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 3FBCAC07C79 for ; Mon, 22 Apr 2024 11:58:53 +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:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=amYOjNBzd2luiEuRNL4CUw8iLzs/VoDjqj9jFqLC+uc=; b=4xYcQbsgNh/Khj bybPV2DqkAHNPhjgN4MxO2YgRgeDBeBf85ogBrQVIAG56dXi3ERABxZ6ImUNuOjuIT2QMx6NtUUKn HXbygpamtrzO3PLtaOROsvEKhf8VIABi3y7tie1hKrj1SGzCnsK72Vzqr4K05MiWDevGt22hYGQF6 NXbsKnNO5mNxZo3mGtvcLEK25GqQ+fcFMf1z43WPEQL7R0E/AqH77QXbPN5nwXMfb1KEJlHXhXLhE yBaEZ9mj2QUnO50zdgkvTddSZCuwrJlrHpmUCPmsSJAtQOz9rWl0uRaocEnIk9JvHZvQFdVEjLFTO SLzfg+yHSzHB37Hd/ixA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rysJm-0000000DRLg-1bcR; Mon, 22 Apr 2024 11:58:42 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rysJj-0000000DRKy-3K8z for linux-arm-kernel@lists.infradead.org; Mon, 22 Apr 2024 11:58:41 +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 117E6339; Mon, 22 Apr 2024 04:59:05 -0700 (PDT) Received: from arm.com (unknown [10.57.76.213]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 1EA213F7BD; Mon, 22 Apr 2024 04:58:29 -0700 (PDT) Date: Mon, 22 Apr 2024 12:58:41 +0100 From: Alexandru Elisei To: Suzuki K Poulose Cc: kvmarm@lists.linux.dev, kvm@vger.kernel.org, linux-coco@lists.linux.dev, linux-arm-kernel@lists.infradead.org, maz@kernel.org, joey.gouly@arm.com, steven.price@arm.com, james.morse@arm.com, oliver.upton@linux.dev, yuzenghui@huawei.com, andrew.jones@linux.dev, eric.auger@redhat.com Subject: Re: [kvm-unit-tests PATCH 08/33] arm: realm: Make uart available before MMU is enabled Message-ID: References: <20240412103408.2706058-1-suzuki.poulose@arm.com> <20240412103408.2706058-9-suzuki.poulose@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20240412103408.2706058-9-suzuki.poulose@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240422_045839_946895_737696E1 X-CRM114-Status: GOOD ( 24.74 ) 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 Hi, On Fri, Apr 12, 2024 at 11:33:43AM +0100, Suzuki K Poulose wrote: > From: Joey Gouly > > A Realm must access any emulated I/O mappings with the PTE_NS_SHARED bit set. > This is modelled as a PTE attribute, but is actually part of the address. > > So, when MMU is disabled, the "physical address" must reflect this bit set. We > access the UART early before the MMU is enabled. So, make sure the UART is > accessed always with the bit set. > > Signed-off-by: Joey Gouly > Signed-off-by: Suzuki K Poulose > --- > lib/arm/asm/pgtable.h | 5 +++++ > lib/arm/io.c | 24 +++++++++++++++++++++++- > lib/arm64/asm/pgtable.h | 5 +++++ > 3 files changed, 33 insertions(+), 1 deletion(-) > > diff --git a/lib/arm/asm/pgtable.h b/lib/arm/asm/pgtable.h > index 350039ff..7e85e7c6 100644 > --- a/lib/arm/asm/pgtable.h > +++ b/lib/arm/asm/pgtable.h > @@ -112,4 +112,9 @@ static inline pte_t *pte_alloc(pmd_t *pmd, unsigned long addr) > return pte_offset(pmd, addr); > } > > +static inline unsigned long arm_shared_phys_alias(void *x) > +{ > + return ((unsigned long)(x) | PTE_NS_SHARED); > +} Is it allowed for a realm to run in aarch32 mode? > + > #endif /* _ASMARM_PGTABLE_H_ */ > diff --git a/lib/arm/io.c b/lib/arm/io.c > index 836fa854..127727e4 100644 > --- a/lib/arm/io.c > +++ b/lib/arm/io.c > @@ -15,6 +15,8 @@ > #include > #include > #include > +#include > +#include > > #include "io.h" > > @@ -30,6 +32,24 @@ static struct spinlock uart_lock; > static volatile u8 *uart0_base = UART_EARLY_BASE; > bool is_pl011_uart; > > +static inline volatile u8 *get_uart_base(void) > +{ > + /* > + * The address of the UART base may be different > + * based on whether we are running with/without > + * MMU enabled. > + * > + * For realms, we must force to use the shared physical > + * alias with MMU disabled, to make sure the I/O can > + * be emulated. > + * When the MMU is turned ON, the mappings are created > + * appropriately. > + */ > + if (mmu_enabled()) > + return uart0_base; > + return (u8 *)arm_shared_phys_alias((void *)uart0_base); > +} > + > static void uart0_init_fdt(void) > { > /* > @@ -109,9 +129,11 @@ void io_init(void) > > void puts(const char *s) > { > + volatile u8 *uart_base = get_uart_base(); > + > spin_lock(&uart_lock); > while (*s) > - writeb(*s++, uart0_base); > + writeb(*s++, uart_base); > spin_unlock(&uart_lock); > } > > diff --git a/lib/arm64/asm/pgtable.h b/lib/arm64/asm/pgtable.h > index 5b9f40b0..871c03e9 100644 > --- a/lib/arm64/asm/pgtable.h > +++ b/lib/arm64/asm/pgtable.h > @@ -28,6 +28,11 @@ extern unsigned long prot_ns_shared; > */ > #define PTE_NS_SHARED (prot_ns_shared) > > +static inline unsigned long arm_shared_phys_alias(void *addr) > +{ > + return ((unsigned long)addr | PTE_NS_SHARED); > +} Have you considered specifying the correct UART address at compile time using ./configure --earlycon? Thanks, Alex > + > /* > * Highest possible physical address supported. > */ > -- > 2.34.1 > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel