From nobody Tue Nov 26 19:51:50 2024 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.13]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A26741C9452; Thu, 22 Aug 2024 12:40:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.13 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724330411; cv=none; b=noWqGY65ogSAR/NL3SvL1fMQbMCLi3GzruIYvHU91G4Z+RhaWtrE29VrLC2A97crr8+wbldEqDix5nBUo41/xbeOmmjn4GRiGtbuLiP8qaoKDNJko/GTdd/9OJki2x3cHSA1b2I8hobVB/s7jC9qjRSQkWYdDncesQGhR6JPvLE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724330411; c=relaxed/simple; bh=QQ0UbpyqdIB6+YfJjPDDx6eJHiL0EplzplL8JUqBi1Y=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=P69T4lUkHpl+CtRZhuI3QgEAW+lTObbS8Ju3eDgt3jk4PDEgzXu8zjuXs2cN3E1/g5rqEYl5wL0WSvm9GSvIdY5LibUaQqWVt2tosqJpe+qq5C2XV5Gfgpb2rlFPOLGrmtq/UB5OND/b/BSzFPWD2LGUIXbcGBt9fkkp3t3GFFU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=none smtp.helo=mgamail.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=mM6FDNtr; arc=none smtp.client-ip=192.198.163.13 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.helo=mgamail.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="mM6FDNtr" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1724330410; x=1755866410; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=QQ0UbpyqdIB6+YfJjPDDx6eJHiL0EplzplL8JUqBi1Y=; b=mM6FDNtrX3g2cWoEB2Y6UX3PpTnvIRjNdJay5l2L7X+HDbxPv/Hwt3hE kWKIxpd1g7p6Q2tC5KSqJPwaDcQEWSX9iZxDhhXPJ6bXl2ynoiriwDt1z ug9REs27zSJTTwgq1L6HUKFm77pjxaE/IoS0IyqO2WFTYSrqFCdADOZEM GNnURKOM6wKWz24lXkZ8oo15dFhZHFmsKKtNqevsYKXf750VANmw7UJAh FSSHx2pPt3POME32lOKY7dYXd5VtGLRzB2l2gKBiOV4kb5qs2opf4MKYz fmBonY0EtMyck1TiZFO5A5cRWf19eoLxbolpn5yeQEgJtYqmkrRVG5Nnw g==; X-CSE-ConnectionGUID: aBfRq49DTcGhxyoeuojZeA== X-CSE-MsgGUID: EyWXIhf/R5+0QzxnGDBKnQ== X-IronPort-AV: E=McAfee;i="6700,10204,11172"; a="25635649" X-IronPort-AV: E=Sophos;i="6.10,167,1719903600"; d="scan'208";a="25635649" Received: from fmviesa008.fm.intel.com ([10.60.135.148]) by fmvoesa107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Aug 2024 05:40:07 -0700 X-CSE-ConnectionGUID: /8lyXqRMRoWLnT3KU/uRSg== X-CSE-MsgGUID: T6DzAN3XT52XnPEN5X1CJg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.10,167,1719903600"; d="scan'208";a="61443073" Received: from black.fi.intel.com ([10.237.72.28]) by fmviesa008.fm.intel.com with ESMTP; 22 Aug 2024 05:40:03 -0700 Received: by black.fi.intel.com (Postfix, from userid 1000) id 3FC324D7; Thu, 22 Aug 2024 15:40:02 +0300 (EEST) From: "Kirill A. Shutemov" To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , "Rafael J. Wysocki" , Andy Lutomirski , Peter Zijlstra , Baoquan He Cc: Ard Biesheuvel , Tom Lendacky , Andrew Morton , Thomas Zimmermann , Sean Christopherson , linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, "Kirill A. Shutemov" , Kai Huang Subject: [PATCHv4 3/4] x86/64/kexec: Map original relocate_kernel() in init_transition_pgtable() Date: Thu, 22 Aug 2024 15:39:59 +0300 Message-ID: <20240822124000.1171321-4-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240822124000.1171321-1-kirill.shutemov@linux.intel.com> References: <20240822124000.1171321-1-kirill.shutemov@linux.intel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The init_transition_pgtable() function sets up transitional page tables. It ensures that the relocate_kernel() function is present in the identity mapping at the same location as in the kernel page tables. relocate_kernel() switches to the identity mapping, and the function must be present at the same location in the virtual address space before and after switching page tables. init_transition_pgtable() maps a copy of relocate_kernel() in image->control_code_page at the relocate_kernel() virtual address, but the original physical address of relocate_kernel() would also work. It is safe to use original relocate_kernel() physical address cannot be overwritten until swap_pages() is called, and the relocate_kernel() virtual address will not be used by then. Map the original relocate_kernel() at the relocate_kernel() virtual address in the identity mapping. It is preparation to replace the init_transition_pgtable() implementation with a call to kernel_ident_mapping_init(). Note that while relocate_kernel() switches to the identity mapping, it does not flush global TLB entries (CR4.PGE is not cleared). This means that in most cases, the kernel still runs relocate_kernel() from the original physical address before the change. Signed-off-by: Kirill A. Shutemov Reviewed-by: Kai Huang --- arch/x86/kernel/machine_kexec_64.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_k= exec_64.c index 9c9ac606893e..645690e81c2d 100644 --- a/arch/x86/kernel/machine_kexec_64.c +++ b/arch/x86/kernel/machine_kexec_64.c @@ -157,7 +157,7 @@ static int init_transition_pgtable(struct kimage *image= , pgd_t *pgd) pte_t *pte; =20 vaddr =3D (unsigned long)relocate_kernel; - paddr =3D __pa(page_address(image->control_code_page)+PAGE_SIZE); + paddr =3D __pa(relocate_kernel); pgd +=3D pgd_index(vaddr); if (!pgd_present(*pgd)) { p4d =3D (p4d_t *)get_zeroed_page(GFP_KERNEL); --=20 2.43.0