From nobody Sun Feb 8 22:06:17 2026 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.9]) (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 67B8E12D75F for ; Tue, 9 Apr 2024 11:30:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.9 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712662233; cv=none; b=HmwoqWNPMCwUJ49keKACvj3gyuXS0kJlwy/pXEPC84D3e6CR1EkXuZxJLubePvmLLLRtLuA+JM8CY/TK9GStoHE0FCJ/3KrhNeTLwPz0/bvvMA0hprC98YYaRGKvkalWFXndXjbrvPDO9cGvX497FVFjPf2A2twS0yz7Lj8DrRY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712662233; c=relaxed/simple; bh=DBcJsWV4nfgk/8fw3M6vcKnfFbP1zoB1PzLmLNRfgyE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=hcZXTqaBlb8zgSq0d562HnXoZhzgsX5O3piC7F38ZaPqZJ0/XC8T0BFGbz4lRY6RwaZ4qvYL7ygAjJchN8L0PirCM5j4ZJmY5PG0vtoHYKChJaQN6rxhyYUqZIxpzsTnTRtW90jRX1YkkJt1bVaTdzLJ2HJva5XzQnEMeWd9Bxw= 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=npaABGW3; arc=none smtp.client-ip=198.175.65.9 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="npaABGW3" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1712662232; x=1744198232; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=DBcJsWV4nfgk/8fw3M6vcKnfFbP1zoB1PzLmLNRfgyE=; b=npaABGW3ZiTiRiQZQ6bPIEc0m0Qn2yApAwArDHHFO/QmzGWJWKytFRkC kGvl2WHp7GDwE73D8HtokeEU6R0Fs+XzCy1iYa/P99N2oQSf5Qhk6C1A7 8/JkF9LSwbCzPvjZw7JJVQD2soRSp2W6h4NVdecCQKDNdfmaCDotBkzy9 h2m9U47CBAe0KWsD0o6QGZbia/v+PS+w7q+B5BnCrYgonUGn8Wiy2o+YV jLpnY2sdFiHGXn7ZfPfkAZvZ/u69lFi4GmbGstBPtwDeA19hoqEYy3mH6 rZMag7EsR6wG+mmIEE3tEV0Ll8ZIZv3b0T+XV2WgTlTgwEwa+dNpdITgK A==; X-CSE-ConnectionGUID: uhmJcgCSSeOBO9mFvx1v0Q== X-CSE-MsgGUID: iU4l+MOkS5KTc36wqfSqBw== X-IronPort-AV: E=McAfee;i="6600,9927,11038"; a="30460383" X-IronPort-AV: E=Sophos;i="6.07,189,1708416000"; d="scan'208";a="30460383" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orvoesa101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Apr 2024 04:30:29 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,11038"; a="937093331" X-IronPort-AV: E=Sophos;i="6.07,189,1708416000"; d="scan'208";a="937093331" Received: from black.fi.intel.com ([10.237.72.28]) by fmsmga001.fm.intel.com with ESMTP; 09 Apr 2024 04:30:24 -0700 Received: by black.fi.intel.com (Postfix, from userid 1000) id 11CC1C09; Tue, 9 Apr 2024 14:30:18 +0300 (EEST) From: "Kirill A. Shutemov" To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org Cc: "Rafael J. Wysocki" , Peter Zijlstra , Adrian Hunter , Kuppuswamy Sathyanarayanan , Elena Reshetova , Jun Nakajima , Rick Edgecombe , Tom Lendacky , "Kalra, Ashish" , Sean Christopherson , "Huang, Kai" , Baoquan He , kexec@lists.infradead.org, linux-coco@lists.linux.dev, linux-kernel@vger.kernel.org, "Kirill A . Shutemov" Subject: [PATCHv10 12/18] x86/mm: Do not zap page table entries mapping unaccepted memory table during kdump. Date: Tue, 9 Apr 2024 14:30:04 +0300 Message-ID: <20240409113010.465412-13-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240409113010.465412-1-kirill.shutemov@linux.intel.com> References: <20240409113010.465412-1-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" From: Ashish Kalra During crashkernel boot only pre-allocated crash memory is presented as E820_TYPE_RAM. This can cause page table entries mapping unaccepted memory table to be zapped during phys_pte_init(), phys_pmd_init(), phys_pud_init() and phys_p4d_init() as SNP/TDX guest use E820_TYPE_ACPI to store the unaccepted memory table and pass it between the kernels on kexec/kdump. E820_TYPE_ACPI covers not only ACPI data, but also EFI tables and might be required by kernel to function properly. The problem was discovered during debugging kdump for SNP guest. The unaccepted memory table stored with E820_TYPE_ACPI and passed between the kernels on kdump was getting zapped as the PMD entry mapping this is above the E820_TYPE_RAM range for the reserved crashkernel memory. Signed-off-by: Ashish Kalra Signed-off-by: Kirill A. Shutemov --- arch/x86/mm/init_64.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 7e177856ee4f..28002cc7a37d 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -469,7 +469,9 @@ phys_pte_init(pte_t *pte_page, unsigned long paddr, uns= igned long paddr_end, !e820__mapped_any(paddr & PAGE_MASK, paddr_next, E820_TYPE_RAM) && !e820__mapped_any(paddr & PAGE_MASK, paddr_next, - E820_TYPE_RESERVED_KERN)) + E820_TYPE_RESERVED_KERN) && + !e820__mapped_any(paddr & PAGE_MASK, paddr_next, + E820_TYPE_ACPI)) set_pte_init(pte, __pte(0), init); continue; } @@ -524,7 +526,9 @@ phys_pmd_init(pmd_t *pmd_page, unsigned long paddr, uns= igned long paddr_end, !e820__mapped_any(paddr & PMD_MASK, paddr_next, E820_TYPE_RAM) && !e820__mapped_any(paddr & PMD_MASK, paddr_next, - E820_TYPE_RESERVED_KERN)) + E820_TYPE_RESERVED_KERN) && + !e820__mapped_any(paddr & PMD_MASK, paddr_next, + E820_TYPE_ACPI)) set_pmd_init(pmd, __pmd(0), init); continue; } @@ -611,7 +615,9 @@ phys_pud_init(pud_t *pud_page, unsigned long paddr, uns= igned long paddr_end, !e820__mapped_any(paddr & PUD_MASK, paddr_next, E820_TYPE_RAM) && !e820__mapped_any(paddr & PUD_MASK, paddr_next, - E820_TYPE_RESERVED_KERN)) + E820_TYPE_RESERVED_KERN) && + !e820__mapped_any(paddr & PUD_MASK, paddr_next, + E820_TYPE_ACPI)) set_pud_init(pud, __pud(0), init); continue; } @@ -698,7 +704,9 @@ phys_p4d_init(p4d_t *p4d_page, unsigned long paddr, uns= igned long paddr_end, !e820__mapped_any(paddr & P4D_MASK, paddr_next, E820_TYPE_RAM) && !e820__mapped_any(paddr & P4D_MASK, paddr_next, - E820_TYPE_RESERVED_KERN)) + E820_TYPE_RESERVED_KERN) && + !e820__mapped_any(paddr & P4D_MASK, paddr_next, + E820_TYPE_ACPI)) set_p4d_init(p4d, __p4d(0), init); continue; } --=20 2.43.0