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commit fd19d3b45164466a4adce7cbff448ba9189e1427 upstream.
The function updates context->root_level but didn't call
update_last_nonleaf_level so the previous and potentially wrong value
was used for page walks. For example, a zero value of last_nonleaf_level
would allow a potential out-of-bounds access in arch/x86/mmu/paging_tmpl.h's
walk_addr_generic function (CVE-2017-12188).
Fixes: 155a97a3d7c78b46cef6f1a973c831bc5a4f82bb
Signed-off-by: Ladi Prosek <lprosek@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 829ee279aed43faa5cb1e4d65c0cad52f2426c53 upstream.
is_last_gpte() is not equivalent to the pseudo-code given in commit
6bb69c9b69c31 ("KVM: MMU: simplify last_pte_bitmap") because an incorrect
value of last_nonleaf_level may override the result even if level == 1.
It is critical for is_last_gpte() to return true on level == 1 to
terminate page walks. Otherwise memory corruption may occur as level
is used as an index to various data structures throughout the page
walking code. Even though the actual bug would be wherever the MMU is
initialized (as in the previous patch), be defensive and ensure here
that is_last_gpte() returns the correct value.
This patch is also enough to fix CVE-2017-12188.
Fixes: 6bb69c9b69c315200ddc2bc79aee14c0184cf5b2
Cc: Andy Honig <ahonig@google.com>
Signed-off-by: Ladi Prosek <lprosek@redhat.com>
[Panic if walk_addr_generic gets an incorrect level; this is a serious
bug and it's not worth a WARN_ON where the recovery path might hide
further exploitable issues; suggested by Andrew Honig. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 9bc1f09f6fa76fdf31eb7d6a4a4df43574725f93 upstream.
INFO: task gnome-terminal-:1734 blocked for more than 120 seconds.
Not tainted 4.12.0-rc4+ #8
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
gnome-terminal- D 0 1734 1015 0x00000000
Call Trace:
__schedule+0x3cd/0xb30
schedule+0x40/0x90
kvm_async_pf_task_wait+0x1cc/0x270
? __vfs_read+0x37/0x150
? prepare_to_swait+0x22/0x70
do_async_page_fault+0x77/0xb0
? do_async_page_fault+0x77/0xb0
async_page_fault+0x28/0x30
This is triggered by running both win7 and win2016 on L1 KVM simultaneously,
and then gives stress to memory on L1, I can observed this hang on L1 when
at least ~70% swap area is occupied on L0.
This is due to async pf was injected to L2 which should be injected to L1,
L2 guest starts receiving pagefault w/ bogus %cr2(apf token from the host
actually), and L1 guest starts accumulating tasks stuck in D state in
kvm_async_pf_task_wait() since missing PAGE_READY async_pfs.
This patch fixes the hang by doing async pf when executing L1 guest.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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That parameter isn't used in these functions,
it's probably a historical artifact.
Signed-off-by: Bandan Das <bsd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Pull KVM updates from Paolo Bonzini:
- ARM: GICv3 ITS emulation and various fixes. Removal of the
old VGIC implementation.
- s390: support for trapping software breakpoints, nested
virtualization (vSIE), the STHYI opcode, initial extensions
for CPU model support.
- MIPS: support for MIPS64 hosts (32-bit guests only) and lots
of cleanups, preliminary to this and the upcoming support for
hardware virtualization extensions.
- x86: support for execute-only mappings in nested EPT; reduced
vmexit latency for TSC deadline timer (by about 30%) on Intel
hosts; support for more than 255 vCPUs.
- PPC: bugfixes.
