If there are no assigned devices, the guest PAT are not providing
any useful information and can be overridden to writeback; VMX
always does this because it has the "IPAT" bit in its extended
page table entries, but SVM does not have anything similar.
Hook into VFIO and legacy device assignment so that they
provide this information to KVM.

Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Tested-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Commit 1cde2930 ("sched/preempt: Add static_key() to preempt_notifiers")
had two problems.  First, the preempt-notifier API needs to sleep with the
addition of the static_key, we do however need to hold off preemption
while modifying the preempt notifier list, otherwise a preemption could
observe an inconsistent list state.  KVM correctly registers and
unregisters preempt notifiers with preemption disabled, so the sleep
caused dmesg splats.

Second, KVM registers and unregisters preemption notifiers very often
(in vcpu_load/vcpu_put).  With a single uniprocessor guest the static key
would move between 0 and 1 continuously, hitting the slow path on every
userspace exit.

To fix this, wrap the static_key inc/dec in a new API, and call it from
KVM.

Fixes: 1cde2930 ("sched/preempt: Add static_key() to preempt_notifiers")
Reported-by: Pontus Fuchs <pontus.fuchs@gmail.com>
Reported-by: Takashi Iwai <tiwai@suse.de>
Tested-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Tabs rather than spaces

Signed-off-by: Kevin Mulvey <kmulvey@linux.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

fix brace spacing

Signed-off-by: Kevin Mulvey <kmulvey@linux.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

The allocation size of the kvm_irq_routing_table depends on
the number of irq routing entries because they are all
allocated with one kzalloc call.

When the irq routing table gets bigger this requires high
order allocations which fail from time to time:

	qemu-kvm: page allocation failure: order:4, mode:0xd0

This patch fixes this issue by breaking up the allocation of
the table and its entries into individual kzalloc calls.
These could all be satisfied with order-0 allocations, which
are less likely to fail.

The downside of this change is the lower performance, because
of more calls to kzalloc. But given how often kvm_set_irq_routing
is called in the lifetime of a guest, it doesn't really
matter much.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
[Avoid sparse warning through rcu_access_pointer. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Back in the days, vgic.c used to have an intimate knowledge of
the actual GICv2. These days, this has been abstracted away into
hardware-specific backends.

Remove the now useless arm-gic.h #include directive, making it
clear that GICv2 specific code doesn't belong here.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

Commit fd1d0ddf (KVM: arm/arm64: check IRQ number on userland
injection) rightly limited the range of interrupts userspace can
inject in a guest, but failed to consider the (unlikely) case where
a guest is configured with 1024 interrupts.

In this case, interrupts ranging from 1020 to 1023 are unuseable,
as they have a special meaning for the GIC CPU interface.

Make sure that these number cannot be used as an IRQ. Also delete
a redundant (and similarily buggy) check in kvm_set_irq.

Reported-by: Peter Maydell <peter.maydell@linaro.org>
Cc: Andre Przywara <andre.przywara@arm.com>
Cc: <stable@vger.kernel.org> # 4.1, 4.0, 3.19, 3.18
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

If a GICv3-enabled guest tries to configure Group0, we print a
warning on the console (because we don't support Group0 interrupts).

This is fairly pointless, and would allow a guest to spam the
console. Let's just drop the warning.

Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

So far, we configured the world-switch by having a small array
of pointers to the save and restore functions, depending on the
GIC used on the platform.

Loading these values each time is a bit silly (they never change),
and it makes sense to rely on the instruction patching instead.

This leads to a nice cleanup of the code.

Acked-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Commit 47a98b15 ("arm/arm64: KVM: support for un-queuing active
IRQs") introduced handling of the GICD_I[SC]ACTIVER registers,
but only for the GICv2 emulation. For the sake of completeness and
as this is a pre-requisite for save/restore of the GICv3 distributor
state, we should also emulate their handling in the distributor and
redistributor frames of an emulated GICv3.

Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

Only two ioctls have to be modified; the address space id is
placed in the higher 16 bits of their slot id argument.

As of this patch, no architecture defines more than one
address space; x86 will be the first.

Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

We need to hide SMRAM from guests not running in SMM.  Therefore, all
uses of kvm_read_guest* and kvm_write_guest* must be changed to use
different address spaces, depending on whether the VCPU is in system
management mode.  We need to introduce a new family of functions for
this purpose.

For now, the VCPU-based functions have the same behavior as the
existing per-VM ones, they just accept a different type for the
first argument.  Later however they will be changed to use one of many
"struct kvm_memslots" stored in struct kvm, through an architecture hook.
VM-based functions will unconditionally use the first memslots pointer.

Whenever possible, this patch introduces slot-based functions with an
__ prefix, with two wrappers for generic and vcpu-based actions.
The exceptions are kvm_read_guest and kvm_write_guest, which are copied
into the new functions kvm_vcpu_read_guest and kvm_vcpu_write_guest.

Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Most of the function that wrap it can be rewritten without it, except
for gfn_to_pfn_prot.  Just inline it into gfn_to_pfn_prot, and rewrite
the other function on top of gfn_to_pfn_memslot*.

Reviewed-by: Radim Krcmar <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

The memory slot is already available from gfn_to_memslot_dirty_bitmap.
Isn't it a shame to look it up again?  Plus, it makes gfn_to_page_many_atomic
agnostic of multiple VCPU address spaces.

Reviewed-by: Radim Krcmar <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

This lets the function access the new memory slot without going through
kvm_memslots and id_to_memslot.  It will simplify the code when more
than one address space will be supported.

Unfortunately, the "const"ness of the new argument must be casted
away in two places.  Fixing KVM to accept const struct kvm_memory_slot
pointers would require modifications in pretty much all architectures,
and is left for later.

Reviewed-by: Radim Krcmar <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Prepare for the case of multiple address spaces.

Reviewed-by: Radim Krcmar <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Architecture-specific helpers are not supposed to muck with
struct kvm_userspace_memory_region contents.  Add const to
enforce this.

In order to eliminate the only write in __kvm_set_memory_region,
the cleaning of deleted slots is pulled up from update_memslots
to __kvm_set_memory_region.

Reviewed-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Reviewed-by: Radim Krcmar <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

kvm_memslots provides lockdep checking.  Use it consistently instead of
explicit dereferencing of kvm->memslots.

Reviewed-by: Radim Krcmar <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

kvm_alloc_memslots is extracted out of previously scattered code
that was in kvm_init_memslots_id and kvm_create_vm.

kvm_free_memslot and kvm_free_memslots are new names of
kvm_free_physmem and kvm_free_physmem_slot, but they also take
an explicit pointer to struct kvm_memslots.

This will simplify the transition to multiple address spaces,
each represented by one pointer to struct kvm_memslots.

Reviewed-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Reviewed-by: Radim Krcmar <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

gfn_to_pfn_async is used in just one place, and because of x86-specific
treatment that place will need to look at the memory slot.  Hence inline
it into try_async_pf and export __gfn_to_pfn_memslot.

The patch also switches the subsequent call to gfn_to_pfn_prot to use
__gfn_to_pfn_memslot.  This is a small optimization.  Finally, remove
the now-unused async argument of __gfn_to_pfn.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

On cpu hotplug only KVM emits an unconditional message that its notifier
has been called. It certainly can be assumed that calling cpu hotplug
notifiers work, therefore there is no added value if KVM prints a message.

If an error happens on cpu online KVM will still emit a warning.

So let's remove this superfluous message.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Caching memslot value and using mark_page_dirty_in_slot() avoids another
O(log N) search when dirtying the page.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Message-Id: <1428695247-27603-1-git-send-email-rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

