From patchwork Thu Jan 31 14:58:48 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Julien Thierry X-Patchwork-Id: 10790775 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id D0F8C746 for ; Thu, 31 Jan 2019 15:10:53 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id BD3D231385 for ; Thu, 31 Jan 2019 15:10:53 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id BB36B31394; Thu, 31 Jan 2019 15:10:53 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 3B1CB313DA for ; Thu, 31 Jan 2019 15:10:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:References: In-Reply-To:Message-Id:Date:Subject:To:From:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=koAJK98JO1cS8ELeU67c+bYo34vEbep3LgKIpTVbpAQ=; b=Odku7SB8SsAXwonGg8hCn09J4G /84VLsSlwnCHsCFbmsfMPMmG3pd4eufmDpTM7Y/iXTaaXtFyMsWW1SanTZ4fTT+202Wzsy/mvhJO4 rALDGz8D8O9E36rj3SxSoSmCZHBab5R1fPFQNte/zHu4WKK8po3lhY+QalEWNwPoCWErd350LpGMo VgiwqLjQyBxy1v309g2JWe1Ib1osyhfDSQt1PQGXaz9qgmhC18qIVdFPJNBzyvKG0muS3Yfi59Li9 BiwhJZTeNi1/5kURGZkNvNP4M7amBFcOMcoFt4XuRWq4ECbLEQlWF71h/uhx8So9f8+hqSmo0iIan j1KRfTHw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gpDzO-0007WI-Ql; Thu, 31 Jan 2019 15:10:50 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gpDoa-0006QL-6y for linux-arm-kernel@lists.infradead.org; Thu, 31 Jan 2019 14:59:45 +0000 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 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> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190131_065940_363457_1E926803 X-CRM114-Status: GOOD ( 15.31 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mark.rutland@arm.com, daniel.thompson@linaro.org, Julien Thierry , marc.zyngier@arm.com, catalin.marinas@arm.com, will.deacon@arm.com, linux-kernel@vger.kernel.org, christoffer.dall@arm.com, james.morse@arm.com, joel@joelfernandes.org, kvmarm@lists.cs.columbia.edu MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP 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; }