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (302 commits)
KVM: PPC: Introduce KVM_CAP_PPC_HTM
MIPS: Select HAVE_KVM for MIPS64_R{2,6}
MIPS: KVM: Reset CP0_PageMask during host TLB flush
MIPS: KVM: Fix ptr->int cast via KVM_GUEST_KSEGX()
MIPS: KVM: Sign extend MFC0/RDHWR results
MIPS: KVM: Fix 64-bit big endian dynamic translation
MIPS: KVM: Fail if ebase doesn't fit in CP0_EBase
MIPS: KVM: Use 64-bit CP0_EBase when appropriate
MIPS: KVM: Set CP0_Status.KX on MIPS64
MIPS: KVM: Make entry code MIPS64 friendly
MIPS: KVM: Use kmap instead of CKSEG0ADDR()
MIPS: KVM: Use virt_to_phys() to get commpage PFN
MIPS: Fix definition of KSEGX() for 64-bit
KVM: VMX: Add VMCS to CPU's loaded VMCSs before VMPTRLD
kvm: x86: nVMX: maintain internal copy of current VMCS
KVM: PPC: Book3S HV: Save/restore TM state in H_CEDE
KVM: PPC: Book3S HV: Pull out TM state save/restore into separate procedures
KVM: arm64: vgic-its: Simplify MAPI error handling
KVM: arm64: vgic-its: Make vgic_its_cmd_handle_mapi similar to other handlers
KVM: arm64: vgic-its: Turn device_id validation into generic ID validation
...
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Historically a lot of these existed because we did not have
a distinction between what was modular code and what was providing
support to modules via EXPORT_SYMBOL and friends. That changed
when we forked out support for the latter into the export.h file.
This means we should be able to reduce the usage of module.h
in code that is obj-y Makefile or bool Kconfig. In the case of
kvm where it is modular, we can extend that to also include files
that are building basic support functionality but not related
to loading or registering the final module; such files also have
no need whatsoever for module.h
The advantage in removing such instances is that module.h itself
sources about 15 other headers; adding significantly to what we feed
cpp, and it can obscure what headers we are effectively using.
Since module.h was the source for init.h (for __init) and for
export.h (for EXPORT_SYMBOL) we consider each instance for the
presence of either and replace as needed.
Several instances got replaced with moduleparam.h since that was
really all that was required for those particular files.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kvm@vger.kernel.org
Link: http://lkml.kernel.org/r/20160714001901.31603-8-paul.gortmaker@windriver.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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To support execute only mappings on behalf of L1 hypervisors,
reuse ACC_USER_MASK to signify if the L1 hypervisor has the R bit
set.
For the nested EPT case, we assumed that the U bit was always set
since there was no equivalent in EPT page tables. Strictly
speaking, this was not necessary because handle_ept_violation
never set PFERR_USER_MASK in the error code (uf=0 in the
parlance of update_permission_bitmask). We now have to set
both U and UF correctly, respectively in FNAME(gpte_access)
and in handle_ept_violation.
Also in handle_ept_violation bit 3 of the exit qualification is
not enough to detect a present PTE; all three bits 3-5 have to
be checked.
Signed-off-by: Bandan Das <bsd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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To support execute only mappings on behalf of L1
hypervisors, we need to teach set_spte() to honor all three of
L1's XWR bits. As a start, add a new variable "shadow_present_mask"
that will be set for non-EPT shadow paging and clear for EPT.
Signed-off-by: Bandan Das <bsd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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We have two versions of the above function.
To prevent confusion and bugs in the future, remove
the non-FNAME version entirely and replace all calls
with the actual check.
Signed-off-by: Bandan Das <bsd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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This is safe because this function is called
on host controlled page table and non-present/non-MMIO
sptes never use bits 1..31. For the EPT case, this
ensures that cases where only the execute bit is set
is marked valid.
Signed-off-by: Bandan Das <bsd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Signed-off-by: Andrea Gelmini <andrea.gelmini@gelma.net>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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In theory, nothing prevents the compiler from write-tearing PTEs, or
split PTE writes. These partially-modified PTEs can be fetched by other
cores and cause mayhem. I have not really encountered such case in
real-life, but it does seem possible.
For example, the compiler may try to do something creative for
kvm_set_pte_rmapp() and perform multiple writes to the PTE.
Signed-off-by: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
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Pull KVM updates from Paolo Bonzini:
"Small release overall.
x86:
- miscellaneous fixes
- AVIC support (local APIC virtualization, AMD version)
s390:
- polling for interrupts after a VCPU goes to halted state is now
enabled for s390
- use hardware provided information about facility bits that do not
need any hypervisor activity, and other fixes for cpu models and
facilities
- improve perf output
- floating interrupt controller improvements.
