From patchwork Thu Jun 11 09:09:55 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 11599651 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 7F432912 for ; Thu, 11 Jun 2020 09:33:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6734D207C3 for ; Thu, 11 Jun 2020 09:33:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591868005; bh=YpTPkF+pnFoMogA4X2GFObKXLTgxGc72fp25PaLmSWs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=DzRMswMdQAiQ2Kb2J06IenObJ7AKlUxCTFTwHia74kJqt1gzrZIYTmSyhifD8ORkb ctpoKZSEMVz1+U30eieeW2iCY5qW4a3tAoFxkvIFOXFoBd0WhZNMz1ySxgHTIb6WR1 5wU956eqEBOe/9rJV5W7i7hdOBD/iXp7VZXfBBqs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726876AbgFKJdY (ORCPT ); Thu, 11 Jun 2020 05:33:24 -0400 Received: from mail.kernel.org ([198.145.29.99]:39518 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726708AbgFKJdX (ORCPT ); Thu, 11 Jun 2020 05:33:23 -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 397D020760; Thu, 11 Jun 2020 09:33:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591868003; bh=YpTPkF+pnFoMogA4X2GFObKXLTgxGc72fp25PaLmSWs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NEmNmzYzkA3y84M3ZhGDWpR28WRid82ZRnELneRdXX6lslEhH/jLhEcfpklnNwbXm Jf3k8/KVtLZPQjtEvZSGncXQBrxjjVwCk1rOd4fHkwLKP0b3E8wilQB/XIck1bbMGK rW0+mquEnEKuI+67r29r1PQRODQcdio00lvkcKkI= 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 1jjJDy-0022ZT-PS; Thu, 11 Jun 2020 10:10:14 +0100 From: Marc Zyngier To: Paolo Bonzini Cc: Alexandru Elisei , Andrew Scull , James Morse , Mark Rutland , Julien Thierry , Suzuki K Poulose , kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org, stable@vger.kernel.org Subject: [PATCH 10/11] KVM: arm64: Synchronize sysreg state on injecting an AArch32 exception Date: Thu, 11 Jun 2020 10:09:55 +0100 Message-Id: <20200611090956.1537104-11-maz@kernel.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200611090956.1537104-1-maz@kernel.org> References: <20200611090956.1537104-1-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, ascull@google.com, james.morse@arm.com, mark.rutland@arm.com, julien.thierry.kdev@gmail.com, suzuki.poulose@arm.com, kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org, stable@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 On a VHE system, the EL1 state is left in the CPU most of the time, and only syncronized back to memory when vcpu_put() is called (most of the time on preemption). Which means that when injecting an exception, we'd better have a way to either: (1) write directly to the EL1 sysregs (2) synchronize the state back to memory, and do the changes there For an AArch64, we already do (1), so we are safe. Unfortunately, doing the same thing for AArch32 would be pretty invasive. Instead, we can easily implement (2) by calling the put/load architectural backends, and keep preemption disabled. We can then reload the state back into EL1. Cc: stable@vger.kernel.org Reported-by: James Morse Signed-off-by: Marc Zyngier --- arch/arm64/kvm/aarch32.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/arch/arm64/kvm/aarch32.c b/arch/arm64/kvm/aarch32.c index 0a356aa91aa1..40a62a99fbf8 100644 --- a/arch/arm64/kvm/aarch32.c +++ b/arch/arm64/kvm/aarch32.c @@ -33,6 +33,26 @@ static const u8 return_offsets[8][2] = { [7] = { 4, 4 }, /* FIQ, unused */ }; +static bool pre_fault_synchronize(struct kvm_vcpu *vcpu) +{ + preempt_disable(); + if (vcpu->arch.sysregs_loaded_on_cpu) { + kvm_arch_vcpu_put(vcpu); + return true; + } + + preempt_enable(); + return false; +} + +static void post_fault_synchronize(struct kvm_vcpu *vcpu, bool loaded) +{ + if (loaded) { + kvm_arch_vcpu_load(vcpu, smp_processor_id()); + preempt_enable(); + } +} + /* * When an exception is taken, most CPSR fields are left unchanged in the * handler. However, some are explicitly overridden (e.g. M[4:0]). @@ -155,7 +175,10 @@ static void prepare_fault32(struct kvm_vcpu *vcpu, u32 mode, u32 vect_offset) void kvm_inject_undef32(struct kvm_vcpu *vcpu) { + bool loaded = pre_fault_synchronize(vcpu); + prepare_fault32(vcpu, PSR_AA32_MODE_UND, 4); + post_fault_synchronize(vcpu, loaded); } /* @@ -168,6 +191,9 @@ static void inject_abt32(struct kvm_vcpu *vcpu, bool is_pabt, u32 vect_offset; u32 *far, *fsr; bool is_lpae; + bool loaded; + + loaded = pre_fault_synchronize(vcpu); if (is_pabt) { vect_offset = 12; @@ -191,6 +217,8 @@ static void inject_abt32(struct kvm_vcpu *vcpu, bool is_pabt, /* no need to shuffle FS[4] into DFSR[10] as its 0 */ *fsr = DFSR_FSC_EXTABT_nLPAE; } + + post_fault_synchronize(vcpu, loaded); } void kvm_inject_dabt32(struct kvm_vcpu *vcpu, unsigned long addr)