This API shouldn't have 32/64-bit issues, but VFS assumes it does
unless told otherwise.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
This adds the API for userspace to instantiate an XICS device in a VM
and connect VCPUs to it. The API consists of a new device type for
the KVM_CREATE_DEVICE ioctl, a new capability KVM_CAP_IRQ_XICS, which
functions similarly to KVM_CAP_IRQ_MPIC, and the KVM_IRQ_LINE ioctl,
which is used to assert and deassert interrupt inputs of the XICS.
The XICS device has one attribute group, KVM_DEV_XICS_GRP_SOURCES.
Each attribute within this group corresponds to the state of one
interrupt source. The attribute number is the same as the interrupt
source number.
This does not support irq routing or irqfd yet.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>
The hassle of getting refcounting right was greater than the hassle
of keeping a list of devices to destroy on VM exit.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Hook the MPIC code up to the KVM interfaces, add locking, etc.
Signed-off-by: Scott Wood <scottwood@freescale.com>
[agraf: add stub function for kvmppc_mpic_set_epr, non-booke, 64bit]
Signed-off-by: Alexander Graf <agraf@suse.de>
Currently, devices that are emulated inside KVM are configured in a
hardcoded manner based on an assumption that any given architecture
only has one way to do it. If there's any need to access device state,
it is done through inflexible one-purpose-only IOCTLs (e.g.
KVM_GET/SET_LAPIC). Defining new IOCTLs for every little thing is
cumbersome and depletes a limited numberspace.
This API provides a mechanism to instantiate a device of a certain
type, returning an ID that can be used to set/get attributes of the
device. Attributes may include configuration parameters (e.g.
register base address), device state, operational commands, etc. It
is similar to the ONE_REG API, except that it acts on devices rather
than vcpus.
Both device types and individual attributes can be tested without having
to create the device or get/set the attribute, without the need for
separately managing enumerated capabilities.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Now that we have most irqfd code completely platform agnostic, let's move
irqfd's resample capability return to generic code as well.
Signed-off-by: Alexander Graf <agraf@suse.de>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Setting up IRQ routes is nothing IOAPIC specific. Extract everything
that really is generic code into irqchip.c and only leave the ioapic
specific bits to irq_comm.c.
Signed-off-by: Alexander Graf <agraf@suse.de>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
The current irq_comm.c file contains pieces of code that are generic
across different irqchip implementations, as well as code that is
fully IOAPIC specific.
Split the generic bits out into irqchip.c.
Signed-off-by: Alexander Graf <agraf@suse.de>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
The IRQ routing set ioctl lives in the hacky device assignment code inside
of KVM today. This is definitely the wrong place for it. Move it to the much
more natural kvm_main.c.
Signed-off-by: Alexander Graf <agraf@suse.de>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Quite a bit of code in KVM has been conditionalized on availability of
IOAPIC emulation. However, most of it is generically applicable to
platforms that don't have an IOPIC, but a different type of irq chip.
Make code that only relies on IRQ routing, not an APIC itself, on
CONFIG_HAVE_KVM_IRQ_ROUTING, so that we can reuse it later.
Signed-off-by: Alexander Graf <agraf@suse.de>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
The concept of routing interrupt lines to an irqchip is nothing
that is IOAPIC specific. Every irqchip has a maximum number of pins
that can be linked to irq lines.
So let's add a new define that allows us to reuse generic code for
non-IOAPIC platforms.
Signed-off-by: Alexander Graf <agraf@suse.de>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Only deliver the posted interrupt when target vcpu is running
and there is no previous interrupt pending in pir.
Signed-off-by: Yang Zhang <yang.z.zhang@Intel.com>
Reviewed-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
We already know the trigger mode of a given interrupt when programming
the ioapice entry. So it's not necessary to set it in each interrupt
delivery.
Signed-off-by: Yang Zhang <yang.z.zhang@Intel.com>
Reviewed-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Both TMR and EOI exit bitmap need to be updated when ioapic changed
or vcpu's id/ldr/dfr changed. So use common function instead eoi exit
bitmap specific function.
Signed-off-by: Yang Zhang <yang.z.zhang@Intel.com>
Reviewed-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Current interrupt coalescing logci which only used by RTC has conflict
with Posted Interrupt.
This patch introduces a new mechinism to use eoi to track interrupt:
When delivering an interrupt to vcpu, the pending_eoi set to number of
vcpu that received the interrupt. And decrease it when each vcpu writing
eoi. No subsequent RTC interrupt can deliver to vcpu until all vcpus
write eoi.
