From patchwork Fri Sep 4 10:45:25 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 11756657 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 309EA618 for ; Fri, 4 Sep 2020 10:49:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1673020770 for ; Fri, 4 Sep 2020 10:49:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599216553; bh=hmTzNCRw9Bnl08lfTQaej6KTlWoJiiEpQDkEk/c0Aks=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Pcjjwd5Q5tDP94iBM9ppwlC1s8ftvifVV0mWjS54fQEbM8fGGeCuqxZWR6C266Q+1 R4PkDVYY9p9Ri4cwHEdWbpUUAiHMLDqgS40O1y0RPFiPrqhOBQif505U8QQzl3I+5J RKqUn7/2zt4oDngmIjDfw6L2EpO/k84YP1K1WjiA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730105AbgIDKss (ORCPT ); Fri, 4 Sep 2020 06:48:48 -0400 Received: from mail.kernel.org ([198.145.29.99]:58878 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729751AbgIDKqE (ORCPT ); Fri, 4 Sep 2020 06:46:04 -0400 Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D7291208B3; Fri, 4 Sep 2020 10:46:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599216364; bh=hmTzNCRw9Bnl08lfTQaej6KTlWoJiiEpQDkEk/c0Aks=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dGtTdZ/9CM6hJODWnwcEqiJArtoqasldXiXtf/KhBCObWCtKIaelb3FVWAnyqq/Kz e37h4QTJzk6nFQlrj4WjKYd7t4JtRHCV5g7gh5RUfhT+3y51mudhEcuH0gkwomC5lB ywzTlIhDlD8/2a6zMXOW+K99rzOdVDNfLeGpGQ+A= Received: from 78.163-31-62.static.virginmediabusiness.co.uk ([62.31.163.78] helo=why.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1kE9EI-0098oH-Bg; Fri, 04 Sep 2020 11:46:02 +0100 From: Marc Zyngier To: Paolo Bonzini Cc: Alexandru Elisei , Andrew Jones , Eric Auger , Gavin Shan , Steven Price , kernel-team@android.com, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org Subject: [PATCH 4/9] KVM: arm64: pvtime: Fix stolen time accounting across migration Date: Fri, 4 Sep 2020 11:45:25 +0100 Message-Id: <20200904104530.1082676-5-maz@kernel.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200904104530.1082676-1-maz@kernel.org> References: <20200904104530.1082676-1-maz@kernel.org> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 62.31.163.78 X-SA-Exim-Rcpt-To: pbonzini@redhat.com, alexandru.elisei@arm.com, drjones@redhat.com, eric.auger@redhat.com, gshan@redhat.com, steven.price@arm.com, kernel-team@android.com, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Andrew Jones When updating the stolen time we should always read the current stolen time from the user provided memory, not from a kernel cache. If we use a cache then we'll end up resetting stolen time to zero on the first update after migration. Signed-off-by: Andrew Jones Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20200804170604.42662-5-drjones@redhat.com --- arch/arm64/include/asm/kvm_host.h | 1 - arch/arm64/kvm/pvtime.c | 23 +++++++++-------------- include/linux/kvm_host.h | 20 ++++++++++++++++++++ 3 files changed, 29 insertions(+), 15 deletions(-) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 65568b23868a..dd9c3b25aa1e 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -368,7 +368,6 @@ struct kvm_vcpu_arch { /* Guest PV state */ struct { - u64 steal; u64 last_steal; gpa_t base; } steal; diff --git a/arch/arm64/kvm/pvtime.c b/arch/arm64/kvm/pvtime.c index 241ded7ee0ad..75234321d896 100644 --- a/arch/arm64/kvm/pvtime.c +++ b/arch/arm64/kvm/pvtime.c @@ -13,26 +13,22 @@ void kvm_update_stolen_time(struct kvm_vcpu *vcpu) { struct kvm *kvm = vcpu->kvm; + u64 base = vcpu->arch.steal.base; u64 last_steal = vcpu->arch.steal.last_steal; - u64 steal; - __le64 steal_le; - u64 offset; + u64 offset = offsetof(struct pvclock_vcpu_stolen_time, stolen_time); + u64 steal = 0; int idx; - u64 base = vcpu->arch.steal.base; if (base == GPA_INVALID) return; - /* Let's do the local bookkeeping */ - steal = vcpu->arch.steal.steal; - vcpu->arch.steal.last_steal = READ_ONCE(current->sched_info.run_delay); - steal += vcpu->arch.steal.last_steal - last_steal; - vcpu->arch.steal.steal = steal; - - steal_le = cpu_to_le64(steal); idx = srcu_read_lock(&kvm->srcu); - offset = offsetof(struct pvclock_vcpu_stolen_time, stolen_time); - kvm_put_guest(kvm, base + offset, steal_le); + if (!kvm_get_guest(kvm, base + offset, steal)) { + steal = le64_to_cpu(steal); + vcpu->arch.steal.last_steal = READ_ONCE(current->sched_info.run_delay); + steal += vcpu->arch.steal.last_steal - last_steal; + kvm_put_guest(kvm, base + offset, cpu_to_le64(steal)); + } srcu_read_unlock(&kvm->srcu, idx); } @@ -66,7 +62,6 @@ gpa_t kvm_init_stolen_time(struct kvm_vcpu *vcpu) * Start counting stolen time from the time the guest requests * the feature enabled. */ - vcpu->arch.steal.steal = 0; vcpu->arch.steal.last_steal = current->sched_info.run_delay; idx = srcu_read_lock(&kvm->srcu); diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 84371fb06209..05e3c2fb3ef7 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -749,6 +749,26 @@ int kvm_write_guest_offset_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc, int kvm_gfn_to_hva_cache_init(struct kvm *kvm, struct gfn_to_hva_cache *ghc, gpa_t gpa, unsigned long len); +#define __kvm_get_guest(kvm, gfn, offset, v) \ +({ \ + unsigned long __addr = gfn_to_hva(kvm, gfn); \ + typeof(v) __user *__uaddr = (typeof(__uaddr))(__addr + offset); \ + int __ret = -EFAULT; \ + \ + if (!kvm_is_error_hva(__addr)) \ + __ret = get_user(v, __uaddr); \ + __ret; \ +}) + +#define kvm_get_guest(kvm, gpa, v) \ +({ \ + gpa_t __gpa = gpa; \ + struct kvm *__kvm = kvm; \ + \ + __kvm_get_guest(__kvm, __gpa >> PAGE_SHIFT, \ + offset_in_page(__gpa), v); \ +}) + #define __kvm_put_guest(kvm, gfn, offset, v) \ ({ \ unsigned long __addr = gfn_to_hva(kvm, gfn); \