Pull x86 cdso updates from Peter Anvin:
"Vdso cleanups and improvements largely from Andy Lutomirski. This
makes the vdso a lot less ''special''"
* 'x86/vdso' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/vdso, build: Make LE access macros clearer, host-safe
x86/vdso, build: Fix cross-compilation from big-endian architectures
x86/vdso, build: When vdso2c fails, unlink the output
x86, vdso: Fix an OOPS accessing the HPET mapping w/o an HPET
x86, mm: Replace arch_vma_name with vm_ops->name for vsyscalls
x86, mm: Improve _install_special_mapping and fix x86 vdso naming
mm, fs: Add vm_ops->name as an alternative to arch_vma_name
x86, vdso: Fix an OOPS accessing the HPET mapping w/o an HPET
x86, vdso: Remove vestiges of VDSO_PRELINK and some outdated comments
x86, vdso: Move the vvar and hpet mappings next to the 64-bit vDSO
x86, vdso: Move the 32-bit vdso special pages after the text
x86, vdso: Reimplement vdso.so preparation in build-time C
x86, vdso: Move syscall and sysenter setup into kernel/cpu/common.c
x86, vdso: Clean up 32-bit vs 64-bit vdso params
x86, mm: Ensure correct alignment of the fixmap
When running as a dom0 in PVH mode, foreign pfns that are accessed
must be added to our p2m which is managed by xen. This is done via
XENMEM_add_to_physmap_range hypercall. This is needed for toolstack
building guests and mapping guest memory, xentrace mapping xen pages,
etc.
Signed-off-by: Mukesh Rathor <mukesh.rathor@oracle.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
_PAGE_IOMAP is used in xen_remap_domain_mfn_range() to prevent the
pfn_pte() call in remap_area_mfn_pte_fn() from using the p2m to translate
the MFN. If mfn_pte() is used instead, the p2m look up is avoided and
the use of _PAGE_IOMAP is no longer needed.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Pull x86 vdso changes from Peter Anvin:
"This is the revamp of the 32-bit vdso and the associated cleanups.
This adds timekeeping support to the 32-bit vdso that we already have
in the 64-bit vdso. Although 32-bit x86 is legacy, it is likely to
remain in the embedded space for a very long time to come.
This removes the traditional COMPAT_VDSO support; the configuration
variable is reused for simply removing the 32-bit vdso, which will
produce correct results but obviously suffer a performance penalty.
Only one beta version of glibc was affected, but that version was
unfortunately included in one OpenSUSE release.
This is not the end of the vdso cleanups. Stefani and Andy have
agreed to continue work for the next kernel cycle; in fact Andy has
already produced another set of cleanups that came too late for this
cycle.
An incidental, but arguably important, change is that this ensures
that unused space in the VVAR page is properly zeroed. It wasn't
before, and would contain whatever garbage was left in memory by BIOS
or the bootloader. Since the VVAR page is accessible to user space
this had the potential of information leaks"
* 'x86-vdso-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits)
x86, vdso: Fix the symbol versions on the 32-bit vDSO
x86, vdso, build: Don't rebuild 32-bit vdsos on every make
x86, vdso: Actually discard the .discard sections
x86, vdso: Fix size of get_unmapped_area()
x86, vdso: Finish removing VDSO32_PRELINK
x86, vdso: Move more vdso definitions into vdso.h
x86: Load the 32-bit vdso in place, just like the 64-bit vdsos
x86, vdso32: handle 32 bit vDSO larger one page
x86, vdso32: Disable stack protector, adjust optimizations
x86, vdso: Zero-pad the VVAR page
x86, vdso: Add 32 bit VDSO time support for 64 bit kernel
x86, vdso: Add 32 bit VDSO time support for 32 bit kernel
x86, vdso: Patch alternatives in the 32-bit VDSO
x86, vdso: Introduce VVAR marco for vdso32
x86, vdso: Cleanup __vdso_gettimeofday()
x86, vdso: Replace VVAR(vsyscall_gtod_data) by gtod macro
x86, vdso: __vdso_clock_gettime() cleanup
x86, vdso: Revamp vclock_gettime.c
mm: Add new func _install_special_mapping() to mmap.c
x86, vdso: Make vsyscall_gtod_data handling x86 generic
...
This reverts commit a9c8e4beee.
PTEs in Xen PV guests must contain machine addresses if _PAGE_PRESENT
is set and pseudo-physical addresses is _PAGE_PRESENT is clear.
This is because during a domain save/restore (migration) the page
table entries are "canonicalised" and uncanonicalised". i.e., MFNs are
converted to PFNs during domain save so that on a restore the page
table entries may be rewritten with the new MFNs on the destination.
This canonicalisation is only done for PTEs that are present.
This change resulted in writing PTEs with MFNs if _PAGE_PROTNONE (or
_PAGE_NUMA) was set but _PAGE_PRESENT was clear. These PTEs would be
migrated as-is which would result in unexpected behaviour in the
destination domain. Either a) the MFN would be translated to the
wrong PFN/page; b) setting the _PAGE_PRESENT bit would clear the PTE
because the MFN is no longer owned by the domain; or c) the present
bit would not get set.
Symptoms include "Bad page" reports when munmapping after migrating a
domain.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: <stable@vger.kernel.org> [3.12+]
Checkin
b0b49f2673 x86, vdso: Remove compat vdso support
... removed the VDSO from the fixmap, and thus FIX_VDSO; remove a
stray reference in Xen.
Found by Fengguang Wu's test robot.
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Link: http://lkml.kernel.org/r/4bb4690899106eb11430b1186d5cc66ca9d1660c.1394751608.git.luto@amacapital.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Steven Noonan forwarded a users report where they had a problem starting
vsftpd on a Xen paravirtualized guest, with this in dmesg:
BUG: Bad page map in process vsftpd pte:8000000493b88165 pmd:e9cc01067
page:ffffea00124ee200 count:0 mapcount:-1 mapping: (null) index:0x0
page flags: 0x2ffc0000000014(referenced|dirty)
addr:00007f97eea74000 vm_flags:00100071 anon_vma:ffff880e98f80380 mapping: (null) index:7f97eea74
CPU: 4 PID: 587 Comm: vsftpd Not tainted 3.12.7-1-ec2 #1
Call Trace:
dump_stack+0x45/0x56
print_bad_pte+0x22e/0x250
unmap_single_vma+0x583/0x890
unmap_vmas+0x65/0x90
exit_mmap+0xc5/0x170
mmput+0x65/0x100
do_exit+0x393/0x9e0
do_group_exit+0xcc/0x140
SyS_exit_group+0x14/0x20
system_call_fastpath+0x1a/0x1f
Disabling lock debugging due to kernel taint
BUG: Bad rss-counter state mm:ffff880e9ca60580 idx:0 val:-1
BUG: Bad rss-counter state mm:ffff880e9ca60580 idx:1 val:1
The issue could not be reproduced under an HVM instance with the same
kernel, so it appears to be exclusive to paravirtual Xen guests. He
bisected the problem to commit 1667918b64 ("mm: numa: clear numa
hinting information on mprotect") that was also included in 3.12-stable.
The problem was related to how xen translates ptes because it was not
accounting for the _PAGE_NUMA bit. This patch splits pte_present to add
a pteval_present helper for use by xen so both bare metal and xen use
the same code when checking if a PTE is present.
[mgorman@suse.de: wrote changelog, proposed minor modifications]
[akpm@linux-foundation.org: fix typo in comment]
Reported-by: Steven Noonan <steven@uplinklabs.net>
Tested-by: Steven Noonan <steven@uplinklabs.net>
Signed-off-by: Elena Ufimtseva <ufimtseva@gmail.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: <stable@vger.kernel.org> [3.12+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull x86 asmlinkage (LTO) changes from Peter Anvin:
"This patchset adds more infrastructure for link time optimization
(LTO).
This patchset was pulled into my tree late because of a
miscommunication (part of the patchset was picked up by other
maintainers). However, the patchset is strictly build-related and
seems to be okay in testing"
* 'x86-asmlinkage-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86, asmlinkage, xen: Fix type of NMI
x86, asmlinkage, xen, kvm: Make {xen,kvm}_lock_spinning global and visible
x86: Use inline assembler instead of global register variable to get sp
x86, asmlinkage, paravirt: Make paravirt thunks global
x86, asmlinkage, paravirt: Don't rely on local assembler labels
x86, asmlinkage, lguest: Fix C functions used by inline assembler
The paravirt thunks use a hack of using a static reference to a static
function to reference that function from the top level statement.
This assumes that gcc always generates static function names in a specific
format, which is not necessarily true.
Simply make these functions global and asmlinkage or __visible. This way the
static __used variables are not needed and everything works.
Functions with arguments are __visible to keep the register calling
convention on 32bit.
Changed in paravirt and in all users (Xen and vsmp)
v2: Use __visible for functions with arguments
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Ido Yariv <ido@wizery.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1382458079-24450-5-git-send-email-andi@firstfloor.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
We also optimize one - the TLB flush. The native operation would
needlessly IPI offline VCPUs causing extra wakeups. Using the
Xen one avoids that and lets the hypervisor determine which
VCPU needs the TLB flush.
Signed-off-by: Mukesh Rathor <mukesh.rathor@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
.. which are surprisingly small compared to the amount for PV code.
PVH uses mostly native mmu ops, we leave the generic (native_*) for
the majority and just overwrite the baremetal with the ones we need.
At startup, we are running with pre-allocated page-tables
courtesy of the tool-stack. But we still need to graft them
in the Linux initial pagetables. However there is no need to
unpin/pin and change them to R/O or R/W.
Note that the xen_pagetable_init due to 7836fec9d0994cc9c9150c5a33f0eb0eb08a335a
"xen/mmu/p2m: Refactor the xen_pagetable_init code." does not
need any changes - we just need to make sure that xen_post_allocator_init
does not alter the pvops from the default native one.
Signed-off-by: Mukesh Rathor <mukesh.rathor@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Stefano noticed that the code runs only under 64-bit so
the comments about 32-bit are pointless.
Also we change the condition for xen_revector_p2m_tree
returning the same value (because it could not allocate
a swath of space to put the new P2M in) or it had been
called once already. In such we return early from the
function.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
The revectoring and copying of the P2M only happens when
!auto-xlat and on 64-bit builds. It is not obvious from
the code, so lets have seperate 32 and 64-bit functions.
We also invert the check for auto-xlat to make the code
flow simpler.
Suggested-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
- SWIOTLB has tracing added when doing bounce buffer.
- Xen ARM/ARM64 can use Xen-SWIOTLB. This work allows Linux to
safely program real devices for DMA operations when running as
a guest on Xen on ARM, without IOMMU support.*1
- xen_raw_printk works with PVHVM guests if needed.
Bug-fixes:
- Make memory ballooning work under HVM with large MMIO region.
- Inform hypervisor of MCFG regions found in ACPI DSDT.
- Remove deprecated IRQF_DISABLED.
- Remove deprecated __cpuinit.
[*1]:
"On arm and arm64 all Xen guests, including dom0, run with second stage
translation enabled. As a consequence when dom0 programs a device for a
DMA operation is going to use (pseudo) physical addresses instead
machine addresses. This work introduces two trees to track physical to
machine and machine to physical mappings of foreign pages. Local pages
are assumed mapped 1:1 (physical address == machine address). It
enables the SWIOTLB-Xen driver on ARM and ARM64, so that Linux can
translate physical addresses to machine addresses for dma operations
when necessary. " (Stefano).
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Merge tag 'stable/for-linus-3.13-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull Xen updates from Konrad Rzeszutek Wilk:
"This has tons of fixes and two major features which are concentrated
around the Xen SWIOTLB library.
The short <blurb> is that the tracing facility (just one function) has
been added to SWIOTLB to make it easier to track I/O progress.
Additionally under Xen and ARM (32 & 64) the Xen-SWIOTLB driver
"is used to translate physical to machine and machine to physical
addresses of foreign[guest] pages for DMA operations" (Stefano) when
booting under hardware without proper IOMMU.
There are also bug-fixes, cleanups, compile warning fixes, etc.
The commit times for some of the commits is a bit fresh - that is b/c
we wanted to make sure we have the Ack's from the ARM folks - which
with the string of back-to-back conferences took a bit of time. Rest
assured - the code has been stewing in #linux-next for some time.
Features:
- SWIOTLB has tracing added when doing bounce buffer.
- Xen ARM/ARM64 can use Xen-SWIOTLB. This work allows Linux to
safely program real devices for DMA operations when running as a
guest on Xen on ARM, without IOMMU support. [*1]
- xen_raw_printk works with PVHVM guests if needed.
Bug-fixes:
- Make memory ballooning work under HVM with large MMIO region.
- Inform hypervisor of MCFG regions found in ACPI DSDT.
- Remove deprecated IRQF_DISABLED.
- Remove deprecated __cpuinit.
[*1]:
"On arm and arm64 all Xen guests, including dom0, run with second
stage translation enabled. As a consequence when dom0 programs a
device for a DMA operation is going to use (pseudo) physical
addresses instead machine addresses. This work introduces two trees
to track physical to machine and machine to physical mappings of
foreign pages. Local pages are assumed mapped 1:1 (physical address
== machine address). It enables the SWIOTLB-Xen driver on ARM and
ARM64, so that Linux can translate physical addresses to machine
addresses for dma operations when necessary. " (Stefano)"
* tag 'stable/for-linus-3.13-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: (32 commits)
xen/arm: pfn_to_mfn and mfn_to_pfn return the argument if nothing is in the p2m
arm,arm64/include/asm/io.h: define struct bio_vec
swiotlb-xen: missing include dma-direction.h
pci-swiotlb-xen: call pci_request_acs only ifdef CONFIG_PCI
arm: make SWIOTLB available
xen: delete new instances of added __cpuinit
xen/balloon: Set balloon's initial state to number of existing RAM pages
xen/mcfg: Call PHYSDEVOP_pci_mmcfg_reserved for MCFG areas.
xen: remove deprecated IRQF_DISABLED
x86/xen: remove deprecated IRQF_DISABLED
swiotlb-xen: fix error code returned by xen_swiotlb_map_sg_attrs
swiotlb-xen: static inline xen_phys_to_bus, xen_bus_to_phys, xen_virt_to_bus and range_straddles_page_boundary
grant-table: call set_phys_to_machine after mapping grant refs
arm,arm64: do not always merge biovec if we are running on Xen
swiotlb: print a warning when the swiotlb is full
swiotlb-xen: use xen_dma_map/unmap_page, xen_dma_sync_single_for_cpu/device
xen: introduce xen_dma_map/unmap_page and xen_dma_sync_single_for_cpu/device
tracing/events: Fix swiotlb tracepoint creation
swiotlb-xen: use xen_alloc/free_coherent_pages
xen: introduce xen_alloc/free_coherent_pages
...
If split page table lock is in use, we embed the lock into struct page
of table's page. We have to disable split lock, if spinlock_t is too
big be to be embedded, like when DEBUG_SPINLOCK or DEBUG_LOCK_ALLOC
enabled.
This patch add support for dynamic allocation of split page table lock
if we can't embed it to struct page.
page->ptl is unsigned long now and we use it as spinlock_t if
sizeof(spinlock_t) <= sizeof(long), otherwise it's pointer to spinlock_t.
The spinlock_t allocated in pgtable_page_ctor() for PTE table and in
pgtable_pmd_page_ctor() for PMD table. All other helpers converted to
support dynamically allocated page->ptl.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* stefano/swiotlb-xen-9.1:
swiotlb-xen: fix error code returned by xen_swiotlb_map_sg_attrs
swiotlb-xen: static inline xen_phys_to_bus, xen_bus_to_phys, xen_virt_to_bus and range_straddles_page_boundary
grant-table: call set_phys_to_machine after mapping grant refs
arm,arm64: do not always merge biovec if we are running on Xen
swiotlb: print a warning when the swiotlb is full
swiotlb-xen: use xen_dma_map/unmap_page, xen_dma_sync_single_for_cpu/device
xen: introduce xen_dma_map/unmap_page and xen_dma_sync_single_for_cpu/device
swiotlb-xen: use xen_alloc/free_coherent_pages
xen: introduce xen_alloc/free_coherent_pages
arm64/xen: get_dma_ops: return xen_dma_ops if we are running as xen_initial_domain
arm/xen: get_dma_ops: return xen_dma_ops if we are running as xen_initial_domain
swiotlb-xen: introduce xen_swiotlb_set_dma_mask
xen/arm,arm64: enable SWIOTLB_XEN
xen: make xen_create_contiguous_region return the dma address
xen/x86: allow __set_phys_to_machine for autotranslate guests
arm/xen,arm64/xen: introduce p2m
arm64: define DMA_ERROR_CODE
arm: make SWIOTLB available
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Conflicts:
arch/arm/include/asm/dma-mapping.h
drivers/xen/swiotlb-xen.c
[Conflicts arose b/c "arm: make SWIOTLB available" v8 was in Stefano's
branch, while I had v9 + Ack from Russel. I also fixed up white-space
issues]
Use xen_alloc_coherent_pages and xen_free_coherent_pages to allocate or
free coherent pages.
We need to be careful handling the pointer returned by
xen_alloc_coherent_pages, because on ARM the pointer is not equal to
phys_to_virt(*dma_handle). In fact virt_to_phys only works for kernel
direct mapped RAM memory.
In ARM case the pointer could be an ioremap address, therefore passing
it to virt_to_phys would give you another physical address that doesn't
correspond to it.
Make xen_create_contiguous_region take a phys_addr_t as start parameter to
avoid the virt_to_phys calls which would be incorrect.
Changes in v6:
- remove extra spaces.
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Modify xen_create_contiguous_region to return the dma address of the
newly contiguous buffer.
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Changes in v4:
- use virt_to_machine instead of virt_to_bus.
Jan Beulich spotted that the PAT MSR settings in the Xen public
document that "the first (PAT6) column was wrong across the
board, and the column for PAT7 was missing altogether."
This updates it to be in sync.
CC: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Pull perparatory x86 kasrl changes from Ingo Molnar:
"This contains changes from the ongoing KASLR work, by Kees Cook.
The main changes are the use of a read-only IDT on x86 (which
decouples the userspace visible virtual IDT address from the physical
address), and a rework of ELF relocation support, in preparation of
random, boot-time kernel image relocation."
* 'x86-kaslr-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86, relocs: Refactor the relocs tool to merge 32- and 64-bit ELF
x86, relocs: Build separate 32/64-bit tools
x86, relocs: Add 64-bit ELF support to relocs tool
x86, relocs: Consolidate processing logic
x86, relocs: Generalize ELF structure names
x86: Use a read-only IDT alias on all CPUs
Pull x86 fixes from Ingo Molnar:
"Misc fixes"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mm: Flush lazy MMU when DEBUG_PAGEALLOC is set
x86/mm/cpa/selftest: Fix false positive in CPA self test
x86/mm/cpa: Convert noop to functional fix
x86, mm: Patch out arch_flush_lazy_mmu_mode() when running on bare metal
x86, mm, paravirt: Fix vmalloc_fault oops during lazy MMU updates
Make a copy of the IDT (as seen via the "sidt" instruction) read-only.
This primarily removes the IDT from being a target for arbitrary memory
write attacks, and has the added benefit of also not leaking the kernel
base offset, if it has been relocated.
We already did this on vendor == Intel and family == 5 because of the
F0 0F bug -- regardless of if a particular CPU had the F0 0F bug or
not. Since the workaround was so cheap, there simply was no reason to
be very specific. This patch extends the readonly alias to all CPUs,
but does not activate the #PF to #UD conversion code needed to deliver
the proper exception in the F0 0F case except on Intel family 5
processors.
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: http://lkml.kernel.org/r/20130410192422.GA17344@www.outflux.net
Cc: Eric Northup <digitaleric@google.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Invoking arch_flush_lazy_mmu_mode() results in calls to
preempt_enable()/disable() which may have performance impact.
Since lazy MMU is not used on bare metal we can patch away
arch_flush_lazy_mmu_mode() so that it is never called in such
environment.