Signed-off-by: Yang Zhang <yang.z.zhang@Intel.com>
Reviewed-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Userspace may deliver RTC interrupt without query the status. So we
want to track RTC EOI for this case.
Signed-off-by: Yang Zhang <yang.z.zhang@Intel.com>
Reviewed-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Need the EOI to track interrupt deliver status, so force vmexit
on EOI for rtc interrupt when enabling virtual interrupt delivery.
Signed-off-by: Yang Zhang <yang.z.zhang@Intel.com>
Reviewed-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Add a new parameter to know vcpus who received the interrupt.
Signed-off-by: Yang Zhang <yang.z.zhang@Intel.com>
Reviewed-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
rtc_status is used to track RTC interrupt delivery status. The pending_eoi
will be increased by vcpu who received RTC interrupt and will be decreased
when EOI to this interrupt.
Also, we use dest_map to record the destination vcpu to avoid the case that
vcpu who didn't get the RTC interupt, but issued EOI with same vector of RTC
and descreased pending_eoi by mistake.
Signed-off-by: Yang Zhang <yang.z.zhang@Intel.com>
Reviewed-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Add vcpu info to ioapic_update_eoi, so we can know which vcpu
issued this EOI.
Signed-off-by: Yang Zhang <yang.z.zhang@Intel.com>
Reviewed-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
The routine kvm_spurious_fault() is an x86 specific routine, so
move it from virt/kvm/kvm_main.c to arch/x86/kvm/x86.c.
Fixes this sparse warning when building on arm64:
virt/kvm/kvm_main.c⚠️ symbol 'kvm_spurious_fault' was not declared. Should it be static?
Signed-off-by: Geoff Levand <geoff@infradead.org>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
The routines get_user_page_nowait(), kvm_io_bus_sort_cmp(), kvm_io_bus_insert_dev()
and kvm_io_bus_get_first_dev() are only referenced within kvm_main.c, so give them
static linkage.
Fixes sparse warnings like these:
virt/kvm/kvm_main.c: warning: symbol 'get_user_page_nowait' was not declared. Should it be static?
Signed-off-by: Geoff Levand <geoff@infradead.org>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
PIO and MMIO are separate address spaces, but
ioeventfd registration code mistakenly detected
two eventfds as duplicate if they use the same address,
even if one is PIO and another one MMIO.
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
For a given vcpu, kvm_apic_match_dest() will tell you whether
the vcpu in the destination list quickly. Drop kvm_calculate_eoi_exitmap()
and use kvm_apic_match_dest() instead.
Signed-off-by: Yang Zhang <yang.z.zhang@Intel.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
This patch adds support for kvm_gfn_to_hva_cache_init functions for
reads and writes that will cross a page. If the range falls within
the same memslot, then this will be a fast operation. If the range
is split between two memslots, then the slower kvm_read_guest and
kvm_write_guest are used.
Tested: Test against kvm_clock unit tests.
Signed-off-by: Andrew Honig <ahonig@google.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
If the guest specifies a IOAPIC_REG_SELECT with an invalid value and follows
that with a read of the IOAPIC_REG_WINDOW KVM does not properly validate
that request. ioapic_read_indirect contains an
ASSERT(redir_index < IOAPIC_NUM_PINS), but the ASSERT has no effect in
non-debug builds. In recent kernels this allows a guest to cause a kernel
oops by reading invalid memory. In older kernels (pre-3.3) this allows a
guest to read from large ranges of host memory.
Tested: tested against apic unit tests.
Signed-off-by: Andrew Honig <ahonig@google.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
This helps in filtering out the eligible candidates further and
thus potentially helps in quickly allowing preempted lockholders to run.
Note that if a vcpu was spinning during preemption we filter them
by checking whether they are preempted due to pause loop exit.
Reviewed-by: Chegu Vinod <chegu_vinod@hp.com>
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Note that we mark as preempted only when vcpu's task state was
Running during preemption.
Thanks Jiannan, Avi for preemption notifier ideas. Thanks Gleb, PeterZ
for their precious suggestions. Thanks Srikar for an idea on avoiding
rcu lock while checking task state that improved overcommit numbers.
Reviewed-by: Chegu Vinod <chegu_vinod@hp.com>
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Enhance KVM_IOEVENTFD with a new flag that allows to attach to virtio-ccw
devices on s390 via the KVM_VIRTIO_CCW_NOTIFY_BUS.
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Currently, eventfd introduces module_init/module_exit functions
to initialize/cleanup the irqfd workqueue. This only works, however,
if no other module_init/module_exit functions are built into the
same module.
Let's just move the initialization and cleanup to kvm_init and kvm_exit.
