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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 20C35C433EF for ; Wed, 13 Oct 2021 16:56:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0A06561053 for ; Wed, 13 Oct 2021 16:56:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238101AbhJMQ6q (ORCPT ); Wed, 13 Oct 2021 12:58:46 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:51399 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237916AbhJMQ6c (ORCPT ); Wed, 13 Oct 2021 12:58:32 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1634144188; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=OQc5t39oYfKEqQbzvm+Biugqq6bcM4boL4RoaIoHD1Y=; b=PeIITYqcVPSbsV8xiT14ECiJsZwqAMJVKAAORNcX558L0mHvf+kVk2F/4ybu4iINqkpvXU wHSKEGhncmJAqkk2S1JbrlWpHaEsZ9pMwo/W/YI+XkLC4EvCT2Ad9YVhrjKFjhr4aWROVC g7pgdN3pmaxe5DIjRdQbDIH76i+Zk2s= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-538-u2ouWplOOjK_H_t0WEoH1w-1; Wed, 13 Oct 2021 12:56:23 -0400 X-MC-Unique: u2ouWplOOjK_H_t0WEoH1w-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 75263801AA7; Wed, 13 Oct 2021 16:56:22 +0000 (UTC) Received: from virtlab701.virt.lab.eng.bos.redhat.com (virtlab701.virt.lab.eng.bos.redhat.com [10.19.152.228]) by smtp.corp.redhat.com (Postfix) with ESMTP id EBAC95DA60; Wed, 13 Oct 2021 16:56:21 +0000 (UTC) From: Paolo Bonzini To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: fwilhelm@google.com, seanjc@google.com, oupton@google.com, stable@vger.kernel.org Subject: [PATCH 8/8] KVM: SEV-ES: go over the sev_pio_data buffer in multiple passes if needed Date: Wed, 13 Oct 2021 12:56:16 -0400 Message-Id: <20211013165616.19846-9-pbonzini@redhat.com> In-Reply-To: <20211013165616.19846-1-pbonzini@redhat.com> References: <20211013165616.19846-1-pbonzini@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The PIO scratch buffer is larger than a single page, and therefore it is not possible to copy it in a single step to vcpu->arch/pio_data. Bound each call to emulator_pio_in/out to a single page; keep track of how many I/O operations are left in vcpu->arch.sev_pio_count, so that the operation can be restarted in the complete_userspace_io callback. For OUT, this means that the previous kvm_sev_es_outs implementation becomes an iterator of the loop, and we can consume the sev_pio_data buffer before leaving to userspace. For IN, instead, consuming the buffer and decreasing sev_pio_count is always done in the complete_userspace_io callback, because that is when the memcpy is done into sev_pio_data. Cc: stable@vger.kernel.org Fixes: 7ed9abfe8e9f ("KVM: SVM: Support string IO operations for an SEV-ES guest") Reported-by: Felix Wilhelm Signed-off-by: Paolo Bonzini --- arch/x86/include/asm/kvm_host.h | 1 + arch/x86/kvm/x86.c | 73 +++++++++++++++++++++++++-------- 2 files changed, 57 insertions(+), 17 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 6bed6c416c6c..5a0298aa56ba 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -703,6 +703,7 @@ struct kvm_vcpu_arch { struct kvm_pio_request pio; void *pio_data; void *sev_pio_data; + unsigned sev_pio_count; u8 event_exit_inst_len; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index a485e185ad00..09c1e64495d3 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -12378,38 +12378,76 @@ int kvm_sev_es_mmio_read(struct kvm_vcpu *vcpu, gpa_t gpa, unsigned int bytes, EXPORT_SYMBOL_GPL(kvm_sev_es_mmio_read); static int kvm_sev_es_outs(struct kvm_vcpu *vcpu, unsigned int size, - unsigned int port, unsigned int count) + unsigned int port); + +static int complete_sev_es_emulated_outs(struct kvm_vcpu *vcpu) { - int ret = emulator_pio_out(vcpu, size, port, - vcpu->arch.sev_pio_data, count); + vcpu->arch.pio.count = 0; + if (vcpu->arch.sev_pio_count) + return kvm_sev_es_outs(vcpu, + vcpu->arch.pio.size, + vcpu->arch.pio.port); + return 1; +} + +static int kvm_sev_es_outs(struct kvm_vcpu *vcpu, unsigned int size, + unsigned int port) +{ + for (;;) { + unsigned int count = + min_t(unsigned int, PAGE_SIZE / size, vcpu->arch.sev_pio_count); + int ret = emulator_pio_out(vcpu, size, port, vcpu->arch.sev_pio_data, count); + + /* memcpy done already by emulator_pio_out. */ + vcpu->arch.sev_pio_count -= count; + vcpu->arch.sev_pio_data += count * vcpu->arch.pio.size; + if (!ret) + break; - if (ret) { /* Emulation done by the kernel. */ - return ret; + vcpu->arch.pio.count = 0; + if (!vcpu->arch.sev_pio_count) + return 1; } - vcpu->arch.pio.count = 0; + vcpu->arch.complete_userspace_io = complete_sev_es_emulated_outs; return 0; } -static int complete_sev_es_emulated_ins(struct kvm_vcpu *vcpu) +static int kvm_sev_es_ins(struct kvm_vcpu *vcpu, unsigned int size, + unsigned int port); + +static void __complete_sev_es_emulated_ins(struct kvm_vcpu *vcpu) { - memcpy(vcpu->arch.sev_pio_data, vcpu->arch.pio_data, - vcpu->arch.pio.count * vcpu->arch.pio.size); - vcpu->arch.pio.count = 0; + unsigned count = vcpu->arch.pio.count; + complete_emulator_pio_in(vcpu, vcpu->arch.sev_pio_data); + vcpu->arch.sev_pio_count -= count; + vcpu->arch.sev_pio_data += count * vcpu->arch.pio.size; +} +static int complete_sev_es_emulated_ins(struct kvm_vcpu *vcpu) +{ + __complete_sev_es_emulated_ins(vcpu); + if (vcpu->arch.sev_pio_count) + return kvm_sev_es_ins(vcpu, + vcpu->arch.pio.size, + vcpu->arch.pio.port); return 1; } static int kvm_sev_es_ins(struct kvm_vcpu *vcpu, unsigned int size, - unsigned int port, unsigned int count) + unsigned int port) { - int ret = emulator_pio_in(vcpu, size, port, - vcpu->arch.sev_pio_data, count); + for (;;) { + unsigned int count = + min_t(unsigned int, PAGE_SIZE / size, vcpu->arch.sev_pio_count); + if (!__emulator_pio_in(vcpu, size, port, count)) + break; - if (ret) { /* Emulation done by the kernel. */ - return ret; + __complete_sev_es_emulated_ins(vcpu); + if (!vcpu->arch.sev_pio_count) + return 1; } vcpu->arch.complete_userspace_io = complete_sev_es_emulated_ins; @@ -12421,8 +12459,9 @@ int kvm_sev_es_string_io(struct kvm_vcpu *vcpu, unsigned int size, int in) { vcpu->arch.sev_pio_data = data; - return in ? kvm_sev_es_ins(vcpu, size, port, count) - : kvm_sev_es_outs(vcpu, size, port, count); + vcpu->arch.sev_pio_count = count; + return in ? kvm_sev_es_ins(vcpu, size, port) + : kvm_sev_es_outs(vcpu, size, port); } EXPORT_SYMBOL_GPL(kvm_sev_es_string_io); -- 2.27.0