From nobody Tue Feb 10 05:46:38 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) client-ip=192.237.175.120; envelope-from=xen-devel-bounces@lists.xenproject.org; helo=lists.xenproject.org; Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org ARC-Seal: i=1; a=rsa-sha256; t=1601153799; cv=none; d=zohomail.com; s=zohoarc; b=Xm2ntjYd8pxT/QIEl9QQMS+fnRgROuKnSjkOIt6nVS1+WUSU9C/n/BAnNKKIFTnUpHSWPEika3BVaKrDmx/S3fmKM4mIBu397bnz45NmeC/JCRobpIS6RV5N9MOjbpikNif3aZSw3wxa4WWX7gYJPG/HOI+ABoCJpt0nzqih7LU= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1601153799; h=Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Help:List-Unsubscribe:Message-ID:References:Sender:Subject:To; bh=NUzIF6jd0VTOPVLuT+sNzYSm2gJRa4g7nKnovFDCX/4=; b=Xx8fAMgDTj8rvfn+e1a/sFPgwpAZw/fZSnjzWt9qOAfeyreeTSrfWNLZu8m7ONaMkhNln6HgwEaJsGPjxbhLDkvDlHV52bcQcQNenZ1M+njS4ORmpacNZqDGRTJ7/Ie/jYzmO4ZxVp7zKwoyC0y4QdVyGSlcK7nZfg5oN5bYvYI= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Return-Path: Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) by mx.zohomail.com with SMTPS id 1601153799268692.0056845939805; Sat, 26 Sep 2020 13:56:39 -0700 (PDT) Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kMHEy-0003ky-8D; Sat, 26 Sep 2020 20:56:20 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kMHEx-0003jG-1M for xen-devel@lists.xenproject.org; Sat, 26 Sep 2020 20:56:19 +0000 Received: from mail.xenproject.org (unknown [104.130.215.37]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id ef8786d4-b800-44f6-b276-ef25a066fe34; Sat, 26 Sep 2020 20:56:09 +0000 (UTC) Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kMHEj-0000CR-M8; Sat, 26 Sep 2020 20:56:05 +0000 Received: from 54-240-197-235.amazon.com ([54.240.197.235] helo=ufe34d9ed68d054.ant.amazon.com) by xenbits.xenproject.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1kMHEj-0004I0-Cz; Sat, 26 Sep 2020 20:56:05 +0000 X-Inumbo-ID: ef8786d4-b800-44f6-b276-ef25a066fe34 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=xen.org; s=20200302mail; h=References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From; bh=NUzIF6jd0VTOPVLuT+sNzYSm2gJRa4g7nKnovFDCX/4=; b=LTV2p20sIv7akePa3vPAhyBsX 6m1ks6BSd9/ovS4zKP1LFTtQEVcidvgjUs6GPfnq/4ugmsbWZEAR6JM5+bhyZwu3bDry6kMJtc5yt T9Zlm87OqBIeeZpqXwIUfTSzm1ZglFmh4YKYTsxrJ9yrt7J4Vi7UotexGCPPFRZkw8jgM=; From: Julien Grall To: xen-devel@lists.xenproject.org Cc: alex.bennee@linaro.org, masami.hiramatsu@linaro.org, ehem+xen@m5p.com, bertrand.marquis@arm.com, andre.przywara@arm.com, Julien Grall , Stefano Stabellini , Julien Grall , Volodymyr Babchuk , Wei Xu Subject: [PATCH 2/4] xen/arm: acpi: The fixmap area should always be cleared during failure/unmap Date: Sat, 26 Sep 2020 21:55:40 +0100 Message-Id: <20200926205542.9261-3-julien@xen.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200926205542.9261-1-julien@xen.org> References: <20200926205542.9261-1-julien@xen.org> X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" X-ZohoMail-DKIM: pass (identity @xen.org) Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" From: Julien Grall Commit 022387ee1ad3 "xen/arm: mm: Don't open-code Xen PT update in {set, clear}_fixmap()" enforced that each set_fixmap() should be paired with a clear_fixmap(). Any failure to follow the model would result to a platform crash. Unfortunately, the use of fixmap in the ACPI code was overlooked as it is calling set_fixmap() but not clear_fixmap(). The function __acpi_os_map_table() is reworked