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The PAPR API allows three sorts of per-virtual-processor areas to be
registered (VPA, SLB shadow buffer, and dispatch trace log), and
furthermore, these can be registered and unregistered for another
virtual CPU. Currently we just update the vcpu fields pointing to
these areas at the time of registration or unregistration. If this
is done on another vcpu, there is the possibility that the target vcpu
is using those fields at the time and could end up using a bogus
pointer and corrupting memory.
This fixes the race by making the target cpu itself do the update, so
we can be sure that the update happens at a time when the fields
aren't being used. Each area now has a struct kvmppc_vpa which is
used to manage these updates. There is also a spinlock which protects
access to all of the kvmppc_vpa structs, other than to the pinned_addr
fields. (We could have just taken the spinlock when using the vpa,
slb_shadow or dtl fields, but that would mean taking the spinlock on
every guest entry and exit.)
This also changes 'struct dtl' (which was undefined) to 'struct dtl_entry',
which is what the rest of the kernel uses.
Thanks to Michael Ellerman <michael@ellerman.id.au> for pointing out
the need to initialize vcpu->arch.vpa_update_lock.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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Currently on POWER7, if we are running the guest on a core and we don't
need all the hardware threads, we do nothing to ensure that the unused
threads aren't executing in the kernel (other than checking that they
are offline). We just assume they're napping and we don't do anything
to stop them trying to enter the kernel while the guest is running.
This means that a stray IPI can wake up the hardware thread and it will
then try to enter the kernel, but since the core is in guest context,
it will execute code from the guest in hypervisor mode once it turns the
MMU on, which tends to lead to crashes or hangs in the host.
This fixes the problem by adding two new one-byte flags in the
kvmppc_host_state structure in the PACA which are used to interlock
between the primary thread and the unused secondary threads when entering
the guest. With these flags, the primary thread can ensure that the
unused secondaries are not already in kernel mode (i.e. handling a stray
IPI) and then indicate that they should not try to enter the kernel
if they do get woken for any reason. Instead they will go into KVM code,
find that there is no vcpu to run, acknowledge and clear the IPI and go
back to nap mode.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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On PPC, CR2-CR4 are nonvolatile, thus have to be saved across function calls.
We didn't respect that for any architecture until Paul spotted it in his
patch for Book3S-HV. This patch saves/restores CR for all KVM capable PPC hosts.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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SPAPR support includes various in-kernel hypercalls, improving performance
by cutting out the exit to userspace. H_BULK_REMOVE is implemented in this
patch.
Signed-off-by: Matt Evans <matt@ozlabs.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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So far, we've always called prepare_to_enter even when all we did was return
to the host. This patch changes that semantic to only call prepare_to_enter
when we actually want to get back into the guest.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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When we get a performance monitor interrupt, we need to make sure that
the host receives it. So reinject it like we reinject the other host
destined interrupts.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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When reinjecting an interrupt into the host interrupt handler after we're
back in host kernel land, we need to tell the kernel where the interrupt
happened. We can't tell it that we were in guest state, because that might
lead to random code walking host addresses. So instead, we tell it that
we came from the interrupt reinject code.
This helps getting reasonable numbers out of perf.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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When during guest context we get a performance monitor interrupt, we
currently bail out and oops. Let's route it to its correct handler
instead.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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The tlbncfg registers should be populated with their respective TLB's
values. Fix the obvious typo.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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There was some unused code in the exit code path that must have been
a leftover from earlier iterations. While it did no harm, it's superfluous
and thus should be removed.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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The comment for program interrupts triggered when using bookehv was
misleading. Update it to mention why MSR_GS indicates that we have
to inject an interrupt into the guest again, not emulate it.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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When during guest execution we get a machine check interrupt, we don't
know how to handle it yet. So let's add the error printing code back
again that we dropped accidently earlier and tell user space that something
went really wrong.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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For BookE HV the guest visible MSR is shared->msr and is identical to
the MSR that is in use while the guest is running, because we can't trap
reads from/to MSR.
So shadow_msr is unused there. Indicate that with a comment.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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We need to make sure that no MAS updates happen automatically while we
have the guest MAS registers loaded. So move the disabling code a bit
higher up so that it covers the full time we have guest values in MAS
registers.
The race this patch fixes should never occur, but it makes the code a
bit more logical to do it this way around.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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The SET_VCPU macro is a leftover from times when the vcpu struct wasn't
stored in the thread on vcpu_load/put. It's not needed anymore. Remove it.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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Instead if doing
#ifndef CONFIG_64BIT
...
#else
...
#endif
we should rather do
#ifdef CONFIG_64BIT
...
#else
...
