Certain clocks (such as TSC) in older 2.6 guests overaccount for lost
ticks, causing severe time drift. Interrupt reinjection magnifies the
problem.
Provide an option to disable it.
[avi: allow room for expansion in case we want to disable reinjection
of other timers]
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
count_load_time assignment is bogus: its supposed to contain what it
means, not the expiration time.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
As suggested by Avi, this patch introduces a counter of VCPUs that have
LVT0 set to NMI mode. Only if the counter > 0, we push the PIT ticks via
all LAPIC LVT0 lines to enable NMI watchdog support.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Acked-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
This patch refactors the NMI watchdog delivery patch, consolidating
tests and providing a proper API for delivering watchdog events.
An included micro-optimization is to check only for apic_hw_enabled in
kvm_apic_local_deliver (the test for LVT mask is covering the
soft-disabled case already).
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Acked-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
LINT0 of the LAPIC can be used to route PIT events as NMI watchdog ticks
into the guest. This patch aligns the in-kernel irqchip emulation with
the user space irqchip with already supports this feature. The trick is
to route PIT interrupts to all LAPIC's LVT0 lines.
Rebased and slightly polished patch originally posted by Sheng Yang.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Sheng Yang <sheng.yang@intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Every call of kvm_set_irq() should offer an irq_source_id, which is
allocated by kvm_request_irq_source_id(). Based on irq_source_id, we
identify the irq source and implement logical OR for shared level
interrupts.
The allocated irq_source_id can be freed by kvm_free_irq_source_id().
Currently, we support at most sizeof(unsigned long) different irq sources.
[Amit: - rebase to kvm.git HEAD
- move definition of KVM_USERSPACE_IRQ_SOURCE_ID to common file
- move kvm_request_irq_source_id to the update_irq ioctl]
[Xiantao: - Add kvm/ia64 stuff and make it work for kvm/ia64 guests]
Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Offline or uninitialized vcpu's can be executed if requested to perform
userspace work.
Follow Avi's suggestion to handle halted vcpu's in the main loop,
simplifying kvm_emulate_halt(). Introduce a new vcpu->requests bit to
indicate events that promote state from halted to running.
Also standardize vcpu wake sites.
Signed-off-by: Marcelo Tosatti <mtosatti <at> redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
sparse says:
arch/x86/kvm/x86.c:107:32: warning: symbol 'kvm_find_assigned_dev' was not declared. Should it be static?
arch/x86/kvm/i8254.c:225:6: warning: symbol 'kvm_pit_ack_irq' was not declared. Should it be static?
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Avi Kivity <avi@qumranet.com>
Spurious acks can be generated, for example if the PIC is being reset.
Handle those acks gracefully rather than flooding the log with warnings.
Signed-off-by: Avi Kivity <avi@qumranet.com>
The PIT injection logic is problematic under the following cases:
1) If there is a higher priority vector to be delivered by the time
kvm_pit_timer_intr_post is invoked ps->inject_pending won't be set.
This opens the possibility for missing many PIT event injections (say if
guest executes hlt at this point).
2) ps->inject_pending is racy with more than two vcpus. Since there's no locking
around read/dec of pt->pending, two vcpu's can inject two interrupts for a single
pt->pending count.
Fix 1 by using an irq ack notifier: only reinject when the previous irq
has been acked. Fix 2 with appropriate locking around manipulation of
pending count and irq_ack by the injection / ack paths.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
In order to be able to do range hrtimers we need to use accessor functions
to the "expire" member of the hrtimer struct.
This patch converts KVM to these accessors.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Only abort guest entry if the timer count went from 0->1, since for 1->2
or larger the bit will either be set already or a timer irq will have
been injected.
Using atomic_inc_and_test() for it also introduces an SMP barrier
to the LAPIC version (thought it was unecessary because of timer
migration, but guest can be scheduled to a different pCPU between exit
and kvm_vcpu_block(), so there is the possibility for a race).
