From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 422DFC282DA for ; Thu, 31 Jan 2019 14:59:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 22811218DA for ; Thu, 31 Jan 2019 14:59:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732788AbfAaO7m (ORCPT ); Thu, 31 Jan 2019 09:59:42 -0500 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:45574 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732720AbfAaO7k (ORCPT ); Thu, 31 Jan 2019 09:59:40 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id DBDD480D; Thu, 31 Jan 2019 06:59:39 -0800 (PST) Received: from e112298-lin.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id BF9DA3F59C; Thu, 31 Jan 2019 06:59:37 -0800 (PST) From: Julien Thierry To: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org, daniel.thompson@linaro.org, joel@joelfernandes.org, marc.zyngier@arm.com, christoffer.dall@arm.com, james.morse@arm.com, catalin.marinas@arm.com, will.deacon@arm.com, mark.rutland@arm.com, Julien Thierry , kvmarm@lists.cs.columbia.edu Subject: [PATCH v10 10/25] arm64: kvm: Unmask PMR before entering guest Date: Thu, 31 Jan 2019 14:58:48 +0000 Message-Id: <1548946743-38979-11-git-send-email-julien.thierry@arm.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1548946743-38979-1-git-send-email-julien.thierry@arm.com> References: <1548946743-38979-1-git-send-email-julien.thierry@arm.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Interrupts masked by ICC_PMR_EL1 will not be signaled to the CPU. This means that hypervisor will not receive masked interrupts while running a guest. We need to make sure that all maskable interrupts are masked from the time we call local_irq_disable() in the main run loop, and remain so until we call local_irq_enable() after returning from the guest, and we need to ensure that we see no interrupts at all (including pseudo-NMIs) in the middle of the VM world-switch, while at the same time we need to ensure we exit the guest when there are interrupts for the host. We can accomplish this with pseudo-NMIs enabled by: (1) local_irq_disable: set the priority mask (2) enter guest: set PSTATE.I (3) clear the priority mask (4) eret to guest (5) exit guest: set the priotiy mask clear PSTATE.I (and restore other host PSTATE bits) (6) local_irq_enable: clear the priority mask. Signed-off-by: Julien Thierry Acked-by: Catalin Marinas Reviewed-by: Marc Zyngier Reviewed-by: Christoffer Dall Cc: Christoffer Dall Cc: Marc Zyngier Cc: Catalin Marinas Cc: Will Deacon Cc: kvmarm@lists.cs.columbia.edu --- arch/arm64/include/asm/kvm_host.h | 16 ++++++++++++++++ arch/arm64/kvm/hyp/switch.c | 16 ++++++++++++++++ 2 files changed, 32 insertions(+) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 7732d0b..292c882 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -24,6 +24,7 @@ #include #include +#include #include #include #include @@ -474,10 +475,25 @@ static inline int kvm_arch_vcpu_run_pid_change(struct kvm_vcpu *vcpu) static inline void kvm_arm_vhe_guest_enter(void) { local_daif_mask(); + + /* + * Having IRQs masked via PMR when entering the guest means the GIC + * will not signal the CPU of interrupts of lower priority, and the + * only way to get out will be via guest exceptions. + * Naturally, we want to avoid this. + */ + if (system_uses_irq_prio_masking()) { + gic_write_pmr(GIC_PRIO_IRQON); + dsb(sy); + } } static inline void kvm_arm_vhe_guest_exit(void) { + /* + * local_daif_restore() takes care to properly restore PSTATE.DAIF + * and the GIC PMR if the host is using IRQ priorities. + */ local_daif_restore(DAIF_PROCCTX_NOIRQ); /* diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c index b0b1478..6a4c2d6 100644 --- a/arch/arm64/kvm/hyp/switch.c +++ b/arch/arm64/kvm/hyp/switch.c @@ -22,6 +22,7 @@ #include +#include #include #include #include @@ -521,6 +522,17 @@ int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu) struct kvm_cpu_context *guest_ctxt; u64 exit_code; + /* + * Having IRQs masked via PMR when entering the guest means the GIC + * will not signal the CPU of interrupts of lower priority, and the + * only way to get out will be via guest exceptions. + * Naturally, we want to avoid this. + */ + if (system_uses_irq_prio_masking()) { + gic_write_pmr(GIC_PRIO_IRQON); + dsb(sy); + } + vcpu = kern_hyp_va(vcpu); host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context); @@ -573,6 +585,10 @@ int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu) */ __debug_switch_to_host(vcpu); + /* Returning to host will clear PSR.I, remask PMR if needed */ + if (system_uses_irq_prio_masking()) + gic_write_pmr(GIC_PRIO_IRQOFF); + return exit_code; } -- 1.9.1