MIPS:
- miscellaneous fixes
PPC:
- bugfixes only
ARM:
- 16K page size support
- generic firmware probing layer for timer and GIC
Christoffer Dall (KVM-ARM maintainer) says:
"There are a few changes in this pull request touching things
outside KVM, but they should all carry the necessary acks and it
made the merge process much easier to do it this way."
though actually the irqchip maintainers' acks didn't make it into the
patches. Marc Zyngier, who is both irqchip and KVM-ARM maintainer,
later acked at http://mid.gmane.org/573351D1.4060303@arm.com ('more
formally and for documentation purposes')"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (82 commits)
KVM: MTRR: remove MSR 0x2f8
KVM: x86: make hwapic_isr_update and hwapic_irr_update look the same
svm: Manage vcpu load/unload when enable AVIC
svm: Do not intercept CR8 when enable AVIC
svm: Do not expose x2APIC when enable AVIC
KVM: x86: Introducing kvm_x86_ops.apicv_post_state_restore
svm: Add VMEXIT handlers for AVIC
svm: Add interrupt injection via AVIC
KVM: x86: Detect and Initialize AVIC support
svm: Introduce new AVIC VMCB registers
KVM: split kvm_vcpu_wake_up from kvm_vcpu_kick
KVM: x86: Introducing kvm_x86_ops VCPU blocking/unblocking hooks
KVM: x86: Introducing kvm_x86_ops VM init/destroy hooks
KVM: x86: Rename kvm_apic_get_reg to kvm_lapic_get_reg
KVM: x86: Misc LAPIC changes to expose helper functions
KVM: shrink halt polling even more for invalid wakeups
KVM: s390: set halt polling to 80 microseconds
KVM: halt_polling: provide a way to qualify wakeups during poll
KVM: PPC: Book3S HV: Re-enable XICS fast path for irqfd-generated interrupts
kvm: Conditionally register IRQ bypass consumer
...
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 asm updates from Ingo Molnar:
"The main changes in this cycle were:
- MSR access API fixes and enhancements (Andy Lutomirski)
- early exception handling improvements (Andy Lutomirski)
- user-space FS/GS prctl usage fixes and improvements (Andy
Lutomirski)
- Remove the cpu_has_*() APIs and replace them with equivalents
(Borislav Petkov)
- task switch micro-optimization (Brian Gerst)
- 32-bit entry code simplification (Denys Vlasenko)
- enhance PAT handling in enumated CPUs (Toshi Kani)
... and lots of other cleanups/fixlets"
* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (70 commits)
x86/arch_prctl/64: Restore accidentally removed put_cpu() in ARCH_SET_GS
x86/entry/32: Remove asmlinkage_protect()
x86/entry/32: Remove GET_THREAD_INFO() from entry code
x86/entry, sched/x86: Don't save/restore EFLAGS on task switch
x86/asm/entry/32: Simplify pushes of zeroed pt_regs->REGs
selftests/x86/ldt_gdt: Test set_thread_area() deletion of an active segment
x86/tls: Synchronize segment registers in set_thread_area()
x86/asm/64: Rename thread_struct's fs and gs to fsbase and gsbase
x86/arch_prctl/64: Remove FSBASE/GSBASE < 4G optimization
x86/segments/64: When load_gs_index fails, clear the base
x86/segments/64: When loadsegment(fs, ...) fails, clear the base
x86/asm: Make asm/alternative.h safe from assembly
x86/asm: Stop depending on ptrace.h in alternative.h
x86/entry: Rename is_{ia32,x32}_task() to in_{ia32,x32}_syscall()
x86/asm: Make sure verify_cpu() has a good stack
x86/extable: Add a comment about early exception handlers
x86/msr: Set the return value to zero when native_rdmsr_safe() fails
x86/paravirt: Make "unsafe" MSR accesses unsafe even if PARAVIRT=y
x86/paravirt: Add paravirt_{read,write}_msr()
x86/msr: Carry on after a non-"safe" MSR access fails
...
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After the THP refcounting change, obtaining a compound pages from
get_user_pages() no longer allows us to assume the entire compound page
is immediately mappable from a secondary MMU.
A secondary MMU doesn't want to call get_user_pages() more than once for
each compound page, in order to know if it can map the whole compound
page. So a secondary MMU needs to know from a single get_user_pages()
invocation when it can map immediately the entire compound page to avoid
a flood of unnecessary secondary MMU faults and spurious
atomic_inc()/atomic_dec() (pages don't have to be pinned by MMU notifier
users).