Noticed by Avi.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
Modify member in_range() of structure kvm_io_device to pass length and the type
of the I/O (write or read).
This modification allows to use kvm_io_device with coalesced MMIO.
Signed-off-by: Laurent Vivier <Laurent.Vivier@bull.net>
Signed-off-by: Avi Kivity <avi@qumranet.com>
The in-kernel PIT emulation ignores pending timers if operating
under mode 3, which for example Hurd uses.
This mode should output a square wave, high for (N+1)/2 counts and low
for (N-1)/2 counts. As we only care about the resulting interrupts, the
period is N, and mode 3 is the same as mode 2 with regard to
interrupts.
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Avi Kivity <avi@qumranet.com>
Noticed by sparse:
arch/x86/kvm/vmx.c:1583:6: warning: symbol 'vmx_disable_intercept_for_msr' was not declared. Should it be static?
arch/x86/kvm/x86.c:3406:5: warning: symbol 'kvm_task_switch_16' was not declared. Should it be static?
arch/x86/kvm/x86.c:3429:5: warning: symbol 'kvm_task_switch_32' was not declared. Should it be static?
arch/x86/kvm/mmu.c:1968:6: warning: symbol 'kvm_mmu_remove_one_alloc_mmu_page' was not declared. Should it be static?
arch/x86/kvm/mmu.c:2014:6: warning: symbol 'mmu_destroy_caches' was not declared. Should it be static?
arch/x86/kvm/lapic.c:862:5: warning: symbol 'kvm_lapic_get_base' was not declared. Should it be static?
arch/x86/kvm/i8254.c:94:5: warning: symbol 'pit_get_gate' was not declared. Should it be static?
arch/x86/kvm/i8254.c:196:5: warning: symbol '__pit_timer_fn' was not declared. Should it be static?
arch/x86/kvm/i8254.c:561:6: warning: symbol '__inject_pit_timer_intr' was not declared. Should it be static?
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
If a timer fires after kvm_inject_pending_timer_irqs() but before
local_irq_disable() the code will enter guest mode and only inject such
timer interrupt the next time an unrelated event causes an exit.
It would be simpler if the timer->pending irq conversion could be done
with IRQ's disabled, so that the above problem cannot happen.
For now introduce a new vcpu requests bit to cancel guest entry.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
Migrate the PIT timer to the physical CPU which vcpu0 is scheduled on,
similarly to what is done for the LAPIC timers, otherwise PIT interrupts
will be delayed until an unrelated event causes an exit.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
Otherwise hlt emulation fails if PIT is not injecting IRQ's.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
The in-kernel PIT emulation ignores pending timers if operating under
mode 4, which for example DragonFlyBSD uses (and Plan9 too, apparently).
Mode 4 seems to be similar to one-shot mode, other than the fact that it
starts counting after the next CLK pulse once programmed, while mode 1
starts counting immediately, so add a FIXME to enhance precision.
Fixes sourceforge bug 1952988.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Acked-by: Sheng Yang <sheng.yang@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
Rename div64_64 to div64_u64 to make it consistent with the other divide
functions, so it clearly includes the type of the divide. Move its definition
to math64.h as currently no architecture overrides the generic implementation.
They can still override it of course, but the duplicated declarations are
avoided.
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Cc: Avi Kivity <avi@qumranet.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Patrick McHardy <kaber@trash.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Timers that fire between guest hlt and vcpu_block's add_wait_queue() are
ignored, possibly resulting in hangs.
Also make sure that atomic_inc and waitqueue_active tests happen in the
specified order, otherwise the following race is open:
CPU0 CPU1
if (waitqueue_active(wq))
add_wait_queue()
if (!atomic_read(pit_timer->pending))
schedule()
atomic_inc(pit_timer->pending)
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
The patch moves the PIT model from userspace to kernel, and increases
the timer accuracy greatly.
[marcelo: make last_injected_time per-guest]
Signed-off-by: Sheng Yang <sheng.yang@intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Tested-and-Acked-by: Alex Davis <alex14641@yahoo.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
