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 6403DC47258 for ; Wed, 31 Jan 2024 23:04:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:Cc:To:From:Subject:Message-ID: References:Mime-Version:In-Reply-To:Date:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=JSrvfJvEM0pRzPGwJ4uLF4hTapcdMzn2RJscIkIJIMI=; b=1rtyT73mqfS1ZKr5LTrMXHSES/ YtBi0cJFGXirO9Y3JqqBEh0yjwJJMFrPWfXi5hLhdFLclOSumk+zJalLNozvkssiEoNoOXq36Ajxw zOLYZQnHWM0tL4vwTZ8Z3CcwcJxCXr8Or1ezmTVZMqhwwOn/ZPzxgtoKyb04kxqvefPLiJVIgXBW9 z0loCjdxsIvJzqJMUqvHPC0EKy3gCWi1g9NDRKqQ79ajDLtLmfPbJSC+JRTruWZStE1z6N+RVz0je dGzs4j2YSlIgYqEolLkJCZLGbYCrcQGCBwDWeeiUZZVLDNu+K/jHIY39oHNPlSiWHgSsQweGJXd70 fvZi/YIg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rVJca-00000005mlE-2Cqp; Wed, 31 Jan 2024 23:03:56 +0000 Received: from mail-yw1-x1149.google.com ([2607:f8b0:4864:20::1149]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1rVJcW-00000005mhY-3z9w for linux-arm-kernel@lists.infradead.org; Wed, 31 Jan 2024 23:03:55 +0000 Received: by mail-yw1-x1149.google.com with SMTP id 00721157ae682-6040597d005so6064517b3.2 for ; Wed, 31 Jan 2024 15:03:51 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1706742230; x=1707347030; darn=lists.infradead.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=DZwweSSUYQvO/z20yvIqcaNFaLAc1RqILCFOCkMXbPM=; b=TiTjIi9vIE+5x3Js+nd0hjyP9UDJV8Xk/yx5e/rcKcUTNfom4I/6QLqBxqrXLo+gZ0 AQNI0Cx0PRKRQcO9cZI3NeuzgUlPYLIxPLxyJRSlvI9guaKYPStta1WEQJI+Tn7e2dDG yf8dvVysuIDRzrpmlBJryBcdXpx98THYSlrQIX6I0aEmwByivDsNe74d8MLl8NC/dO0R 1HYDekY9iZuyQHS3yP2h2nUvb+I8fg+bTZxdcFQVIV7wqmtHu2nGZYx0EcxiR7lLGvMg oeHrr3MzDVSEdeQd+FJ1l8EJs8l7KKM/JMImneYI6+dtvffA9D0T2au/apJECiQS5evf Sv+A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1706742230; x=1707347030; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=DZwweSSUYQvO/z20yvIqcaNFaLAc1RqILCFOCkMXbPM=; b=VBwOnu2LtClxDBig6askaz3vZhwGfExphT5FsFRIt4kjCVUCDTr/R+hQnP2dLCLDhE fN7F8Tz8TRRTe+Kw8aIloScmxOD739l83GOgnrq1cU9yBUKKUNHVEfjLWlFzRLsUDwDa NYY2IOVgSf3BggjWU3wr7Jg6TARRfG6OA/6Ofh7mhEfV1RUOo0mFZ1eYlW4lYiOeA9iH cyDuzkWYG/fS05GhVVRFzr6pomErjdiWoit1Fhl460NZS8tDERqrRsi/BxJEbcnzoiWd gdYyiX820/D+ZXdtSNotB6n+xdl5Via6tks71C4vnMNqORc4qGggSIK3XzRoNuhOMQmd gL4A== X-Gm-Message-State: AOJu0YyCxyLfbm+2N8jsg5H7A6MLBJmOwz/s093Q/6zozASPS5y2tNW/ Q1uA5YRUrgyXtjH6amQIz8QxjxGGdQVx1amQmXqW/R2mjp9/Wh+MivbOKVVikFjlnjchTAzOpvb AAA== X-Google-Smtp-Source: AGHT+IFJbItnQs4Y8jmKkE5kxYlZxxDLejMwZjXJSJ/Pnb1uodzlMpEbl5+L7dgh/lCtAx5a7aAZSZtZzuc= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a05:690c:dd6:b0:5fc:43cb:cb1e with SMTP id db22-20020a05690c0dd600b005fc43cbcb1emr691136ywb.10.1706742230591; Wed, 31 Jan 2024 15:03:50 -0800 (PST) Date: Wed, 31 Jan 2024 15:03:48 -0800 In-Reply-To: <20231102155111.28821-3-guang.zeng@intel.com> Mime-Version: 1.0 References: <20231102155111.28821-1-guang.zeng@intel.com> <20231102155111.28821-3-guang.zeng@intel.com> Message-ID: Subject: Re: [RFC PATCH v1 2/8] KVM: selftests: x86: Support guest running on canonical linear-address organization From: Sean Christopherson To: Zeng Guang Cc: Paolo Bonzini , Shuah Khan , Marc Zyngier , Oliver Upton , James Morse , Suzuki K Poulose , Zenghui Yu , Anup Patel , Atish Patra , David Hildenbrand , kvm@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240131_150353_002582_4D8F68B1 X-CRM114-Status: GOOD ( 