Ideally instead of the page->_mapcount < 1 check, get_user_pages()
should return the granularity of the "page" mapping in the "mm" passed
to get_user_pages(). However it's non trivial change to pass the "pmd"
status belonging to the "mm" walked by get_user_pages up the stack (up
to the caller of get_user_pages). So the fix just checks if there is
not a single pte mapping on the page returned by get_user_pages, and in
turn if the caller can assume that the whole compound page is mapped in
the current "mm" (in a pmd_trans_huge()). In such case the entire
compound page is safe to map into the secondary MMU without additional
get_user_pages() calls on the surrounding tail/head pages. In addition
of being faster, not having to run other get_user_pages() calls also
reduces the memory footprint of the secondary MMU fault in case the pmd
split happened as result of memory pressure.
Without this fix after a MADV_DONTNEED (like invoked by QEMU during
postcopy live migration or balloning) or after generic swapping (with a
failure in split_huge_page() that would only result in pmd splitting and
not a physical page split), KVM would map the whole compound page into
the shadow pagetables, despite regular faults or userfaults (like
UFFDIO_COPY) may map regular pages into the primary MMU as result of the
pte faults, leading to the guest mode and userland mode going out of
sync and not working on the same memory at all times.
Any other secondary MMU notifier manager (KVM is just one of the many
MMU notifier users) will need the same information if it doesn't want to
run a flood of get_user_pages_fast and it can support multiple
granularity in the secondary MMU mappings, so I think it is justified to
be exposed not just to KVM.
The other option would be to move transparent_hugepage_adjust to
mm/huge_memory.c but that currently has all kind of KVM data structures
in it, so it's definitely not a cut-and-paste work, so I couldn't do a
fix as cleaner as this one for 4.6.
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: "Li, Liang Z" <liang.z.li@intel.com>
Cc: Amit Shah <amit.shah@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The obsolete sp should not be used on current vCPUs and should not hurt
vCPU's running, so skip it from for_each_gfn_sp() and
for_each_gfn_indirect_valid_sp()
The side effort is we will double check role.invalid in kvm_mmu_get_page()
but i think it is okay as role is well cached
Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Signed-off-by: Ingo Molnar <mingo@kernel.org>
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In absence of shadow dirty mask, there is no need to set page dirty
if page has never been writable. This is a tiny optimization but
good to have for people who care much about dirty page tracking.
Signed-off-by: Yu Zhao <yuzhao@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1459266123-21878-6-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Ingo Molnar:
"Misc fixes:
- fix hotplug bugs
- fix irq live lock
- fix various topology handling bugs
- fix APIC ACK ordering
- fix PV iopl handling
- fix speling
- fix/tweak memcpy_mcsafe() return value
- fix fbcon bug
- remove stray prototypes"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/msr: Remove unused native_read_tscp()
x86/apic: Remove declaration of unused hw_nmi_is_cpu_stuck
x86/oprofile/nmi: Add missing hotplug FROZEN handling
x86/hpet: Use proper mask to modify hotplug action
x86/apic/uv: Fix the hotplug notifier
x86/apb/timer: Use proper mask to modify hotplug action
x86/topology: Use total_cpus not nr_cpu_ids for logical packages
x86/topology: Fix Intel HT disable
x86/topology: Fix logical package mapping
x86/irq: Cure live lock in fixup_irqs()
x86/tsc: Prevent NULL pointer deref in calibrate_delay_is_known()
x86/apic: Fix suspicious RCU usage in smp_trace_call_function_interrupt()
x86/iopl: Fix iopl capability check on Xen PV
x86/iopl/64: Properly context-switch IOPL on Xen PV
selftests/x86: Add an iopl test
x86/mm, x86/mce: Fix return type/value for memcpy_mcsafe()
x86/video: Don't assume all FB devices are PCI devices
arch/x86/irq: Purge useless handler declarations from hw_irq.h
x86: Fix misspellings in comments
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walk_shadow_page_lockless_begin/end()
Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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There is already a barrier inside of kvm_flush_remote_tlbs() which can
help to make sure everyone sees our modifications to the page tables and
see changes to vcpu->mode here. So remove the smp_mb in the
kvm_mmu_commit_zap_page() and update the comment.
Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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PKEYS defines a new status bit in the PFEC. PFEC.PK (bit 5), if some
conditions is true, the fault is considered as a PKU violation.
pkru_mask indicates if we need to check PKRU.ADi and PKRU.WDi, and
does cache some conditions for permission_fault.
[ Huaitong: Xiao helps to modify many sections. ]
Signed-off-by: Huaitong Han <huaitong.han@intel.com>
Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Pull in some merge window leftovers.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Pull KVM updates from Paolo Bonzini:
"One of the largest releases for KVM... Hardly any generic
changes, but lots of architecture-specific updates.
ARM:
- VHE support so that we can run the kernel at EL2 on ARMv8.1 systems
- PMU support for guests
- 32bit world switch rewritten in C
- various optimizations to the vgic save/restore code.
PPC:
- enabled KVM-VFIO integration ("VFIO device")
- optimizations to speed up IPIs between vcpus
- in-kernel handling of IOMMU hypercalls
- support for dynamic DMA windows (DDW).
s390:
- provide the floating point registers via sync regs;
- separated instruction vs. data accesses
- dirty log improvements for huge guests
- bugfixes and documentation improvements.
x86:
- Hyper-V VMBus hypercall userspace exit
- alternative implementation of lowest-priority interrupts using
vector hashing (for better VT-d posted interrupt support)
- fixed guest debugging with nested virtualizations
- improved interrupt tracking in the in-kernel IOAPIC
- generic infrastructure for tracking writes to guest
memory - currently its only use is to speedup the legacy shadow
paging (pre-EPT) case, but in the future it will be used for
virtual GPUs as well
- much cleanup (LAPIC, kvmclock, MMU, PIT), including ubsan fixes"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (217 commits)
KVM: x86: remove eager_fpu field of struct kvm_vcpu_arch
KVM: x86: disable MPX if host did not enable MPX XSAVE features
arm64: KVM: vgic-v3: Only wipe LRs on vcpu exit
arm64: KVM: vgic-v3: Reset LRs at boot time
arm64: KVM: vgic-v3: Do not save an LR known to be empty
arm64: KVM: vgic-v3: Save maintenance interrupt state only if required
arm64: KVM: vgic-v3: Avoid accessing ICH registers
KVM: arm/arm64: vgic-v2: Make GICD_SGIR quicker to hit
KVM: arm/arm64: vgic-v2: Only wipe LRs on vcpu exit
KVM: arm/arm64: vgic-v2: Reset LRs at boot time
KVM: arm/arm64: vgic-v2: Do not save an LR known to be empty
KVM: arm/arm64: vgic-v2: Move GICH_ELRSR saving to its own function
KVM: arm/arm64: vgic-v2: Save maintenance interrupt state only if required
KVM: arm/arm64: vgic-v2: Avoid accessing GICH registers
KVM: s390: allocate only one DMA page per VM
KVM: s390: enable STFLE interpretation only if enabled for the guest
KVM: s390: wake up when the VCPU cpu timer expires
KVM: s390: step the VCPU timer while in enabled wait
KVM: s390: protect VCPU cpu timer with a seqcount
KVM: s390: step VCPU cpu timer during kvm_run ioctl
...
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KVM has special logic to handle pages with pte.u=1 and pte.w=0 when
CR0.WP=1. These pages' SPTEs flip continuously between two states:
U=1/W=0 (user and supervisor reads allowed, supervisor writes not allowed)
and U=0/W=1 (supervisor reads and writes allowed, user writes not allowed).
When SMEP is in effect, however, U=0 will enable kernel execution of
this page. To avoid this, KVM also sets NX=1 in the shadow PTE together
with U=0, making the two states U=1/W=0/NX=gpte.NX and U=0/W=1/NX=1.
When guest EFER has the NX bit cleared, the reserved bit check thinks
that the latter state is invalid; teach it that the smep_andnot_wp case
will also use the NX bit of SPTEs.
