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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7B9FAC6FD19 for ; Mon, 13 Mar 2023 12:50:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=eP2tRCC86heXKWz99eE0hVRktYxutGQt4HaGDbXJ6lg=; b=SdSI4N7ed5Rwzh WMC78Y4pIGLerPzirqzlNoq8Ba5BrhN3wocLEdcJjaZEPjg+tbbwqSTHiRpvgcQ+99X38+7cj7dJb u1l3KDKeA3a5NZQpCJqWyTOG48KWNt2aWxOJIzcDTsR5t+pATKA1jSBZZE73MgibZ2nHf+eanPhe4 grz7zhnXM276bZK9vLHjMD+clNrvB/134oaoSwGX0WIyZ5epquBnp4+ZJ+LNG9uDsk6TEaQ+c8IPv otrDFfQv5m4X+PHfDZaervbk/4y69gFwWZfsVE3D3m3oTlZZa3yBIgLws0jSgYWXPjqYgIs2MBW/b 1YaJ6UxEmpwog/OilLQg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1pbhcd-005hyd-7C; Mon, 13 Mar 2023 12:49:51 +0000 Received: from ams.source.kernel.org ([2604:1380:4601:e00::1]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1pbhbk-005hhw-QH for linux-arm-kernel@lists.infradead.org; Mon, 13 Mar 2023 12:49:01 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 3F3B4B81072; Mon, 13 Mar 2023 12:48:55 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E0C73C433D2; Mon, 13 Mar 2023 12:48:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1678711733; bh=4bJ3J6pFQm4HD8LaHyxFJDa0kckSx5QJN4hO2pYexLQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VI00s0pxYPllC0AMB7o+M+YZqmdXzaLBVHuRBOLN36DUZJGALP+eKtciIq+9xgfcy eP6eRTvbpSDmydE3rNH5vfqJfM3HGzNbkXqW8GHEIPx0AMcSL/Pci9/dBR9AJNin8k MyhPBnhSBRb/tYKRUsWmZtnfUSx7tjQo5mBKhge9ZLklagzv6Cj7Fcnj/bKBW7DJB3 0/V8PWU/ZLXk03bfcyRA+BRMVXyTK403AL/2wrMOh/r9CHi3TMA7dYo6xAD5n19bRT Iq+tVkPzQAFo343FDUj6x+BH7bOnNN/Zk0b7qZT/UtVUc5DUt1UPktf7ISkkH+H90G 39gEq6pvItSXw== Received: from sofa.misterjones.org ([185.219.108.64] helo=valley-girl.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1pbhbf-00HEdE-PY; Mon, 13 Mar 2023 12:48:51 +0000 From: Marc Zyngier To: kvmarm@lists.linux.dev, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: James Morse , Suzuki K Poulose , Oliver Upton , Zenghui Yu , Ricardo Koller , Simon Veith , Reiji Watanabe , Colton Lewis , Joey Gouly , dwmw2@infradead.org Subject: [PATCH v2 01/19] KVM: arm64: timers: Convert per-vcpu virtual offset to a global value Date: Mon, 13 Mar 2023 12:48:19 +0000 Message-Id: <20230313124837.2264882-2-maz@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230313124837.2264882-1-maz@kernel.org> References: <20230313124837.2264882-1-maz@kernel.org> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: kvmarm@lists.linux.dev, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, james.morse@arm.com, suzuki.poulose@arm.com, oliver.upton@linux.dev, yuzenghui@huawei.com, ricarkol@google.com, sveith@amazon.de, reijiw@google.com, coltonlewis@google.com, joey.gouly@arm.com, dwmw2@infradead.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230313_054858_040585_50004C9E X-CRM114-Status: GOOD ( 24.39 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Having a per-vcpu virtual offset is a pain. It needs to be synchronized on each update, and expands badly to a setup where different timers can have different offsets, or have composite offsets (as with NV). So let's start by replacing the use of the CNTVOFF_EL2 shadow register (which we want to reclaim for NV anyway), and make the virtual timer carry a pointer to a VM-wide offset. This simplifies the code significantly. It also addresses two terrible bugs: - The use of CNTVOFF_EL2 leads to some nice offset corruption when the sysreg gets reset, as reported by Joey. - The kvm mutex is taken from a vcpu ioctl, which goes against the locking rules... Reported-by: Joey Gouly Reviewed-by: Reiji Watanabe Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20230224173915.GA17407@e124191.cambridge.arm.com --- arch/arm64/include/asm/kvm_host.h | 3 +++ arch/arm64/kvm/arch_timer.c | 45 +++++++------------------------ arch/arm64/kvm/hypercalls.c | 2 +- include/kvm/arm_arch_timer.h | 15 +++++++++++ 4 files changed, 29 insertions(+), 36 deletions(-) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index a1892a8f6032..bcd774d74f34 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -193,6 +193,9 @@ struct kvm_arch { /* Interrupt controller */ struct vgic_dist vgic; + /* Timers */ + struct arch_timer_vm_data timer_data; + /* Mandated version of PSCI */ u32 psci_version; diff --git a/arch/arm64/kvm/arch_timer.c b/arch/arm64/kvm/arch_timer.c index 00610477ec7b..e1af4301b913 100644 --- a/arch/arm64/kvm/arch_timer.c +++ b/arch/arm64/kvm/arch_timer.c @@ -84,14 +84,10 @@ u64 timer_get_cval(struct arch_timer_context *ctxt) static u64 timer_get_offset(struct arch_timer_context *ctxt) { - struct kvm_vcpu *vcpu = ctxt->vcpu; + if (ctxt->offset.vm_offset) + return *ctxt->offset.vm_offset; - switch(arch_timer_ctx_index(ctxt)) { - case TIMER_VTIMER: - return __vcpu_sys_reg(vcpu, CNTVOFF_EL2); - default: - return 0; - } + return 0; } static void timer_set_ctl(struct arch_timer_context *ctxt, u32 ctl) @@ -128,15 +124,12 @@ static void timer_set_cval(struct arch_timer_context *ctxt, u64 cval) static void timer_set_offset(struct arch_timer_context *ctxt, u64 offset) { - struct kvm_vcpu *vcpu = ctxt->vcpu; - - switch(arch_timer_ctx_index(ctxt)) { - case TIMER_VTIMER: - __vcpu_sys_reg(vcpu, CNTVOFF_EL2) = offset; - break; - default: + if (!ctxt->offset.vm_offset) { WARN(offset, "timer %ld\n", arch_timer_ctx_index(ctxt)); + return; } + + WRITE_ONCE(*ctxt->offset.vm_offset, offset); } u64 kvm_phys_timer_read(void) @@ -765,25 +758,6 @@ int kvm_timer_vcpu_reset(struct kvm_vcpu *vcpu) return 0; } -/* Make the updates of cntvoff for all vtimer contexts atomic */ -static void update_vtimer_cntvoff(struct kvm_vcpu *vcpu, u64 cntvoff) -{ - unsigned long i; - struct kvm *kvm = vcpu->kvm; - struct kvm_vcpu *tmp; - - mutex_lock(&kvm->lock); - kvm_for_each_vcpu(i, tmp, kvm) - timer_set_offset(vcpu_vtimer(tmp), cntvoff); - - /* - * When called from the vcpu create path, the CPU being created is not - * included in the loop above, so we just set it here as well. - */ - timer_set_offset(vcpu_vtimer(vcpu), cntvoff); - mutex_unlock(&kvm->lock); -} - void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu) { struct arch_timer_cpu *timer = vcpu_timer(vcpu); @@ -791,10 +765,11 @@ void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu) struct arch_timer_context *ptimer = vcpu_ptimer(vcpu); vtimer->vcpu = vcpu; + vtimer->offset.vm_offset = &vcpu->kvm->arch.timer_data.voffset; ptimer->vcpu = vcpu; /* Synchronize cntvoff across all vtimers of a VM. */ - update_vtimer_cntvoff(vcpu, kvm_phys_timer_read()); + timer_set_offset(vtimer, kvm_phys_timer_read()); timer_set_offset(ptimer, 0); hrtimer_init(&timer->bg_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_HARD); @@ -840,7 +815,7 @@ int kvm_arm_timer_set_reg(struct kvm_vcpu *vcpu, u64 regid, u64 value) break; case KVM_REG_ARM_TIMER_CNT: timer = vcpu_vtimer(vcpu); - update_vtimer_cntvoff(vcpu, kvm_phys_timer_read() - value); + timer_set_offset(timer, kvm_phys_timer_read() - value); break; case KVM_REG_ARM_TIMER_CVAL: timer = vcpu_vtimer(vcpu); diff --git a/arch/arm64/kvm/hypercalls.c b/arch/arm64/kvm/hypercalls.c index 64c086c02c60..5da884e11337 100644 --- a/arch/arm64/kvm/hypercalls.c +++ b/arch/arm64/kvm/hypercalls.c @@ -44,7 +44,7 @@ static void kvm_ptp_get_time(struct kvm_vcpu *vcpu, u64 *val) feature = smccc_get_arg1(vcpu); switch (feature) { case KVM_PTP_VIRT_COUNTER: - cycles = systime_snapshot.cycles - vcpu_read_sys_reg(vcpu, CNTVOFF_EL2); + cycles = systime_snapshot.cycles - vcpu->kvm->arch.timer_data.voffset; break; case KVM_PTP_PHYS_COUNTER: cycles = systime_snapshot.cycles; diff --git a/include/kvm/arm_arch_timer.h b/include/kvm/arm_arch_timer.h index 71916de7c6c4..c52a6e6839da 100644 --- a/include/kvm/arm_arch_timer.h +++ b/include/kvm/arm_arch_timer.h @@ -23,6 +23,19 @@ enum kvm_arch_timer_regs { TIMER_REG_CTL, }; +struct arch_timer_offset { + /* + * If set, pointer to one of the offsets in the kvm's offset + * structure. If NULL, assume a zero offset. + */ + u64 *vm_offset; +}; + +struct arch_timer_vm_data { + /* Offset applied to the virtual timer/counter */ + u64 voffset; +}; + struct arch_timer_context { struct kvm_vcpu *vcpu; @@ -32,6 +45,8 @@ struct arch_timer_context { /* Emulated Timer (may be unused) */ struct hrtimer hrtimer; + /* Offset for this counter/timer */ + struct arch_timer_offset offset; /* * We have multiple paths which can save/restore the timer state onto * the hardware, so we need some way of keeping track of where the -- 2.34.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel