From patchwork Tue Dec 17 14:23:10 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 13911913 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 8F5E8E7717F for ; Tue, 17 Dec 2024 14:26:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=xWDQI4Tbi5JmEExx2FNvY0+ludG6f4zG98KflS4blsU=; b=fQ+e6fsVV8CUi452FzHYprdGWZ pPjqZpILiAt9Cq19E1nI5oHZKvKOg34L38fFJXf1mG2VR/pgHIrBaMbzhL/jLAl8GHt3Xtz8WuZR8 1g/UQMS2UUa2WEy4e8MYuT/yrTqqB1KWgOshb1NChErFNg4DukT2EXpmfXSzsHtSRDUJ3RH/ESwNM YiUXpuBIUipAlaBljZXnHoZLwgztQ++EbZjdA+MoLxMSR41eYL9AOsOkuOcq4etlTOohQBgvZlTzV /5NGmAUk1r5XsWGpAZ6cud6GcYXLOzu+gJWLuBNaPsGNaymK/4Yb8D5TLTPaNbLgv9glvdqxmqeJN /u7h2n3Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tNYX7-0000000DkP3-3kKR; Tue, 17 Dec 2024 14:26:45 +0000 Received: from nyc.source.kernel.org ([147.75.193.91]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tNYTv-0000000DjXD-3wuj for linux-arm-kernel@lists.infradead.org; Tue, 17 Dec 2024 14:23:29 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by nyc.source.kernel.org (Postfix) with ESMTP id 60693A418CB; Tue, 17 Dec 2024 14:21:36 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BA74CC4CEDF; Tue, 17 Dec 2024 14:23:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1734445406; bh=vlsfcXymn4b9NeLxHEDUu84AmG2cgjXdssBzlNCdyJg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WoyXhyV7O8IPecw1swP6vLUef/+mwO1bmWrduoHkDdAkyngaDD1J8wArleD+3a/aM RI4zHFICUJrBEcEU06rqTnNi1AArwH3fUdsJFJCm7ekLKKbZi7bVM3FbUatAoC/ZIK 1p+Fqv1gNd75dun8UzVWb5b55OP1c6TkKJrUrLRINp5Dm3L14AFQleb7cIye3ICDZQ GykvpB0QHd9ApHtvXsJ9ujfH0ushkf4nM5f5dYRsMqxH2p7Iue/fekhbL3uBGj19k3 yi6atdjD5KicMJmJ7NORt5/UNlswAt2+VvI27YcFi7YwKdkHktEUttEbS6zBCVOzVU KZJae0hlzqGwQ== 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 1tNYTs-004aJx-NW; Tue, 17 Dec 2024 14:23:24 +0000 From: Marc Zyngier To: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org Cc: Joey Gouly , Suzuki K Poulose , Oliver Upton , Zenghui Yu , Bjorn Andersson , Christoffer Dall , Ganapatrao Kulkarni , Chase Conklin , Eric Auger Subject: [PATCH v2 02/12] KVM: arm64: nv: Sync nested timer state with FEAT_NV2 Date: Tue, 17 Dec 2024 14:23:10 +0000 Message-Id: <20241217142321.763801-3-maz@kernel.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20241217142321.763801-1-maz@kernel.org> References: <20241217142321.763801-1-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, linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org, joey.gouly@arm.com, suzuki.poulose@arm.com, oliver.upton@linux.dev, yuzenghui@huawei.com, andersson@kernel.org, christoffer.dall@arm.com, gankulkarni@os.amperecomputing.com, chase.conklin@arm.com, eauger@redhat.com 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-20241217_062328_106409_A3FBEC2E X-CRM114-Status: GOOD ( 17.69 ) 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Emulating the timers with FEAT_NV2 is a bit odd, as the timers can be reconfigured behind our back without the hypervisor even noticing. In the VHE case, that's an actual regression in the architecture... Co-developed-by: Christoffer Dall Signed-off-by: Christoffer Dall Signed-off-by: Marc Zyngier --- arch/arm64/kvm/arch_timer.c | 44 ++++++++++++++++++++++++++++++++++++ arch/arm64/kvm/arm.c | 3 +++ include/kvm/arm_arch_timer.h | 1 + 3 files changed, 48 insertions(+) diff --git a/arch/arm64/kvm/arch_timer.c b/arch/arm64/kvm/arch_timer.c index 1215df5904185..ee5f732fbbece 100644 --- a/arch/arm64/kvm/arch_timer.c +++ b/arch/arm64/kvm/arch_timer.c @@ -905,6 +905,50 @@ void kvm_timer_vcpu_put(struct kvm_vcpu *vcpu) kvm_timer_blocking(vcpu); } +void kvm_timer_sync_nested(struct kvm_vcpu *vcpu) +{ + /* + * When NV2 is on, guest hypervisors have their EL1 timer register + * accesses redirected to the VNCR page. Any guest action taken on + * the timer is postponed until the next exit, leading to a very + * poor quality of emulation. + */ + if (!is_hyp_ctxt(vcpu)) + return; + + if (!vcpu_el2_e2h_is_set(vcpu)) { + /* + * A non-VHE guest hypervisor doesn't have any direct access + * to its timers: the EL2 registers trap (and the HW is + * fully emulated), while the EL0 registers access memory + * despite the access being notionally direct. Boo. + * + * We update the hardware timer registers with the + * latest value written by the guest to the VNCR page + * and let the hardware take care of the rest. + */ + write_sysreg_el0(__vcpu_sys_reg(vcpu, CNTV_CTL_EL0), SYS_CNTV_CTL); + write_sysreg_el0(__vcpu_sys_reg(vcpu, CNTV_CVAL_EL0), SYS_CNTV_CVAL); + write_sysreg_el0(__vcpu_sys_reg(vcpu, CNTP_CTL_EL0), SYS_CNTP_CTL); + write_sysreg_el0(__vcpu_sys_reg(vcpu, CNTP_CVAL_EL0), SYS_CNTP_CVAL); + } else { + /* + * For a VHE guest hypervisor, the EL2 state is directly + * stored in the host EL1 timers, while the emulated EL0 + * state is stored in the VNCR page. The latter could have + * been updated behind our back, and we must reset the + * emulation of the timers. + */ + struct timer_map map; + get_timer_map(vcpu, &map); + + soft_timer_cancel(&map.emul_vtimer->hrtimer); + soft_timer_cancel(&map.emul_ptimer->hrtimer); + timer_emulate(map.emul_vtimer); + timer_emulate(map.emul_ptimer); + } +} + /* * With a userspace irqchip we have to check if the guest de-asserted the * timer and if so, unmask the timer irq signal on the host interrupt diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index a102c3aebdbc4..fa3089822f9f3 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -1228,6 +1228,9 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu) if (unlikely(!irqchip_in_kernel(vcpu->kvm))) kvm_timer_sync_user(vcpu); + if (vcpu_has_nv(vcpu)) + kvm_timer_sync_nested(vcpu); + kvm_arch_vcpu_ctxsync_fp(vcpu); /* diff --git a/include/kvm/arm_arch_timer.h b/include/kvm/arm_arch_timer.h index fd650a8789b91..6e3f6b7ff2b22 100644 --- a/include/kvm/arm_arch_timer.h +++ b/include/kvm/arm_arch_timer.h @@ -98,6 +98,7 @@ int __init kvm_timer_hyp_init(bool has_gic); int kvm_timer_enable(struct kvm_vcpu *vcpu); void kvm_timer_vcpu_reset(struct kvm_vcpu *vcpu); void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu); +void kvm_timer_sync_nested(struct kvm_vcpu *vcpu); void kvm_timer_sync_user(struct kvm_vcpu *vcpu); bool kvm_timer_should_notify_user(struct kvm_vcpu *vcpu); void kvm_timer_update_run(struct kvm_vcpu *vcpu);