Cc: stable@vger.kernel.org
Reviewed-by: Xiao Guangrong <guangrong.xiao@linux.inel.com>
Fixes: c258b62b264fdc469b6d3610a907708068145e3b
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Branch-free code is fun and everybody knows how much Avi loves it,
but last_pte_bitmap takes it a bit to the extreme. Since the code
is simply doing a range check, like
(level == 1 ||
((gpte & PT_PAGE_SIZE_MASK) && level < N)
we can make it branch-free without storing the entire truth table;
it is enough to cache N.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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mmu_sync_children can only process up to 16 pages at a time. Check
if we need to reschedule, and do not bother zapping the pages until
that happens.
Reviewed-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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kvm_mmu_get_page is the only caller of kvm_sync_page_transient
and kvm_sync_pages. Moving the handling of the invalid_list there
removes the need for the underdocumented kvm_sync_page_transient
function.
Reviewed-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Return true if the page was synced (and the TLB must be flushed)
and false if the page was zapped.
Reviewed-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Calling kvm_unlink_unsync_page in the middle of __kvm_sync_page makes
things unnecessarily tricky. If kvm_mmu_prepare_zap_page is called,
it will call kvm_unlink_unsync_page too. So kvm_unlink_unsync_page can
be called just as well at the beginning or the end of __kvm_sync_page...
which means that we might do it in kvm_sync_page too and remove the
parameter.
kvm_sync_page ends up being the same code that kvm_sync_pages used
to have before the previous patch.
Reviewed-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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If the last argument is true, kvm_unlink_unsync_page is called anyway in
__kvm_sync_page (either by kvm_mmu_prepare_zap_page or by __kvm_sync_page
itself). Therefore, kvm_sync_pages can just call kvm_sync_page, instead
of going through kvm_unlink_unsync_page+__kvm_sync_page.
Reviewed-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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By doing this, kvm_sync_pages can use __kvm_sync_page instead of
reinventing it. Because of kvm_mmu_flush_or_zap, the code does not
end up being more complex than before, and more cleanups to kvm_sync_pages
will come in the next patches.
Reviewed-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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This is a generalization of mmu_pte_write_flush_tlb, that also
takes care of calling kvm_mmu_commit_zap_page. The next
patches will introduce more uses.
Reviewed-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Give a special invalid index to the root of the walk, so that we
can check the consistency of kvm_mmu_pages and mmu_page_path.
Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
[Extracted from a bigger patch proposed by Guangrong. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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kvm_mmu_pages_init is doing some really yucky stuff. It is setting
up a sentinel for mmu_page_clear_parents; however, because of a) the
way levels are numbered starting from 1 and b) the way mmu_page_path
sizes its arrays with PT64_ROOT_LEVEL-1 elements, the access can be
out of bounds. This is harmless because the code overwrites up to the
first two elements of parents->idx and these are initialized, and
because the sentinel is not needed in this case---mmu_page_clear_parents
exits anyway when it gets to the end of the array. However ubsan
complains, and everyone else should too.
This fix does three things. First it makes the mmu_page_path arrays
PT64_ROOT_LEVEL elements in size, so that we can write to them without
checking the level in advance. Second it disintegrates kvm_mmu_pages_init
between mmu_unsync_walk (to reset the struct kvm_mmu_pages) and
for_each_sp (to place the NULL sentinel at the end of the current path).
This is okay because the mmu_page_path is only used in
mmu_pages_clear_parents; mmu_pages_clear_parents itself is called within
a for_each_sp iterator, and hence always after a call to mmu_pages_next.
Third it changes mmu_pages_clear_parents to just use the sentinel to
stop iteration, without checking the bounds on level.
