Commit Graph

731 Commits

Author SHA1 Message Date
Linus Torvalds e4e65676f2 Fixes and features for 3.18.
Apart from the usual cleanups, here is the summary of new features:
 
 - s390 moves closer towards host large page support
 
 - PowerPC has improved support for debugging (both inside the guest and
   via gdbstub) and support for e6500 processors
 
 - ARM/ARM64 support read-only memory (which is necessary to put firmware
   in emulated NOR flash)
 
 - x86 has the usual emulator fixes and nested virtualization improvements
   (including improved Windows support on Intel and Jailhouse hypervisor
   support on AMD), adaptive PLE which helps overcommitting of huge guests.
   Also included are some patches that make KVM more friendly to memory
   hot-unplug, and fixes for rare caching bugs.
 
 Two patches have trivial mm/ parts that were acked by Rik and Andrew.
 
 Note: I will soon switch to a subkey for signing purposes.  To verify
 future signed pull requests from me, please update my key with
 "gpg --recv-keys 9B4D86F2".  You should see 3 new subkeys---the
 one for signing will be a 2048-bit RSA key, 4E6B09D7.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM updates from Paolo Bonzini:
 "Fixes and features for 3.18.

  Apart from the usual cleanups, here is the summary of new features:

   - s390 moves closer towards host large page support

   - PowerPC has improved support for debugging (both inside the guest
     and via gdbstub) and support for e6500 processors

   - ARM/ARM64 support read-only memory (which is necessary to put
     firmware in emulated NOR flash)

   - x86 has the usual emulator fixes and nested virtualization
     improvements (including improved Windows support on Intel and
     Jailhouse hypervisor support on AMD), adaptive PLE which helps
     overcommitting of huge guests.  Also included are some patches that
     make KVM more friendly to memory hot-unplug, and fixes for rare
     caching bugs.

  Two patches have trivial mm/ parts that were acked by Rik and Andrew.

  Note: I will soon switch to a subkey for signing purposes"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (157 commits)
  kvm: do not handle APIC access page if in-kernel irqchip is not in use
  KVM: s390: count vcpu wakeups in stat.halt_wakeup
  KVM: s390/facilities: allow TOD-CLOCK steering facility bit
  KVM: PPC: BOOK3S: HV: CMA: Reserve cma region only in hypervisor mode
  arm/arm64: KVM: Report correct FSC for unsupported fault types
  arm/arm64: KVM: Fix VTTBR_BADDR_MASK and pgd alloc
  kvm: Fix kvm_get_page_retry_io __gup retval check
  arm/arm64: KVM: Fix set_clear_sgi_pend_reg offset
  kvm: x86: Unpin and remove kvm_arch->apic_access_page
  kvm: vmx: Implement set_apic_access_page_addr
  kvm: x86: Add request bit to reload APIC access page address
  kvm: Add arch specific mmu notifier for page invalidation
  kvm: Rename make_all_cpus_request() to kvm_make_all_cpus_request() and make it non-static
  kvm: Fix page ageing bugs
  kvm/x86/mmu: Pass gfn and level to rmapp callback.
  x86: kvm: use alternatives for VMCALL vs. VMMCALL if kernel text is read-only
  kvm: x86: use macros to compute bank MSRs
  KVM: x86: Remove debug assertion of non-PAE reserved bits
  kvm: don't take vcpu mutex for obviously invalid vcpu ioctls
  kvm: Faults which trigger IO release the mmap_sem
  ...
2014-10-08 05:27:39 -04:00
Paolo Bonzini e77d99d4a4 Changes for KVM for arm/arm64 for 3.18
This includes a bunch of changes:
  - Support read-only memory slots on arm/arm64
  - Various changes to fix Sparse warnings
  - Correctly detect write vs. read Stage-2 faults
  - Various VGIC cleanups and fixes
  - Dynamic VGIC data strcuture sizing
  - Fix SGI set_clear_pend offset bug
  - Fix VTTBR_BADDR Mask
  - Correctly report the FSC on Stage-2 faults
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Merge tag 'kvm-arm-for-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into kvm-next