When userland injects a SPI via the KVM_IRQ_LINE ioctl we currently
only check it against a fixed limit, which historically is set
to 127. With the new dynamic IRQ allocation the effective limit may
actually be smaller (64).
So when now a malicious or buggy userland injects a SPI in that
range, we spill over on our VGIC bitmaps and bytemaps memory.
I could trigger a host kernel NULL pointer dereference with current
mainline by injecting some bogus IRQ number from a hacked kvmtool:
-----------------
....
DEBUG: kvm_vgic_inject_irq(kvm, cpu=0, irq=114, level=1)
DEBUG: vgic_update_irq_pending(kvm, cpu=0, irq=114, level=1)
DEBUG: IRQ #114 still in the game, writing to bytemap now...
Unable to handle kernel NULL pointer dereference at virtual address 00000000
pgd = ffffffc07652e000
[00000000] *pgd=00000000f658b003, *pud=00000000f658b003, *pmd=0000000000000000
Internal error: Oops: 96000006 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 1053 Comm: lkvm-msi-irqinj Not tainted 4.0.0-rc7+ #3027
Hardware name: FVP Base (DT)
task: ffffffc0774e9680 ti: ffffffc0765a8000 task.ti: ffffffc0765a8000
PC is at kvm_vgic_inject_irq+0x234/0x310
LR is at kvm_vgic_inject_irq+0x30c/0x310
pc : [<ffffffc0000ae0a8>] lr : [<ffffffc0000ae180>] pstate: 80000145
.....

So this patch fixes this by checking the SPI number against the
actual limit. Also we remove the former legacy hard limit of
127 in the ioctl code.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
CC: <stable@vger.kernel.org> # 4.0, 3.19, 3.18
[maz: wrap KVM_ARM_IRQ_GIC_MAX with #ifndef __KERNEL__,
as suggested by Christopher Covington]
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

irqfd/arm curently does not support routing. kvm_irq_map_gsi is
supposed to return all the routing entries associated with the
provided gsi and return the number of those entries. We should
return 0 at this point.

Signed-off-by: Eric Auger <eric.auger@linaro.org>
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

This creates a debugfs directory for each HV guest (assuming debugfs
is enabled in the kernel config), and within that directory, a file
by which the contents of the guest's HPT (hashed page table) can be
read.  The directory is named vmnnnn, where nnnn is the PID of the
process that created the guest.  The file is named "htab".  This is
intended to help in debugging problems in the host's management
of guest memory.

The contents of the file consist of a series of lines like this:

  3f48 4000d032bf003505 0000000bd7ff1196 00000003b5c71196

The first field is the index of the entry in the HPT, the second and
third are the HPT entry, so the third entry contains the real page
number that is mapped by the entry if the entry's valid bit is set.
The fourth field is the guest's view of the second doubleword of the
entry, so it contains the guest physical address.  (The format of the
second through fourth fields are described in the Power ISA and also
in arch/powerpc/include/asm/mmu-hash64.h.)

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>

kvm_write_guest_cached() does not mark all written pages as dirty and
code comments in kvm_gfn_to_hva_cache_init() talk about NULL memslot
with cross page accesses.  Fix all the easy way.

The check is '<= 1' to have the same result for 'len = 0' cache anywhere
in the page.  (nr_pages_needed is 0 on page boundary.)

Fixes: 8f964525 ("KVM: Allow cross page reads and writes from cached translations.")
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Message-Id: <20150408121648.GA3519@potion.brq.redhat.com>
Reviewed-by: Wanpeng Li <wanpeng.li@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

The corresponding write functions just use __copy_to_user.  Do the
same on the read side.

This reverts what's left of commit 86ab8cff (KVM: introduce
gfn_to_hva_read/kvm_read_hva/kvm_read_hva_atomic, 2012-08-21)

Cc: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <1427976500-28533-1-git-send-email-pbonzini@redhat.com>

We have introduced struct kvm_s390_irq a while ago which allows to
inject all kinds of interrupts as defined in the Principles of
Operation.
Add ioctl to inject interrupts with the extended struct kvm_s390_irq

Signed-off-by: Jens Freimann <jfrei@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>

Currently we have struct kvm_exit_mmio for encapsulating MMIO abort
data to be passed on from syndrome decoding all the way down to the
VGIC register handlers. Now as we switch the MMIO handling to be
routed through the KVM MMIO bus, it does not make sense anymore to
use that structure already from the beginning. So we keep the data in
local variables until we put them into the kvm_io_bus framework.
Then we fill kvm_exit_mmio in the VGIC only, making it a VGIC private
structure. On that way we replace the data buffer in that structure
with a pointer pointing to a single location in a local variable, so
we get rid of some copying on the way.
With all of the virtual GIC emulation code now being registered with
the kvm_io_bus, we can remove all of the old MMIO handling code and
its dispatching functionality.