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Reported-by: Mike Krinkin <krinkin.m.u@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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The goto and temporary variable are unnecessary, just use return
statements.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Register the notifier to receive write track event so that we can update
our shadow page table
It makes kvm_mmu_pte_write() be the callback of the notifier, no function
is changed
Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Now, all non-leaf shadow page are page tracked, if gfn is not tracked
there is no non-leaf shadow page of gfn is existed, we can directly
make the shadow page of gfn to unsync
Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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non-leaf shadow pages are always write protected, it can be the user
of page track
Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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If the page fault is caused by write access on write tracked page, the
real shadow page walking is skipped, we lost the chance to clear write
flooding for the page structure current vcpu is using
Fix it by locklessly waking shadow page table to clear write flooding
on the shadow page structure out of mmu-lock. So that we change the
count to atomic_t
Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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The page fault caused by write access on the write tracked page can not
be fixed, it always need to be emulated. page_fault_handle_page_track()
is the fast path we introduce here to skip holding mmu-lock and shadow
page table walking
However, if the page table is not present, it is worth making the page
table entry present and readonly to make the read access happy
mmu_need_write_protect() need to be cooked to avoid page becoming writable
when making page table present or sync/prefetch shadow page table entries
Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Split rmap_write_protect() and introduce the function to abstract the write
protection based on the slot
This function will be used in the later patch
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Abstract the common operations from account_shadowed() and
unaccount_shadowed(), then introduce kvm_mmu_gfn_disallow_lpage()
and kvm_mmu_gfn_allow_lpage()
These two functions will be used by page tracking in the later patch
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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kvm_lpage_info->write_count is used to detect if the large page mapping
for the gfn on the specified level is allowed, rename it to disallow_lpage
to reflect its purpose, also we rename has_wrprotected_page() to
mmu_gfn_lpage_is_disallowed() to make the code more clearer
Later we will extend this mechanism for page tracking: if the gfn is
tracked then large mapping for that gfn on any level is not allowed.
The new name is more straightforward
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Signed-off-by: Adam Buchbinder <adam.buchbinder@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: trivial@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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To make the intention clearer, use list_last_entry instead of
list_entry.
Signed-off-by: Geliang Tang <geliangtang@163.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Rather than placing a handle_mmio_page_fault() call in each
vcpu->arch.mmu.page_fault() handler, moving it up to
kvm_mmu_page_fault() makes the code better:
- avoids code duplication
- for kvm_arch_async_page_ready(), which is the other caller of
vcpu->arch.mmu.page_fault(), removes an extra error_code check
- avoids returning both RET_MMIO_PF_* values and raw integer values
from vcpu->arch.mmu.page_fault()
Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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These two have only slight differences:
- whether 'addr' is of type u64 or of type gva_t
- whether they have 'direct' parameter or not
Concerning the former, quickly_check_mmio_pf()'s u64 is better because
'addr' needs to be able to have both a guest physical address and a
guest virtual address.
The latter is just a stylistic issue as we can always calculate the mode
from the 'vcpu' as is_mmio_page_fault() does. This patch keeps the
parameter to make the following patch cleaner.
In addition, the patch renames the function to mmio_info_in_cache() to
make it clear what it actually checks for.
Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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To date, we have implemented two I/O usage models for persistent memory,
PMEM (a persistent "ram disk") and DAX (mmap persistent memory into
userspace). This series adds a third, DAX-GUP, that allows DAX mappings
to be the target of direct-i/o. It allows userspace to coordinate
DMA/RDMA from/to persistent memory.
The implementation leverages the ZONE_DEVICE mm-zone that went into
4.3-rc1 (also discussed at kernel summit) to flag pages that are owned
and dynamically mapped by a device driver. The pmem driver, after
mapping a persistent memory range into the system memmap via
devm_memremap_pages(), arranges for DAX to distinguish pfn-only versus
page-backed pmem-pfns via flags in the new pfn_t type.
The DAX code, upon seeing a PFN_DEV+PFN_MAP flagged pfn, flags the
resulting pte(s) inserted into the process page tables with a new
_PAGE_DEVMAP flag. Later, when get_user_pages() is walking ptes it keys
off _PAGE_DEVMAP to pin the device hosting the page range active.
Finally, get_page() and put_page() are modified to take references
against the device driver established page mapping.
Finally, this need for "struct page" for persistent memory requires
memory capacity to store the memmap array. Given the memmap array for a
large pool of persistent may exhaust available DRAM introduce a
mechanism to allocate the memmap from persistent memory. The new
"struct vmem_altmap *" parameter to devm_memremap_pages() enables
arch_add_memory() to use reserved pmem capacity rather than the page
allocator.
This patch (of 18):
The core has developed a need for a "pfn_t" type [1]. Move the existing
pfn_t in KVM to kvm_pfn_t [2].
[1]: https://lists.01.org/pipermail/linux-nvdimm/2015-September/002199.html
[2]: https://lists.01.org/pipermail/linux-nvdimm/2015-September/002218.html
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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