ arch/arm64/kvm/handle_exit.c | 2 ++ 2 files changed, 4 insertions(+) diff --git a/arch/arm/kvm/handle_exit.c b/arch/arm/kvm/handle_exit.c index 4c979d4..a96a804 100644 --- a/arch/arm/kvm/handle_exit.c +++ b/arch/arm/kvm/handle_exit.c @@ -93,6 +93,8 @@ static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run) else kvm_vcpu_block(vcpu); + kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu)); + return 1; } diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c index e28be51..34b8bd0 100644 --- a/arch/arm64/kvm/handle_exit.c +++ b/arch/arm64/kvm/handle_exit.c @@ -66,6 +66,8 @@ static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run) else kvm_vcpu_block(vcpu); + kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu)); + return 1; } -- 2.0.0