[ hpa: the previous patch "Fix vmalloc_fault oops during lazy MMU
updates" may cause a minor performance regression on
bare metal. This patch resolves that performance regression. It is
somewhat unclear to me if this is a good -stable candidate. ]
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: http://lkml.kernel.org/r/1364045796-10720-2-git-send-email-konrad.wilk@oracle.com
Tested-by: Josh Boyer <jwboyer@redhat.com>
Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: <stable@vger.kernel.org> SEE NOTE ABOVE
Occassionaly on a DL380 G4 the guest would crash quite early with this:
(XEN) d244:v0: unhandled page fault (ec=0003)
(XEN) Pagetable walk from ffffffff84dc7000:
(XEN) L4[0x1ff] = 00000000c3f18067 0000000000001789
(XEN) L3[0x1fe] = 00000000c3f14067 000000000000178d
(XEN) L2[0x026] = 00000000dc8b2067 0000000000004def
(XEN) L1[0x1c7] = 00100000dc8da067 0000000000004dc7
(XEN) domain_crash_sync called from entry.S
(XEN) Domain 244 (vcpu#0) crashed on cpu#3:
(XEN) ----[ Xen-4.1.3OVM x86_64 debug=n Not tainted ]----
(XEN) CPU: 3
(XEN) RIP: e033:[<ffffffff81263f22>]
(XEN) RFLAGS: 0000000000000216 EM: 1 CONTEXT: pv guest
(XEN) rax: 0000000000000000 rbx: ffffffff81785f88 rcx: 000000000000003f
(XEN) rdx: 0000000000000000 rsi: 00000000dc8da063 rdi: ffffffff84dc7000
The offending code shows it to be a loop writting the value zero
(%rax) in the %rdi (the L4 provided by Xen) register:
0: 44 00 00 add %r8b,(%rax)
3: 31 c0 xor %eax,%eax
5: b9 40 00 00 00 mov $0x40,%ecx
a: 66 0f 1f 84 00 00 00 nopw 0x0(%rax,%rax,1)
11: 00 00
13: ff c9 dec %ecx
15:* 48 89 07 mov %rax,(%rdi) <-- trapping instruction
18: 48 89 47 08 mov %rax,0x8(%rdi)
1c: 48 89 47 10 mov %rax,0x10(%rdi)
which fails. xen_setup_kernel_pagetable recycles some of the Xen's
page-table entries when it has switched over to its Linux page-tables.
Right before try to clear the page, we make a hypercall to change
it from _RO to _RW and that works (otherwise we would hit an BUG()).
And the _RW flag is set for that page:
(XEN) L1[0x1c7] = 001000004885f067 0000000000004dc7
The error code is 3, so PFEC_page_present and PFEC_write_access, so page is
present (correct), and we tried to write to the page, but a violation
occurred. The one theory is that the the page entries in hardware
(which are cached) are not up to date with what we just set. Especially
as we have just done an CR3 write and flushed the multicalls.
This patch does solve the problem by flusing out the TLB page
entry after changing it from _RO to _RW and we don't hit this
issue anymore.
Fixed-Oracle-Bug: 16243091 [ON OCCASIONS VM START GOES INTO
'CRASH' STATE: CLEAR_PAGE+0X12 ON HP DL380 G4]
Reported-and-Tested-by: Saar Maoz <Saar.Maoz@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
We move the setting of write_cr3 from the early bootup variant
(see git commit 0cc9129d75
"x86-64, xen, mmu: Provide an early version of write_cr3.")
to a more appropiate location.
This new location sets all of the other non-early variants
of pvops calls - and most importantly is before the
alternative_asm mechanism kicks in.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
With commit 8170e6bed4 ("x86, 64bit: Use a #PF handler to materialize
early mappings on demand") we started hitting an early bootup crash
where the Xen hypervisor would inform us that:
(XEN) d7:v0: unhandled page fault (ec=0000)
(XEN) Pagetable walk from ffffea000005b2d0:
(XEN) L4[0x1d4] = 0000000000000000 ffffffffffffffff
(XEN) domain_crash_sync called from entry.S
(XEN) Domain 7 (vcpu#0) crashed on cpu#3:
(XEN) ----[ Xen-4.2.0 x86_64 debug=n Not tainted ]----
.. that Xen was unable to context switch back to dom0.
Looking at the calling stack we find:
[<ffffffff8103feba>] xen_get_user_pgd+0x5a <--
[<ffffffff8103feba>] xen_get_user_pgd+0x5a
[<ffffffff81042d27>] xen_write_cr3+0x77
[<ffffffff81ad2d21>] init_mem_mapping+0x1f9
[<ffffffff81ac293f>] setup_arch+0x742
[<ffffffff81666d71>] printk+0x48
We are trying to figure out whether we need to up-date the user PGD as
well. Please keep in mind that under 64-bit PV guests we have a limited
amount of rings: 0 for the Hypervisor, and 1 for both the Linux kernel
and user-space. As such the Linux pvops'fied version of write_cr3
checks if it has to update the user-space cr3 as well.
That clearly is not needed during early bootup. The recent changes (see
above git commit) streamline the x86 page table allocation to be much
simpler (And also incidentally the #PF handler ends up in spirit being
similar to how the Xen toolstack sets up the initial page-tables).
The fix is to have an early-bootup version of cr3 that just loads the
kernel %cr3. The later version - which also handles user-page
modifications will be used after the initial page tables have been
setup.
[ hpa: removed a redundant #ifdef and made the new function __init.
Also note that x86-32 already has such an early xen_write_cr3. ]
Tested-by: "H. Peter Anvin" <hpa@zytor.com>
Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Link: http://lkml.kernel.org/r/1361579812-23709-1-git-send-email-konrad.wilk@oracle.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Coming patches to x86/mm2 require the changes and advanced baseline in
x86/boot.
Resolved Conflicts:
arch/x86/kernel/setup.c
mm/nobootmem.c
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
- Add necessary infrastructure to make balloon driver work under ARM.
- Add /dev/xen/privcmd interfaces to work with ARM and PVH.
- Improve Xen PCIBack wild-card parsing.
- Add Xen ACPI PAD (Processor Aggregator) support - so can offline/online
sockets depending on the power consumption.
- PVHVM + kexec = use an E820_RESV region for the shared region so we don't
overwrite said region during kexec reboot.
- Cleanups, compile fixes.
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Merge tag 'stable/for-linus-3.8-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen
Pull Xen updates from Konrad Rzeszutek Wilk:
- Add necessary infrastructure to make balloon driver work under ARM.
- Add /dev/xen/privcmd interfaces to work with ARM and PVH.
- Improve Xen PCIBack wild-card parsing.
- Add Xen ACPI PAD (Processor Aggregator) support - so can offline/
online sockets depending on the power consumption.
- PVHVM + kexec = use an E820_RESV region for the shared region so we
don't overwrite said region during kexec reboot.
- Cleanups, compile fixes.
Fix up some trivial conflicts due to the balloon driver now working on
ARM, and there were changes next to the previous work-arounds that are
now gone.
* tag 'stable/for-linus-3.8-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
xen/PVonHVM: fix compile warning in init_hvm_pv_info
xen: arm: implement remap interfaces needed for privcmd mappings.
xen: correctly use xen_pfn_t in remap_domain_mfn_range.
xen: arm: enable balloon driver
xen: balloon: allow PVMMU interfaces to be compiled out
xen: privcmd: support autotranslated physmap guests.
xen: add pages parameter to xen_remap_domain_mfn_range
xen/acpi: Move the xen_running_on_version_or_later function.
xen/xenbus: Remove duplicate inclusion of asm/xen/hypervisor.h
xen/acpi: Fix compile error by missing decleration for xen_domain.
xen/acpi: revert pad config check in xen_check_mwait
xen/acpi: ACPI PAD driver
xen-pciback: reject out of range inputs
xen-pciback: simplify and tighten parsing of device IDs
xen PVonHVM: use E820_Reserved area for shared_info
For Xen on ARM a PFN is 64 bits so we need to use the appropriate
type here.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
[v2: include the necessary header,
Reported-by: Fengguang Wu <fengguang.wu@intel.com> ]
Also introduce xen_unmap_domain_mfn_range. These are the parts of
Mukesh's "xen/pvh: Implement MMU changes for PVH" which are also
needed as a baseline for ARM privcmd support.
The original patch was:
Signed-off-by: Mukesh Rathor <mukesh.rathor@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This derivative is also:
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Page table area are pre-mapped now after
x86, mm: setup page table in top-down
x86, mm: Remove early_memremap workaround for page table accessing on 64bit
mapping_pagetable_reserve is not used anymore, so remove it.
Also remove operation in mask_rw_pte(), as modified allow_low_page
always return pages that are already mapped, moreover
xen_alloc_pte_init, xen_alloc_pmd_init, etc, will mark the page RO
before hooking it into the pagetable automatically.
-v2: add changelog about mask_rw_pte() from Stefano.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1353123563-3103-27-git-send-email-yinghai@kernel.org
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
As Mukesh explained it, the MMUEXT_TLB_FLUSH_ALL allows the
hypervisor to do a TLB flush on all active vCPUs. If instead
we were using the generic one (which ends up being xen_flush_tlb)
we end up making the MMUEXT_TLB_FLUSH_LOCAL hypercall. But
before we make that hypercall the kernel will IPI all of the
vCPUs (even those that were asleep from the hypervisor
perspective). The end result is that we needlessly wake them
up and do a TLB flush when we can just let the hypervisor
do it correctly.
This patch gives around 50% speed improvement when migrating
idle guest's from one host to another.
Oracle-bug: 14630170
CC: stable@vger.kernel.org
Tested-by: Jingjie Jiang <jingjie.jiang@oracle.com>
Suggested-by: Mukesh Rathor <mukesh.rathor@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
- Register a pfn_is_ram helper to speed up reading of /proc/vmcore.
Bug-fixes:
- Three pvops call for Xen were undefined causing BUG_ONs.
- Add a quirk so that the shutdown watches (used by kdump) are not used with older Xen (3.4).
- Fix ungraceful state transition for the HVC console.
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Merge tag 'stable/for-linus-3.7-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen
Pull Xen fixes from Konrad Rzeszutek Wilk:
"This has four bug-fixes and one tiny feature that I forgot to put
initially in my tree due to oversight.
The feature is for kdump kernels to speed up the /proc/vmcore reading.
There is a ram_is_pfn helper function that the different platforms can
register for. We are now doing that.
The bug-fixes cover some embarrassing struct pv_cpu_ops variables
being set to NULL on Xen (but not baremetal). We had a similar issue
in the past with {write|read}_msr_safe and this fills the three
missing ones. The other bug-fix is to make the console output (hvc)
be capable of dealing with misbehaving backends and not fall flat on
its face. Lastly, a quirk for older XenBus implementations that came
with an ancient v3.4 hypervisor (so RHEL5 based) - reading of certain
non-existent attributes just hangs the guest during bootup - so we
take precaution of not doing that on such older installations.
Feature:
- Register a pfn_is_ram helper to speed up reading of /proc/vmcore.
Bug-fixes:
- Three pvops call for Xen were undefined causing BUG_ONs.
- Add a quirk so that the shutdown watches (used by kdump) are not
used with older Xen (3.4).
- Fix ungraceful state transition for the HVC console."
* tag 'stable/for-linus-3.7-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
xen/pv-on-hvm kexec: add quirk for Xen 3.4 and shutdown watches.
xen/bootup: allow {read|write}_cr8 pvops call.
xen/bootup: allow read_tscp call for Xen PV guests.
xen pv-on-hvm: add pfn_is_ram helper for kdump
xen/hvc: handle backend CLOSED without CLOSING
A long time ago, in v2.4, VM_RESERVED kept swapout process off VMA,
currently it lost original meaning but still has some effects:
| effect | alternative flags
-+------------------------+---------------------------------------------
1| account as reserved_vm | VM_IO
2| skip in core dump | VM_IO, VM_DONTDUMP
3| do not merge or expand | VM_IO, VM_DONTEXPAND, VM_HUGETLB, VM_PFNMAP
4| do not mlock | VM_IO, VM_DONTEXPAND, VM_HUGETLB, VM_PFNMAP
This patch removes reserved_vm counter from mm_struct. Seems like nobody
cares about it, it does not exported into userspace directly, it only
reduces total_vm showed in proc.