Changes for KVM for arm/arm64 for 3.18

This includes a bunch of changes:
 - Support read-only memory slots on arm/arm64
 - Various changes to fix Sparse warnings
 - Correctly detect write vs. read Stage-2 faults
 - Various VGIC cleanups and fixes
 - Dynamic VGIC data strcuture sizing
 - Fix SGI set_clear_pend offset bug
 - Fix VTTBR_BADDR Mask
 - Correctly report the FSC on Stage-2 faults

Conflicts:
	virt/kvm/eventfd.c
	[duplicate, different patch where the kvm-arm version broke x86.
	 The kvm tree instead has the right one]
2014-09-27 11:03:33 +02:00
Andres Lagar-Cavilla bb0ca6acd4 kvm: Fix kvm_get_page_retry_io __gup retval check
Confusion around -EBUSY and zero (inside a BUG_ON no less).

Reported-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andres Lagar-Cavilla <andreslc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-26 10:21:29 +02:00
Christoffer Dall 0fea6d7628 arm/arm64: KVM: Fix set_clear_sgi_pend_reg offset
The sgi values calculated in read_set_clear_sgi_pend_reg() and
write_set_clear_sgi_pend_reg() were horribly incorrectly multiplied by 4
with catastrophic results in that subfunctions ended up overwriting
memory not allocated for the expected purpose.

This showed up as bugs in kfree() and the kernel complaining a lot of
you turn on memory debugging.

This addresses: http://marc.info/?l=kvm&m=141164910007868&w=2

Reported-by: Shannon Zhao <zhaoshenglong@huawei.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2014-09-25 19:38:25 +02:00
Tang Chen fe71557afb kvm: Add arch specific mmu notifier for page invalidation
This will be used to let the guest run while the APIC access page is
not pinned.  Because subsequent patches will fill in the function
for x86, place the (still empty) x86 implementation in the x86.c file
instead of adding an inline function in kvm_host.h.

Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-24 14:07:59 +02:00
Tang Chen 445b823695 kvm: Rename make_all_cpus_request() to kvm_make_all_cpus_request() and make it non-static
Different architectures need different requests, and in fact we
will use this function in architecture-specific code later. This
will be outside kvm_main.c, so make it non-static and rename it to
kvm_make_all_cpus_request().

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-24 14:07:59 +02:00
Andres Lagar-Cavilla 5712846808 kvm: Fix page ageing bugs
1. We were calling clear_flush_young_notify in unmap_one, but we are
within an mmu notifier invalidate range scope. The spte exists no more
(due to range_start) and the accessed bit info has already been
propagated (due to kvm_pfn_set_accessed). Simply call
clear_flush_young.

2. We clear_flush_young on a primary MMU PMD, but this may be mapped
as a collection of PTEs by the secondary MMU (e.g. during log-dirty).
This required expanding the interface of the clear_flush_young mmu
notifier, so a lot of code has been trivially touched.

3. In the absence of shadow_accessed_mask (e.g. EPT A bit), we emulate
the access bit by blowing the spte. This requires proper synchronizing
with MMU notifier consumers, like every other removal of spte's does.

Signed-off-by: Andres Lagar-Cavilla <andreslc@google.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-24 14:07:58 +02:00
David Matlack 2ea75be321 kvm: don't take vcpu mutex for obviously invalid vcpu ioctls
vcpu ioctls can hang the calling thread if issued while a vcpu is running.
However, invalid ioctls can happen when userspace tries to probe the kind
of file descriptors (e.g. isatty() calls ioctl(TCGETS)); in that case,
we know the ioctl is going to be rejected as invalid anyway and we can
fail before trying to take the vcpu mutex.

This patch does not change functionality, it just makes invalid ioctls
fail faster.

Cc: stable@vger.kernel.org
Signed-off-by: David Matlack <dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-24 14:07:55 +02:00
Andres Lagar-Cavilla 234b239bea kvm: Faults which trigger IO release the mmap_sem
When KVM handles a tdp fault it uses FOLL_NOWAIT. If the guest memory
has been swapped out or is behind a filemap, this will trigger async
readahead and return immediately. The rationale is that KVM will kick
back the guest with an "async page fault" and allow for some other
guest process to take over.

If async PFs are enabled the fault is retried asap from an async
workqueue. If not, it's retried immediately in the same code path. In
either case the retry will not relinquish the mmap semaphore and will
block on the IO. This is a bad thing, as other mmap semaphore users
now stall as a function of swap or filemap latency.

This patch ensures both the regular and async PF path re-enter the
fault allowing for the mmap semaphore to be relinquished in the case
of IO wait.

Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Andres Lagar-Cavilla <andreslc@google.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-24 14:07:54 +02:00
Paolo Bonzini 3c3c29fd0d kvm-vfio: do not use module_init
/me got confused between the kernel and QEMU.  In the kernel, you can
only have one module_init function, and it will prevent unloading the
module unless you also have the corresponding module_exit function.

So, commit 80ce163972 (KVM: VFIO: register kvm_device_ops dynamically,
2014-09-02) broke unloading of the kvm module, by adding a module_init
function and no module_exit.

Repair it by making kvm_vfio_ops_init weak, and checking it in
kvm_init.

Cc: Will Deacon <will.deacon@arm.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Alex Williamson <Alex.Williamson@redhat.com>
Fixes: 80ce163972
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-24 14:06:36 +02:00
Christoffer Dall 29f1b65b59 KVM: EVENTFD: Remove inclusion of irq.h
Commit c77dcac (KVM: Move more code under CONFIG_HAVE_KVM_IRQFD) added
functionality that depends on definitions in ioapic.h when
__KVM_HAVE_IOAPIC is defined.

At the same time, kvm-arm commit 0ba0951 (KVM: EVENTFD: remove inclusion
of irq.h) removed the inclusion of irq.h, an architecture-specific header
that is not present on ARM but which happened to include ioapic.h on x86.

Include ioapic.h directly in eventfd.c if __KVM_HAVE_IOAPIC is defined.
This fixes x86 and lets ARM use eventfd.c.

Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-24 12:06:25 +02:00
Paolo Bonzini 9542639387 Fixes unaligned access to the gicv2 virtual cpu status.
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Merge tag 'kvm-arm-for-v3.17-rc7-or-final' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into kvm-master

Fixes unaligned access to the gicv2 virtual cpu status.
2014-09-23 15:18:02 +02:00
Christoffer Dall 1f2bb4acc1 arm/arm64: KVM: Fix unaligned access bug on gicv2 access
We were using an atomic bitop on the vgic_v2.vgic_elrsr field which was
not aligned to the natural size on 64-bit platforms.  This bug showed up
after QEMU correctly identifies the pl011 line as being level-triggered,
and not edge-triggered.

These data structures are protected by a spinlock so simply use a
non-atomic version of the accessor instead.

Tested-by: Joel Schopp <joel.schopp@amd.com>
Reported-by: Riku Voipio <riku.voipio@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2014-09-22 23:05:56 +02:00
Sam Bobroff 27fbe64bfa KVM: correct null pid check in kvm_vcpu_yield_to()
Correct a simple mistake of checking the wrong variable
before a dereference, resulting in the dereference not being
properly protected by rcu_dereference().

Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-22 13:21:29 +02:00
Marc Zyngier a98f26f183 arm/arm64: KVM: vgic: make number of irqs a configurable attribute
In order to make the number of interrupts configurable, use the new
fancy device management API to add KVM_DEV_ARM_VGIC_GRP_NR_IRQS as
a VGIC configurable attribute.

Userspace can now specify the exact size of the GIC (by increments
of 32 interrupts).

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2014-09-18 18:48:58 -07:00
Marc Zyngier 4956f2bc1f arm/arm64: KVM: vgic: delay vgic allocation until init time
It is now quite easy to delay the allocation of the vgic tables
until we actually require it to be up and running (when the first
vcpu is kicking around, or someones tries to access the GIC registers).

This allow us to allocate memory for the exact number of CPUs we
have. As nobody configures the number of interrupts just yet,
use a fallback to VGIC_NR_IRQS_LEGACY.

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2014-09-18 18:48:58 -07:00
Marc Zyngier 5fb66da640 arm/arm64: KVM: vgic: kill VGIC_NR_IRQS
Nuke VGIC_NR_IRQS entierly, now that the distributor instance
contains the number of IRQ allocated to this GIC.

Also add VGIC_NR_IRQS_LEGACY to preserve the current API.

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2014-09-18 18:48:57 -07:00
Marc Zyngier c3c918361a arm/arm64: KVM: vgic: handle out-of-range MMIO accesses
Now that we can (almost) dynamically size the number of interrupts,
we're facing an interesting issue:

We have to evaluate at runtime whether or not an access hits a valid
register, based on the sizing of this particular instance of the
distributor. Furthermore, the GIC spec says that accessing a reserved
register is RAZ/WI.

For this, add a new field to our range structure, indicating the number
of bits a single interrupts uses. That allows us to find out whether or
not the access is in range.

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2014-09-18 18:48:57 -07:00
Marc Zyngier fc675e355e arm/arm64: KVM: vgic: kill VGIC_MAX_CPUS
We now have the information about the number of CPU interfaces in
the distributor itself. Let's get rid of VGIC_MAX_CPUS, and just
rely on KVM_MAX_VCPUS where we don't have the choice. Yet.

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2014-09-18 18:48:57 -07:00
Marc Zyngier fb65ab63b8 arm/arm64: KVM: vgic: Parametrize VGIC_NR_SHARED_IRQS
Having a dynamic number of supported interrupts means that we
cannot relly on VGIC_NR_SHARED_IRQS being fixed anymore.

Instead, make it take the distributor structure as a parameter,
so it can return the right value.

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2014-09-18 18:48:56 -07:00
Marc Zyngier c1bfb577ad arm/arm64: KVM: vgic: switch to dynamic allocation
So far, all the VGIC data structures are statically defined by the
*maximum* number of vcpus and interrupts it supports. It means that
we always have to oversize it to cater for the worse case.

Start by changing the data structures to be dynamically sizeable,
and allocate them at runtime.

The sizes are still very static though.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2014-09-18 18:48:52 -07:00
Marc Zyngier 71afaba4a2 KVM: ARM: vgic: plug irq injection race
As it stands, nothing prevents userspace from injecting an interrupt
before the guest's GIC is actually initialized.

This goes unnoticed so far (as everything is pretty much statically
allocated), but ends up exploding in a spectacular way once we switch
to a more dynamic allocation (the GIC data structure isn't there yet).

The fix is to test for the "ready" flag in the VGIC distributor before
trying to inject the interrupt. Note that in order to avoid breaking
userspace, we have to ignore what is essentially an error.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
2014-09-18 18:45:06 -07:00
Christoffer Dall 7e362919a5 arm/arm64: KVM: vgic: Clarify and correct vgic documentation
The VGIC virtual distributor implementation documentation was written a
very long time ago, before the true nature of the beast had been
partially absorbed into my bloodstream.  Clarify the docs.

Plus, it fixes an actual bug.  ICFRn, pfff.

Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2014-09-18 18:44:32 -07:00
Christoffer Dall 9da48b5502 arm/arm64: KVM: vgic: Fix SGI writes to GICD_I{CS}PENDR0
Writes to GICD_ISPENDR0 and GICD_ICPENDR0 ignore all settings of the
pending state for SGIs.  Make sure the implementation handles this
correctly.

Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2014-09-18 18:44:32 -07:00
Christoffer Dall faa1b46c3e arm/arm64: KVM: vgic: Improve handling of GICD_I{CS}PENDRn
Writes to GICD_ISPENDRn and GICD_ICPENDRn are currently not handled
correctly for level-triggered interrupts.  The spec states that for
level-triggered interrupts, writes to the GICD_ISPENDRn activate the
output of a flip-flop which is in turn or'ed with the actual input
interrupt signal.  Correspondingly, writes to GICD_ICPENDRn simply
deactivates the output of that flip-flop, but does not (of course) affect
the external input signal.  Reads from GICC_IAR will also deactivate the
flip-flop output.

This requires us to track the state of the level-input separately from
the state in the flip-flop.  We therefore introduce two new variables on
the distributor struct to track these two states.  Astute readers may
notice that this is introducing more state than required (because an OR
of the two states gives you the pending state), but the remaining vgic
code uses the pending bitmap for optimized operations to figure out, at
the end of the day, if an interrupt is pending or not on the distributor
side.  Refactoring the code to consider the two state variables all the
places where we currently access the precomputed pending value, did not
look pretty.

Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2014-09-18 18:44:31 -07:00
Christoffer Dall cced50c928 arm/arm64: KVM: vgic: Clear queued flags on unqueue
If we unqueue a level-triggered interrupt completely, and the LR does
not stick around in the active state (and will therefore no longer
generate a maintenance interrupt), then we should clear the queued flag
so that the vgic can actually queue this level-triggered interrupt at a
later time and deal with its pending state then.

