From patchwork Tue Jun 9 08:49:21 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 11594923 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 3AB4E739 for ; Tue, 9 Jun 2020 08:49:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1B698207C3 for ; Tue, 9 Jun 2020 08:49:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591692591; bh=YpTPkF+pnFoMogA4X2GFObKXLTgxGc72fp25PaLmSWs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=SUJBhebnX+QTMVlnZy+QNp7+sB/EN+x8XX3Jj0Lv4vWxE5QXXIRE/mVXMtzxXTHwq WWbdv4v1PUdWxVKA1clR1ZbhDmVmqmB70sKIw4jTAXtlmcatwo5a3ruXGw4JdR4RXP crZWhbjRp9YCTqDjN3bFBLiGhb8yPRGN1GFBqaNU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728358AbgFIIts (ORCPT ); Tue, 9 Jun 2020 04:49:48 -0400 Received: from mail.kernel.org ([198.145.29.99]:38296 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728338AbgFIItn (ORCPT ); Tue, 9 Jun 2020 04:49:43 -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 0B24E2078D; Tue, 9 Jun 2020 08:49:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591692582; bh=YpTPkF+pnFoMogA4X2GFObKXLTgxGc72fp25PaLmSWs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=W/6DplRB61Jn98Sp4t1KeQRbvrrCWHNQO0TdHaoZ1vGlAjbZFAGhoexEwsXl+syKO XzwLFhQSjpvJIsx34gFf93rF+ITlwYmEWl+qfAvUWFEukPluntlxQ+pOtH1XX/vue8 Goz+luN8WPRdylarBtn5CiFELwsXNaJ0DCPxQXSE= 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 1jiZwy-001PEa-J1; Tue, 09 Jun 2020 09:49:40 +0100 From: Marc Zyngier To: kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: James Morse , Julien Thierry , Suzuki K Poulose , kernel-team@android.com, stable@vger.kernel.org Subject: [PATCH 2/2] KVM: arm64: Synchronize sysreg state on injecting an AArch32 exception Date: Tue, 9 Jun 2020 09:49:21 +0100 Message-Id: <20200609084921.1448445-3-maz@kernel.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200609084921.1448445-1-maz@kernel.org> References: <20200609084921.1448445-1-maz@kernel.org> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 62.31.163.78 X-SA-Exim-Rcpt-To: kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, james.morse@arm.com, julien.thierry.kdev@gmail.com, suzuki.poulose@arm.com, kernel-team@android.com, 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)