I didn't bother to rename kvm_exit_mmio (to vgic_mmio or something),
because that touches a lot of code lines without any good reason.

This is based on an original patch by Nikolay.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Cc: Nikolay Nikolaev <n.nikolaev@virtualopensystems.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

Using the framework provided by the recent vgic.c changes, we
register a kvm_io_bus device on mapping the virtual GICv3 resources.
The distributor mapping is pretty straight forward, but the
redistributors need some more love, since they need to be tagged with
the respective redistributor (read: VCPU) they are connected with.
We use the kvm_io_bus framework to register one devices per VCPU.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

Currently we handle the redistributor registers in two separate MMIO
regions, one for the overall behaviour and SPIs and one for the
SGIs/PPIs. That latter forces the creation of _two_ KVM I/O bus
devices for each redistributor.
Since the spec mandates those two pages to be contigious, we could as
well merge them and save the churn with the second KVM I/O bus device.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

Using the framework provided by the recent vgic.c changes we register
a kvm_io_bus device when initializing the virtual GICv2.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

Currently we use a lot of VGIC specific code to do the MMIO
dispatching.
Use the previous reworks to add kvm_io_bus style MMIO handlers.

Those are not yet called by the MMIO abort handler, also the actual
VGIC emulator function do not make use of it yet, but will be enabled
with the following patches.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

The vgic_find_range() function in vgic.c takes a struct kvm_exit_mmio
argument, but actually only used the length field in there. Since we
need to get rid of that structure in that part of the code anyway,
let's rework the function (and it's callers) to pass the length
argument to the function directly.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

The name "kvm_mmio_range" is a bit bold, given that it only covers
the VGIC's MMIO ranges. To avoid confusion with kvm_io_range, rename
it to vgic_io_range.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

iodev.h contains definitions for the kvm_io_bus framework. This is
needed both by the generic KVM code in virt/kvm as well as by
architecture specific code under arch/. Putting the header file in
virt/kvm and using local includes in the architecture part seems at
least dodgy to me, so let's move the file into include/kvm, so that a
more natural "#include <kvm/iodev.h>" can be used by all of the code.
This also solves a problem later when using struct kvm_io_device
in arm_vgic.h.
Fixing up the FSF address in the GPL header and a wrong include path
on the way.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

This is needed in e.g. ARM vGIC emulation, where the MMIO handling
depends on the VCPU that does the access.

Signed-off-by: Nikolay Nikolaev <n.nikolaev@virtualopensystems.com>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

KVM guest can fail to startup with following trace on host:

qemu-system-x86: page allocation failure: order:4, mode:0x40d0
Call Trace:
  dump_stack+0x47/0x67
  warn_alloc_failed+0xee/0x150
  __alloc_pages_direct_compact+0x14a/0x150
  __alloc_pages_nodemask+0x776/0xb80
  alloc_kmem_pages+0x3a/0x110
  kmalloc_order+0x13/0x50
  kmemdup+0x1b/0x40
  __kvm_set_memory_region+0x24a/0x9f0 [kvm]
  kvm_set_ioapic+0x130/0x130 [kvm]
  kvm_set_memory_region+0x21/0x40 [kvm]
  kvm_vm_ioctl+0x43f/0x750 [kvm]

Failure happens when attempting to allocate pages for
'struct kvm_memslots', however it doesn't have to be
present in physically contiguous (kmalloc-ed) address
space, change allocation to kvm_kvzalloc() so that
it will be vmalloc-ed when its size is more then a page.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

When all bits in mask are not set,
kvm_arch_mmu_enable_log_dirty_pt_masked() has nothing to do.  But since
it needs to be called from the generic code, it cannot be inlined, and
a few function calls, two when PML is enabled, are wasted.

Since it is common to see many pages remain clean, e.g. framebuffers can
stay calm for a long time, it is worth eliminating this overhead.

Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>