22.87 ) 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: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Nov 02, 2023, Zeng Guang wrote: > Setup execution environment running on 64-bit linear addresses for > user and supervisor mode. > > Define the linear address based on 48-bit canonical format in which > bits 63:47 of the address are identical. All addresses to system data > structure are shifted to supervisor-mode address space. > > Extend page table mapping for supervisor mode to same guest physical > address. This allows guest in supervisor mode can run in the > corresponding canonical linear address space. > > Signed-off-by: Zeng Guang > --- > .../selftests/kvm/include/x86_64/processor.h | 6 ++++ > tools/testing/selftests/kvm/lib/kvm_util.c | 6 ++-- > .../selftests/kvm/lib/x86_64/processor.c | 28 ++++++++++++------- > 3 files changed, 28 insertions(+), 12 deletions(-) > > diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h > index 25bc61dac5fb..00f7337a520a 100644 > --- a/tools/testing/selftests/kvm/include/x86_64/processor.h > +++ b/tools/testing/selftests/kvm/include/x86_64/processor.h > @@ -1256,4 +1256,10 @@ void virt_map_level(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr, > #define PFERR_GUEST_PAGE_MASK BIT_ULL(PFERR_GUEST_PAGE_BIT) > #define PFERR_IMPLICIT_ACCESS BIT_ULL(PFERR_IMPLICIT_ACCESS_BIT) > > +/* > + * X86 kernel linear address defines > + */ > +#define KERNEL_LNA_OFFSET 0xffff800000000000 Please don't make up acronyms, I can more or less glean what LNA is from the context _here_, but in other usage I would truly have no idea. > diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c > index 9f4b8c47edce..6f4295a13d00 100644 > --- a/tools/testing/selftests/kvm/lib/x86_64/processor.c > +++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c > @@ -227,6 +227,13 @@ void __virt_pg_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr, int level) > void virt_arch_pg_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr) > { > __virt_pg_map(vm, vaddr, paddr, PG_LEVEL_4K); > + > + /* > + * Map same paddr to kernel linear address space. Make execution > + * environment supporting running both in user and kernel mode. > + */ > + if (!(vaddr & BIT_ULL(63))) > + __virt_pg_map(vm, (uint64_t)KERNEL_ADDR(vaddr), paddr, PG_LEVEL_4K); I really don't like the idea of piling hacks on top of selftests' misguided infrastructure. Letting tests control virtual addresses is all kinds of stupid. Except for ARM's ucall_arch_init(), I don't think there's a single user of virt_map() that _needs_ a specific address, e.g. most tests just identity map the GPA. So rather than fudge things by stuffing two mappings, which is wasteful for 99% of mappings and will likely be a maintenance nightmare, I think we should go straight to getting x86's kernel mappings setup correctly from time zero. >From KUT experience, using USER mappings for kernel accesses is explosions waiting to happen due to SMAP and SMEP. And expecting developers to remember to sprinkle KERNEL_ADDR() everywhere is not remotely maintainable. In other words, give virt_arch_pg_map() (or ideally, the common virt_map()) over picking the virtual address, and then plumb in information as to whether the allocation is USER vs. SUPERVISOR. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel