From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, Vlastimil Babka <vbabka@suse.cz>,
Thomas Gleixner <tglx@linutronix.de>,
David Woodhouse <dwmw@amazon.co.uk>,
Guenter Roeck <linux@roeck-us.net>
Subject: [PATCH 4.4 35/43] x86/speculation/l1tf: Extend 64bit swap file size limit
Date: Tue, 14 Aug 2018 19:18:11 +0200 [thread overview]
Message-ID: <20180814171519.410521293@linuxfoundation.org> (raw)
In-Reply-To: <20180814171517.014285600@linuxfoundation.org>
4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Vlastimil Babka <vbabka@suse.cz>
commit 1a7ed1ba4bba6c075d5ad61bb75e3fbc870840d6 upstream
The previous patch has limited swap file size so that large offsets cannot
clear bits above MAX_PA/2 in the pte and interfere with L1TF mitigation.
It assumed that offsets are encoded starting with bit 12, same as pfn. But
on x86_64, offsets are encoded starting with bit 9.
Thus the limit can be raised by 3 bits. That means 16TB with 42bit MAX_PA
and 256TB with 46bit MAX_PA.
Fixes: 377eeaa8e11f ("x86/speculation/l1tf: Limit swap file size to MAX_PA/2")
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/mm/init.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -778,7 +778,15 @@ unsigned long max_swapfile_size(void)
if (boot_cpu_has_bug(X86_BUG_L1TF)) {
/* Limit the swap file size to MAX_PA/2 for L1TF workaround */
- pages = min_t(unsigned long, l1tf_pfn_limit() + 1, pages);
+ unsigned long l1tf_limit = l1tf_pfn_limit() + 1;
+ /*
+ * We encode swap offsets also with 3 bits below those for pfn
+ * which makes the usable limit higher.
+ */
+#ifdef CONFIG_X86_64
+ l1tf_limit <<= PAGE_SHIFT - SWP_OFFSET_FIRST_BIT;
+#endif
+ pages = min_t(unsigned long, l1tf_limit, pages);
}
return pages;
}
next prev parent reply other threads:[~2018-08-14 17:48 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-14 17:17 [PATCH 4.4 00/43] 4.4.148-stable review Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 01/43] ext4: fix check to prevent initializing reserved inodes Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 02/43] tpm: fix race condition in tpm_common_write() Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 03/43] ipv4+ipv6: Make INET*_ESP select CRYPTO_ECHAINIV Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 04/43] fork: unconditionally clear stack on fork Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 05/43] parisc: Enable CONFIG_MLONGCALLS by default Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 07/43] xen/netfront: dont cache skb_shinfo() Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 08/43] ACPI / LPSS: Add missing prv_offset setting for byt/cht PWM devices Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 09/43] scsi: sr: Avoid that opening a CD-ROM hangs with runtime power management enabled Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 10/43] root dentries need RCU-delayed freeing Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 11/43] fix mntput/mntput race Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 12/43] fix __legitimize_mnt()/mntput() race Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 13/43] IB/core: Make testing MR flags for writability a static inline function Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 14/43] IB/mlx4: Mark user MR as writable if actual virtual memory is writable Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 15/43] IB/ocrdma: fix out of bounds access to local buffer Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 16/43] ARM: dts: imx6sx: fix irq for pcie bridge Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 17/43] x86/paravirt: Fix spectre-v2 mitigations for paravirt guests Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 18/43] x86/speculation: Protect against userspace-userspace spectreRSB Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 19/43] kprobes/x86: Fix %p uses in error messages Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 20/43] x86/irqflags: Provide a declaration for native_save_fl Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 21/43] x86/speculation/l1tf: Increase 32bit PAE __PHYSICAL_PAGE_SHIFT Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 22/43] x86/mm: Move swap offset/type up in PTE to work around erratum Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 23/43] x86/mm: Fix swap entry comment and macro Greg Kroah-Hartman
2018-08-14 17:18 ` [PATCH 4.4 24/43] mm: x86: move _PAGE_SWP_SOFT_DIRTY from bit 7 to bit 1 Greg Kroah-Hartman
2018-08-14 17:18 ` [PATCH 4.4 25/43] x86/speculation/l1tf: Change order of offset/type in swap entry Greg Kroah-Hartman
2018-08-14 17:18 ` [PATCH 4.4 26/43] x86/speculation/l1tf: Protect swap entries against L1TF Greg Kroah-Hartman
2018-08-14 17:18 ` [PATCH 4.4 27/43] x86/speculation/l1tf: Protect PROT_NONE PTEs against speculation Greg Kroah-Hartman
2018-08-14 17:18 ` [PATCH 4.4 28/43] x86/speculation/l1tf: Make sure the first page is always reserved Greg Kroah-Hartman
2018-08-14 17:18 ` [PATCH 4.4 29/43] x86/speculation/l1tf: Add sysfs reporting for l1tf Greg Kroah-Hartman
2018-08-14 17:18 ` [PATCH 4.4 30/43] mm: Add vm_insert_pfn_prot() Greg Kroah-Hartman
2018-08-14 17:18 ` [PATCH 4.4 31/43] mm: fix cache mode tracking in vm_insert_mixed() Greg Kroah-Hartman
2018-09-07 17:05 ` Ben Hutchings
2018-09-07 20:03 ` Greg Kroah-Hartman
2018-08-14 17:18 ` [PATCH 4.4 32/43] x86/speculation/l1tf: Disallow non privileged high MMIO PROT_NONE mappings Greg Kroah-Hartman
2018-08-14 17:18 ` [PATCH 4.4 33/43] x86/speculation/l1tf: Limit swap file size to MAX_PA/2 Greg Kroah-Hartman
2018-08-14 17:18 ` [PATCH 4.4 34/43] x86/bugs: Move the l1tf function and define pr_fmt properly Greg Kroah-Hartman
2018-08-14 17:18 ` Greg Kroah-Hartman [this message]
2018-08-14 17:18 ` [PATCH 4.4 36/43] x86/cpufeatures: Add detection of L1D cache flush support Greg Kroah-Hartman
2018-08-14 17:18 ` [PATCH 4.4 37/43] x86/speculation/l1tf: Protect PAE swap entries against L1TF Greg Kroah-Hartman
2018-08-14 17:18 ` [PATCH 4.4 38/43] x86/speculation/l1tf: Fix up pte->pfn conversion for PAE Greg Kroah-Hartman
2018-08-14 17:18 ` [PATCH 4.4 39/43] x86/speculation/l1tf: Invert all not present mappings Greg Kroah-Hartman
2018-08-14 17:18 ` [PATCH 4.4 40/43] x86/speculation/l1tf: Make pmd/pud_mknotpresent() invert Greg Kroah-Hartman
2018-08-14 17:18 ` [PATCH 4.4 41/43] x86/mm/pat: Make set_memory_np() L1TF safe Greg Kroah-Hartman
2018-09-09 16:46 ` Ben Hutchings
2018-09-09 17:06 ` Guenter Roeck
2018-09-10 7:16 ` Greg Kroah-Hartman
2018-08-14 17:18 ` [PATCH 4.4 42/43] x86/mm/kmmio: Make the tracer robust against L1TF Greg Kroah-Hartman
2018-08-14 17:18 ` [PATCH 4.4 43/43] x86/speculation/l1tf: Fix up CPU feature flags Greg Kroah-Hartman
2018-08-15 6:15 ` [PATCH 4.4 00/43] 4.4.148-stable review Greg Kroah-Hartman
2018-08-15 13:10 ` Guenter Roeck
2018-08-15 20:52 ` Dan Rue
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