This way, it is also clearer where kvm startup may fail.
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
This patch makes the parameter old a const pointer to the old memory
slot and adds a new parameter named change to know the change being
requested: the former is for removing extra copying and the latter is
for cleaning up the code.
Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
This patch drops the parameter old, a copy of the old memory slot, and
adds a new parameter named change to know the change being requested.
This not only cleans up the code but also removes extra copying of the
memory slot structure.
Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
This will be used for cleaning up prepare/commit_memory_region() later.
Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Except ia64's stale code, KVM_SET_MEMORY_REGION support, this is only
used for sanity checks in __kvm_set_memory_region() which can easily
be changed to use slot id instead.
Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
X86 does not use this any more. The remaining user, s390's !user_alloc
check, can be simply removed since KVM_SET_MEMORY_REGION ioctl is no
longer supported.
Note: fixed powerpc's indentations with spaces to suppress checkpatch
errors.
Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
I'm not sure why, but the hlist for each entry iterators were conceived
list_for_each_entry(pos, head, member)
The hlist ones were greedy and wanted an extra parameter:
hlist_for_each_entry(tpos, pos, head, member)
Why did they need an extra pos parameter? I'm not quite sure. Not only
they don't really need it, it also prevents the iterator from looking
exactly like the list iterator, which is unfortunate.
Besides the semantic patch, there was some manual work required:
- Fix up the actual hlist iterators in linux/list.h
- Fix up the declaration of other iterators based on the hlist ones.
- A very small amount of places were using the 'node' parameter, this
was modified to use 'obj->member' instead.
- Coccinelle didn't handle the hlist_for_each_entry_safe iterator
properly, so those had to be fixed up manually.
The semantic patch which is mostly the work of Peter Senna Tschudin is here:
@@
iterator name hlist_for_each_entry, hlist_for_each_entry_continue, hlist_for_each_entry_from, hlist_for_each_entry_rcu, hlist_for_each_entry_rcu_bh, hlist_for_each_entry_continue_rcu_bh, for_each_busy_worker, ax25_uid_for_each, ax25_for_each, inet_bind_bucket_for_each, sctp_for_each_hentry, sk_for_each, sk_for_each_rcu, sk_for_each_from, sk_for_each_safe, sk_for_each_bound, hlist_for_each_entry_safe, hlist_for_each_entry_continue_rcu, nr_neigh_for_each, nr_neigh_for_each_safe, nr_node_for_each, nr_node_for_each_safe, for_each_gfn_indirect_valid_sp, for_each_gfn_sp, for_each_host;
type T;
expression a,c,d,e;
identifier b;
statement S;
@@
-T b;
<+... when != b
(
hlist_for_each_entry(a,
- b,
c, d) S
|
hlist_for_each_entry_continue(a,
- b,
c) S
|
hlist_for_each_entry_from(a,
- b,
c) S
|
hlist_for_each_entry_rcu(a,
- b,
c, d) S
|
hlist_for_each_entry_rcu_bh(a,
- b,
c, d) S
|
hlist_for_each_entry_continue_rcu_bh(a,
- b,
c) S
|
for_each_busy_worker(a, c,
- b,
d) S
|
ax25_uid_for_each(a,
- b,
c) S
|
ax25_for_each(a,
- b,
c) S
|
inet_bind_bucket_for_each(a,
- b,
c) S
|
sctp_for_each_hentry(a,
- b,
c) S
|
sk_for_each(a,
- b,
c) S
|
sk_for_each_rcu(a,
- b,
c) S
|
sk_for_each_from
-(a, b)
+(a)
S
+ sk_for_each_from(a) S
|
sk_for_each_safe(a,
- b,
c, d) S
|
sk_for_each_bound(a,
- b,
c) S
|
hlist_for_each_entry_safe(a,
- b,
c, d, e) S
|
hlist_for_each_entry_continue_rcu(a,
- b,
c) S
|
nr_neigh_for_each(a,
- b,
c) S
|
nr_neigh_for_each_safe(a,
- b,
c, d) S
|
nr_node_for_each(a,
- b,
c) S
|
nr_node_for_each_safe(a,
- b,
c, d) S
|
- for_each_gfn_sp(a, c, d, b) S
+ for_each_gfn_sp(a, c, d) S
|
- for_each_gfn_indirect_valid_sp(a, c, d, b) S
+ for_each_gfn_indirect_valid_sp(a, c, d) S
|
for_each_host(a,
- b,
c) S
|
for_each_host_safe(a,
- b,
c, d) S
|
for_each_mesh_entry(a,
- b,
c, d) S
)
...+>
[akpm@linux-foundation.org: drop bogus change from net/ipv4/raw.c]
[akpm@linux-foundation.org: drop bogus hunk from net/ipv6/raw.c]
[akpm@linux-foundation.org: checkpatch fixes]
[akpm@linux-foundation.org: fix warnings]
[akpm@linux-foudnation.org: redo intrusive kvm changes]
Tested-by: Peter Senna Tschudin <peter.senna@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This field was needed to differentiate memory slots created by the new
API, KVM_SET_USER_MEMORY_REGION, from those by the old equivalent,
KVM_SET_MEMORY_REGION, whose support was dropped long before:
commit b74a07beed
KVM: Remove kernel-allocated memory regions
Although we also have private memory slots to which KVM allocates
memory with vm_mmap(), !user_alloc slots in other words, the slot id
should be enough for differentiating them.
