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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (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 8751ACDB483 for ; Thu, 19 Oct 2023 09:24:19 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qtPFW-0001Y5-4L; Thu, 19 Oct 2023 05:23:26 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qtPFU-0001O0-Fh for qemu-devel@nongnu.org; Thu, 19 Oct 2023 05:23:24 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qtPFQ-0006X2-4K for qemu-devel@nongnu.org; Thu, 19 Oct 2023 05:23:24 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1697707395; 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: in-reply-to:in-reply-to:references:references; bh=/WyLcUPHtfbwR5iPsldid+h/rFbvL5xLR+xTTX/yt/c=; b=SHzIJaBftrwYK1H1tZAsnXT+ImJdma8AqKsIke1T33/5VXLYjL22rvIbW0SZoxXvwUAqjx dVHZdH8NroRSVrsXUzA5DSUoMrHM0g8OEjEl9CAOozorDJAt455BCSwzbbo2gMTgePrHLh bxvFEg+UQhAV2SKbgHVIZC8rs6Kady4= Received: from mail-lf1-f69.google.com (mail-lf1-f69.google.com [209.85.167.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-583-W1LM7j0AMcios_YFVU4JWQ-1; Thu, 19 Oct 2023 05:23:12 -0400 X-MC-Unique: W1LM7j0AMcios_YFVU4JWQ-1 Received: by mail-lf1-f69.google.com with SMTP id 2adb3069b0e04-5079630993dso6712526e87.1 for ; Thu, 19 Oct 2023 02:23:12 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1697707391; x=1698312191; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=/WyLcUPHtfbwR5iPsldid+h/rFbvL5xLR+xTTX/yt/c=; b=iZ5YSdLqj0Ijtg6Px1kVC2L5hZY1bmlvHp2MlTY3cxOCHMOZloxJW/gc/Qyg1JQC5j aVlwmuxRsaNpRHC2DNNLgFXsaXKk+TwM8KbpLmunfUAwipsxukSVR+8VXsZ4m4G+R0+n uAs66zVLBLMEdmW8V/ERnx8/tvlxUQlNNTTxrJpV5Ut8S7aAM2/f7Kz3LNdpv0e1XHur c3T7SWshGrBbDhgpTun3BOmM+WpmFd6PaAKqRf3K57faVhMfctpPlY/MOIvig5HYVLDb JjLBivpkdXzorQUxps6gP+ltGlY/o5PisdG5fCI91tpSNzNnJC6PHFXXbdy4ugdpCm9K 21UQ== X-Gm-Message-State: AOJu0Yw6PaDbF7XgNKQuc7XtROLUxeNsnnP02Krw5P/UXsArUV6WTiAl Jgub0lFXgrQ8CYglZD7kYPpoNbnTPaIu+1VBQlq+1v35wfIfTEBY6AvNOATnxCg/057h1TiIkMB pPaDY1yL1bmfeplo= X-Received: by 2002:a05:6512:3584:b0:507:b935:9f5f with SMTP id m4-20020a056512358400b00507b9359f5fmr1018454lfr.24.1697707390994; Thu, 19 Oct 2023 02:23:10 -0700 (PDT) X-Google-Smtp-Source: AGHT+IFOes4g3ZAbBGS7tQdEjrdM4/kivYVl+CYh/7o2EDH+JRgFh74aqdjMYiRlaOcFJvMBUCF0Nw== X-Received: by 2002:a05:6512:3584:b0:507:b935:9f5f with SMTP id m4-20020a056512358400b00507b9359f5fmr1018440lfr.24.1697707390583; Thu, 19 Oct 2023 02:23:10 -0700 (PDT) Received: from redhat.com ([2a02:14f:1f2:2037:f34:d61b:7da0:a7be]) by smtp.gmail.com with ESMTPSA id u20-20020a05600c19d400b0040841e79715sm2372694wmq.27.2023.10.19.02.23.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 19 Oct 2023 02:23:10 -0700 (PDT) Date: Thu, 19 Oct 2023 05:23:04 -0400 From: "Michael S. Tsirkin" To: Jonathan Cameron Cc: linuxarm@huawei.com, qemu-devel@nongnu.org, linux-cxl@vger.kernel.org, Michael Tokarev , Fan Ni , Philippe =?iso-8859-1?Q?Mathieu-Daud=E9?