#endif
which is a lot easier to read. Change the bookehv implementation to
stick with this rule.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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When using exit timing stats, we clobber r9 in the NEED_EMU case,
so better move that part down a few lines and fix it that way.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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The semantics of BOOKE_IRQPRIO_MAX changed to denote the highest available
irqprio + 1, so let's reflect that in the code too.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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Instead of checking whether we should reschedule only when we exited
due to an interrupt, let's always check before entering the guest back
again. This gets the target more in line with the other archs.
Also while at it, generalize the whole thing so that eventually we could
have a single kvmppc_prepare_to_enter function for all ppc targets that
does signal and reschedule checking for us.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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When we fail to emulate an instruction for the guest, we better go in and
tell it that we failed to emulate it, by throwing an illegal instruction
exception.
Please beware that we basically never get around to telling the guest that
we failed thanks to the debugging code right above it. If user space however
decides that it wants to ignore the debug, we would at least do "the right
thing" afterwards.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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The e500mc patches left some debug code in that we don't need. Remove it.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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We can't run e500v2 kvm on e500mc kernels, so indicate that by
making the 2 options mutually exclusive in kconfig.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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The CONFIG_KVM_E500 option really indicates that we're running on a V2 machine,
not on a machine of the generic E500 class. So indicate that properly and
change the config name accordingly.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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There's always a chance we're unable to read a guest instruction. The guest
could have its TLB mapped execute-, but not readable, something odd happens
and our TLB gets flushed. So it's a good idea to be prepared for that case
and have a fallback that allows us to fix things up in that case.
Add fixup code that keeps guest code from potentially crashing our host kernel.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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If we hit any exception whatsoever in the restore path and r1/r2 aren't the
host registers, we don't get a working oops. So it's always a good idea to
restore them as early as possible.
This time, it actually has practical reasons to do so too, since we need to
have the host page fault handler fix up our guest instruction read code. And
for that to work we need r1/r2 restored.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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When setting MSR for an e500mc guest, we implicitly always set MSR_GS
to make sure the guest is in guest state. Since we have this implicit
rule there, we don't need to explicitly pass MSR_GS to set_msr().
Remove all explicit setters of MSR_GS.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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When one vcpu wants to kick another, it can issue a special IPI instruction
called msgsnd. This patch emulates this instruction, its clearing counterpart
and the infrastructure required to actually trigger that interrupt inside
a guest vcpu.
With this patch, SMP guests on e500mc work.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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Add processor support for e500mc, using hardware virtualization support
(GS-mode).
Current issues include:
- No support for external proxy (coreint) interrupt mode in the guest.
Includes work by Ashish Kalra <Ashish.Kalra@freescale.com>,
Varun Sethi <Varun.Sethi@freescale.com>, and
Liu Yu <yu.liu@freescale.com>.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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e500mc has a normal PPC FPU, rather than SPE which is found
on e500v1/v2.
Based on code from Liu Yu <yu.liu@freescale.com>.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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Chips such as e500mc that implement category E.HV in Power ISA 2.06
provide hardware virtualization features, including a new MSR mode for
guest state. The guest OS can perform many operations without trapping
into the hypervisor, including transitions to and from guest userspace.
Since we can use SRR1[GS] to reliably tell whether an exception came from
guest state, instead of messing around with IVPR, we use DO_KVM similarly
to book3s.
Current issues include:
- Machine checks from guest state are not routed to the host handler.
- The guest can cause a host oops by executing an emulated instruction
in a page that lacks read permission. Existing e500/4xx support has
the same problem.
Includes work by Ashish Kalra <Ashish.Kalra@freescale.com>,
Varun Sethi <Varun.Sethi@freescale.com>, and
Liu Yu <yu.liu@freescale.com>.
Signed-off-by: Scott Wood <scottwood@freescale.com>
[agraf: remove pt_regs usage]
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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DO_KVM will need to identify the particular exception type.
There is an existing set of arbitrary numbers that Linux passes,
but it's an undocumented mess that sort of corresponds to server/classic
exception vectors but not really.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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tlbilx is the new, preferred invalidation instruction. It is not
found on e500 prior to e500mc, but there should be no harm in
supporting it on all e500.
Based on code from Ashish Kalra <Ashish.Kalra@freescale.com>.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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Rather than invalidate everything when a TLB1 entry needs to be
taken down, keep track of which host TLB1 entries are used for
a given guest TLB1 entry, and invalidate just those entries.
Based on code from Ashish Kalra <Ashish.Kalra@freescale.com>
and Liu Yu <yu.liu@freescale.com>.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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The PID handling is e500v1/v2-specific, and is moved to e500.c.
The MMU sregs code and kvmppc_core_vcpu_translate will be shared with
e500mc, and is moved from e500.c to e500_tlb.c.