Note: corresponding function parameters will be removed later.
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
As Xiao pointed out, there are a few problems with it:
- kvm_arch_commit_memory_region() write protects the memory slot only
for GET_DIRTY_LOG when modifying the flags.
- FNAME(sync_page) uses the old spte value to set a new one without
checking KVM_MEM_READONLY flag.
Since we flush all shadow pages when creating a new slot, the simplest
fix is to disallow such problematic flag changes: this is safe because
no one is doing such things.
Reviewed-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Cc: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
KVM_SET_USER_MEMORY_REGION forces __kvm_set_memory_region() to identify
what kind of change is being requested by checking the arguments. The
current code does this checking at various points in code and each
condition being used there is not easy to understand at first glance.
This patch consolidates these checks and introduces an enum to name the
possible changes to clean up the code.
Although this does not introduce any functional changes, there is one
change which optimizes the code a bit: if we have nothing to change, the
new code returns 0 immediately.
Note that the return value for this case cannot be changed since QEMU
relies on it: we noticed this when we changed it to -EINVAL and got a
section mismatch error at the final stage of live migration.
Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
yield_to returns -ESRCH, When source and target of yield_to
run queue length is one. When we see three successive failures of
yield_to we assume we are in potential undercommit case and abort
from PLE handler.
The assumption is backed by low probability of wrong decision
for even worst case scenarios such as average runqueue length
between 1 and 2.
More detail on rationale behind using three tries:
if p is the probability of finding rq length one on a particular cpu,
and if we do n tries, then probability of exiting ple handler is:
p^(n+1) [ because we would have come across one source with rq length
1 and n target cpu rqs with length 1 ]
so
num tries: probability of aborting ple handler (1.5x overcommit)
1 1/4
2 1/8
3 1/16
We can increase this probability with more tries, but the problem is
the overhead.
Also, If we have tried three times that means we would have iterated
over 3 good eligible vcpus along with many non-eligible candidates. In
worst case if we iterate all the vcpus, we reduce 1x performance and
overcommit performance get hit.
note that we do not update last boosted vcpu in failure cases.
Thank Avi for raising question on aborting after first fail from yield_to.
Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Tested-by: Chegu Vinod <chegu_vinod@hp.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Virtual interrupt delivery avoids KVM to inject vAPIC interrupts
manually, which is fully taken care of by the hardware. This needs
some special awareness into existing interrupr injection path:
- for pending interrupt, instead of direct injection, we may need
update architecture specific indicators before resuming to guest.
- A pending interrupt, which is masked by ISR, should be also
considered in above update action, since hardware will decide
when to inject it at right time. Current has_interrupt and
get_interrupt only returns a valid vector from injection p.o.v.
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Yang Zhang <yang.z.zhang@Intel.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
We've been ignoring read-only mappings and programming everything
into the iommu as read-write. Fix this to only include the write
access flag when read-only is not set.
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Memory slot flags can be altered without changing other parameters of
the slot. The read-only attribute is the only one the IOMMU cares
about, so generate an un-map, re-map when this occurs. This also
avoid unnecessarily re-mapping the slot when no IOMMU visible changes
are made.
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
One such variable, slot, is enough for holding a pointer temporarily.
We also remove another local variable named slot, which is limited in
a block, since it is confusing to have the same name in this function.
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Don't need the check for deleting an existing slot or just modifiying
the flags.
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
This makes the separation between the sanity checks and the rest of the
code a bit clearer.
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Calling kvm_mmu_slot_remove_write_access() for a deleted slot does
nothing but search for non-existent mmu pages which have mappings to
that deleted memory; this is safe but a waste of time.
Since we want to make the function rmap based in a later patch, in a
manner which makes it unsafe to be called for a deleted slot, we makes
the caller see if the slot is non-zero and being dirty logged.
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Sanjay Lal