Thus VM_RESERVED can be replaced with VM_IO or pair VM_DONTEXPAND | VM_DONTDUMP.
remap_pfn_range() and io_remap_pfn_range() set VM_IO|VM_DONTEXPAND|VM_DONTDUMP.
remap_vmalloc_range() set VM_DONTEXPAND | VM_DONTDUMP.
[akpm@linux-foundation.org: drivers/vfio/pci/vfio_pci.c fixup]
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Carsten Otte <cotte@de.ibm.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Eric Paris <eparis@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Morris <james.l.morris@oracle.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Kentaro Takeda <takedakn@nttdata.co.jp>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Venkatesh Pallipadi <venki@google.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Register pfn_is_ram helper speed up reading /proc/vmcore in the kdump
kernel. See commit message of 997c136f51 ("fs/proc/vmcore.c: add hook
to read_from_oldmem() to check for non-ram pages") for details.
It makes use of a new hvmop HVMOP_get_mem_type which was introduced in
xen 4.2 (23298:26413986e6e0) and backported to 4.1.1.
The new function is currently only enabled for reading /proc/vmcore.
Later it will be used also for the kexec kernel. Since that requires
more changes in the generic kernel make it static for the time being.
Signed-off-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* stable/128gb.v5.1:
xen/mmu: If the revector fails, don't attempt to revector anything else.
xen/p2m: When revectoring deal with holes in the P2M array.
xen/mmu: Release just the MFN list, not MFN list and part of pagetables.
xen/mmu: Remove from __ka space PMD entries for pagetables.
xen/mmu: Copy and revector the P2M tree.
xen/p2m: Add logic to revector a P2M tree to use __va leafs.
xen/mmu: Recycle the Xen provided L4, L3, and L2 pages
xen/mmu: For 64-bit do not call xen_map_identity_early
xen/mmu: use copy_page instead of memcpy.
xen/mmu: Provide comments describing the _ka and _va aliasing issue
xen/mmu: The xen_setup_kernel_pagetable doesn't need to return anything.
Revert "xen/x86: Workaround 64-bit hypervisor and 32-bit initial domain." and "xen/x86: Use memblock_reserve for sensitive areas."
xen/x86: Workaround 64-bit hypervisor and 32-bit initial domain.
xen/x86: Use memblock_reserve for sensitive areas.
xen/p2m: Fix the comment describing the P2M tree.
Conflicts:
arch/x86/xen/mmu.c
The pagetable_init is the old xen_pagetable_setup_done and xen_pagetable_setup_start
rolled in one.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* 'x86/platform' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (9690 commits)
x86: Document x86_init.paging.pagetable_init()
x86: xen: Cleanup and remove x86_init.paging.pagetable_setup_done()
x86: Move paging_init() call to x86_init.paging.pagetable_init()
x86: Rename pagetable_setup_start() to pagetable_init()
x86: Remove base argument from x86_init.paging.pagetable_setup_start
Linux 3.6-rc5
HID: tpkbd: work even if the new Lenovo Keyboard driver is not configured
Remove user-triggerable BUG from mpol_to_str
xen/pciback: Fix proper FLR steps.
uml: fix compile error in deliver_alarm()
dj: memory scribble in logi_dj
Fix order of arguments to compat_put_time[spec|val]
xen: Use correct masking in xen_swiotlb_alloc_coherent.
xen: fix logical error in tlb flushing
xen/p2m: Fix one-off error in checking the P2M tree directory.
powerpc: Don't use __put_user() in patch_instruction
powerpc: Make sure IPI handlers see data written by IPI senders
powerpc: Restore correct DSCR in context switch
powerpc: Fix DSCR inheritance in copy_thread()
powerpc: Keep thread.dscr and thread.dscr_inherit in sync
...
At this stage x86_init.paging.pagetable_setup_done is only used in the
XEN case. Move its content in the x86_init.paging.pagetable_init setup
function and remove the now unused x86_init.paging.pagetable_setup_done
remaining infrastructure.
Signed-off-by: Attilio Rao <attilio.rao@citrix.com>
Acked-by: <konrad.wilk@oracle.com>
Cc: <Ian.Campbell@citrix.com>
Cc: <Stefano.Stabellini@eu.citrix.com>
Cc: <xen-devel@lists.xensource.com>
Link: http://lkml.kernel.org/r/1345580561-8506-5-git-send-email-attilio.rao@citrix.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Move the paging_init() call to the platform specific pagetable_init()
function, so we can get rid of the extra pagetable_setup_done()
function pointer.
Signed-off-by: Attilio Rao <attilio.rao@citrix.com>
Acked-by: <konrad.wilk@oracle.com>
Cc: <Ian.Campbell@citrix.com>
Cc: <Stefano.Stabellini@eu.citrix.com>
Cc: <xen-devel@lists.xensource.com>
Link: http://lkml.kernel.org/r/1345580561-8506-4-git-send-email-attilio.rao@citrix.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
In preparation for unifying the pagetable_setup_start() and
pagetable_setup_done() setup functions, rename appropriately all the
infrastructure related to pagetable_setup_start().
Signed-off-by: Attilio Rao <attilio.rao@citrix.com>
Ackedd-by: <konrad.wilk@oracle.com>
Cc: <Ian.Campbell@citrix.com>
Cc: <Stefano.Stabellini@eu.citrix.com>
Cc: <xen-devel@lists.xensource.com>
Link: http://lkml.kernel.org/r/1345580561-8506-3-git-send-email-attilio.rao@citrix.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
We either use swapper_pg_dir or the argument is unused. Preparatory
patch to simplify platform pagetable setup further.
Signed-off-by: Attilio Rao <attilio.rao@citrix.com>
Ackedb-by: <konrad.wilk@oracle.com>
Cc: <Ian.Campbell@citrix.com>
Cc: <Stefano.Stabellini@eu.citrix.com>
Cc: <xen-devel@lists.xensource.com>
Link: http://lkml.kernel.org/r/1345580561-8506-2-git-send-email-attilio.rao@citrix.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Callers of xen_remap_domain_range() need to know if the remap failed
because frame is currently paged out. So they can retry the remap
later on. Return -ENOENT in this case.
This assumes that the error codes returned by Xen are a subset of
those used by the kernel. It is unclear if this is defined as part of
the hypercall ABI.
Acked-by: Andres Lagar-Cavilla <andres@lagarcavilla.org>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
While TLB_FLUSH_ALL gets passed as 'end' argument to
flush_tlb_others(), the Xen code was made to check its 'start'
parameter. That may give a incorrect op.cmd to MMUEXT_INVLPG_MULTI
instead of MMUEXT_TLB_FLUSH_MULTI. Then it causes some page can not
be flushed from TLB.
This patch fixed this issue.
Reported-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Alex Shi <alex.shi@intel.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Tested-by: Yongjie Ren <yongjie.ren@intel.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
If the P2M revectoring would fail, we would try to continue on by
cleaning the PMD for L1 (PTE) page-tables. The xen_cleanhighmap
is greedy and erases the PMD on both boundaries. Since the P2M
array can share the PMD, we would wipe out part of the __ka
that is still used in the P2M tree to point to P2M leafs.
This fixes it by bypassing the revectoring and continuing on.
If the revector fails, a nice WARN is printed so we can still
troubleshoot this.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
We call memblock_reserve for [start of mfn list] -> [PMD aligned end
of mfn list] instead of <start of mfn list> -> <page aligned end of mfn list].
This has the disastrous effect that if at bootup the end of mfn_list is
not PMD aligned we end up returning to memblock parts of the region
past the mfn_list array. And those parts are the PTE tables with
the disastrous effect of seeing this at bootup:
Write protecting the kernel read-only data: 10240k
Freeing unused kernel memory: 1860k freed
Freeing unused kernel memory: 200k freed
(XEN) mm.c:2429:d0 Bad type (saw 1400000000000002 != exp 7000000000000000) for mfn 116a80 (pfn 14e26)
...
(XEN) mm.c:908:d0 Error getting mfn 116a83 (pfn 14e2a) from L1 entry 8000000116a83067 for l1e_owner=0, pg_owner=0
(XEN) mm.c:908:d0 Error getting mfn 4040 (pfn 5555555555555555) from L1 entry 0000000004040601 for l1e_owner=0, pg_owner=0
.. and so on.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Please first read the description in "xen/mmu: Copy and revector the
P2M tree."
At this stage, the __ka address space (which is what the old
P2M tree was using) is partially disassembled. The cleanup_highmap
has removed the PMD entries from 0-16MB and anything past _brk_end
up to the max_pfn_mapped (which is the end of the ramdisk).
The xen_remove_p2m_tree and code around has ripped out the __ka for
the old P2M array.
Here we continue on doing it to where the Xen page-tables were.
It is safe to do it, as the page-tables are addressed using __va.
For good measure we delete anything that is within MODULES_VADDR
and up to the end of the PMD.
At this point the __ka only contains PMD entries for the start
of the kernel up to __brk.
[v1: Per Stefano's suggestion wrapped the MODULES_VADDR in debug]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Please first read the description in "xen/p2m: Add logic to revector a
P2M tree to use __va leafs" patch.
The 'xen_revector_p2m_tree()' function allocates a new P2M tree
copies the contents of the old one in it, and returns the new one.
At this stage, the __ka address space (which is what the old
P2M tree was using) is partially disassembled. The cleanup_highmap
has removed the PMD entries from 0-16MB and anything past _brk_end
up to the max_pfn_mapped (which is the end of the ramdisk).
We have revectored the P2M tree (and the one for save/restore as well)
to use new shiny __va address to new MFNs. The xen_start_info
has been taken care of already in 'xen_setup_kernel_pagetable()' and
xen_start_info->shared_info in 'xen_setup_shared_info()', so
we are free to roam and delete PMD entries - which is exactly what
we are going to do. We rip out the __ka for the old P2M array.
[v1: Fix smatch warnings]
[v2: memset was doing 0 instead of 0xff]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
As we are not using them. We end up only using the L1 pagetables
and grafting those to our page-tables.
[v1: Per Stefano's suggestion squashed two commits]
[v2: Per Stefano's suggestion simplified loop]
[v3: Fix smatch warnings]
[v4: Add more comments]
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Linus Torvalds