Revision 9a291a7c9428155e8e623e4a3989f8be47134df5 authored by James Morse on 02 June 2017, 21:46:46 UTC, committed by Linus Torvalds on 02 June 2017, 22:07:38 UTC
KVM uses get_user_pages() to resolve its stage2 faults. KVM sets the FOLL_HWPOISON flag causing faultin_page() to return -EHWPOISON when it finds a VM_FAULT_HWPOISON. KVM handles these hwpoison pages as a special case. (check_user_page_hwpoison()) When huge pages are involved, this doesn't work so well. get_user_pages() calls follow_hugetlb_page(), which stops early if it receives VM_FAULT_HWPOISON from hugetlb_fault(), eventually returning -EFAULT to the caller. The step to map this to -EHWPOISON based on the FOLL_ flags is missing. The hwpoison special case is skipped, and -EFAULT is returned to user-space, causing Qemu or kvmtool to exit. Instead, move this VM_FAULT_ to errno mapping code into a header file and use it from faultin_page() and follow_hugetlb_page(). With this, KVM works as expected. This isn't a problem for arm64 today as we haven't enabled MEMORY_FAILURE, but I can't see any reason this doesn't happen on x86 too, so I think this should be a fix. This doesn't apply earlier than stable's v4.11.1 due to all sorts of cleanup. [james.morse@arm.com: add vm_fault_to_errno() call to faultin_page()] suggested. Link: http://lkml.kernel.org/r/20170525171035.16359-1-james.morse@arm.com [akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/20170524160900.28786-1-james.morse@arm.com Signed-off-by: James Morse <james.morse@arm.com> Acked-by: Punit Agrawal <punit.agrawal@arm.com> Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Cc: <stable@vger.kernel.org> [4.11.1+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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afs_vl.h
/* AFS Volume Location Service client interface
*
* Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#ifndef AFS_VL_H
#define AFS_VL_H
#include "afs.h"
#define AFS_VL_PORT 7003 /* volume location service port */
#define VL_SERVICE 52 /* RxRPC service ID for the Volume Location service */
enum AFSVL_Operations {
VLGETENTRYBYID = 503, /* AFS Get Cache Entry By ID operation ID */
VLGETENTRYBYNAME = 504, /* AFS Get Cache Entry By Name operation ID */
VLPROBE = 514, /* AFS Probe Volume Location Service operation ID */
};
enum AFSVL_Errors {
AFSVL_IDEXIST = 363520, /* Volume Id entry exists in vl database */
AFSVL_IO = 363521, /* I/O related error */
AFSVL_NAMEEXIST = 363522, /* Volume name entry exists in vl database */
AFSVL_CREATEFAIL = 363523, /* Internal creation failure */
AFSVL_NOENT = 363524, /* No such entry */
AFSVL_EMPTY = 363525, /* Vl database is empty */
AFSVL_ENTDELETED = 363526, /* Entry is deleted (soft delete) */
AFSVL_BADNAME = 363527, /* Volume name is illegal */
AFSVL_BADINDEX = 363528, /* Index is out of range */
AFSVL_BADVOLTYPE = 363529, /* Bad volume type */
AFSVL_BADSERVER = 363530, /* Illegal server number (out of range) */
AFSVL_BADPARTITION = 363531, /* Bad partition number */
AFSVL_REPSFULL = 363532, /* Run out of space for Replication sites */
AFSVL_NOREPSERVER = 363533, /* No such Replication server site exists */
AFSVL_DUPREPSERVER = 363534, /* Replication site already exists */
AFSVL_RWNOTFOUND = 363535, /* Parent R/W entry not found */
AFSVL_BADREFCOUNT = 363536, /* Illegal Reference Count number */
AFSVL_SIZEEXCEEDED = 363537, /* Vl size for attributes exceeded */
AFSVL_BADENTRY = 363538, /* Bad incoming vl entry */
AFSVL_BADVOLIDBUMP = 363539, /* Illegal max volid increment */
AFSVL_IDALREADYHASHED = 363540, /* RO/BACK id already hashed */
AFSVL_ENTRYLOCKED = 363541, /* Vl entry is already locked */
AFSVL_BADVOLOPER = 363542, /* Bad volume operation code */
AFSVL_BADRELLOCKTYPE = 363543, /* Bad release lock type */
AFSVL_RERELEASE = 363544, /* Status report: last release was aborted */
AFSVL_BADSERVERFLAG = 363545, /* Invalid replication site server flag */
AFSVL_PERM = 363546, /* No permission access */
AFSVL_NOMEM = 363547, /* malloc/realloc failed to alloc enough memory */
};
/*
* maps to "struct vldbentry" in vvl-spec.pdf
*/
struct afs_vldbentry {
char name[65]; /* name of volume (with NUL char) */
afs_voltype_t type; /* volume type */
unsigned num_servers; /* num servers that hold instances of this vol */
unsigned clone_id; /* cloning ID */
unsigned flags;
#define AFS_VLF_RWEXISTS 0x1000 /* R/W volume exists */
#define AFS_VLF_ROEXISTS 0x2000 /* R/O volume exists */
#define AFS_VLF_BACKEXISTS 0x4000 /* backup volume exists */
afs_volid_t volume_ids[3]; /* volume IDs */
struct {
struct in_addr addr; /* server address */
unsigned partition; /* partition ID on this server */
unsigned flags; /* server specific flags */
#define AFS_VLSF_NEWREPSITE 0x0001 /* unused */
#define AFS_VLSF_ROVOL 0x0002 /* this server holds a R/O instance of the volume */
#define AFS_VLSF_RWVOL 0x0004 /* this server holds a R/W instance of the volume */
#define AFS_VLSF_BACKVOL 0x0008 /* this server holds a backup instance of the volume */
} servers[8];
};
#endif /* AFS_VL_H */
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