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 837F5C433EF for ; Tue, 26 Oct 2021 13:56:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 67A7060230 for ; Tue, 26 Oct 2021 13:56:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236296AbhJZN6d (ORCPT ); Tue, 26 Oct 2021 09:58:33 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:21513 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232606AbhJZN6c (ORCPT ); Tue, 26 Oct 2021 09:58:32 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1635256567; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=GqvoimveYlYhulmJuY+J/4zhaZ7J2u8WeVOP1SKbbjw=; b=JDhLD0vRUdv7iHt2cbxNudJyKs67HXUelstff1ldQYQslYV9Mz58tOFQKhcvee7GEYO3wr VXDXAbvnA8NQgN31SIYJbEr/2j90oE9hMAp7tslmNwSOHVaa0O5DS4XY/MznalpSLlIIAD qMYBo4UxNwtT6074X1ghFcM8Ijp3P9A= 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-483-g5TmEK-YMNG_kSEzmGqIaQ-1; Tue, 26 Oct 2021 09:56:03 -0400 X-MC-Unique: g5TmEK-YMNG_kSEzmGqIaQ-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 87C9280A5C0; Tue, 26 Oct 2021 13:56:02 +0000 (UTC) Received: from starship (unknown [10.40.194.243]) by smtp.corp.redhat.com (Postfix) with ESMTP id E48E010023B8; Tue, 26 Oct 2021 13:56:00 +0000 (UTC) Message-ID: Subject: Re: [PATCH 08/13] KVM: x86: inline kernel_pio into its sole caller From: Maxim Levitsky To: Paolo Bonzini , linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: seanjc@google.com Date: Tue, 26 Oct 2021 16:55:59 +0300 In-Reply-To: <20211022153616.1722429-9-pbonzini@redhat.com> References: <20211022153616.1722429-1-pbonzini@redhat.com> <20211022153616.1722429-9-pbonzini@redhat.com> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.36.5 (3.36.5-2.fc32) MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Fri, 2021-10-22 at 11:36 -0400, Paolo Bonzini wrote: > The caller of kernel_pio already has arguments for most of what kernel_pio > fishes out of vcpu->arch.pio. This is the first step towards ensuring that > vcpu->arch.pio.* is only used when exiting to userspace. > > We can now also WARN if emulated PIO performs successful in-kernel iterations > before having to fall back to userspace. The code is not ready for that, and > it should never happen. > > No functional change intended. > > Signed-off-by: Paolo Bonzini > --- > arch/x86/kvm/x86.c | 39 +++++++++++++++++---------------------- > 1 file changed, 17 insertions(+), 22 deletions(-) > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index b26647a5ea22..d6b8df7cea80 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -6886,37 +6886,32 @@ static int emulator_cmpxchg_emulated(struct x86_emulate_ctxt *ctxt, > return emulator_write_emulated(ctxt, addr, new, bytes, exception); > } > > -static int kernel_pio(struct kvm_vcpu *vcpu, void *pd) > -{ > - int r = 0, i; > - > - for (i = 0; i < vcpu->arch.pio.count; i++) { > - if (vcpu->arch.pio.in) > - r = kvm_io_bus_read(vcpu, KVM_PIO_BUS, vcpu->arch.pio.port, > - vcpu->arch.pio.size, pd); > - else > - r = kvm_io_bus_write(vcpu, KVM_PIO_BUS, > - vcpu->arch.pio.port, vcpu->arch.pio.size, > - pd); > - if (r) > - break; > - pd += vcpu->arch.pio.size; > - } > - return r; > -} > - > static int emulator_pio_in_out(struct kvm_vcpu *vcpu, int size, > unsigned short port, > unsigned int count, bool in) > { > + void *data = vcpu->arch.pio_data; > + unsigned i; > + int r; > + > vcpu->arch.pio.port = port; > vcpu->arch.pio.in = in; > - vcpu->arch.pio.count = count; > + vcpu->arch.pio.count = count; > vcpu->arch.pio.size = size; > > - if (!kernel_pio(vcpu, vcpu->arch.pio_data)) > - return 1; > + for (i = 0; i < count; i++) { > + if (in) > + r = kvm_io_bus_read(vcpu, KVM_PIO_BUS, port, size, data); > + else > + r = kvm_io_bus_write(vcpu, KVM_PIO_BUS, port, size, data); > + if (r) > + goto userspace_io; > + data += size; > + } > + return 1; > > +userspace_io: > + WARN_ON(i != 0); > vcpu->run->exit_reason = KVM_EXIT_IO; > vcpu->run->io.direction = in ? KVM_EXIT_IO_IN : KVM_EXIT_IO_OUT; > vcpu->run->io.size = size; Reviewed-by: Maxim Levitsky Best regards, Maxim Levitsky