Partially based on patches from Liu Yu <yu.liu@freescale.com>.
Signed-off-by: Scott Wood <scottwood@freescale.com>
[agraf: fix bisectability]
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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Move vcpu to the beginning of vcpu_e500 to give it appropriate
prominence, especially if more fields end up getting added to the
end of vcpu_e500 (and vcpu ends up in the middle).
Remove gratuitous "extern" and add parameter names to prototypes.
Signed-off-by: Scott Wood <scottwood@freescale.com>
[agraf: fix bisectability]
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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Keeping two separate headers for e500-specific things was a
pain, and wasn't even organized along any logical boundary.
There was TLB stuff in <asm/kvm_e500.h> despite the existence of
arch/powerpc/kvm/e500_tlb.h, and nothing in <asm/kvm_e500.h> needed
to be referenced from outside arch/powerpc/kvm.
Signed-off-by: Scott Wood <scottwood@freescale.com>
[agraf: fix bisectability]
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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This is in preparation for merging in the contents of
arch/powerpc/include/asm/kvm_e500.h.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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e500mc will want to do lpid allocation/deallocation here.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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This gives us a place to put load/put actions that correspond to
code that is booke-specific but not specific to a particular core.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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We'll use it on e500mc as well.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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Split e500 (v1/v2) and e500mc/e5500 to allow optimization of feature
checks that differ between the two.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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Currently 32-bit only cares about this for choice of exception
vector, which is done in core-specific code. However, KVM will
want to distinguish as well.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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Now that we do neither double buffering nor heuristic selection of the
write protection method these are not needed anymore.
Note: some drivers have their own implementation of set_bit_le() and
making it generic needs a bit of work; so we use test_and_set_bit_le()
and will later replace it with generic set_bit_le().
Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Avi Kivity <avi@redhat.com>
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We have seen some problems of the current implementation of
get_dirty_log() which uses synchronize_srcu_expedited() for updating
dirty bitmaps; e.g. it is noticeable that this sometimes gives us ms
order of latency when we use VGA displays.
Furthermore the recent discussion on the following thread
"srcu: Implement call_srcu()"
http://lkml.org/lkml/2012/1/31/211
also motivated us to implement get_dirty_log() without SRCU.
This patch achieves this goal without sacrificing the performance of
both VGA and live migration: in practice the new code is much faster
than the old one unless we have too many dirty pages.
Implementation:
The key part of the implementation is the use of xchg() operation for
clearing dirty bits atomically. Since this allows us to update only
BITS_PER_LONG pages at once, we need to iterate over the dirty bitmap
until every dirty bit is cleared again for the next call.
Although some people may worry about the problem of using the atomic
memory instruction many times to the concurrently accessible bitmap,
it is usually accessed with mmu_lock held and we rarely see concurrent
accesses: so what we need to care about is the pure xchg() overheads.
Another point to note is that we do not use for_each_set_bit() to check
which ones in each BITS_PER_LONG pages are actually dirty. Instead we
simply use __ffs() in a loop. This is much faster than repeatedly call
find_next_bit().
Performance:
The dirty-log-perf unit test showed nice improvements, some times faster
than before, except for some extreme cases; for such cases the speed of
getting dirty page information is much faster than we process it in the
userspace.
For real workloads, both VGA and live migration, we have observed pure
improvements: when the guest was reading a file during live migration,
we originally saw a few ms of latency, but with the new method the
latency was less than 200us.
Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Avi Kivity <avi@redhat.com>
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Dropped such mappings when we enabled dirty logging and we will never
create new ones until we stop the logging.
For this we introduce a new function which can be used to write protect
a range of PT level pages: although we do not need to care about a range
of pages at this point, the following patch will need this feature to
optimize the write protection of many pages.
Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Avi Kivity <avi@redhat.com>
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We will use this in the following patch to implement another function
which needs to write protect pages using the rmap information.
Note that there is a small change in debug printing for large pages:
we do not differentiate them from others to avoid duplicating code.
Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Avi Kivity <avi@redhat.com>
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check_and_clear_guest_paused does not need to be exported as it isn't used
by any modules, remove the export.
Signed-off-by: Eric B Munson <emunson@mgebm.net>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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S390's kvm_vcpu_stat does not contain halt_wakeup member.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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A suspended VM can cause spurious soft lockup warnings. To avoid these, the
watchdog now checks if the kernel knows it was stopped by the host and skips
the warning if so. When the watchdog is reset successfully, clear the guest
paused flag.
Signed-off-by: Eric B Munson <emunson@mgebm.net>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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Now that we have a flag that will tell the guest it was suspended, create an
interface for that communication using a KVM ioctl.
Signed-off-by: Eric B Munson <emunson@mgebm.net>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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