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From: Dan Williams <dan.j.williams@intel.com>
To: linux-nvdimm@lists.01.org
Cc: Tony Luck <tony.luck@intel.com>,
	x86@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	"H. Peter Anvin" <hpa@zytor.com>,
	linux-fsdevel@vger.kernel.org,
	Thomas Gleixner <tglx@linutronix.de>,
	hch@lst.de, linux-edac@vger.kernel.org
Subject: [PATCH v6 11/13] x86/mm/pat: Prepare {reserve, free}_memtype() for "decoy" addresses
Date: Fri, 13 Jul 2018 21:50:27 -0700	[thread overview]
Message-ID: <153154382700.34503.10197588570935341739.stgit@dwillia2-desk3.amr.corp.intel.com> (raw)
In-Reply-To: <153154376846.34503.15480221419473501643.stgit@dwillia2-desk3.amr.corp.intel.com>

In preparation for using set_memory_uc() instead set_memory_np() for
isolating poison from speculation, teach the memtype code to sanitize
physical addresses vs __PHYSICAL_MASK.

The motivation for using set_memory_uc() for this case is to allow
ongoing access to persistent memory pages via the pmem-driver +
memcpy_mcsafe() until the poison is repaired.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: <linux-edac@vger.kernel.org>
Cc: <x86@kernel.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 arch/x86/mm/pat.c |   16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 1555bd7d3449..6788ffa990f8 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -512,6 +512,17 @@ static int free_ram_pages_type(u64 start, u64 end)
 	return 0;
 }
 
+static u64 sanitize_phys(u64 address)
+{
+	/*
+	 * When changing the memtype for pages containing poison allow
+	 * for a "decoy" virtual address (bit 63 clear) passed to
+	 * set_memory_X(). __pa() on a "decoy" address results in a
+	 * physical address with it 63 set.
+	 */
+	return address & __PHYSICAL_MASK;
+}
+
 /*
  * req_type typically has one of the:
  * - _PAGE_CACHE_MODE_WB
@@ -533,6 +544,8 @@ int reserve_memtype(u64 start, u64 end, enum page_cache_mode req_type,
 	int is_range_ram;
 	int err = 0;
 
+	start = sanitize_phys(start);
+	end = sanitize_phys(end);
 	BUG_ON(start >= end); /* end is exclusive */
 
 	if (!pat_enabled()) {
@@ -609,6 +622,9 @@ int free_memtype(u64 start, u64 end)
 	if (!pat_enabled())
 		return 0;
 
+	start = sanitize_phys(start);
+	end = sanitize_phys(end);
+
 	/* Low ISA region is always mapped WB. No need to track */
 	if (x86_platform.is_untracked_pat_range(start, end))
 		return 0;

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  parent reply	other threads:[~2018-07-14  5:00 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-14  4:49 [PATCH v6 00/13] mm: Teach memory_failure() about ZONE_DEVICE pages Dan Williams
2018-07-14  4:49 ` [PATCH v6 01/13] device-dax: Convert to vmf_insert_mixed and vm_fault_t Dan Williams
2018-07-14  4:49 ` [PATCH v6 02/13] device-dax: Enable page_mapping() Dan Williams
2018-07-14  4:49 ` [PATCH v6 03/13] device-dax: Set page->index Dan Williams
2018-07-14  4:49 ` [PATCH v6 04/13] filesystem-dax: " Dan Williams
2018-07-14  4:49 ` [PATCH v6 05/13] mm, madvise_inject_error: Disable MADV_SOFT_OFFLINE for ZONE_DEVICE pages Dan Williams
2018-07-17  6:47   ` Naoya Horiguchi
2018-07-14  4:50 ` [PATCH v6 06/13] mm, dev_pagemap: Do not clear ->mapping on final put Dan Williams
2018-07-23 16:12   ` Dave Jiang
2018-07-23 16:23     ` Jerome Glisse
2018-07-14  4:50 ` [PATCH v6 07/13] mm, madvise_inject_error: Let memory_failure() optionally take a page reference Dan Williams
2018-07-17  6:52   ` Naoya Horiguchi
2018-07-14  4:50 ` [PATCH v6 08/13] mm, memory_failure: Collect mapping size in collect_procs() Dan Williams
2018-07-14  4:50 ` [PATCH v6 09/13] filesystem-dax: Introduce dax_lock_mapping_entry() Dan Williams
2018-08-06  9:21   ` Jan Kara
2018-07-14  4:50 ` [PATCH v6 10/13] mm, memory_failure: Teach memory_failure() about dev_pagemap pages Dan Williams
2018-08-06  9:27   ` Jan Kara
2018-07-14  4:50 ` Dan Williams [this message]
2018-07-24  7:36   ` [PATCH v6 11/13] x86/mm/pat: Prepare {reserve, free}_memtype() for "decoy" addresses Ingo Molnar
2018-07-24 15:46     ` Dave Jiang
2018-07-14  4:50 ` [PATCH v6 12/13] x86/memory_failure: Introduce {set, clear}_mce_nospec() Dan Williams
2018-07-14  4:50 ` [PATCH v6 13/13] libnvdimm, pmem: Restore page attributes when clearing errors Dan Williams
2018-07-19 17:57 ` [PATCH v6 00/13] mm: Teach memory_failure() about ZONE_DEVICE pages Dave Jiang
2018-07-24  7:39   ` Ingo Molnar

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