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 D22F0D2F7CE for ; Thu, 17 Oct 2024 12:02:50 +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: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=tMuWVDJiToZps3Pr0n7BblXGgvz3obGBkEvdF1kmPr4=; b=FwZ3Ii00TUFKAMkHg+PSz7sGHJ MM53UIp1UoZv65CpWLfuP+W6qxl5RPkVGrZR+KFE5T6/3IgXORSaTU78fAxgvbvtzvyys+l67ORKn pH5AUYKxwH8FQSaHBoq7QfWA4U7CgXSxi8eiTAEs6jVo2A/NF+6eCjwCqUhssJM1neUjAWJEZrINO G0cgBvwzSwfNL7eFDa80EVOKvoeRDdfczS2ZNCZk27voM1aTDIkfK0pLTvoeL4oSW5dunuC722x9f XkX/VwEIBH8FKrgP6PAcSbnICwR8UuILx5Ym4LZ9FcE9xNcCgNza0UKDtj7g2S6UeujTKyzsHqttn 965O1sFw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1t1PDB-0000000EiYi-22ee; Thu, 17 Oct 2024 12:02:37 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1t1P9t-0000000Ei2z-1ctK for linux-arm-kernel@lists.infradead.org; Thu, 17 Oct 2024 11:59:21 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id D1DF1FEC; Thu, 17 Oct 2024 04:59:39 -0700 (PDT) Received: from [10.57.22.188] (unknown [10.57.22.188]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 5CE593F71E; Thu, 17 Oct 2024 04:59:07 -0700 (PDT) Message-ID: <710c066e-75fa-4f12-b27a-c8948d02bb4b@arm.com> Date: Thu, 17 Oct 2024 12:59:06 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 19/43] KVM: arm64: Handle realm MMIO emulation Content-Language: en-GB To: Steven Price , kvm@vger.kernel.org, kvmarm@lists.linux.dev Cc: Catalin Marinas , Marc Zyngier , Will Deacon , James Morse , Oliver Upton , Zenghui Yu , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Joey Gouly , Alexandru Elisei , Christoffer Dall , Fuad Tabba , linux-coco@lists.linux.dev, Ganapatrao Kulkarni , Gavin Shan , Shanker Donthineni , Alper Gun , "Aneesh Kumar K . V" References: <20241004152804.72508-1-steven.price@arm.com> <20241004152804.72508-20-steven.price@arm.com> From: Suzuki K Poulose In-Reply-To: <20241004152804.72508-20-steven.price@arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241017_045913_566958_11F8EE3C X-CRM114-Status: GOOD ( 22.30 ) 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 On 04/10/2024 16:27, Steven Price wrote: > MMIO emulation for a realm cannot be done directly with the VM's > registers as they are protected from the host. However, for emulatable > data aborts, the RMM uses GPRS[0] to provide the read/written value. > We can transfer this from/to the equivalent VCPU's register entry and > then depend on the generic MMIO handling code in KVM. > > For a MMIO read, the value is placed in the shared RecExit structure > during kvm_handle_mmio_return() rather than in the VCPU's register > entry. > > Signed-off-by: Steven Price > --- > v3: Adapt to previous patch changes > --- > arch/arm64/kvm/mmio.c | 10 +++++++++- > arch/arm64/kvm/rme-exit.c | 6 ++++++ > 2 files changed, 15 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/kvm/mmio.c b/arch/arm64/kvm/mmio.c > index cd6b7b83e2c3..66a838b3776a 100644 > --- a/arch/arm64/kvm/mmio.c > +++ b/arch/arm64/kvm/mmio.c > @@ -6,6 +6,7 @@ > > #include > #include > +#include > #include > > #include "trace.h" > @@ -90,6 +91,9 @@ int kvm_handle_mmio_return(struct kvm_vcpu *vcpu) > > vcpu->mmio_needed = 0; > > + if (vcpu_is_rec(vcpu)) > + vcpu->arch.rec.run->enter.flags |= REC_ENTER_EMULATED_MMIO; > + > if (!kvm_vcpu_dabt_iswrite(vcpu)) { > struct kvm_run *run = vcpu->run; Should we additionally handle injecting an abort if there was no valid syndrome information ? Like we do for protected VMs and normal VMs when userspace doesn't offer to help ? > > @@ -108,7 +112,11 @@ int kvm_handle_mmio_return(struct kvm_vcpu *vcpu) > trace_kvm_mmio(KVM_TRACE_MMIO_READ, len, run->mmio.phys_addr, > &data); > data = vcpu_data_host_to_guest(vcpu, data, len); > - vcpu_set_reg(vcpu, kvm_vcpu_dabt_get_rd(vcpu), data); > + > + if (vcpu_is_rec(vcpu)) > + vcpu->arch.rec.run->enter.gprs[0] = data; I wonder if we can skip this here and we can sync the "enter.gprs[]" from vcpu state at rec_enter, similar to what we do for PSCI/HOST call exits. Also the ESR_ELx_SRT is always x0 for a Realm exit. So, we should always find the enter.gpr[0] in vcpu.regs[0] at rec_enter. Suzuki > + else > + vcpu_set_reg(vcpu, kvm_vcpu_dabt_get_rd(vcpu), data); > } > > /* > diff --git a/arch/arm64/kvm/rme-exit.c b/arch/arm64/kvm/rme-exit.c > index e96ea308212c..1ddbff123149 100644 > --- a/arch/arm64/kvm/rme-exit.c > +++ b/arch/arm64/kvm/rme-exit.c > @@ -25,6 +25,12 @@ static int rec_exit_reason_notimpl(struct kvm_vcpu *vcpu) > > static int rec_exit_sync_dabt(struct kvm_vcpu *vcpu) > { > + struct realm_rec *rec = &vcpu->arch.rec; > + > + if (kvm_vcpu_dabt_iswrite(vcpu) && kvm_vcpu_dabt_isvalid(vcpu)) > + vcpu_set_reg(vcpu, kvm_vcpu_dabt_get_rd(vcpu), > + rec->run->exit.gprs[0]); > + > return kvm_handle_guest_abort(vcpu); > } >