Note: This should actually be properly fixed to handle the active state
on the distributor.

Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2014-09-18 18:44:31 -07:00
Christoffer Dall dbf20f9d81 arm/arm64: KVM: Rename irq_active to irq_queued
We have a special bitmap on the distributor struct to keep track of when
level-triggered interrupts are queued on the list registers.  This was
named irq_active, which is confusing, because the active state of an
interrupt as per the GIC spec is a different thing, not specifically
related to edge-triggered/level-triggered configurations but rather
indicates an interrupt which has been ack'ed but not yet eoi'ed.

Rename the bitmap and the corresponding accessor functions to irq_queued
to clarify what this is actually used for.

Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2014-09-18 18:44:30 -07:00
Christoffer Dall 227844f538 arm/arm64: KVM: Rename irq_state to irq_pending
The irq_state field on the distributor struct is ambiguous in its
meaning; the comment says it's the level of the input put, but that
doesn't make much sense for edge-triggered interrupts.  The code
actually uses this state variable to check if the interrupt is in the
pending state on the distributor so clarify the comment and rename the
actual variable and accessor methods.

Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2014-09-18 18:44:30 -07:00
Christoffer Dall a875dafcf9 Merge remote-tracking branch 'kvm/next' into queue
Conflicts:
	arch/arm64/include/asm/kvm_host.h
	virt/kvm/arm/vgic.c
2014-09-18 18:15:32 -07:00
Will Deacon 80ce163972 KVM: VFIO: register kvm_device_ops dynamically
Now that we have a dynamic means to register kvm_device_ops, use that
for the VFIO kvm device, instead of relying on the static table.

This is achieved by a module_init call to register the ops with KVM.

Cc: Gleb Natapov <gleb@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Alex Williamson <Alex.Williamson@redhat.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-17 13:10:10 +02:00
Cornelia Huck 84877d9333 KVM: s390: register flic ops dynamically
Using the new kvm_register_device_ops() interface makes us get rid of
an #ifdef in common code.

Cc: Gleb Natapov <gleb@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-17 13:10:09 +02:00
Will Deacon c06a841bf3 KVM: ARM: vgic: register kvm_device_ops dynamically
Now that we have a dynamic means to register kvm_device_ops, use that
for the ARM VGIC, instead of relying on the static table.

Cc: Gleb Natapov <gleb@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-17 13:10:09 +02:00
Will Deacon d60eacb070 KVM: device: add simple registration mechanism for kvm_device_ops
kvm_ioctl_create_device currently has knowledge of all the device types
and their associated ops. This is fairly inflexible when adding support
for new in-kernel device emulations, so move what we currently have out
into a table, which can support dynamic registration of ops by new
drivers for virtual hardware.

Cc: Alex Williamson <Alex.Williamson@redhat.com>
Cc: Alex Graf <agraf@suse.de>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-17 13:10:08 +02:00
Zhang Haoyu 184564efae kvm: ioapic: conditionally delay irq delivery duringeoi broadcast
Currently, we call ioapic_service() immediately when we find the irq is still
active during eoi broadcast. But for real hardware, there's some delay between
the EOI writing and irq delivery.  If we do not emulate this behavior, and
re-inject the interrupt immediately after the guest sends an EOI and re-enables
interrupts, a guest might spend all its time in the ISR if it has a broken
handler for a level-triggered interrupt.

Such livelock actually happens with Windows guests when resuming from
hibernation.

As there's no way to recognize the broken handle from new raised ones, this patch
delays an interrupt if 10.000 consecutive EOIs found that the interrupt was
still high.  The guest can then make a little forward progress, until a proper
IRQ handler is set or until some detection routine in the guest (such as
Linux's note_interrupt()) recognizes the situation.

Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Zhang Haoyu <zhanghy@sangfor.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-16 14:44:48 +02:00
Ard Biesheuvel 85c8555ff0 KVM: check for !is_zero_pfn() in kvm_is_mmio_pfn()
Read-only memory ranges may be backed by the zero page, so avoid
misidentifying it a a MMIO pfn.

This fixes another issue I identified when testing QEMU+KVM_UEFI, where
a read to an uninitialized emulated NOR flash brought in the zero page,
but mapped as a read-write device region, because kvm_is_mmio_pfn()
misidentifies it as a MMIO pfn due to its PG_reserved bit being set.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Fixes: b88657674d ("ARM: KVM: user_mem_abort: support stage 2 MMIO page mapping")
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-14 16:26:05 +02:00
Eric Auger 0ba09511dd KVM: EVENTFD: remove inclusion of irq.h
No more needed. irq.h would be void on ARM.

Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Eric Auger <eric.auger@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2014-09-11 11:31:19 +01:00
Christian Borntraeger f2a2516088 KVM: remove redundant assignments in __kvm_set_memory_region
__kvm_set_memory_region sets r to EINVAL very early.
Doing it again is not necessary. The same is true later on, where
r is assigned -ENOMEM twice.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-05 12:01:15 +02:00
Christian Borntraeger a13f533b2f KVM: remove redundant assigment of return value in kvm_dev_ioctl
The first statement of kvm_dev_ioctl is
        long r = -EINVAL;

No need to reassign the same value.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-05 12:01:15 +02:00
Christian Borntraeger 3465611318 KVM: remove redundant check of in_spin_loop
The expression `vcpu->spin_loop.in_spin_loop' is always true,
because it is evaluated only when the condition
`!vcpu->spin_loop.in_spin_loop' is false.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-05 12:01:14 +02:00
David Matlack ee3d1570b5 kvm: fix potentially corrupt mmio cache
vcpu exits and memslot mutations can run concurrently as long as the
vcpu does not aquire the slots mutex. Thus it is theoretically possible
for memslots to change underneath a vcpu that is handling an exit.

If we increment the memslot generation number again after
synchronize_srcu_expedited(), vcpus can safely cache memslot generation
without maintaining a single rcu_dereference through an entire vm exit.
And much of the x86/kvm code does not maintain a single rcu_dereference
of the current memslots during each exit.

We can prevent the following case:

   vcpu (CPU 0)                             | thread (CPU 1)
--------------------------------------------+--------------------------
1  vm exit                                  |
2  srcu_read_unlock(&kvm->srcu)             |
3  decide to cache something based on       |
     old memslots                           |
4                                           | change memslots
                                            | (increments generation)
5                                           | synchronize_srcu(&kvm->srcu);
6  retrieve generation # from new memslots  |
7  tag cache with new memslot generation    |
8  srcu_read_unlock(&kvm->srcu)             |
...                                         |
   <action based on cache occurs even       |
    though the caching decision was based   |
    on the old memslots>                    |
...                                         |
   <action *continues* to occur until next  |
    memslot generation change, which may    |
    be never>                               |
                                            |

By incrementing the generation after synchronizing with kvm->srcu readers,
we ensure that the generation retrieved in (6) will become invalid soon
after (8).

Keeping the existing increment is not strictly necessary, but we
do keep it and just move it for consistency from update_memslots to
install_new_memslots.  It invalidates old cached MMIOs immediately,
instead of having to wait for the end of synchronize_srcu_expedited,
which makes the code more clearly correct in case CPU 1 is preempted
right after synchronize_srcu() returns.

To avoid halving the generation space in SPTEs, always presume that the
low bit of the generation is zero when reconstructing a generation number
out of an SPTE.  This effectively disables MMIO caching in SPTEs during
the call to synchronize_srcu_expedited.  Using the low bit this way is
somewhat like a seqcount---where the protected thing is a cache, and
instead of retrying we can simply punt if we observe the low bit to be 1.

Cc: stable@vger.kernel.org
Signed-off-by: David Matlack <dmatlack@google.com>
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Reviewed-by: David Matlack <dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-03 10:03:41 +02:00
Paolo Bonzini 00f034a12f KVM: do not bias the generation number in kvm_current_mmio_generation
The next patch will give a meaning (a la seqcount) to the low bit of the
generation number.  Ensure that it matches between kvm->memslots->generation
and kvm_current_mmio_generation().

Cc: stable@vger.kernel.org
Reviewed-by: David Matlack <dmatlack@google.com>
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-03 10:03:35 +02:00
Radim Krčmář 13a34e067e KVM: remove garbage arg to *hardware_{en,dis}able
In the beggining was on_each_cpu(), which required an unused argument to
kvm_arch_ops.hardware_{en,dis}able, but this was soon forgotten.