so: - We know before the mapping whether the fixmap region is big enough for the mapping. - It will fail if the fixmap is always inuse. The function __acpi_os_unmap_table() will now call clear_fixmap(). Reported-by: Wei Xu Signed-off-by: Julien Grall Reviewed-by: Rahul Singh Tested-by: Rahul Singh --- The discussion on the original thread [1] suggested to also zap it on x86. This is technically not necessary today, so it is left alone for now. I looked at making the fixmap code common but the index are inverted between Arm and x86. [1] https://lore.kernel.org/xen-devel/5E26C935.9080107@hisilicon.com/ --- xen/arch/arm/acpi/lib.c | 75 +++++++++++++++++++++++++++++++---------- 1 file changed, 58 insertions(+), 17 deletions(-) diff --git a/xen/arch/arm/acpi/lib.c b/xen/arch/arm/acpi/lib.c index 2192a5519171..eebaca695562 100644 --- a/xen/arch/arm/acpi/lib.c +++ b/xen/arch/arm/acpi/lib.c @@ -25,38 +25,79 @@ #include #include =20 +static bool fixmap_inuse; + char *__acpi_map_table(paddr_t phys, unsigned long size) { - unsigned long base, offset, mapped_size; - int idx; + unsigned long base, offset; + mfn_t mfn; + unsigned int idx; =20 /* No arch specific implementation after early boot */ if ( system_state >=3D SYS_STATE_boot ) return NULL; =20 offset =3D phys & (PAGE_SIZE - 1); - mapped_size =3D PAGE_SIZE - offset; - set_fixmap(FIXMAP_ACPI_BEGIN, maddr_to_mfn(phys), PAGE_HYPERVISOR); - base =3D FIXMAP_ADDR(FIXMAP_ACPI_BEGIN); + base =3D FIXMAP_ADDR(FIXMAP_ACPI_BEGIN) + offset; + + /* Check the fixmap is big enough to map the region */ + if ( (FIXMAP_ADDR(FIXMAP_ACPI_END) + PAGE_SIZE - base) < size ) + return NULL; + + /* With the fixmap, we can only map one region at the time */ + if ( fixmap_inuse ) + return NULL; =20 - /* Most cases can be covered by the below. */ + fixmap_inuse =3D true; + + size +=3D offset; + mfn =3D maddr_to_mfn(phys); idx =3D FIXMAP_ACPI_BEGIN; - while ( mapped_size < size ) - { - if ( ++idx > FIXMAP_ACPI_END ) - return NULL; /* cannot handle this */ - phys +=3D PAGE_SIZE; - set_fixmap(idx, maddr_to_mfn(phys), PAGE_HYPERVISOR); - mapped_size +=3D PAGE_SIZE; - } =20 - return ((char *) base + offset); + do { + set_fixmap(idx, mfn, PAGE_HYPERVISOR); + size -=3D min(size, (unsigned long)PAGE_SIZE); + mfn =3D mfn_add(mfn, 1); + idx++; + } while ( size > 0 ); + + return (char *)base; } =20 bool __acpi_unmap_table(void *ptr, unsigned long size) { - return ( vaddr >=3D FIXMAP_ADDR(FIXMAP_ACPI_BEGIN) && - vaddr < (FIXMAP_ADDR(FIXMAP_ACPI_END) + PAGE_SIZE) ); + vaddr_t vaddr =3D (vaddr_t)ptr; + unsigned int idx; + + /* We are only handling fixmap address in the arch code */ + if ( vaddr < FIXMAP_ADDR(FIXMAP_ACPI_BEGIN) || + vaddr >=3D FIXMAP_ADDR(FIXMAP_ACPI_END) ) + return false; + + /* + * __acpi_map_table() will always return a pointer in the first page + * for the ACPI fixmap region. The caller is expected to free with + * the same address. + */ + ASSERT((vaddr & PAGE_MASK) =3D=3D FIXMAP_ADDR(FIXMAP_ACPI_BEGIN)); + + /* The region allocated fit in the ACPI fixmap region. */ + ASSERT(size < (FIXMAP_ADDR(FIXMAP_ACPI_END) + PAGE_SIZE - vaddr)); + ASSERT(fixmap_inuse); + + fixmap_inuse =3D false; + + size +=3D FIXMAP_ADDR(FIXMAP_ACPI_BEGIN) - vaddr; + idx =3D FIXMAP_ACPI_BEGIN; + + do + { + clear_fixmap(idx); + size -=3D min(size, (unsigned long)PAGE_SIZE); + idx++; + } while ( size > 0 ); + + return true; } =20 /* True to indicate PSCI 0.2+ is implemented */ --=20 2.17.1