= Subject: Re: [PATCH v4 2/4] hw/cxl: Use switch statements for read and write of cachemem registers Message-ID: <20231019052242-mutt-send-email-mst@kernel.org> References: <20231012140514.3697-1-Jonathan.Cameron@huawei.com> <20231012140514.3697-3-Jonathan.Cameron@huawei.com> <20231018103907-mutt-send-email-mst@kernel.org> <20231018172239.00005f3d@Huawei.com> <20231018173142.00003739@Huawei.com> <20231019100547.00003eef@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231019100547.00003eef@huawei.com> Received-SPF: pass client-ip=170.10.129.124; envelope-from=mst@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Thu, Oct 19, 2023 at 10:09:24AM +0100, Jonathan Cameron wrote: > On Wed, 18 Oct 2023 17:31:42 +0100 > Jonathan Cameron wrote: > > > On Wed, 18 Oct 2023 17:22:39 +0100 > > Jonathan Cameron wrote: > > > > > On Wed, 18 Oct 2023 10:40:45 -0400 > > > "Michael S. Tsirkin" wrote: > > > > > > > On Thu, Oct 12, 2023 at 03:05:12PM +0100, Jonathan Cameron wrote: > > > > > Establishing that only register accesses of size 4 and 8 can occur > > > > > using these functions requires looking at their callers. Make it > > > > > easier to see that by using switch statements. > > > > > Assertions are used to enforce that the register storage is of the > > > > > matching size, allowing fixed values to be used for divisors of > > > > > the array indices. > > > > > > > > > > Suggested-by: Michael Tokarev > > > > > Signed-off-by: Jonathan Cameron > > > > > Reviewed-by: Fan Ni > > > > > > > > Fails with clang: > > > > > > > > ../hw/cxl/cxl-component-utils.c:130:9: error: expected expression > > > > QEMU_BUILD_BUG_ON(sizeof(*cregs->cache_mem_regs_write_mask) != 4); > > > > ^ > > > > ../include/qemu/compiler.h:76:30: note: expanded from macro 'QEMU_BUILD_BUG_ON' > > > > #define QEMU_BUILD_BUG_ON(x) QEMU_BUILD_BUG_MSG(x, "not expecting: " #x) > > > > ^ > > > > ../include/qemu/compiler.h:74:36: note: expanded from macro 'QEMU_BUILD_BUG_MSG' > > > > #define QEMU_BUILD_BUG_MSG(x, msg) _Static_assert(!(x), msg) > > > > ^ > > > > 1 error generated. > > > > > > > > See e.g. > > > > > > > > https://gitlab.com/mstredhat/qemu/-/jobs/5320879531 > > > > > > Thanks. Will see if I can figure out what is going wrong. > > > This code seems cursed. I need to figure out a way to run the CI again. > > > Ran into credit problems I couldn't solve last time I tried. > > > > > > In meantime I can replicate this locally but not immediately obvious to me > > > why it is failing. > > > > Any clang experts around? This seems to be fixed by reducing the scope > > > > case 4: > > { > > QEMU_BUILD_BUG_ON(); > > } > > I have no idea why though... > > > > For anyone following along I asked a friendly compiler guy... > > https://github.com/llvm/llvm-project/issues/69572 > > Given that we realistically need to work around this whatever the outcome > I'll add some brackets and send an update. > > thanks, > > Jonathan We don't seem to use QEMU_BUILD_BUG_ON outside of functions - just add brackets inside it? > > > > > > > > Jonathan > > > > > > > > > > > > > > > > > > > > --- > > > > > v4: Use QEMU_BUILD_BUG_ON() instead of static_assert with missing > > > > > error message. > > > > > > > > > > hw/cxl/cxl-component-utils.c | 65 +++++++++++++++++++++++------------- > > > > > 1 file changed, 42 insertions(+), 23 deletions(-) > > > > > > > > > > diff --git a/hw/cxl/cxl-component-utils.c b/hw/cxl/cxl-component-utils.c > > > > > index f3bbf0fd13..d1997a52e6 100644 > > > > > --- a/hw/cxl/cxl-component-utils.c > > > > > +++ b/hw/cxl/cxl-component-utils.c > > > > > @@ -67,16 +67,24 @@ static uint64_t cxl_cache_mem_read_reg(void *opaque, hwaddr offset, > > > > > CXLComponentState *cxl_cstate = opaque; > > > > > ComponentRegisters *cregs = &cxl_cstate->crb; > > > > > > > > > > - if (size == 8) { > > > > > + switch (size) { > > > > > + case 4: > > > > > + if (cregs->special_ops && cregs->special_ops->read) { > > > > > + return cregs->special_ops->read(cxl_cstate, offset, 4); > > > > > + } else { > > > > > + QEMU_BUILD_BUG_ON(sizeof(*cregs->cache_mem_registers) != 4); > > > > > + return cregs->cache_mem_registers[offset / 4]; > > > > > + } > > > > > + case 8: > > > > > qemu_log_mask(LOG_UNIMP, > > > > > "CXL 8 byte cache mem registers not implemented\n"); > > > > > return 0; > > > > > - } > > > > > - > > > > > - if (cregs->special_ops && cregs->special_ops->read) { > > > > > - return cregs->special_ops->read(cxl_cstate, offset, size); > > > > > - } else { > > > > > - return cregs->cache_mem_registers[offset / sizeof(*cregs->cache_mem_registers)]; > > > > > + default: > > > > > + /* > > > > > + * In line with specifiction limitaions on access sizes, this > > > > > + * routine is not called with other sizes. > > > > > + */ > > > > > + g_assert_not_reached(); > > > > > } > > > > > } > > > > > > > > > > @@ -117,25 +125,36 @@ static void cxl_cache_mem_write_reg(void *opaque, hwaddr offset, uint64_t value, > > > > > ComponentRegisters *cregs = &cxl_cstate->crb; > > > > > uint32_t mask; > > > > > > > > > > - if (size == 8) { > > > > > + switch (size) { > > > > > + case 4: > > > > > + QEMU_BUILD_BUG_ON(sizeof(*cregs->cache_mem_regs_write_mask) != 4); > > > > > + QEMU_BUILD_BUG_ON(sizeof(*cregs->cache_mem_registers) != 4); > > > > > + mask = cregs->cache_mem_regs_write_mask[offset / 4]; > > > > > + value &= mask; > > > > > + /* RO bits should remain constant. Done by reading existing value */ > > > > > + value |= ~mask & cregs->cache_mem_registers[offset / 4]; > > > > > + if (cregs->special_ops && cregs->special_ops->write) { > > > > > + cregs->special_ops->write(cxl_cstate, offset, value, size); > > > > > + return; > > > > > + } > > > > > + > > > > > + if (offset >= A_CXL_HDM_DECODER_CAPABILITY && > > > > > + offset <= A_CXL_HDM_DECODER3_TARGET_LIST_HI) { > > > > > + dumb_hdm_handler(cxl_cstate, offset, value); > > > > > + } else { > > > > > + cregs->cache_mem_registers[offset / 4] = value; > > > > > + } > > > > > + return; > > > > > + case 8: > > > > > qemu_log_mask(LOG_UNIMP, > > > > > "CXL 8 byte cache mem registers not implemented\n"); > > > > > return; > > > > > - } > > > > > - mask = cregs->cache_mem_regs_write_mask[offset / sizeof(*cregs->cache_mem_regs_write_mask)]; > > > > > - value &= mask; > > > > > - /* RO bits should remain constant. Done by reading existing value */ > > > > > - value |= ~mask & cregs->cache_mem_registers[offset / sizeof(*cregs->cache_mem_registers)]; > > > > > - if (cregs->special_ops && cregs->special_ops->write) { > > > > > - cregs->special_ops->write(cxl_cstate, offset, value, size); > > > > > - return; > > > > > - } > > > > > - > > > > > - if (offset >= A_CXL_HDM_DECODER_CAPABILITY && > > > > > - offset <= A_CXL_HDM_DECODER3_TARGET_LIST_HI) { > > > > > - dumb_hdm_handler(cxl_cstate, offset, value); > > > > > - } else { > > > > > - cregs->cache_mem_registers[offset / sizeof(*cregs->cache_mem_registers)] = value; > > > > > + default: > > > > > + /* > > > > > + * In line with specifiction limitaions on access sizes, this > > > > > + * routine is not called with other sizes. > > > > > + */ > > > > > + g_assert_not_reached(); > > > > > } > > > > > } > > > > > > > > > > -- > > > > > 2.39.2 > > > > > > > > > > > > > > > > >