Remove unnecessary arguments that stem from this.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-08-29 16:35:55 +02:00
Christoffer Dall 0f8a4de3e0 KVM: Unconditionally export KVM_CAP_READONLY_MEM
The idea between capabilities and the KVM_CHECK_EXTENSION ioctl is that
userspace can, at run-time, determine if a feature is supported or not.
This allows KVM to being supporting a new feature with a new kernel
version without any need to update user space.  Unfortunately, since the
definition of KVM_CAP_READONLY_MEM was guarded by #ifdef
__KVM_HAVE_READONLY_MEM, such discovery still required a user space
update.

Therefore, unconditionally export KVM_CAP_READONLY_MEM and change the
in-kernel conditional to rely on __KVM_HAVE_READONLY_MEM.

Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-08-29 13:47:04 +02:00
Will Deacon de56fb1923 KVM: vgic: declare probe function pointer as const
We extract the vgic probe function from the of_device_id data pointer,
which is const. Kill the sparse warning by ensuring that the local
function pointer is also marked as const.

Cc: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2014-08-27 22:49:45 +02:00
Will Deacon 1fa451bcc6 KVM: vgic: return int instead of bool when checking I/O ranges
vgic_ioaddr_overlap claims to return a bool, but in reality it returns
an int. Shut sparse up by fixing the type signature.

Cc: Christoffer Dall <christoffer.dall@linaro.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2014-08-27 22:49:45 +02:00
Christoffer Dall 64d831269c KVM: Introduce gfn_to_hva_memslot_prot
To support read-only memory regions on arm and arm64, we have a need to
resolve a gfn to an hva given a pointer to a memslot to avoid looping
through the memslots twice and to reuse the hva error checking of
gfn_to_hva_prot(), add a new gfn_to_hva_memslot_prot() function and
refactor gfn_to_hva_prot() to use this function.

Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2014-08-27 22:46:08 +02:00
Radim Krčmář e790d9ef64 KVM: add kvm_arch_sched_in
Introduce preempt notifiers for architecture specific code.
Advantage over creating a new notifier in every arch is slightly simpler
code and guaranteed call order with respect to kvm_sched_in.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-08-21 18:45:21 +02:00
Christian Borntraeger 7103f60de8 KVM: avoid unnecessary synchronize_rcu
We dont have to wait for a grace period if there is no oldpid that
we are going to free. putpid also checks for NULL, so this patch
only fences synchronize_rcu.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-08-21 13:50:22 +02:00
Chen Gang 30d1e0e806 virt/kvm/assigned-dev.c: Set 'dev->irq_source_id' to '-1' after free it
As a generic function, deassign_guest_irq() assumes it can be called
even if assign_guest_irq() is not be called successfully (which can be
triggered by ioctl from user mode, indirectly).

So for assign_guest_irq() failure process, need set 'dev->irq_source_id'
to -1 after free 'dev->irq_source_id', or deassign_guest_irq() may free
it again.

Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-08-19 15:12:28 +02:00
Michael S. Tsirkin 350b8bdd68 kvm: iommu: fix the third parameter of kvm_iommu_put_pages (CVE-2014-3601)
The third parameter of kvm_iommu_put_pages is wrong,
It should be 'gfn - slot->base_gfn'.

By making gfn very large, malicious guest or userspace can cause kvm to
go to this error path, and subsequently to pass a huge value as size.
Alternatively if gfn is small, then pages would be pinned but never
unpinned, causing host memory leak and local DOS.

Passing a reasonable but large value could be the most dangerous case,
because it would unpin a page that should have stayed pinned, and thus
allow the device to DMA into arbitrary memory.  However, this cannot
happen because of the condition that can trigger the error:

- out of memory (where you can't allocate even a single page)
  should not be possible for the attacker to trigger

- when exceeding the iommu's address space, guest pages after gfn
  will also exceed the iommu's address space, and inside
  kvm_iommu_put_pages() the iommu_iova_to_phys() will fail.  The
  page thus would not be unpinned at all.

Reported-by: Jack Morgenstein <jackm@mellanox.com>
Cc: stable@vger.kernel.org
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-08-19 15:04:45 +02:00